Relative Performance of Propensity Score Matching Strategies for Subgroup Analyses

Cost-effectiveness of outpatient adherence to recommendations for monitoring of patients hospitalized for heart failure

AIMS

A set of indicators to assess the quality of care for patients hospitalized for heart failure was developed by an expert working group of the Italian Health Ministry. Because a better performance profile measured using these indicators does not necessarily translate to better outcomes, a study to validate these indicators through their relationship with measurable clinical outcomes and healthcare costs supported by the Italian National Health System was carried out.

METHODS AND RESULTS

Residents of four Italian regions (Lombardy, Marche, Lazio, and Sicily) who were newly hospitalized for heart failure (irrespective of stage and New York Heart Association class) during 2014-2015 entered in the cohort and followed up until 2019. Adherence to evidence-based recommendations [i.e. renin-angiotensin-aldosterone system (RAS) inhibitors, beta-blockers, mineralocorticoid receptor antagonists (MRAs), and echocardiograms (ECCs)] experienced during the first year after index discharge was assessed. Composite clinical outcomes (cardiovascular hospital admissions and all-cause mortality) and healthcare costs (hospitalizations, drugs, and outpatient services) were assessed during the follow-up. The restricted mean survival time at 5 years (denoted as the number of months free from clinical outcomes), the hazard of clinical outcomes (according to the Cox model), and average annual healthcare cost (expressed in euros per person-year) were compared between adherent and non-adherent patients. A non-parametric bootstrap method based on 1000 resamples was used to account for uncertainty in cost-effectiveness estimates. A total of 41 406 patients were included in this study (46.3% males, mean age 76.9 ± 9.4 years). Adherence to RAS inhibitors, beta-blockers, MRAs, and ECCs were 64%, 57%, 62%, and 20% among the cohort members, respectively. Compared with non-adherent patients, those who adhered to ECCs, RAS inhibitors, beta-blockers, and MRAs experienced (i) a delay in the composite outcome of 1.6, 1.9, 1.6, and 0.6 months and reduced risks of 9% (95% confidence interval, 2-14%), 11% (7-14%), 8% (5-11%), and 4% (-1-8%), respectively; and (ii) lower (€262, €92, and €571 per year for RAS inhibitors, beta-blockers, and MRAs, respectively) and higher costs (€511 per year for ECC). Adherence to RAS inhibitors, beta-blockers, and MRAs showed a delay in the composite outcome and a saving of costs in 98%, 84%, and 93% of the 1000 bootstrap replications, respectively.

CONCLUSIONS

Strict monitoring of patients with heart failure through regular clinical examinations and drug therapies should be considered the cornerstone of national guidelines and audits.

Assessing the Benefits and Harms of Pharmacotherapy in Older Adults with Frailty: Insights from Pharmacoepidemiologic Studies of Routine Health Care Data

The objective of this review is to summarize and appraise the research methodology, emerging findings, and future directions in pharmacoepidemiologic studies assessing the benefits and harms of pharmacotherapies in older adults with different levels of frailty. Older adults living with frailty are at elevated risk for poor health outcomes and adverse effects from pharmacotherapy. However, current evidence is limited due to the under-enrollment of frail older adults and the lack of validated frailty assessments in clinical trials. Recent advancements in measuring frailty in administrative claims and electronic health records (database-derived frailty scores) have enabled researchers to identify patients with frailty and to evaluate the heterogeneity of treatment effects by patients' frailty levels using routine health care data. When selecting a database-derived frailty score, researchers must consider the type of data (e.g., different coding systems), the length of the predictor assessment period, the extent of validation against clinically validated frailty measures, and the possibility of surveillance bias arising from unequal access to care. We reviewed 13 pharmacoepidemiologic studies published on PubMed from 2013 to 2023 that evaluated the benefits and harms of cardiovascular medications, diabetes medications, anti-neoplastic agents, antipsychotic medications, and vaccines by frailty levels. These studies suggest that, while greater frailty is positively associated with adverse treatment outcomes, older adults with frailty can still benefit from pharmacotherapy. Therefore, we recommend routine frailty subgroup analyses in pharmacoepidemiologic studies. Despite data and design limitations, the findings from such studies may be informative to tailor pharmacotherapy for older adults across the frailty spectrum.

Association between Asian race and perioperative outcomes after carotid revascularization varies with Asian procedure density

OBJECTIVE

Postoperative outcomes following carotid revascularization are understudied in Asian patients. We aimed to assess whether disease severity and postoperative outcomes following carotid revascularization differ between Asian and White patients, and whether this varies with Asian procedure density.

METHODS

We analyzed the Vascular Quality Initiative Carotid Endarterectomy and Carotid Artery Stenting datasets from 2003 to 2021. Regions were divided into tertiles based on Asian procedure density. Propensity scores were used to match Asian and White patients based on patient factors and procedure type. The primary outcome variable was a collapsed composite of in-hospital ipsilateral stroke/death/myocardial infarction. χ2 tests were used to assess association between Asian race and disease severity, center and surgeon volume, and 1-year outcomes. Logistic and Cox regressions were performed between the matched cohorts.

RESULTS

A total of 1766 Asian and 159,608 White patients underwent carotid revascularization, and we identified 2704 patients (1352 Asian and 1352 White) in the matched cohorts. Among propensity matched patients, all-comer Asian patients more commonly had >80% ipsilateral stenosis (63% vs 52%; P < .001) and a moderate/severe preoperative Rankin score (7.6% vs 5.1%; P = .007). The rate of in-hospital stroke/death/myocardial infarction was higher in Asian patients (2.6% vs 1.3%; P = .012), and this disparity was more pronounced in the lowest tertile of Asian procedure density (4.3% vs 0.5%; P < .001). Logistic regression in the propensity-matched cohort demonstrated Asian race was associated with lower odds of intervention at highest volume centers (odds ratio [OR], 0.3; 95% confidence interval [CI], 0.2-0.3; P < .001) and by highest volume surgeons (OR, 0.3; 95% CI, 0.3-0.4; P < .001). Asian race was associated with higher odds of in-hospital stroke/death/myocardial infarction (OR, 2.0; 95% CI, 1.1-3.8; P = .031), and there was a significant interaction between Asian procedure density and the relationship between Asian race and this outcome (interaction P = .001). After accounting for center and surgeon volume, the association of Asian race and the composite outcome was mitigated (OR, 1.5; 95% CI, 0.7-3.3; P = .300). Cox regression between the matched cohorts demonstrated that Asian race was associated with lower 1-year mortality (hazard ratio, 0.5; 95% CI, 0.3-0.7; P = .001) and higher risk of 1-year reintervention (hazard ratio, 16; 95% CI, 1.8-142; P = .013).

CONCLUSIONS

Asian patients are more likely to present with a higher degree of carotid stenosis, higher preoperative risk, and experience worse perioperative outcomes. The association of Asian race with perioperative stroke/death/myocardial infarction varies with Asian procedure density and is also confounded by center and surgeon volume. These results highlight the importance of understanding referral patterns and cultural effects on outcomes disparities in Asian patients.

Association of systemic inflammatory markers with postoperative arrhythmias in esophageal cancer: a propensity score matching

BACKGROUND

The severity and prognosis of an array of inflammatory diseases have been predicted using systemic inflammatory indices, such as the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio, lymphocyte-to-monocyte ratio (LMR), derived neutrophil-to-lymphocyte ratio (dNLR), and systemic immune inflammation index (SII). The purpose of this study was to examine the association between systemic inflammatory markers and postoperative arrhythmias (PA) in esophageal cancer patients.

METHODS

In the study, laboratory-related parameters were gathered and examined in 278 patients (non-PA = 221, PA = 57). Fit separate propensity score matching (PSM) within subgroup strata (surgery approaches); match within strata, and aggregate for main analysis. Finally, we established a 1:1(57:57) model. The ability of inflammatory makers on the first post-esophagectomy day to distinguish PA from postoperative non-arrhythmia (non-PA) by receiver operating characteristic (ROC) analysis.

RESULTS

On the first post-esophagectomy day, there was a greater difference between PA and non-PA in terms of white blood cell (WBC) and neutrophil (NE), Neutrophil percentage (NE%), NLR, dNLR, LMR, and SII. After PSM, the following variables were substantially different between non-PA and PA: NE%, NLR, dNLR, and SII. It was found that WBC, NE, NE%, NLR, dNLR, LMR, and SII had the area under the curve (AUC) that was higher than 0.500 in ROC analysis, with NLR and SII having the highest AUC (AUC = 0.661). The indicators were subjected to binary logistic regression analysis, which increased the indicators' predictive ability (AUC = 0.707, sensitivity = 0.877).

CONCLUSION

On the first post-esophagectomy day, systemic inflammatory indicators were significantly correlated with both PA and non-PA, and high SII and NLR are reliable markers of PA.

Sodium-Glucose Cotransporter 2 Inhibitors and Nephrolithiasis Risk in Patients With Type 2 Diabetes

Importance

Type 2 diabetes (T2D) is associated with an increased risk of kidney stones. Sodium-glucose cotransporter 2 inhibitors (SGLT2is) might lower the risk of nephrolithiasis by altering urine composition. However, no studies have investigated the association between SGLT2i use and nephrolithiasis risk in patients receiving routine care in the US.

Objective

To investigate the association between SGLT2i use and nephrolithiasis risk in clinical practice.

Design, Setting, and Participants

This new-user, active comparator cohort study used data from commercially insured adults (aged ≥18 years) with T2D who initiated treatment with SGLT2is, glucagon-like peptide 1 receptor agonists (GLP-1RAs), or dipeptidyl peptidase 4 inhibitors (DPP4is) between April 1, 2013, and December 31, 2020. The data were analyzed from July 2021 through June 2023.

Exposure

New initiation of an SGLT2i, GLP-1RA, or DPP4i.

Main Outcomes and Measures

The primary outcome was nephrolithiasis diagnosed by International Classification of Diseases codes in the inpatient or outpatient setting. New SGLT2i users were 1:1 propensity score matched to new users of a GLP-1RA or DPP4i in pairwise comparisons. Incidence rates, rate differences (RDs), and estimated hazard ratios (HRs) with 95% CIs were calculated.

Results

After 1:1 propensity score matching, a total of 716 406 adults with T2D (358 203 pairs) initiating an SGLT2i or a GLP-1RA (mean [SD] age, 61.4 [9.7] years for both groups; 51.4% vs 51.2% female; 48.6% vs 48.5% male) and 662 056 adults (331 028 pairs) initiating an SGLT2i or a DPP4i (mean [SD] age, 61.8 [9.3] vs 61.7 [10.1] years; 47.4% vs 47.3% female; 52.6% vs 52.7% male) were included. Over a median follow-up of 192 (IQR, 88-409) days, the risk of nephrolithiasis was lower in patients initiating an SGLT2i than among those initiating a GLP-1RA (14.9 vs 21.3 events per 1000 person-years; HR, 0.69 [95% CI, 0.67-0.72]; RD, -6.4 [95% CI, -7.1 to -5.7]) or a DPP4i (14.6 vs 19.9 events per 1000 person-years; HR, 0.74 [95% CI, 0.71-0.77]; RD, -5.3 [95% CI, -6.0 to -4.6]). The association between SGLT2i use and nephrolithiasis risk was similar by sex, race and ethnicity, history of chronic kidney disease, and obesity. The magnitude of the risk reduction with SGLT2i use was larger among adults aged younger than 70 years vs aged 70 years or older (HR, 0.85 [95% CI, 0.79-0.91]; RD, -3.46 [95% CI, -4.87 to -2.05] per 1000 person-years; P for interaction <.001).

Conclusions and Relevance

These findings suggest that in adults with T2D, SGLT2i use may lower the risk of nephrolithiasis compared with GLP-1RAs or DPP4is and could help to inform decision-making when prescribing glucose-lowering agents for patients who may be at risk for developing nephrolithiasis.

Supplemental Nutrition Assistance Program and Adherence to Antihypertensive Medications

Importance

Nonadherence to antihypertensive medications is associated with uncontrolled blood pressure, higher mortality rates, and increased health care costs, and food insecurity is one of the modifiable medication nonadherence risk factors. The Supplemental Nutrition Assistance Program (SNAP), a social intervention program for addressing food insecurity, may help improve adherence to antihypertensive medications.

Objective

To evaluate whether receipt of SNAP benefits can modify the consequences of food insecurity on nonadherence to antihypertensive medications.

Design, Setting, and Participants

A retrospective cohort study design was used to assemble a cohort of antihypertensive medication users from the linked Medical Expenditure Panel Survey (MEPS)-National Health Interview Survey (NHIS) dataset for 2016 to 2017. The MEPS is a national longitudinal survey on verified self-reported prescribed medication use and health care access measures, and the NHIS is an annual cross-sectional survey of US households that collects comprehensive health information, health behavior, and sociodemographic data, including receipt of SNAP benefits. Receipt of SNAP benefits in the past 12 months and food insecurity status in the past 30 days were assessed through standard questionnaires during the study period. Data analysis was performed from March to December 2021.

Exposure

Status of SNAP benefit receipt.

Main Outcomes and Measures

The main outcome, nonadherence to antihypertensive medication refill adherence (MRA), was defined using the MEPS data as the total days' supply divided by 365 days for each antihypertensive medication class. Patients were considered nonadherent if their overall MRA was less than 80%. Food insecurity status in the 30 days prior to the survey was modeled as the effect modifier. Inverse probability of treatment (IPT) weighting was used to control for measured confounding effects of baseline covariates. A probit model was used, weighted by the product of the computed IPT weights and MEPS weights, to estimate the population average treatment effects (PATEs) of SNAP benefit receipt on nonadherence. A stratified analysis approach was used to assess for potential effect modification by food insecurity status.

Results

This analysis involved 6692 antihypertensive medication users, of whom 1203 (12.8%) reported receiving SNAP benefits and 1338 (14.8%) were considered as food insecure. The mean (SD) age was 63.0 (13.3) years; 3632 (51.3%) of the participants were women and 3060 (45.7%) were men. Although SNAP was not associated with nonadherence to antihypertensive medications in the overall population, it was associated with a 13.6-percentage point reduction in nonadherence (PATE, -13.6 [95% CI, -25.0 to -2.3]) among the food-insecure subgroup but not among their food-secure counterparts.

Conclusions and Relevance

This analysis of a national observational dataset suggests that patients with hypertension who receive SNAP benefits may be less likely to become nonadherent to antihypertensive medication, especially if they are experiencing food insecurity. Further examination of the role of SNAP as a potential intervention for preventing nonadherence to antihypertensive medications through prospectively designed interventional studies or natural experiment study designs is needed.

Comparison of major abdominal emergency surgery outcomes across organizational models of emergency surgical care: Analysis of the UK NELA national database

BACKGROUND

Emergency general surgery (EGS) admissions account for a large proportion of surgical care and represent the majority of surgical patients who suffer in-hospital mortality. Health care systems continue to experience growing demand for emergency services: one way in which this is being increasingly addressed is dedicated subspecialty teams for emergency surgical admissions, most commonly termed "emergency general surgery" in the United Kingdom. This study aims to understand the impact of the emergency general surgery model of care on outcomes from emergency laparotomies.

METHODS

Data was obtained from the National Emergency Laparotomy Audit database. Patients were dichotomized into EGS hospital or non-EGS hospital. Emergency general surgery hospital is defined as a hospital where >50% of in-hours emergency laparotomy operating is performed by an emergency general surgeon. The primary outcome was in-hospital mortality. Secondary outcomes were intensive therapy unit (ITU) length of stay and duration of hospital stay. A propensity score weighting approach was used to reduce confounding and selection bias.

RESULTS

There were 115,509 patients from 175 hospitals included in the final analysis. The EGS hospital care group included 5,789 patients versus 109,720 patients in the non-EGS group. Following propensity score weighting, mean standardized mean difference reduced from 0.055 to <0.001. In-hospital mortality was similar (10.8% vs. 11.1%, p = 0.094), with mean length of stay (16.7 days vs. 16.1 days, p < 0.001) and ITU stay (2.8 days vs. 2.6 days, p < 0.001) persistently longer in patients treated in EGS systems.

CONCLUSION

No significant association between the emergency surgery hospital model of care and in-hospital mortality in emergency laparotomy patients was seen. There is a significant association between the emergency surgery hospital model of care and an increased length of ITU stay and overall hospital stay. Further studies are required to examine the impact of changing models of EGS delivery in the United Kingdom.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level III.

Association between sedation during spinal anesthesia and mortality in older patients undergoing hip fracture surgery: A nationwide retrospective cohort study in Japan

STUDY OBJECTIVE

Intraoperative sedation plays an important role in the management of regional anesthesia. Few studies have investigated the association of sedation during spinal anesthesia with postoperative mortality in older patients as a primary outcome. This study aimed to test the hypothesis that sedation during spinal anesthesia increases postoperative mortality in older patients undergoing hip fracture surgery.

DESIGN

Retrospective, cohort study.

SETTING

Acute and subacute care hospitals in Japan.

PATIENTS

Patients aged 65 years and older who received hip fracture surgery under spinal anesthesia between April 2014 and May 2022.

EXPOSURE

Sedation during spinal anesthesia.

MEASUREMENTS

Postoperative in-hospital all-cause mortality within 30 days.

MAIN RESULTS

In total, 25,554 eligible patients were identified. Propensity score matching created 4735 pairs, and baseline patient characteristics were acceptably balanced between the sedation and non-sedation groups. There was no significant difference in 30-day postoperative mortality between the two groups (hazard ratio [95% CIs]: 0.92 [0.59-1.44]).

CONCLUSIONS

There was no association between sedation during hip fracture surgery in older patients under spinal anesthesia and postoperative mortality. However, these results are limited to our population, and further prospective studies are needed to determine the safety of sedation.

The risk of revision is higher following shoulder hemiarthroplasty compared with total shoulder arthroplasty for osteoarthritis: a matched cohort study of 11,556 patients from the National Joint Registry, UK

BACKGROUND AND PURPOSE

Total shoulder arthroplasty (TSA) and hemiarthroplasty (HA) are used in the management of osteoarthritis of the glenohumeral joint. We aimed to determine whether TSA or HA resulted in a lower risk of adverse outcomes in patients of all ages with osteoarthritis and an intact rotator cuff and in a subgroup of patients aged 60 years or younger.

PATIENTS AND METHODS

Shoulder arthroplasties recorded in the National Joint Registry, UK, between April 1, 2012 and June 30, 2021, were linked to Hospital Episode Statistics in England. Elective TSAs and HAs were matched on propensity scores based on 11 variables. The primary outcome was all-cause revision. Secondary outcomes were combined revision/non-revision reoperations, 30-day inpatient complications, 1-year mortality, and length of stay. 95% confidence intervals (CI) were reported.

RESULTS

11,556 shoulder arthroplasties were included: 7,641 TSAs, 3,915 HAs. At 8 years 95% (CI 94-96) of TSAs and 91% (CI 90-92) of HAs remained unrevised. The hazard ratio (HR) varied across follow-up: 4-year HR 2.7 (CI 1.9-3.5), 8-year HR 2.0 (CI 0.5-3.5). Rotator cuff insufficiency was the most common revision indication. In patients aged 60 years or younger prosthesis survival at 8 years was 92% (CI 89-94) following TSA and 84% (CI 80-87) following HA.

CONCLUSION

The risk of revision was higher following HA in patients with osteoarthritis and an intact rotator cuff. Patients aged 60 years and younger had a higher risk of revision following HA.

Patients with high nuclear grade pT1-ccRCC are more suitable for radical nephrectomy than partial nephrectomy: a multicenter retrospective study using propensity score

BACKGROUND

Partial nephrectomy (PN) is usually recommended for T1 stage clear cell renal cell carcinoma (ccRCC) regardless of the nuclear grades. However, the question remains unresolved as to whether PN is non-inferior to RN in patients with T1-ccRCC at higher risk of recurrence. In fact, we found that patients with high nuclear grades treated with PN had poorer prognosis compared with those treated with radical nephrectomy (RN). Therefore, this study was designed to evaluate the associations of PN and RN in the four nuclear grade subsets with oncologic outcomes.

METHODS

A retrospective study was conducted in three Chinese urological centers that included 1,714 patients who underwent PN or RN for sporadic, unilateral, pT1, N0, and M0 ccRCC without positive surgical margins and neoadjuvant therapy between 2010 and 2019. Associations of nephrectomy type with local ipsilateral recurrence, distant metastases, and all-cause mortality (ACM) were evaluated using the Kaplan-Meier method and multivariable Cox proportional hazards regression models after overlap weighting (OW).

RESULTS

A total of 1675 patients entered the OW cohort. After OW, in comparison to PN, RN associated with a reduced risk of local ipsilateral recurrence in the G2 subset (HR = 0.148, 95% CI 0.046-0.474; p < 0.05), G3 subset (HR = 0.097, 95% CI 0.021-0.455; p < 0.05), and G4 subset (HR = 0.091, 95% CI 0.011-0.736; p < 0.05), and resulting in increased five-year local recurrence-free survival rates of 7.0%, 17.9%, and 36.2%, respectively. An association between RN and a reduced risk of distant metastases in the G4 subset (HR = 0.071, 95% CI 0.016-0.325; p < 0.05), with the five-year distant metastases-free survival rate increasing by 33.1% was also observed. No significant difference in ACM between PN and RN was identified.

CONCLUSIONS

Our findings substantiate that opting for RN, as opposed to PN, is more advantageous for local recurrence-free survival and distant metastases-free survival in patients with high nuclear grade (especially G4) pT1-ccRCC. We recommend placing a heightened emphasis on enhancing preoperative nuclear grade assessment, as it can significantly influence the choice of surgical plan.

TRIAL REGISTRATION

This study was registered at Chinese Clinical Trial Registry (ID: ChiCTR2200063333).

Stratified analysis in comparative effectiveness studies that emulate randomized trials

PURPOSE

For observational cohort studies that employ matching by propensity scores (PS), preliminary stratification by consequential predictors of outcome better emulates stratified randomization and potentially reduces variance and bias through relaxed dependence on modeling assumptions. We assessed the impact of pre-stratification in two real-life examples. For both, prior evidence from placebo-controlled randomized clinical trials (RCTs) suggested small or no risk reduction, but observational analysis suggested protection, presumably the result of confounding bias.

STUDY DESIGN AND SETTING

The study populations consisted of Medicare beneficiaries (2014-18) with type 2 diabetes initiating either (i) empagliflozin versus dipeptidyl peptidase-4 inhibitors (DPP-4i) or (ii) empagliflozin versus glucagon-like peptide-1 receptor agonists (GLP-1RA). The outcome was myocardial infarction or stroke. We estimated hazard ratios (HR) and rate differences (RD) after controlling for 143 pre-exposure covariates via 1:1 PS matching after (1) PS estimation in the total cohort (total-cohort PS-matching) and (2) PS estimation separately by baseline cardiovascular disease (stratified PS matching).

RESULTS

Stratified PS matching resulted in HRs that exceeded those from total-cohort PS-matching by 13% and 9%, respectively, for the comparisons of empagliflozin to DPP-4i and GLP-1RA. Against both comparators, HRs and RDs after stratified PS matching were closer to the null, with slightly higher variances (2%-3%) than those after total-cohort PS matching.

CONCLUSION

Stratified PS matching produced effect estimates closer to the expected trial findings than total-cohort PS matching. The price paid in increased variance was minimal.

Association Between Use of Fluoroquinolones and Risk of Mitral or Aortic Valve Regurgitation: A Nationwide Cohort Study

Biological plausibility suggests that fluoroquinolones may lead to mitral valve regurgitation or aortic valve regurgitation (MR/AR) through a collagen degradation pathway. However, available real-world studies were limited and yielded inconsistent findings. We estimated the risk of MR/AR associated with fluoroquinolones compared with other antibiotics with similar indications in a population-based cohort study. We identified adult patients who initiated fluoroquinolones or comparison antibiotics from the nationwide Taiwanese claims database. Patients were followed for up to 60 days after cohort entry. Cox regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of MR/AR comparing fluoroquinolones to comparison antibiotics after 1:1 propensity score (PS) matching. All analyses were conducted by type of fluoroquinolone (fluoroquinolones as a class, respiratory fluoroquinolones, and non-respiratory fluoroquinolones) and comparison antibiotic (amoxicillin/clavulanate or ampicillin/sulbactam, extended-spectrum cephalosporins). Among 6,649,284 eligible patients, the crude incidence rates of MR/AR ranged from 1.44 to 4.99 per 1,000 person-years across different types of fluoroquinolones and comparison antibiotics. However, fluoroquinolone use was not associated with an increased risk in each pairwise PS-matched comparison. HRs were 1.00 (95% CI, 0.89-1.11) for fluoroquinolones as a class, 0.96 (95% CI, 0.83-1.12) for respiratory fluoroquinolones, and 0.87 (95% CI, 0.75-1.01) for non-respiratory fluoroquinolones, compared with amoxicillin/clavulanate or ampicillin/sulbactam. Results were similar when fluoroquinolones were compared with extended-spectrum cephalosporins (HRs of 0.96, 95% CI, 0.82-1.12, HR, 1.05, 95% CI, 0.86-1.28, and HR, 0.88, 95% CI, 0.75-1.03, respectively). This large-scale cohort study did not find a higher risk of MR/AR with different types of fluoroquinolones in the adult population.

Reduction in healthcare resource use through 24 months following sinus surgery with steroid-eluting implants in chronic rhinosinusitis patients with and without nasal polyps: a real-world study

OBJECTIVE

To investigate the impact of steroid-eluting implants after endoscopic sinus surgery (ESS) on health care resource use (HCRU) in chronic rhinosinusitis patients with (CRSwNP) and without (CRSsNP) nasal polyps.

METHODS

This retrospective, observational cohort study using real-world evidence data included adult patients with CRS who underwent ESS in 2015-2019 with at least 24 months of data before and after ESS. Patients who received implants were matched to patients who did not based on a propensity score developed using baseline characteristics and NP status. HCRU was compared between cohorts within each CRSwNP and CRSsNP subgroup using chi-square tests (binary variables).

RESULTS

The implant cohort in the CRSwNP subgroup had fewer all-cause outpatient (90.0% vs. 93.9%, p < .001) and all-cause otolaryngology (64.3% vs. 76.4%, p < .001) visits as well as fewer endoscopy (40.5% vs. 47.4%, p = .005) and debridement (48.8% vs. 55.6%, p = .007) procedures than the non-implant cohort. The implant cohort in the CRSsNP subgroup had fewer all-cause outpatient (88.9% vs. 94.2%, p < .001) and all-cause otolaryngology (53.5% vs. 74.4%, p < .001) visits as well as fewer endoscopy (31.8% vs. 41.7%, p < .001) and debridement (36.7% vs. 53.4%, p <.001) procedures than the non-implant cohort. Revision sinus surgery was reduced in the implant cohort in both subgroups, and reached statistical significance in the CRSwNP subgroup (3.8% vs. 6.0%, p = .039) but not in the CRSsNP subgroup (3.6% vs. 4.2%, p = .539).

CONCLUSIONS

Overall, patients receiving implants had lower HCRU for 24 months after sinus surgery independent of nasal polyp status, and revision surgery was reduced in CRSwNP patients. These findings provide additional evidence that long-term reductions in HCRU may be achieved with steroid-eluting implant use during sinus surgery.What is known on this topicPatients with chronic rhinosinusitis with nasal polyps (CRSwNP) have a disproportionately higher burden of disease and consume greater healthcare resources than chronic rhinosinusitis patients without nasal polyps (CRSsNP).CRSwNP patients represent approximately 30% of CRS patients who undergo surgery, but their clinical course is disproportionally complicated by disease recurrence and revision surgery.Steroid-eluting sinus implants have been shown in clinical trials to improve short-term postoperative outcomes after endoscopic sinus surgery (ESS) in CRS patients in general.A recent real-world evidence study reported that steroid-eluting sinus implants following ESS were associated with a reduction in HCRU in CRS patients followed for 18 months, but the impact of implants on HCRU in CRSwNP and CRSsNP patients separately remains unknown. What this study addsIn this observational study, reduced HCRU was observed in CRSwNP and CRSsNP patients who receive steroid-eluting sinus implants.Use of implants in CRSwNP and CRSsNP patients was associated with a significant reduction in healthcare visits (all-cause outpatient, all-cause otolaryngology), and sinus procedures (endoscopy, debridement).Revision surgery was significantly reduced in the implant cohort of CRSwNP patients and trended lower in the implant cohort of CRSsNP patients.Use of implants had no significant impact on all-cause ER/urgent care visits or sinus-related imaging.

Low-Dose Methotrexate and Serious Adverse Events Among Older Adults With Chronic Kidney Disease

Importance

Low-dose methotrexate is used to treat rheumatoid arthritis and psoriasis. Due to its kidney elimination, better evidence is needed to inform its safety in adults with chronic kidney disease (CKD).

Objectives

To compare the 90-day risk of serious adverse events among adults with CKD who started low-dose methotrexate vs those who started hydroxychloroquine and to compare the risk of serious adverse events among adults with CKD starting 2 distinct doses of methotrexate vs those starting hydroxychloroquine.

Design, Setting, and Participants

This retrospective, population-based, new-user cohort study was conducted in Ontario, Canada (2008-2021) using linked administrative health care data. Adults aged 66 years or older with CKD (defined as an estimated glomerular filtration rate [eGFR] <60 mL/min/1.73 m2 but not receiving dialysis) who started low-dose methotrexate (n = 2309) were matched 1:1 with those who started hydroxychloroquine.

Exposure

Low-dose methotrexate (5-35 mg/wk) vs hydroxychloroquine (200-400 mg/d).

Main Outcome and Measure

The primary outcome was a composite of serious adverse events: a hospital visit with myelosuppression, sepsis, pneumotoxic effects, or hepatotoxic effects within 90 days of starting the study drug. Prespecified subgroup analyses were conducted by eGFR category. Propensity score matching was used to balance comparison groups on indicators of baseline health. Risk ratios (RRs) were obtained using modified Poisson regression, and risk differences (RDs) using binomial regression.

Results

In a propensity score-matched cohort of 4618 adults with CKD (3192 [69%] women; median [IQR] age, 76 [71-82] years), the primary outcome was higher in patients who started low-dose methotrexate vs those who started hydroxychloroquine (82 of 2309 [3.55%] vs 40 of 2309 [1.73%]; RR, 2.05 (95% CI, 1.42-2.96); RD, 1.82% [95% CI, 0.91%-2.73%]). In subgroup analysis, the risks increased progressively at lower eGFR (eg, eGFR <45 mL/min/1.73 m2: RR, 2.79 [95% CI, 1.51-5.13]). In the secondary comparison with hydroxychloroquine, methotrexate users at 15 to 35 mg/wk had a higher risk of the primary outcome.

Conclusions and Relevance

In this cohort of 4618 older patients with CKD, the 90-day risk of serious adverse events was higher among those who started low-dose methotrexate than those who started hydroxychloroquine. If verified, these risks should be balanced against the benefits of low-dose methotrexate use.

How to perform prespecified subgroup analyses when using propensity score methods in the case of imbalanced subgroups

BACKGROUND

Looking for treatment-by-subset interaction on a right-censored outcome based on observational data using propensity-score (PS) modeling is of interest. However, there are still issues regarding its implementation, notably when the subsets are very imbalanced in terms of prognostic features and treatment prevalence.

METHODS

We conducted a simulation study to compare two main PS estimation strategies, performed either once on the whole sample ("across subset") or in each subset separately ("within subsets"). Several PS models and estimands are also investigated. We then illustrated those approaches on the motivating example, namely, evaluating the benefits of facial nerve resection in patients with parotid cancer in contact with the nerve, according to pretreatment facial palsy.

RESULTS

Our simulation study demonstrated that both strategies provide close results in terms of bias and variance of the estimated treatment effect, with a slight advantage for the "across subsets" strategy in very small samples, provided that interaction terms between the subset variable and other covariates influencing the choice of treatment are incorporated. PS matching without replacement resulted in biased estimates and should be avoided in the case of very imbalanced subsets.

CONCLUSIONS

When assessing heterogeneity in the treatment effect in small samples, the "across subsets" strategy of PS estimation is preferred. Then, either a PS matching with replacement or a weighting method must be used to estimate the average treatment effect in the treated or in the overlap population. In contrast, PS matching without replacement should be avoided in this setting.

Intraoperative hypotension in noncardiac surgery patients with chronic beta-blocker therapy: A matched cohort analysis

STUDY OBJECTIVE

To explore the incidence of intraoperative hypotension in patients with chronic beta-blocker therapy, expressed as time spent, area and time-weighted average under predefined mean arterial pressure thresholds.

DESIGN

Retrospective analysis of a prospective observational cohort registry.

SETTING

Patients ≥60 years undergoing intermediate- to high-risk noncardiac surgery with routine postoperative troponin measurements on the first three days after surgery.

PATIENTS

1468 matched sets of patients (1:1 ratio with replacement) with and without chronic beta-blocker treatment.

INTERVENTIONS

None.

MEASUREMENTS

The primary outcome was the exposure to intraoperative hypotension in beta-blocker users vs. non-users. Time spent, area and time-weighted average under predefined mean arterial pressure thresholds (55-75 mmHg) were calculated to express the duration and severity of exposure. Secondary outcomes included incidence of postoperative myocardial injury and thirty-day mortality, myocardial infarction (MI) and stroke. Furthermore, analyses for patient subgroup and beta-blocker subtype were conducted.

MAIN RESULTS

In patients with chronic beta-blocker therapy, no increased exposure to intraoperative hypotension was observed for all characteristics and thresholds calculated (all P > .05). Beta-blocker users had lower heart rate before, during and after surgery (70 vs. 74, 61 vs. 65 and 68 vs. 74 bpm, all P < .001, respectively). Postoperative myocardial injury (13.6% vs. 11.6%, P = .269) and thirty-day mortality (2.5% vs. 1.4%, P = .055), MI (1.4% vs. 1.5%, P = .944) and stroke (1.0% vs 0.7%, P =  .474) rates were comparable. The results were consistent in subtype and subgroup analyses.

CONCLUSIONS

In this matched cohort analysis, chronic beta-blocker therapy was not associated with increased exposure to intraoperative hypotension in patients undergoing intermediate- to high-risk noncardiac surgery. Furthermore, differences in patient subgroups and postoperative adverse cardiovascular events as a function of treatment regimen could not be demonstrated.

Comparative cardiovascular safety of LABA/LAMA FDC versus LABA/ICS FDC in patients with chronic obstructive pulmonary disease: a population-based cohort study with a target trial emulation framework

BACKGROUND

Use of combinations of long-acting β2 agonists/long-acting muscarinic antagonists (LABA/LAMA) in patients with chronic obstructive pulmonary disease (COPD) is increasing. Nevertheless, existing evidence on cardiovascular risk associated with LABA/LAMA versus another dual combination, LABA/inhaled corticosteroids (ICS), was limited and discrepant.

AIM

The present cohort study aimed to examine comparative cardiovascular safety of LABA/LAMA and LABA/ICS with a target trial emulation framework, focusing on dual fixed-dose combination (FDC) therapies.

METHODS

We identified patients with COPD who initiated LABA/LAMA FDC or LABA/ICS FDC from a nationwide Taiwanese database during 2017-2020. The outcome of interest was a hospitalized composite cardiovascular events of acute myocardial infarction, unstable angina, heart failure, cardiac dysrhythmia, and ischemic stroke. Cox regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for composite and individual cardiovascular events after matching up to five LABA/LAMA FDC initiators to one LABA/ICS FDC initiator using propensity scores (PS).

RESULTS

Among 75,926 PS-matched patients, use of LABA/LAMA FDC did not show a higher cardiovascular risk compared to use of LABA/ICS FDC, with a HR of 0.89 (95% CI, 0.78-1.01) for the composite events, 0.80 (95% CI, 0.61-1.05) for acute myocardial infarction, 1.48 (95% CI, 0.68-3.25) for unstable angina, 1.00 (95% CI, 0.80-1.24) for congestive heart failure, 0.62 (95% CI, 0.37-1.05) for cardiac dysrhythmia, and 0.82 (95% CI, 0.66-1.02) for ischemic stroke. The results did not vary substantially in several pre-specified sensitivity and subgroup analyses.

CONCLUSION

Our findings provide important reassurance about comparative cardiovascular safety of LABA/LAMA FDC treatment among patients with COPD.

Options of locoregional therapy for primary foci of breast cancer influence the rate of nonregional lymph node metastasis in N2-N3 status patients: a SEER database analysis

OBJECTIVE

We aim to use the SEER database to discuss the effect of various surgical methods of primary foci and other influencing factors on the nonregional lymph node (NRLN) metastasis in invasive ductal carcinoma (IDC) patients.

METHODS

Clinical information of IDC patients used in this study was obtained from the SEER database. The statistical analyses used included a multivariate logistic regression model, the chi-squared test, log-rank test and propensity score matching (PSM).

RESULTS

243,533 patients were included in the analysis. 94.3% of NRLN patients had a high N positivity (N3) but an equal distribution in T status. The proportion of operation type, especially BCM and MRM, differed significantly between the N0-N1 and N2-N3 groups in the NRLN metastasis group and nonmetastasis group. Age > 80 years, positive PR, modified radical mastectomy (MRM)/radical mastectomy (RM) and radiotherapy for primary tumor were shown to be protective factors for NRLN metastasis, and higher N positivity was the most significant risk factors. N2-N3 patients receiving MRM had a lower metastasis to NRLN than those receiving BCM (1.4% vs 3.7%, P < 0.001), while this relevance was not discovered in N0-N1 patients. In N2-N3 patients, a better OS was observed in MRM group than BCM group (P < 0.001).

CONCLUSION

MRM exerted a protective effect on NRLN metastasis compared to BCM in N2-N3 patients but not N0-N1 patients. This implies the need for more consideration when choosing the operation methods of primary foci in patients with high N positivity.

Association of Dexmedetomidine With New-Onset Atrial Fibrillation in Patients With Critical Illness

Importance

Dexmedetomidine is a widely used sedative in the intensive care unit (ICU) and has unique properties that may be associated with reduced occurrence of new-onset atrial fibrillation (NOAF).

Objective

To investigate whether the use of dexmedetomidine is associated with the incidence of NOAF in patients with critical illness.

Design, Setting, and Participants

This propensity score-matched cohort study was conducted using the Medical Information Mart for Intensive Care-IV database, which includes records of patients admitted to the ICU at Beth Israel Deaconess Medical Center in Boston dating 2008 through 2019. Included patients were those aged 18 years or older and hospitalized in the ICU. Data were analyzed from March through May 2022.

Exposure

Patients were divided into 2 groups according to dexmedetomidine exposure: those who received dexmedetomidine within 48 hours after ICU admission (dexmedetomidine group) and those who never received dexmedetomidine (no dexmedetomidine group).

Main Outcomes and Measures

The primary outcome was the occurrence of NOAF within 7 days of ICU admission, as defined by the nurse-recorded rhythm status. Secondary outcomes were ICU length of stay, hospital length of stay, and in-hospital mortality.

Results

This study included 22 237 patients before matching (mean [SD] age, 65.9 [16.7] years; 12 350 male patients [55.5%]). After 1:3 propensity score matching, the cohort included 8015 patients (mean [SD] age, 61.0 [17.1] years; 5240 males [65.4%]), among whom 2106 and 5909 patients were in the dexmedetomidine and no dexmedetomidine groups, respectively. Use of dexmedetomidine was associated with a decreased risk of NOAF (371 patients [17.6%] vs 1323 patients [22.4%]; hazard ratio, 0.80; 95% CI, 0.71-0.90). Although patients in the dexmedetomidine group had longer median (IQR) length of stays in the ICU (4.0 [2.7-6.9] days vs 3.5 [2.5-5.9] days; P < .001) and hospital (10.0 [6.6-16.3] days vs 8.8 [5.9-14.0] days; P < .001), dexmedetomidine was associated with decreased risk of in-hospital mortality (132 deaths [6.3%] vs 758 deaths [12.8%]; hazard ratio, 0.43; 95% CI, 0.36-0.52).

Conclusions and Relevance

This study found that dexmedetomidine was associated with decreased risk of NOAF in patients with critical illness, suggesting that it may be necessary and warranted to evaluate this association in future clinical trials.

The Impact of Nirmatrelvir-Ritonavir in Reducing Hospitalizations Among High-Risk Patients with SARS-Cov-2 During the Omicron Predominant Era

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic has caused significant morbidity and mortality in high-risk populations. Several therapeutics have been developed to reduce the risk of COVID-19 related complications, hospitalizations, and death. In several studies, nirmatrelvir-ritonavir (NR) was reported to reduce the risk of hospitalizations and death. We aimed to evaluate the efficacy of NR in preventing hospitalizations and death during the Omicron predominant period.

METHODS

We retrospectively evaluated patients from June 1, 2022, through September 26, 2022. There was a total of 25,939 documented COVID-19 cases. Using propensity matching, we matched 5,754 NR treated patients with untreated patients.

RESULTS

Post-matching, the median age of the nirmatrelvir-ritonavir (NR) treated group was 58 years (interquartile range [IQR], 43-70 years) and 42% were vaccinated. Post-matching composite outcome of the 30-day hospitalization and mortality in the NR treated group were 0.9% (95%: CI 0.7% to 1.2%) vs. 2.1% (95% CI: 1.8% to 2.5%) in the matched control group, with a difference of -1.2 (-1.7, -0.8), P-value <0.01. The difference rates (NR vs. control) in 30-day all-cause hospitalizations and mortality were -1.2% (95% CI: -1.6% to -0.7%, p-value <0.01) and-0.1% (95% CI, -0.2% to 0.0%, P value= 0.29), respectively. We found similar finding across different age groups (≥65 vs. <65) and the vaccinated group.

CONCLUSION

We report a significant benefit with the use of NR in reducing hospitalizations among various high-risk COVID-19 groups during the Omicron BA.5 predominant period.

Comparing Effectiveness and Safety of SGLT2 Inhibitors vs DPP-4 Inhibitors in Patients With Type 2 Diabetes and Varying Baseline HbA1c Levels

IMPORTANCE

Sodium-glucose cotransporter 2 inhibitor (SGLT2i) therapy has been associated with cardiovascular benefits and a few adverse events; however, whether the comparative effectiveness and safety profiles vary with differences in baseline hemoglobin A1c (HbA1c) levels is unknown.

OBJECTIVE

To compare cardiovascular effectiveness and safety of treatment with SGLT2i vs dipeptidyl peptidase 4 inhibitor (DPP-4i) in adults with type 2 diabetes (T2D) (1) overall and (2) at varying baseline HbA1c levels.

DESIGN, SETTING, AND PARTICIPANTS

A new-user comparative effectiveness and safety research study was conducted among 144 614 commercially insured adults, initiating treatment with SGLT2i or DPP-4i and with a recorded T2D diagnosis at baseline and at least 1 HbA1c laboratory result recorded within 3 months before treatment initiation.

INTERVENTIONS

The intervention consisted of the initiation of treatment with SGLT2i or DPP-4i.

MAIN OUTCOMES AND MEASURES

Primary outcomes were a composite of myocardial infarction, stroke, or all-cause death (modified major adverse cardiovascular events [MACE]) and hospitalization for heart failure (HHF). Safety outcomes were hypovolemia, fractures, falls, genital infections, diabetic ketoacidosis (DKA), acute kidney injury (AKI), and lower-limb amputation. Incidence rate (IR) per 1000 person-years, hazard ratios (HR) and rate differences (RD) with their 95% CIs were estimated controlling for 128 covariates.

RESULTS

A total of 144 614 eligible adults (mean [SD] age, 62 [12.4] years; 54% male participants) with T2D initiating treatment with a SGLT2i (n = 60 523) or a DPP-4i (n = 84 091) were identified; 44 099 had an HbA1c baseline value of less than 7.5%, 52 986 between 7.5% and 9%, and 47 529 greater than 9%. Overall, 87 274 eligible patients were 1:1 propensity score-matched: 24 052 with HbA1c less than 7.5%; 32 290 with HbA1c between 7.5% and 9%; and 30 932 with HbA1c greater than 9% (to convert percentage of total hemoglobin to proportion of total hemoglobin, multiply by 0.01). The initiation of SGLT2i vs DPP-4i was associated with a reduction in the risk of modified MACE (IR per 1000 person-years 17.13 vs 20.18, respectively; HR, 0.85; 95% CI, 0.75-0.95; RD, -3.02; 95% CI, -5.23 to -0.80) and HHF (IR per 1000 person-years 3.68 vs 8.08, respectively; HR, 0.46; 95% CI, 0.35 to 0.57; RD -4.37; 95% CI, -5.62 to -3.12) over a mean follow-up of 8 months, with no evidence of treatment effect heterogeneity across the HbA1c levels. Treatment with SGLT2i showed an increased risk of genital infections and DKA and a reduced AKI risk compared with DPP-4i. Findings were consistent by HbA1c levels, except for a more pronounced risk of genital infections associated with SGLT2i for HbA1c levels of 7.5% to 9% (IR per 1000 person-years 68.5 vs 22.8, respectively; HR, 3.10; 95% CI, 2.68-3.58; RD, 46.22; 95% CI, 40.54-51.90).

CONCLUSIONS AND RELEVANCE

In this comparative effectiveness and safety research study among adults with T2D, SGLT2i vs DPP-4i treatment initiators had a reduced risk of modified MACE and HHF, an increased risk of genital infections and DKA, and a lower risk of AKI, regardless of baseline HbA1c.

Effects of topiramate therapy on serum bicarbonate concentration in a sample of 10,279 veterans

BACKGROUND

Topiramate, which is increasingly being used to treat alcohol use disorder (AUD), is commonly associated with reduced serum bicarbonate concentrations. However, estimates of the prevalence and magnitude of this effect are from small samples and do not address whether topiramate's effects on acid-base balance differ in the presence of an AUD or by topiramate dosage.

METHODS

Veterans Health Administration electronic health record (EHR) data were used to identify patients with a minimum of 180 days of topiramate prescription for any indication and a propensity score-matched control group. We differentiated patients into two subgroups based on the presence of a diagnosis of AUD in the EHR. Baseline alcohol consumption was determined using Alcohol Use Disorders Identification Test-Consumption (AUDIT-C) scores in the EHR. Analysis also included a three-level measure representing mean daily dosage. The topiramate-associated changes in serum bicarbonate concentration were estimated in difference-in-differences linear regression models. A serum bicarbonate concentration <17 mEq/L was considered to represent possible clinically significant metabolic acidosis.

RESULTS

The cohort comprised 4287 topiramate-treated patients and 5992 propensity score-matched controls with a mean follow-up period of 417 days. The mean topiramate-associated reductions in serum bicarbonate concentration were <2 mEq/L in the low (≤88.75), medium (>88.75 and ≤141.70), and high (>141.70) mg/day dosage tertiles, irrespective of AUD history. Concentrations <17 mEq/L occurred in 1.1% of topiramate-treated patients and 0.3% of controls and were not associated with alcohol consumption or an AUD diagnosis.

CONCLUSIONS

The excess prevalence of metabolic acidosis associated with topiramate treatment does not differ with dosage, alcohol consumption, or the presence of an AUD. Baseline and periodic serum bicarbonate concentration measurements are recommended during topiramate therapy. Patients prescribed topiramate should be educated about the symptoms of metabolic acidosis and urged to report their occurrence promptly to a healthcare provider.

Laparoscopy in high-risk emergency general surgery reduces intensive care stay, length of stay and mortality

PURPOSE

Emergency general surgery patients undergoing laparoscopic surgery are at reduced risk of mortality and may require reduced length of critical care stay. This study investigated the effect of laparoscopy on high-risk patients' post-operative care requirements.

METHODS

Data were retrieved for all patients entered into the NELA database between 2013 and 2018. Only high-risk surgical patients (P-POSSUM predicted mortality risk of ≥ 5%) were included. Patients undergoing laparoscopic and open emergency general surgical procedures were compared using a propensity score weighting approach. Outcome measures included total length of critical care (level 3) stay, overall length of stay and inpatient mortality.

RESULTS

A total of 66,517 high-risk patients received emergency major abdominal surgery. A laparoscopic procedure was attempted in 6998 (10.5%); of these, the procedure was competed laparoscopically in 3492 (49.9%) and converted to open in 3506 (50.1%). Following inverse probability treatment weighting adjustment for patient disease and treatment characteristics, high-risk patients undergoing laparoscopic surgery had a shorter median ICU stay (1 day vs 2 days p < 0.001), overall hospital length of stay (11 days vs 14 days p < 0.001) and a lower inpatient mortality (16.0% vs 18.8%, p < 0.001). They were also less likely to have a prolonged ICU stay with an OR of 0.78 (95% CI 0.74-0.83, p < 0.001).

CONCLUSION

The results of this study suggest that in patients at high risk of post-operative mortality, laparoscopic emergency bowel surgery leads to a reduced length of critical care stay, overall length of stay and inpatient mortality compared to traditional laparotomy.

Association of topiramate prescribed for any indication with reduced alcohol consumption in electronic health record data

BACKGROUND AND AIMS

Topiramate is a medication that is widely prescribed to treat a variety of conditions, including alcohol use disorder (AUD). We used electronic health record (EHR) data to measure topiramate's effects on drinking in individuals differentiated by a history of AUD.

DESIGN

Parallel-groups comparison of patients prescribed topiramate and a propensity score-matched comparison group.

SETTING

A large US integrated health-care system.

PARTICIPANTS

Patients with Alcohol Use Disorders Identification Test-Consumption (AUDIT-C) scores prior to and after a minimum of 180 days of topiramate prescription for any indication and a propensity score-matched group. The sample included 5918 patients with an electronic health record diagnosis of alcohol use disorder at any time (AUD-hx-pos) (1738 topiramate-exposed and 4180 controls) and 23 614 patients with no EHR diagnosis of AUD (AUD-hx-neg) (6324 topiramate-exposed and 17 290 controls).

MEASUREMENTS

Regression analyses compared difference-in-difference (DiD) estimates, separately by AUD history. DiD estimates represent exposure-group (i.e. topiramate versus control) differences on the pre-post difference in AUDIT-C score. Effects of baseline AUDIT-C score and daily topiramate dosage were also tested.

FINDINGS

AUD-hx-neg patients who received topiramate had a greater reduction in AUDIT-C score (-0.11) than matched controls (-0.04). This yielded a DiD score of -0.07 [95% confidence interval (CI) = -0.11,-0.03; P = 0.002], with the greatest effect among AUD-hx-neg patients with a baseline AUDIT-C score of 4+ (DiD = -0.35, 95% CI = -0.49, -0.21; P < 0.0001) and those prescribed > 150 mg/day of the medication (DiD = -0.15, 95%CI = -0.23, -0.07; P < 0.001).

DISCUSSION

Among individuals with no history of alcohol use disorder, topiramate appears to be associated with reduced drinking. This small effect is most evident among patients with higher baseline drinking levels and at a higher average daily topiramate dosage.

Effect of empirical antifungal treatment on mortality in non-neutropenic critically ill patients: a propensity-matched retrospective cohort study

To evaluate the effect of empirical antifungal treatment (EAFT) on mortality in critically ill patients without invasive fungal infections (IFIs). This was a single-center propensity score-matched retrospective cohort study involving non-transplanted, non-neutropenic critically ill patients with risk factors for invasive candidiasis (IC) in the absence of IFIs. We compared all-cause hospital mortality and infection-attributable hospital mortality in patients who was given EAFT for suspected IC as the cohort group and those without any systemic antifungal agents as the control group. Among 640 eligible patients, 177 patients given EAFT and 177 control patients were included in the analyses. As compared with controls, EAFT was not associated with the lower risks of all-cause hospital mortality [odds ratio (OR), 0.911; 95% CI, 0.541-1.531; P = 0.724] or infection-attributable hospital mortality (OR, 1.149; 95% CI, 0.632-2.092; P = 0.648). EAFT showed no benefit of improvement of infection at discharge, duration of mechanical ventilation, and antibiotic-free days. However, the later initiation of EAFT was associated with higher risks of all-cause hospital mortality (OR, 1.039; 95% CI, 1.003 to 1.076; P = 0.034) and infection-attributable hospital mortality (OR, 1.046; 95% CI, 1.009 to 1.085; P = 0.015) in patients with suspected IC. This effect was also found in infection-attributable hospital mortality (OR, 1.042; 95% CI, 1.005 to 1.081; P = 0.027) in septic patients with suspected IC. EAFT failed to decrease hospital mortality in non-neutropenic critically ill patients without IFIs. The timing may be critical for EAFT to improve mortality in these patients with suspected IC. ChiCTR2000038811, registered on Oct 3, 2020.

Using primary care data to assess comparative effectiveness and safety of apixaban and rivaroxaban in patients with nonvalvular atrial fibrillation in the UK: an observational cohort study

OBJECTIVE

To compare real-world effectiveness and safety of direct oral anticoagulants (DOACs) in patients with nonvalvular atrial fibrillation (AFib) for prevention of stroke.

STUDY DESIGN AND SETTING

A comparative cohort study in UK general practice data from The Health Improvement Network database.

PARTICIPANTS AND INTERVENTIONS

Before matching, 5655 patients ≥18 years with nonvalvular AFib who initiated at least one DOAC between 1 July 2014 and 31 December 2020 were included. DOACs of interest included apixaban, rivaroxaban, edoxaban and dabigatran, with the primary comparison between apixaban and rivaroxaban. Initiators of DOACs were defined as new users with no record of prescription for any DOAC during 12 months before index date.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was stroke (ischaemic or haemorrhagic). Secondary outcomes included the occurrence of all-cause mortality, myocardial infarction (MI), transient ischaemic attacks (TIA), major bleeding events and a composite angina/MI/stroke (AMS) endpoint.

RESULTS

Compared with rivaroxaban, patients initiating apixaban showed similar rates of stroke (HR: 0.93; 95% CI 0.64 to 1.34), all-cause mortality (HR: 1.03; 95% CI 0.87 to 1.22), MI (HR: 0.95; 95% CI 0.54 to 1.68), TIA (HR: 1.03; 95% CI 0.61 to 1.72) and AMS (HR: 0.96; 95% CI 0.72 to 1.27). Apixaban initiators showed lower rates of major bleeding events (HR: 0.60; 95% CI 0.47 to 0.75).

CONCLUSIONS

Among patients with nonvalvular AFib, apixaban was as effective as rivaroxaban in reducing rate of stroke and safer in terms of major bleeding episodes. This head-to-head comparison supports conclusions drawn from indirect comparisons of DOAC trials against warfarin and demonstrates the potential for real-world evidence to fill evidence gaps and reduce uncertainty in both health technology assessment decision-making and clinical guideline development.

Recommendations for the use of propensity score methods in multiple sclerosis research

BACKGROUND

With many disease-modifying therapies currently approved for the management of multiple sclerosis, there is a growing need to evaluate the comparative effectiveness and safety of those therapies from real-world data sources. Propensity score methods have recently gained popularity in multiple sclerosis research to generate real-world evidence. Recent evidence suggests, however, that the conduct and reporting of propensity score analyses are often suboptimal in multiple sclerosis studies.

OBJECTIVES

To provide practical guidance to clinicians and researchers on the use of propensity score methods within the context of multiple sclerosis research.

METHODS

We summarize recommendations on the use of propensity score matching and weighting based on the current methodological literature, and provide examples of good practice.

RESULTS

Step-by-step recommendations are presented, starting with covariate selection and propensity score estimation, followed by guidance on the assessment of covariate balance and implementation of propensity score matching and weighting. Finally, we focus on treatment effect estimation and sensitivity analyses.

CONCLUSION

This comprehensive set of recommendations highlights key elements that require careful attention when using propensity score methods.

Comparative cardiovascular effectiveness of glucagon-like peptide-1 receptor agonists versus sodium-glucose cotransporter-2 inhibitors in patients with type 2 diabetes: A population-based cohort study

AIMS

To examine the comparative effectiveness of glucagon-like peptide-1 receptor agonists (GLP-1RAs) and sodium-glucose cotransporter-2 (SGLT2) inhibitors for select cardiovascular outcomes and to examine whether the relative risks varied across different patient subgroups in patients with type 2 diabetes.

MATERIALS AND METHODS

We conducted a nationwide cohort study of patients with type 2 diabetes who initiated GLP-1RAs or SGLT2 inhibitors between 2012 and 2018 in Taiwan. The study outcomes included myocardial infarction and total stroke, further classified into ischaemic or haemorrhagic stroke. We estimated the hazard ratios (HRs) and 95% confidence intervals (CIs) for each outcome, comparing GLP-1RAs with SGLT2 inhibitors using Cox proportional hazards models after 1:1 propensity-score (PS) matching. We also examined if there was effect modification by age, underlying chronic kidney disease, or coexisting cardiovascular disease in prespecified subgroup analyses.

RESULTS

Among 26 032 PS-matched patients, GLP-1RA initiators and SGLT2 inhibitor initiators showed similar risks of myocardial infarction (HR 0.99, 95% CI 0.65-1.52), total stroke (HR 0.90, 95% CI 0.69-1.17), ischaemic stroke (HR 0.86, 95% CI 0.65-1.14) and haemorrhagic stroke (HR 0.88, 95% CI 0.63-1.25). However, GLP-1RA treatment was associated with an increased risk of total stroke (HR 1.76, 95% CI 1.06-2.94) and ischaemic stroke (HR 1.88, 95% CI 1.09-3.23) among patients with chronic kidney disease, but not among patients without chronic kidney disease. GLP-1RA therapy seemed to have a lower risk of haemorrhagic stroke among patients with cardiovascular disease (HR 0.64, 95% CI 0.43-0.97), but not in patients without cardiovascular disease.

CONCLUSIONS

Glucagon-like peptide-1 receptor agonists and SGLT2 inhibitors appeared to have comparable effectiveness with regard to several cardiovascular outcomes overall, but their comparative effectiveness may vary in certain patient subgroups.

A Review of Causal Inference for External Comparator Arm Studies

Randomized controlled trials (RCTs) are the gold standard design to establish the efficacy of new drugs and to support regulatory decision making. However, a marked increase in the submission of single-arm trials (SATs) has been observed in recent years, especially in the field of oncology due to the trend towards precision medicine contributing to the rise of new therapeutic interventions for rare diseases. SATs lack results for control patients, and information from external sources can be compiled to provide context for better interpretability of study results. External comparator arm (ECA) studies are defined as a clinical trial (most commonly a SAT) and an ECA of a comparable cohort of patients-commonly derived from real-world settings including registries, natural history studies, or medical records of routine care. This publication aims to provide a methodological overview, to sketch emergent best practice recommendations and to identify future methodological research topics. Specifically, existing scientific and regulatory guidance for ECA studies is reviewed and appropriate causal inference methods are discussed. Further topics include sample size considerations, use of estimands, handling of different data sources regarding differential baseline covariate definitions, differential endpoint measurements and timings. In addition, unique features of ECA studies are highlighted, specifically the opportunity to address bias caused by unmeasured ECA covariates, which are available in the SAT.

Cardiovascular Outcomes in Patients Initiating First-Line Treatment of Type 2 Diabetes With Sodium-Glucose Cotransporter-2 Inhibitors Versus Metformin : A Cohort Study

BACKGROUND

Evidence on the risk for cardiovascular events associated with use of first-line sodium-glucose cotransporter-2 inhibitors (SGLT-2i) compared with metformin is limited.

OBJECTIVE

To assess cardiovascular outcomes among adults with type 2 diabetes (T2D) who initiated first-line treatment with SGLT-2i versus metformin.

DESIGN

Population-based cohort study.

SETTING

Claims data from 2 large U.S. commercial and Medicare databases (April 2013 to March 2020).

PARTICIPANTS

Patients with T2D aged 18 years and older (>65 years in Medicare) initiating treatment with SGLT-2i or metformin during April 2013 to March 2020, without any use of antidiabetic medications before cohort entry, were identified. After 1:2 propensity score matching in each database, pooled hazard ratios (HRs) and 95% CIs were reported.

INTERVENTION

First-line SGLT-2i (canagliflozin, empagliflozin, or dapagliflozin) or metformin.

MEASUREMENTS

Primary outcomes were a composite of hospitalization for myocardial infarction (MI), hospitalization for ischemic or hemorrhagic stroke or all-cause mortality (MI/stroke/mortality), and a composite of hospitalization for heart failure (HHF) or all-cause mortality (HHF/mortality). Safety outcomes including genital infections were assessed.

RESULTS

Among 8613 first-line SGLT-2i initiators matched to 17 226 metformin initiators, SGLT-2i initiators had a similar risk for MI/stroke/mortality (HR, 0.96; 95% CI, 0.77 to 1.19) and a lower risk for HHF/mortality (HR, 0.80; CI, 0.66 to 0.97) during a mean follow-up of 12 months. Initiators receiving SGLT-2i showed a lower risk for HHF (HR, 0.78; CI, 0.63 to 0.97), a numerically lower risk for MI (HR, 0.70; CI, 0.48 to 1.00), and similar risk for stroke, mortality, and MI/stroke/HHF/mortality compared with metformin. Initiators receiving SGLT-2i had a higher risk for genital infections (HR, 2.19; CI, 1.91 to 2.51) and otherwise similar safety as those receiving metformin.

LIMITATION

Treatment selection was not randomized.

CONCLUSION

As first-line T2D treatment, initiators receiving SGLT-2i showed a similar risk for MI/stroke/mortality, lower risk for HHF/mortality and HHF, and a similar safety profile except for an increased risk for genital infections compared with those receiving metformin.

PRIMARY FUNDING SOURCE

Brigham and Women's Hospital and Harvard Medical School.

Association between glucagon-like peptide-1 receptor agonists and biliary-related diseases in patients with type 2 diabetes: A nationwide cohort study

STUDY OBJECTIVE

Clinical trials have suggested that glucagon-like peptide-1 receptor agonists (GLP-1RAs) may be associated with a higher risk of biliary-related diseases in patients with type 2 diabetes. Limited real-world studies have examined the comparative biliary safety of GLP-1RAs versus other antihyperglycemic drugs. We aimed to estimate the comparative risk of biliary-related diseases between GLP-1RAs and sodium glucose cotransporter 2 inhibitors (SGLT2is), which are indicated for patients with similar diabetes severity in Taiwan.

DESIGN

Retrospective cohort study.

DATA SOURCE

Taiwan National Health Insurance Database during 2011 to 2018.

PATIENTS

Patients with type 2 diabetes who initiated GLP-1RAs or SGLT2is.

INTERVENTION

GLP-1RAs versus SGLT2is.

MEASUREMENTS AND MAIN RESULTS

We used an on-treatment approach to examine the effect of continuous use and an intention-to-treat approach to assess the effect of initiation of GLP-1RAs versus SGLT2is. We used Coxregression models to estimate the hazard ratios (HRs) and 95% confidenceintervals (CIs) for the composite hospitalized biliary-related diseases, including acute cholecystitis or cholecystectomy, choledocholithiasis, and acute cholangitis, after matching each GLP-1RA initiator to up to 10 SGLT2iinitiators using propensity scores (PSs). Among 78,253 PS-matched patients, GLP-1RA use was associated with a numerically higher risk of biliary-related diseases versus SGLT2i use in the on-treatment analysis, with an HR of 1.20 (95% CI, 0.93-1.56) for the composite outcome, an HR of 1.22 (95% CI, 0.92-1.62) for acute cholecystitis or cholecystectomy, an HR of 1.20 (95% CI, 0.69-2.07) for choledocholithiasis, and an HR of 1.14 (95% CI,0.82-2.42) for acute cholangitis. The HRs were more pronounced in theintention-to-treat analysis (1.27 [95% CI, 1.05-1.53] for the composite outcome, 1.29 [95% CI, 1.04-1.58] foracute cholecystitis or cholecystectomy, 1.74 [95% CI, 1.23-2.46] for choledocholithiasis, and 1.31 [95% CI, 0.89-1.94] for acute cholangitis). The increased risk of the composite outcome associated with GLP-1RAs was more evident in patients aged 〉60 years, women, and 120 days after treatment initiation. Liraglutide, but not dulaglutide, was associated with an elevated risk.

CONCLUSIONS

GLP-1RAs might be associated with an elevated risk of biliary-related diseases compared to SGLT2is in Asian patients with type 2 diabetes.

SGLT2 Inhibitors and the Risk of Acute Kidney Injury in Older Adults With Type 2 Diabetes

RATIONALE & OBJECTIVE

Sodium-glucose cotransporter 2 (SGLT2) inhibitors have been found to have many benefits for patients with type 2 diabetes. However, whether SGLT2 inhibitors increase the risk of acute kidney injury (AKI) remains unknown. We examined the association of AKI hospitalization with prior initiation of an SGLT2 inhibitor compared with initiation of a dipeptidyl peptidase 4 (DPP-4) inhibitor or a glucagon-like peptide 1 receptor agonist (GLP-1RA) among older adults with type 2 diabetes in routine practice.

STUDY DESIGN

Population-based cohort study.

SETTING & PARTICIPANTS

Older adults aged at least 66 years with type 2 diabetes enrolled in Medicare fee-for-service and who were new users of SGLT2 inhibitor, DPP-4 inhibitor, or GLP-1RA agents in the interval from March 2013 to December 2017.

EXPOSURES

New use of an SGLT2 inhibitor versus new use of a DPP-4 inhibitor or GLP-1RA.

OUTCOME

The primary outcome was hospitalization for AKI, defined as a discharge diagnosis of AKI in the primary or secondary position.

ANALYTICAL APPROACH

New users of SGLT2 inhibitors were matched at a 1:1 ratio to new users of DPP-4 inhibitors or GLP-1RAs using propensity scores in 2 pairwise comparisons. Cox proportional hazards regression models generated hazard ratios (HRs) with 95% CIs in propensity score-matched groups.

RESULTS

Totals of 68,130 and 71,477 new users of SGLT2 inhibitors were matched to new users of DPP-4 inhibitors or GLP-1RAs, respectively. Overall, the mean age of study participants was 72 years. The risk of AKI was lower in the SGLT2 inhibitor group than in the DPP-4 inhibitor group (HR, 0.71 [95% CI, 0.65-0.76]) or the GLP-1RA group (HR, 0.81 [95% CI, 0.75-0.87]).

LIMITATIONS

Residual confounding and lack of laboratory data.

CONCLUSIONS

Among older adults with type 2 diabetes, initiation of an SGLT2 inhibitor was associated with a reduced risk of AKI compared with initiation of a DPP-4 inhibitor or a GLP-1RA.

EFFECTIVENESS OF CASIRIVIMAB-IMDEVIMAB MONOCLONAL ANTIBODY TREATMENT AMONG HIGH-RISK PATIENTS WITH SARS-CoV-2 B.1.617.2 (COVID-19 DELTA VARIANT) INFECTION

Summary

Retrospective analysis of the post–propensity score (PS)–matched cohort of 8426 outpatients balanced in clinical and demographic covariates showed that treatment with casirivimab-imdevimab monoclonal antibody was effective against the SARS-CoV-2 Delta variant to reduce hospitalization, mortality, and intensive care unit admission rates within 30 days.

Background

Real-world data on the effectiveness of neutralizing casirivimab-imdevimab monoclonal antibody (Cas-Imd mAb) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among high-risk patients may inform the response to future SARS-CoV-2 variants.

Methods

This study covers an observational retrospective data analysis in Banner Health Care System sites, mainly in Arizona. During the study period, the prevalence of SARS-CoV-2 Delta variant was between 95% and 100%. Of 29 635 patients who tested positive for coronavirus disease 2019 (COVID-19) between 1 August 2021 and 30 October 2021, in the Banner Health Care System, the study cohort was split into 4213 adult patients who received Cas-Imd mAb (1200 mg) treatment compared to a PS-matched 4213 untreated patients. The primary outcomes were the incidence of all-cause hospitalization, intensive care unit (ICU) admission, and mortality within 30 days of Cas-Imd mAb administration or Delta variant infection.

Results

Compared to the PS-matched untreated cohort, the Cas-Imd mAb cohort had significantly lower all-cause hospitalization (4.2% vs 17.6%; difference in percentages, −13.4 [95% confidence interval {CI}, −14.7 to −12.0]; P < .001), ICU admission (0.3% vs 2.8%; difference, −2.4 [95% CI, −3.0 to −1.9]; P < .001), and mortality (0.2% vs 2.0%; difference, −1.8 [95% CI, −2.3 to −1.3]; P < .001) within 30 days. The Cas-Imd mAb treatment was associated with lower rate of hospitalization (hazard ratio [HR], 0.22 [95% CI, .19–.26]; P < .001) and mortality (HR, 0.11 [95% CI, .06–.21]; P < .001).

Conclusions

Cas-Imd mAb treatment was associated with a lower hospitalization rate, ICU admission, and mortality within 30 days among patients infected with the SARS-CoV-2 Delta variant.

The impact of moderator by confounder interactions in the assessment of treatment effect modification: a simulation study

Background

When performed in an observational setting, treatment effect modification analyses should account for all confounding, where possible. Often, such studies only consider confounding between the exposure and outcome. However, there is scope for misspecification of the confounding adjustment when estimating moderation as the effects of the confounders may themselves be influenced by the moderator. The aim of this study was to investigate bias in estimates of treatment effect modification resulting from failure to account for an interaction between a binary moderator and a confounder on either treatment receipt or the outcome, and to assess the performance of different approaches to account for such interactions.

Methods

The theory behind the reason for bias and factors that impact the magnitude of bias is explained. Monte Carlo simulations were used to assess the performance of different propensity scores adjustment methods and regression adjustment where the adjustment 1) did not account for any moderator-confounder interactions, 2) included moderator-confounder interactions, and 3) was estimated separately in each moderator subgroup. A real-world observational dataset was used to demonstrate this issue.

Results

Regression adjustment and propensity score covariate adjustment were sensitive to the presence of moderator-confounder interactions on outcome, whilst propensity score weighting and matching were more sensitive to the presence of moderator-confounder interactions on treatment receipt. Including the relevant moderator-confounder interactions in the propensity score (for methods using this) or the outcome model (for regression adjustment) rectified this for all methods except propensity score covariate adjustment. For the latter, subgroup-specific propensity scores were required. Analysis of the real-world dataset showed that accounting for a moderator-confounder interaction can change the estimate of effect modification.

Conclusions

When estimating treatment effect modification whilst adjusting for confounders, moderator-confounder interactions on outcome or treatment receipt should be accounted for.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-022-01519-7.

Complications associated with the use of enzyme-inducing and non-enzyme-inducing anti-seizure medications in the Japanese population: A retrospective cohort study

OBJECTIVE

Enzyme-inducing anti-seizure medications (EIASMs) may contribute to the development of complications such as fracture and cardiovascular disease. The objective of the study was to determine whether the use of EIASMs is associated with a higher risk of fracture and cardiovascular outcome in young Japanese patients with epilepsy.

METHOD

Adult patients diagnosed with epilepsy and initiated a monotherapy with an anti-seizure medication (ASM) between 2008 and 2018 were included in the study. The primary outcomes were the occurrence of acute myocardial infarction (AMI) or stroke. The secondary outcome was fracture. We performed a propensity score-matched analysis (1:1) to control for imbalances in patient characteristics, and the matched hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models.

RESULT

Of the 7115 eligible patients, 626 (8.79%) initiated treatment with EIASMs. The median age of the patients was 44 years (interquartile range: 31-54 years), and 56.2% were male. Propensity score matching generated 626 matched pairs of patients treated with EIASMs and non-EIASMs. There were no significant differences in the risk of stroke (EIASM group: n = 28[4.47%], non-EIASM group: n = 22[3.51%], HR: 1.47, 95% CI: 0.79-2.72, p = 0.22) or fracture (EIASM group: n = 7[1.12%], non-EIASM group: n = 5[0.80%], HR: 1.00, 95% CI: 0.29-3.45, p = 1.00) between the two groups. The hazard ratio for the occurrence of AMI could not be calculated due to the small number of events (EIASM group: n = 0[0.00], non-EIASM group: n = 2[0.32]).

SIGNIFICANCE

Our cohort study did not find increased risk of the occurrence of stroke, AMI, or fracture hospitalization with the use of enzyme-inducing ASMs. Although the findings suggested that exposure to EIASMs does not appear to increase the risk of complications in young patients, caution should be taken as patients with epilepsy tend to take medication in the long run.

Evaluating Confounding Control in Estimations of Influenza Antiviral Effectiveness in Electronic Health Plan Data

Observational studies of oseltamivir use and influenza complications could suffer from residual confounding. Using negative control risk periods and a negative control outcome, we examined confounding control in a health-insurance-claims-based study of oseltamivir and influenza complications (pneumonia, all-cause hospitalization, and dispensing of an antibiotic). Within the Food and Drug Administration's Sentinel System, we identified individuals aged ≥18 years who initiated oseltamivir use on the influenza diagnosis date versus those who did not, during 3 influenza seasons (2014-2017). We evaluated primary outcomes within the following 1-30 days (the primary risk period) and 61-90 days (the negative control period) and nonvertebral fractures (the negative control outcome) within days 1-30. We estimated propensity-score-matched risk ratios (RRs) per season. During the 2014-2015 influenza season, oseltamivir use was associated with a reduction in the risk of pneumonia (RR = 0.72, 95% confidence interval (CI): 0.70, 0.75) and all-cause hospitalization (RR = 0.54, 95% CI: 0.53, 0.55) in days 1-30. During days 61-90, estimates were near-null for pneumonia (RR = 1.04, 95% CI: 0.95, 1.15) and hospitalization (RR = 0.94, 95% CI: 0.91, 0.98) but slightly increased for antibiotic dispensing (RR = 1.14, 95% CI: 1.08, 1.21). The RR for fractures was near-null (RR = 1.09, 95% CI: 0.99, 1.20). Estimates for the 2016-2017 influenza season were comparable, while the 2015-2016 season had conflicting results. Our study suggests minimal residual confounding for specific outcomes, but results differed by season.

Effectiveness of angiotensin-neprilysin inhibitor treatment versus renin-angiotensin system blockade in older adults with heart failure in clinical care

OBJECTIVE

To evaluate the effectiveness of angiotensin receptor-neprilysin inhibitor (ARNI) versus renin-angiotensin system (RAS) blockade alone in older adults with heart failure with reduced ejection fraction (HFrEF).

METHODS

We conducted a cohort study using US Medicare fee-for-service claims data (2014-2017). Patients with HFrEF ≥65 years were identified in two cohorts: (1) initiators of ARNI or RAS blockade alone (ACE inhibitor, ACEI; or angiotensin receptor blocker, ARB) and (2) switchers from an ACEI to either ARNI or ARB. HR with 95% CI from Cox proportional hazard regression and 1-year restricted mean survival time (RMST) difference with 95% CI were calculated for a composite outcome of time to first worsening heart failure event or all-cause mortality after adjustment for 71 pre-exposure characteristics through propensity score fine-stratification weighting. All analyses of initiator and switcher cohorts were conducted separately and then combined using fixed effects.

RESULTS

51 208 patients with a mean age of 76 years were included, with 16 193 in the ARNI group. Adjusted HRs comparing ARNI with RAS blockade alone were 0.92 (95% CI 0.84 to 1.00) among initiators and 0.79 (95% CI 0.74 to 0.85) among switchers, with a combined estimate of 0.84 (95% CI 0.80 to 0.89). Adjusted 1-year RMST difference (95% CI) was 4 days in the initiator cohort (-1 to 9) and 12 days (8 to 17) in the switcher cohort, resulting in a pooled estimate of 9 days (6 to 12) favouring ARNI.

CONCLUSION

ARNI treatment was associated with lower risk of a composite effectiveness endpoint compared with RAS blockade alone in older adults with HFrEF.

Assessing Heterogeneity of Treatment Effects in Observational Studies

Here we describe methods for assessing heterogeneity of treatment effects over prespecified subgroups in observational studies, using outcome-model-based (g-formula), inverse probability weighting, doubly robust, and matching estimators of subgroup-specific potential outcome means, conditional average treatment effects, and measures of heterogeneity of treatment effects. We compare the finite-sample performance of different estimators in simulation studies where we vary the total sample size, the relative frequency of each subgroup, the magnitude of treatment effect in each subgroup, and the distribution of baseline covariates, for both continuous and binary outcomes. We find that the estimators' bias and variance vary substantially in finite samples, even when there is no unobserved confounding and no model misspecification. As an illustration, we apply the methods to data from the Coronary Artery Surgery Study (August 1975-December 1996) to compare the effect of surgery plus medical therapy with that of medical therapy alone for chronic coronary artery disease in subgroups defined by previous myocardial infarction or left ventricular ejection fraction.

Propensity score weighting for causal subgroup analysis

A common goal in comparative effectiveness research is to estimate treatment effects on prespecified subpopulations of patients. Though widely used in medical research, causal inference methods for such subgroup analysis (SGA) remain underdeveloped, particularly in observational studies. In this article, we develop a suite of analytical methods and visualization tools for causal SGA. First, we introduce the estimand of subgroup weighted average treatment effect and provide the corresponding propensity score weighting estimator. We show that balancing covariates within a subgroup bounds the bias of the estimator of subgroup causal effects. Second, we propose to use the overlap weighting (OW) method to achieve exact balance within subgroups. We further propose a method that combines OW and LASSO, to balance the bias‐variance tradeoff in SGA. Finally, we design a new diagnostic graph—the Connect‐S plot—for visualizing the subgroup covariate balance. Extensive simulation studies are presented to compare the proposed method with several existing methods. We apply the proposed methods to the patient‐centered results for uterine fibroids (COMPARE‐UF) registry data to evaluate alternative management options for uterine fibroids for relief of symptoms and quality of life.

The effect of the underlying malignancy on short- and medium-term survival of critically ill patients admitted to the intensive care unit: a retrospective analysis based on propensity score matching

Background

Advances in oncology led to a substantial increase in the number of patients requiring admission to the ICU. It is significant to confirm which cancer critical patients can benefit from the ICU care like noncancer patients.

Methods

An observational retrospective cohort study using intensive care unit (ICU) admissions of Medical Information Mart for Intensive Care III from the Beth Israel Deaconess Medical Center in Boston, MA, USA between 2001 and 2012 was conducted. Propensity score matching was used to reduce the imbalance between two matched cohorts. ICU patients with cancer were compared with those without cancer in terms of patients’ characteristics and survival.

Results

There were 38,508 adult patients admitted to ICUs during the period. The median age was 65 years (IQR, 52–77) and 8308 (21.6%) had an underlying malignancy diagnosis. The noncancer group had a significant survive advantage at the point of 28-day, 90-day, 365-day and 1095-day after ICU admission compared with cancer group (P < 0.001 for all) after PSM. Subgroup analysis showed that the diagnosis of malignancy didn’t decrease 28-day and 90-day survive when patients’ age ≥ 65-year, patients in surgical intensive care unit or cardiac surgery recovery unit or traumatic surgical intensive care unit, elective admissions, patients with renal replacement therapy or vasopressor support (P > 0.05 for all).

Conclusions

Malignancy is a common diagnosis among ICU patients. Patients without cancer have a survive advantage compared with patients with cancer in the short- and medium-term. However, in selected groups, cancer critical patients can benefit from the ICU care service like noncancer patients in the short-term.

Comparative effectiveness and safety of high-dose rivaroxaban and apixaban for atrial fibrillation: A propensity score-matched cohort study

STUDY OBJECTIVE

Observational studies assessing direct oral anticoagulant (DOACs) dosage in atrial fibrillation (AF) reported that a lower proportion of patients received high-dose DOACs compared to those in randomized controlled trials (RCTs). Effectiveness and safety of high-dose DOACs relative to apixaban in a real-world AF population need to be addressed. The aim is to assess comparative effectiveness and safety of high-dose rivaroxaban relative to apixaban.

DESIGN

We conducted a cohort study. Setting We built a cohort of patients hospitalized and discharged in community with a primary or secondary AF diagnosis from 2011-2017 using Quebec administrative databases (Med-Echo and RAMQ). Patients Cohort entry was defined as the first OAC claim in new users of high-dose rivaroxaban and apixaban, with no OAC claims in the prior year. Intervention To compare effectiveness and safety of high-dose rivaroxaban to apixaban. Measurement We ascertained patient demographics, comorbidities, CHA2DS2-VASc and HASBLED scores and Charlson score within 3 years prior to cohort entry. Primary effectiveness and safety were a composite of ischemic stroke/systemic thrombosis, death, myocardial infarction, and of intracranial bleeding (ICH), extracranial major bleeding, in the first year following drug initiation. We conducted propensity score matching and estimated hazard ratios (HRs) for outcomes using Cox proportional hazard models. All the analyses were conducted to account for competing risks. Main results The cohort consisted of 4,632 and 6,771 patients received high-dose rivaroxaban and apixaban, respectively. High-dose rivaroxaban users were younger with a mean age of 73.2 years, presented less associated comorbidities and had lower CHA2DS2-VASc scores compared to apixaban. High-dose rivaroxaban at the intention to treat was associated with a higher risk of stroke/SE/death (HR 1.21, 95% CI 1.04-1.40) and worse composite effectiveness (HR 1.21: 1.05-1.40); under treatment exposure, those values were at HR (1.66: 1.21-2.29) and HR (1.58:1.19-2.10), respectively. And, rivaroxaban presented a less favorable safety profile relative to apixaban. Conclusion In this study, composite effectiveness and safety varied between rivaroxaban and apixaban. High-dose apixaban was observed to have a better effectiveness and safety.

Comparative cardiovascular risk in users versus non-users of xanthine oxidase inhibitors and febuxostat versus allopurinol users

OBJECTIVES

The aim of this study is to determine major adverse cardiovascular events (MACE) and all-cause mortality comparing between xanthine oxidase inhibitors (XOIs) and non-XOI users, and between allopurinol and febuxostat.

METHODS

This is a retrospective cohort study of gout patients prescribed anti-hyperuricemic medications between 2013 and 2017 using a territory-wide administrative database. XOI users were matched 1:1 to XOI non-users using propensity scores. Febuxostat users were matched 1:3 to allopurinol users. Subgroup analyses were conducted based on colchicine use.

RESULTS

Of the 13 997 eligible participants, 3607 (25.8%) were XOI users and 10 390 (74.2%) were XOI non-users. After propensity score matching, compared with non-users (n = 3607), XOI users (n = 3607) showed similar incidence of MACE (hazard ratio [HR]: 0.997, 95% CI, 0.879, 1.131; P>0.05) and all-cause mortality (HR = 0.972, 95% CI 0.886, 1.065, P=0.539). Febuxostat (n = 276) users showed a similar risk of MACE compared with allopurinol users (n = 828; HR: 0.672, 95% CI, 0.416, 1.085; P=0.104) with a tendency towards a lower risk of heart failure-related hospitalizations (HR = 0.529, 95% CI 0.272, 1.029; P=0.061). Concurrent colchicine use reduced the risk for all-cause mortality amongst XOI users (HR = 0.671, 95% 0.586, 0.768; P<0.001).

CONCLUSION

In gout patients, XOI users showed similar risk of MACE and all-cause mortality compared with non-users. Compared with allopurinol users, febuxostat users showed similar MACE and all-cause mortality risks but lower heart failure-related hospitalizations.

Association between aspirin use and cardiovascular outcomes in ALLHAT participants with and without chronic kidney disease: A post hoc analysis

It is unclear whether aspirin is beneficial for prevention of CVD in patients with CKD. We performed a secondary analysis of the ALLHAT trial to assess the effect of baseline aspirin use on nonfatal myocardial infarction (MI) or fatal coronary heart disease (CHD), all‐cause mortality, and stroke. Baseline characteristics of aspirin users and nonusers were used to generate propensity‐matched cohorts. Using conditional Cox proportional hazard regression models, we examined the effect of aspirin on the outcomes in the cohort at large and across 3 levels of kidney function (eGFR ≥90, 60–89, and <60). 11 250 ALLHAT participants reported using aspirin at baseline. The propensity‐matched dataset included 6894 nonusers matched with replacement to achieve a balanced analysis population (n = 22 500). Risk of fatal CHD or nonfatal MI (HR = 0.94, 95% CI 0.86–1.02) and stroke (HR = 1.01, 95% CI 0.89–1.15) was not significantly different between groups. Aspirin users were at significantly lower risk of all‐cause mortality compared to nonusers (HR = 0.82, 95% CI 0.76–0.88). Aspirin use was not associated with incidence of fatal CAD or nonfatal MI in patients with CVD (HR = 0.93, CI 0.84–1.04) or without CVD at baseline (HR = 1.04, CI 0.82–1.32). Results were consistent across strata of GFR (interaction p value NS). In hypertensive patients at high cardiovascular risk, aspirin use is not associated with risk of nonfatal MI, fatal CHD, or stroke; however, aspirin use is associated with lower risk of all‐cause mortality. These results are consistent across baseline eGFR.

Transthoracic Versus Transhiatal Esophagectomy for Esophageal Cancer: A Nationwide Propensity Score-Matched Cohort Analysis

Background

Chemoradiation followed by resection has been the standard therapy for resectable (cT1-4aN0-3M0) esophageal carcinoma in the Netherlands since 2010. The optimal surgical approach remains a matter of debate. Therefore, the purpose of this study was to compare the transhiatal and the transthoracic approach concerning morbidity, mortality and oncological quality.

Methods

Data was acquired from the Dutch Upper GI Cancer Audit. Patients who underwent esophagectomy with curative intent and gastric tube reconstruction for mid/distal esophageal or esophagogastric junction carcinoma (cT1-4aN0-3M0) from 2011 to 2016 were included. Patients who underwent a transthoracic and transhiatal esophagectomy were compared after propensity score matching.

Results

After propensity score matching, 1532 of 4143 patients were included for analysis. The transthoracic approach yielded more lymph nodes (transthoracic median 19, transhiatal median 14; p < 0.001). There was no difference in the number of positive lymph nodes, however, the median (y)pN-stage was higher in the transthoracic group (p = 0.044). The transthoracic group experienced more chyle leakage (9.7% vs. 2.7%, p < 0.001), more pulmonary complications (35.5% vs. 26.1%, p < 0.001), and more cardiac complications (15.4% vs. 10.3%, p = 0.003). The transthoracic group required a longer hospital stay (median 14 vs. 11 days, p < 0.001), ICU stay (median 3 vs. 1 day, p < 0.001), and had a higher 30-day/in-hospital mortality rate (4.0% vs. 1.7%, p = 0.009).

Conclusions

In a propensity score-matched cohort, the transthoracic esophagectomy provided a more extensive lymph node dissection, which resulted in a higher lymph node yield, at the cost of increased morbidity and short-term mortality.

The Magnitude of the Warfarin-Amiodarone Drug-Drug Interaction Varies With Renal Function: A Propensity-Matched Cohort Study

Amiodarone inhibits warfarin metabolism and is associated with major bleeding during warfarin therapy. Managing this drug-drug interaction (DDI) is challenging because of substantial interpatient variability in DDI magnitude. Because renal dysfunction induces changes in drug metabolism and protein binding that could alter cytochrome P450 inhibition mechanisms, we hypothesized that renal dysfunction alters the impact of the warfarin-amiodarone DDI. We tested this question in a propensity-matched cohort study of hospitalized patients with atrial fibrillation. Patients were queried from an electronic health record database. Renal function was estimated with creatinine clearance (CrCl). Warfarin response was measured with the warfarin sensitivity index (WSI), a dose-normalized international normalized ratio (INR) measure, and was modeled with multilevel mixed-effects linear regression. Time to supratherapeutic INR (> 4) was modeled using Cox regression. Propensity score matching resulted in 4,518 patients administered amiodarone and 4,518 controls. Amiodarone's effect on warfarin response varied threefold across the renal function range, increasing WSI by 36% in patients with normal renal function (CrCl 115 mL/minute), but by only 11.8% in patients with severe renal dysfunction (CrCl 15 mL/minute). Similarly, amiodarone had a strong effect in patients with normal renal function (hazard ratio (HR) 1.80; 1.23, 2.64), but a negligible effect on supratherapeutic INR hazard in patients with severe renal dysfunction (HR 1.01; 0.75, 1.37). These results suggest that renal function is a novel factor that explains substantial variability in the warfarin-amiodarone DDI. This information could inform warfarin dosage adjustment and monitoring and may have implications for the selection of oral anticoagulation agents in patients treated with amiodarone.

Antifibrinolytic Drugs and Allogeneic Transfusion in Pediatric Multilevel Spine Surgery: A Propensity Score Matched Cohort Study

STUDY DESIGN

Observational cohort study with propensity score matching.

OBJECTIVE

Determine whether antifibrinolytic drug use is associated with decreased allogeneic blood transfusion in multilevel pediatric spine surgery.

SUMMARY OF BACKGROUND DATA

Antifibrinolytic drugs are commonly used in adult multilevel spine surgery to reduce blood loss and allogeneic transfusion; however, only small studies have examined their efficacy in pediatric patients having multilevel spine surgery.

METHODS

Pediatric patients who had posterior multilevel spine surgery between 2016 and 2017 were identified in the national surgery quality improvement program participant use file. Propensity score matching was used to reduce bias from confounding and the rate of intraoperative allogeneic transfusion was compared between patients who received antifibrinolytic drugs and those who did not. Secondary outcomes included intraoperative cell saver volume, postoperative allogeneic transfusion, massive intraoperative transfusion, and adverse events including venous thromboembolism and seizure.

RESULTS

A total of 6904 patients underwent posterior multilevel spine surgery during the study period and 83% received antifibrinolytics. The matched cohort included 604 patients. Antifibrinolytic use had no association with reduced intraoperative allogeneic transfusion: odds ratio (OR) = 0.71 (99% confidence interval [CI] = 0.40-1.26, P = 0.12) or cell saver volume, median volume = 114 mL (0, 250 mL) in antifibrinolytic group versus 100 mL (0, 246 mL) in control group, P = 0.04. There was also no association with reduced postoperative allogeneic transfusion OR = 1.23 (99% CI = 0.54-2.81, P = 0.52) or massive transfusion OR = 1.0 (99% CI = 0.34-2.92, P = 1.0). No patient in the matched cohort had a venous thromboembolism or seizure.

CONCLUSION

Antifibrinolytic drugs are commonly used in pediatric multilevel spine surgery in the United States, but no efficacy was demonstrated in our study. There were no venous thromboembolisms or seizures implying an excellent safety profile in pediatric patients.

LEVEL OF EVIDENCE

3.

Sodium-glucose co-transporter 2 inhibitors and the risk of fractures: A propensity score-matched cohort study

PURPOSE

To determine the risk of fractures associated with sodium-glucose co-transporter 2 inhibitors (SGLT2i) compared with dipeptidyl peptidase-4 inhibitors (DPP4i).

METHODS

We conducted a retrospective cohort study using data from the Truven Health MarketScan (2009-2015) databases. Our cohort included patients newly initiating treatment with SGLT2i or DPP-4i between 1 April 2013 and 31 March 2015 that were matched 1:1 using high dimensional propensity scores. Patients were followed up in an as-treated approach starting from initiation of treatment until the earliest of any fracture, treatment discontinuation, disenrollment, or end of data (31 December 2015). Risk of fractures was determined at any time during the follow-up, early in therapy (1-14 days of the follow-up), and later in therapy (15 days and beyond). Cox proportional hazards models were used to determine hazard ratios and robust 95% confidence intervals (95% CI).

RESULTS

After matching, our cohort included 30 549 patients in each treatment group. Over a median follow-up of 219 days, there were 745 fractures overall. The most common site for fractures was the foot (32.7%). The effect estimates for fracture risk occurring at any time during follow-up, early in therapy, and later in therapy were HR 1.11 [95% CI 0.96-1.28], HR 1.82 [95% CI 0.99-3.32], and HR 1.07 [95% CI 0.92-1.24], respectively.

CONCLUSION

There is a possible increase in risk for fractures early in therapy with SGLT2i. Beyond this initial period, SGLT2is had no apparent effect on the incidence of fractures.

Propensity Score Methods in Health Technology Assessment: Principles, Extended Applications, and Recent Advances

Randomized clinical trials (RCT) are accepted as the gold-standard approaches to measure effects of intervention or treatment on outcomes. They are also the designs of choice for health technology assessment (HTA). Randomization ensures comparability, in both measured and unmeasured pretreatment characteristics, of individuals assigned to treatment and control or comparator. However, even adequately powered RCTs are not always feasible for several reasons such as cost, time, practical and ethical constraints, and limited generalizability. RCTs rely on data collected on selected, homogeneous population under highly controlled conditions; hence, they provide evidence on efficacy of interventions rather than on effectiveness. Alternatively, observational studies can provide evidence on the relative effectiveness or safety of a health technology compared to one or more alternatives when provided under the setting of routine health care practice. In observational studies, however, treatment assignment is a non-random process based on an individual’s baseline characteristics; hence, treatment groups may not be comparable in their pretreatment characteristics. As a result, direct comparison of outcomes between treatment groups might lead to biased estimate of the treatment effect. Propensity score approaches have been used to achieve balance or comparability of treatment groups in terms of their measured pretreatment covariates thereby controlling for confounding bias in estimating treatment effects. Despite the popularity of propensity scores methods and recent important methodological advances, misunderstandings on their applications and limitations are all too common. In this article, we present a review of the propensity scores methods, extended applications, recent advances, and their strengths and limitations.