Applying propensity score methods in medical research: pitfalls and prospects

Non-selective beta-blocker is associated with reduced mortality in critically ill patients with cirrhosis: A real-world study

BACKGROUND

Apart from direct portal pressure reduction, non-selective beta-blockers (NSBB) modulate inflammatory response, which could be beneficial in patients with acute decompensation (AD). We therefore aimed to evaluate the effect of NSBB on 28-day mortality and markers of systemic inflammation in a propensity score-matched (PSM) cohort of AD patients requiring intensive care unit (ICU) admission.

METHODS

Patients were recruited from registry of AD patients requiring ICU admission. Out of total 445 patients, 108 patients on NSBB before admission (NSBB use group) were PSM for age, gender, pre-admission Child-Turcotte-Pugh score and history of previous decompensation to 108 patients not on NSBB (non-NSBB use group) which served as the control group. ICU parameters, markers of systemic inflammation and 28-day mortality were compared by standard statistical tests.

RESULTS

After PSM, no difference was observed in aetiology of cirrhosis, or precipitating event for AD between the groups. Pre-admission creatinine, bilirubin, international normalised ratio and haemoglobin were similar between the groups, whereas pre-admission white cell count (WCC) and neutrophil to lymphocyte ratio (NLR) was lower in NSBB-group. On admission to ICU, NSBB group had lower heart rate (p = 0.006), platelets (p = 0.012), WCC (p = 0.006), NLR (p = 0.039) and C-reactive protein (p = 0.007). Significantly more community acquired bacterial infections (p = 0.006), renal failure (p = 0.033) and higher grades of acute-on-chronic liver failure (ACLF; p = 0.012) were observed in non-NSBB group. Significantly lower 28-day (p = 0.001) and 90-day (p = 0.002) mortality was seen in NSBB group. Univariate and multivariable analysis for 28-day mortality showed that while ACLF at presentation and community acquired bacterial infection were independent negative predictors, prior NSBB use was positive predictors of survival.

CONCLUSIONS

Prior use of NSBB is associated with improved 28- and 90-day mortality in critically ill cirrhosis patients with AD which is mediated probably by blunting of the inflammatory response.

Relationship between health insurance enrolment and unintended pregnancy in Ghana

CONTEXT

The effect of health insurance coverage on sexual and reproductive health, especially unintended pregnancy, has scantly been researched. Using the 2014 Ghana Demographic and Health Survey, the study examined the links between women's health insurance enrolment on unintended pregnancy in Ghana.

METHOD

The sample consisted of 9,396 women aged 15-49 years, but the analysis was limited to the 4,544 women who were pregnant in the two years preceding the survey. The effects of health insurance enrolment on unintended pregnancy was examined with the propensity score matching. The health insurance enrolment was the treatment variable and unintended pregnancy as the outcome variable.

RESULTS

This study showed that 66.0% of all women surveyed had health insurance coverage and 31.8% of all women of childbearing age who were currently or had previously been pregnant reported having at least one unintended pregnancy. Thirty percent of insured women had an unintended pregnancy, compared to 37% of uninsured women. The results showed that education, household wealth index, religion, and type of marital union were significant predictor of health insurance coverage among Ghanaian women. The PSM split the women based on their health insurance status. After matching, the difference between the insured and uninsured women reduces significantly. Results demonstrated that, the probability of unintended pregnancy was 0.312 among insured women and 0.351 among those not insured in Ghana. This implies that having health insurance coverage will help in reducing the likelihood of women experiencing unintended pregnancy.

CONCLUSIONS

Results highlight the importance of the target of universal health coverage under the sustainable development goal 3 and demonstrate that expanding existing health insurance schemes within Ghana could contribute to reducing the number unintended pregnancies experienced each year.

Mortality and morbidity related to hepatitis C virus infection in hospitalized adults-A propensity score matched analysis

The World Health Organization (WHO) aims to reduce HCV mortality, but estimates are difficult to obtain. We aimed to identify electronic health records of individuals with HCV infection, and assess mortality and morbidity. We applied electronic phenotyping strategies on routinely collected data from patients hospitalized at a tertiary referral hospital in Switzerland between 2009 and 2017. Individuals with HCV infection were identified using International Classification of Disease (ICD)-10 codes, prescribed medications and laboratory results (antibody, PCR, antigen or genotype test). Controls were selected using propensity score methods (matching by age, sex, intravenous drug use, alcohol abuse and HIV co-infection). Main outcomes were in-hospital mortality and attributable mortality (in HCV cases and study population). The non-matched dataset included records from 165,972 individuals (287,255 hospital stays). Electronic phenotyping identified 2285 stays with evidence of HCV infection (1677 individuals). Propensity score matching yielded 6855 stays (2285 with HCV, 4570 controls). In-hospital mortality was higher in HCV cases (RR 2.10, 95%CI 1.64 to 2.70). Among those infected, 52.5% of the deaths were attributable to HCV (95%CI 38.9 to 63.1). When cases were matched, the fraction of deaths attributable to HCV was 26.9% (HCV prevalence: 33%), whilst in the non-matched dataset, it was 0.92% (HCV prevalence: 0.8%). In this study, HCV infection was strongly associated with increased mortality. Our methodology may be used to monitor the efforts towards meeting the WHO elimination targets and underline the importance of electronic cohorts as a basis for national longitudinal surveillance.

Creatinine clearance is key to solving the enigma of sex difference in in-hospital mortality after STEMI: Propensity score matching and mediation analysis

BACKGROUND

The precise impact of sex difference on in-hospital mortality in ST-elevation myocardial infarction (STEMI) patients are unclear, and the studies are no longer consistent. Therefore, we sought to evaluate the impact of sex differences in a cohort of STEMI patients.

METHODS

We analyzed the data of 2647 STEMI patients enrolled in the Kermanshah STEMI Cohort from July 2017 to May 2020. To accurately clarify the relationship between sex and hospital mortality, propensity score matching (PSM) and causal mediation analysis was applied to the selected confounder and identified intermediate variables, respectively.

RESULTS

Before matching, the two groups differed on almost every baseline variable and in-hospital death. After matching with 30 selected variables, 574 male and female matched pairs were significantly different only for five baseline variables and women were no longer at greater risk of in-hospital mortality (10.63% vs. 9.76%, p = 0.626). Among the suspected mediating variables, creatinine clearance (CLCR) alone accounts for 74% (0.665/0.895) of the total effect equal to 0.895(95% CI: 0.464-1.332). In this milieu, the relationship between sex and in-hospital death was no longer significant and reversed -0.233(95% CI: -0.623-0.068), which shows the full mediating role of CLCR.

CONCLUSION

Our research could help address sex disparities in STEMI mortality and provide a consequence. Moreover, CLCR alone can fully explain this relationship, which can highlight the importance of CLCR in predicting the short-term outcomes of STEMI patients and provide a useful indicator for clinicians.

A new model for predicting the occurrence of polycystic ovary syndrome: Based on data of tongue and pulse

Background and objective

Polycystic ovary syndrome is one of the most common types of endocrine and metabolic diseases in women of reproductive age that needs to be screened early and assessed non-invasively. The objective of the current study was to develop prediction models for polycystic ovary syndrome based on data of tongue and pulse using machine learning techniques.

Methods

A dataset of 285 polycystic ovary syndrome patients and 201 healthy women were investigated to identify the significant tongue and pulse parameters for predicting polycystic ovary syndrome. In this study, feature selection was performed using least absolute shrinkage and selection operator regression. Several machine learning algorithms (multilayer perceptron classifier, eXtreme gradient boosting classifier, and support vector machine) were used to construct the classification models to predict the presence of polycystic ovary syndrome.

Results

TB-L, TB-a, TB-b, TC-L, TC-a, h3, and h4/h1 in tongue and pulse parameters were statistically associated with polycystic ovary syndrome presence. Among the several machine learning techniques, the support vector machine model was optimal for the comprehensive evaluation of this dataset and deduced the area under the receiver operating characteristic curve, DeLong test, calibration curve, and decision curve analysis.

Conclusion

The machine learning model with tongue and pulse factors can predict the existence of polycystic ovary syndrome precisely.

Use of Instrumental Variable Analyses for Evaluating Comparative Effectiveness in Empirical Applications of Oncology: A Systematic Review

PURPOSE

This systematic review aims to characterize the use and trends of instrumental variables (IVs) in oncology research, assess the quality and completeness of IV reporting, and evaluate the agreement and interpretation of IV results in comparison with other techniques used for determining comparative effectiveness in observational research.

METHODS

We performed a systematic search of observational empirical oncology papers evaluating the comparative effectiveness of cancer treatments using IV methods. EMBASE and MEDLINE (through June 2021) were used for a keyword search; Scopus and Web of Science were used for a citation search. Publication details and characteristics of IV analysis and reporting were extracted from each study to examine the uptake and quality of IV applications.

RESULTS

Sixty-five empirical papers were identified from February 2001 through June 2021. Geographic variation (50.8%) was the most common type of IV used, and the majority of IV applications constructed binary instruments (53.8%). Concurrent analyses using another non-IV method to adjust for confounding were conducted in 56 (86.2%) studies, 17 (30.4%) of which produced results divergent from IV approaches. We observed a modest uptake of IV methods between 2011 and 2021 together with its dissemination, which remained fairly limited to the United States (76.9%). The quality and completeness of IV reporting varied greatly. The underlying assumptions required for a valid IV analysis were only accounted for in full by 20 (30.8%) studies.

CONCLUSION

There are limited use and variable quality of IV analyses in oncology. Future research should look to establish standards to better facilitate the quality, transparency, and completeness of IV reporting in this setting.

Clinical effectiveness of Qilong capsule in patients with ischemic stroke: A prospective, multicenter, non-randomized controlled trial

BACKGROUND

The Qilong capsule (QLC) is a Chinese patented medicine characterized by an equal emphasis on replenishing Qi and activating blood circulation. In 2000, China's FDA approved the use of QLC for ischemic stroke (IS). However, there is not yet much high-quality evidence of the clinical effectiveness of QLC combined with conventional treatment (CT) for IS with Qi deficiency and blood stasis syndrome.

PURPOSE

In this study, we conducted a prospective, multicenter, non-randomized controlled trial at 7 hospitals in China to investigate the clinical effectiveness of QLC combined with CT for IS with Qi deficiency and blood stasis syndrome.

METHODS

Participants aged 35 to 80 years old diagnosed as IS with Qi deficiency and blood stasis syndrome in TCM were recruited. Participants were treated with QLC (intervention group) or non-QLC (control group). The intervention course of QLC was 12 weeks. All participants in two groups received standard treatment. All participants returned for in-person follow-up visits at the 12th week and 24th week. Primary outcome measures included a modified Rankin Scale (mRS), the National Institute of Health Stroke Scale (NIHSS), and the Barthel Index (BI). Secondary outcome measures included TCM syndromes (Qi deficiency syndrome score, blood stasis syndrome score), psychological index (self-rating depression scale, SDS; self-rating anxiety scale, SAS), blood lipid index, blood coagulation index, homocysteine, and favorable functional outcome (mRS 0 - 3). Multiple imputations were used for any missing data. Propensity score matching (PSM) was used to deal with any confounding factors (age, gender, scale score, etc.). Rank alignment transformation variance analysis (ART ANOVA) and generalized linear mixed model (GLMM) were introduced to improve the scientific and accuracy of repeated measurement data. All statistical calculations were carried out with R 3.6.1 statistical analysis software.

RESULTS

A total of 2468 participants were screened from November 2016 to January 2019. Finally, 2302 eligible participants were included in the analysis. There were 1260 participants in the intervention group (QLC group) and 1042 participants in the control group (non-QLC group). After PSM matching, sub-samples of 300 participants in the QLC group and 300 participants in the non-QLC group were finally formed. The final results of clinical effectiveness are the same results shared by the total samples and sub-samples after PSM. In the 24th week after treatment, QLC combined with CT proved to be significantly better than CT alone in reducing the scores of mRS (p < 0.05), NIHSS (p < 0.001), Qi deficiency syndrome (p < 0.01), and blood stasis syndrome (p < 0.001), SAS (p < 0.05), as well as in improving BI score (p < 0.05). The favourable functional outcome (mRS score of 0 to 3 at week 12) was statistically different between QLC and non-QLC group in the sub-samples (p < 0.01, 97% vs 91.7%). The results of the ART ANOVA showed that the improvement of mRS (p < 0.01), BI (p < 0.05) and NIHSS (p < 0.001) in QLC group was better than non-QLC group when the interaction effect was considered. The results of GLMM showed that the reduction of mRS and NIHSS scores of patients in the QLC group were better than those of the non-QLC group (p < 0.001). The BI score of the QLC group in the sub-samples after PSM increased more than the non-QLC group (p < 0.001). There was no evidence showing that QLC can cause serious adverse reactions (ADRs) in treating patients with IS.

CONCLUSION

QLC combined with CT was better than CT alone in reducing mRS score, NIHSS score, Qi deficiency syndrome score, blood stasis syndrome score, and SAS score, as well as improving BI score after treatment. Further high-quality RCTs are needed to confirm the positive results. The study protocol was embedded in a registry study that registered in the Clinical Trials USA Registry (registration No. NCT03174535).

The Incidence and Associated Risk Factors of Contrast-Induced Nephropathy after Contrast-Enhanced Computed Tomography in the Emergency Setting: A Systematic Review

Iodinated contrast media (ICM) during contrast-enhanced computed tomography (CECT) in the emergency department (ED) is essential to diagnose acute conditions, despite risks of contrast-induced nephropathy (CIN) development and its associated complications. This systematic review aims to evaluate the incidence of CIN and CIN-induced complications, and to explore the relevance of classical risk factors for CIN among ED patients receiving ICM. PubMed, Cochrane, and Web of Science were used on 30 August 2021 to search for peer-reviewed English articles reporting on CIN incidence among ED patients aged ≥18 years who underwent an intravenous CECT. The inclusion criteria included studies that were in English, peer-reviewed, and involved ED patients aged ≥18 years who underwent single intravenous CECT. Studies on intra-arterial procedures and preventive strategies, meta-analyses, clinical guidelines, review articles, and case reports were excluded. The JBI critical appraisal checklist was applied to assess the risk of bias. In total, 18 studies were included wherein 15 were retrospective studies while three were prospective studies. We found a relatively higher CIN incidence in the ED, with variations owing to the CIN definitions. Several classical risk factors including acute hypotension remain linked to CIN onset in ED settings unlike factors such as age and diabetes. While risk of adverse renal events due to CIN is low, there is higher risk of CIN-induced mortality in the ED. Therefore, with the higher incidence of CIN and CIN-induced mortality rates in the ED, ICM administration during CECT in the ED should still be clinically justified after assessing both benefits and risks.

Discovery of genes positively modulating treatment effect using potential outcome framework and Bayesian update

BACKGROUND

The recent explosion of cancer genomics provides extensive information about mutations and gene expression changes in cancer. However, most of the identified gene mutations are not clinically utilized. It remains uncertain whether the presence of a certain genetic alteration will affect treatment response. Conventional statistics have limitations for causal inferences and are hard to gain sufficient power in genomic datasets. Here, we developed and evaluated a C-search algorithm for searching the causal genes that maximize the effect of the treatment.

METHODS

The algorithm was developed based on the potential outcome framework and Bayesian posterior update. The precision of the algorithm was validated using a simulation dataset. The algorithm was implemented to a cBioPortal dataset. The genes discovered by the algorithm were externally validated within CancerSCAN screening data from Samsung Medical Center.

RESULTS

Simulation data analysis showed that the C-search algorithm was able to identify nine causal genes out of ten. The C-search algorithm shows the discovery rate rapidly increasing until the 1500 data instances. Meanwhile, the log-rank test shows a slower increase in performance. The C-search algorithm was able to suggest nine causal genes from the cBioPortal Metabric dataset. Treating the patients with the causal genes is associated with better survival outcome in both the cBioPortal dataset and the CancerSCAN dataset which is used for external validation.

CONCLUSIONS

Our C-search algorithm demonstrated better performance to identify causal effects of the genes than multiple log-rank test analysis especially within a limited number of data. The result suggests that the C-search can discover the causal genes from various genetic datasets, where the number of samples is limited compared to the number of variables.

Effectiveness of a community health worker-led case management programme to improve outcomes for people with psychotic disorders in Thailand: a one-year prospective cohort study

BACKGROUND

Intensive case management (ICM) programmes for psychotic patients are effective in improving outcomes, but often unfeasible in resource-poor settings, as they typically require extensive human resources and expertise. We developed and evaluated the effectiveness of a less intensive case management program (LICM), led by community health workers, on one-year social functioning and service use.

METHODS

A prospective cohort study was conducted on patients aged 18 and above residing in a hospital catchment area. Outcomes were compared between LICM (n = 64) and non-LICM participants (n = 485). A counterfactual framework approach was applied to assess causal effects of the LICM on outcomes. The programme effectiveness was analyzed by augmented-inverse probability of treatment weighting (AIPW) to estimate potential outcome mean (POM) and average treatment effect (ATE). Outcomes were employment status and use of emergency, inpatient and outpatient services. Analyses were stratified by the number of previous psychotic relapse (≤ 1, > 1) to assess heterogeneity of treatment effect on those in an early and later stages of psychotic illness.

RESULTS

In the early-stage cohort, the likelihood of being employed at one year post-baseline was significantly greater in LICM participants than non-LICM participants (ATE 0.10, 95%CI 0.05-0.14, p < 0.001), whereas service use of all types, except outpatient, was not significantly different between the two groups. In the later-stage cohort, the likelihoods of employment between the two groups at post-baseline were similar (ATE -0.02, 95%CI -0.19-0.15, p = 0.826), whereas service use of all types was significantly higher in LICM participants.

CONCLUSION

LICM in a setting where community mental services are scarce may benefit those at an early stage of psychotic illness, by leading to better social functioning and no higher use of unscheduled services at the end of the programme, possibly through their better prognosis and medication adherence. A more intensive case management model may be appropriate for those in a later stage of the illness.

Health insurance support on maternal health care: evidence from survey data in India

Background

Maternal health care financing is key to the smooth functioning of health systems in a country. In India, maternal health care still persists as a major public health issue. Adequate health insurance could transform the utilization of maternal health care services. Therefore, we aim to examine the health insurance policies that cover maternal health and their performance in India.

Methods

The unit-level data of social consumption on health by the National Sample Survey Organizations, conducted in India (2017–18), are used. Bivariate analysis, logistic regression and propensity scoring matching are applied.

Results

About 14.1% women are covered by health insurance support at the national level. Uninsured women are less likely to receive full antenatal care (ANC) services and institutional delivery. Socio-economic characteristics play a significant role in utilizing maternal health care benefits through health insurance support.

Conclusions

Our study concludes that the health insurance coverage is the most significant contributor to the better utilization of full ANC and institutional delivery at the national level and hindrances in accessing them. There is a need for proactive and inclusive policy development by the Government of India to incentivize public financing through health insurance, which can shrink the challenges of public health burden and reduce the health risk.

Delays Related to Prior Authorization in Inflammatory Bowel Disease

BACKGROUND

Delays in advancing to biologic therapies are associated with adverse outcomes in inflammatory bowel disease (IBD). Insurer-mandated prior authorizations have been linked to prolonged medication initiation times. We hypothesized that prior authorizations are associated with prolonged biologic initiation time and increased IBD-related healthcare utilization among children with IBD.

METHODS

We performed a retrospective cohort study of 190 pediatric patients with IBD initiating biologics at a tertiary care hospital to measure the association between prior authorization, biologic initiation time (physician recommendation to first dose), and healthcare utilization (hospitalization, surgery, or emergency department visit). Demographic, insurance, and disease severity-related covariables were collected. Multivariable linear regression was used to measure the association between prior authorization and biologic initiation time. Propensity score methods were used to measure the associations between prior authorization and IBD-related healthcare utilization within 180 days and corticosteroid dependence at 90 days, with adjustment for insurance type, demographics, and disease severity-related characteristics.

RESULTS

Median biologic initiation time was 21 days. Prior authorization and complicated prior authorizations (requiring appeal, step therapy, or peer-to-peer review) were associated with 10.2-day (95% confidence interval [CI] 8.2 to 12.3) and 24.6-day (95% CI 16.4 to 32.8) increases in biologic initiation time, respectively. Prior authorizations increased the likelihood of IBD-related healthcare utilization within 180 days by 12.9% (95% CI 2.5 to 23.4) and corticosteroid dependence at 90 days by 14.1% (95% CI 3.3 to 24.8).

CONCLUSIONS

Prior authorizations are associated with prolonged biologic initiation time and increased IBD-related healthcare utilization. Minimizing prior authorization-related delays may expedite biologic delivery and reduce the risk of IBD-related healthcare utilization.

Endobronchial ultrasound-guided transbronchial biopsy with or without a guide sheath for peripheral pulmonary malignancy

Endobronchial ultrasound (EBUS)-guided transbronchial biopsy (TBB) is a common procedure used to diagnose peripheral pulmonary lesions (PPLs). However, existing literature did not conclusively show a difference in the ability of EBUS-TBB with and without a guide sheath (GS) to diagnose PPLs. This multicenter cohort study enrolled patients presenting for EBUS-TBB of PPLs that finally proved to be malignant. The diagnostic yield and complication rate were compared between patients undergoing EBUS-TBB with and without a GS (EBUS-TBB+GS versus EBUS-TBB-GS). A propensity score matching method was used to balance differences of pertinent clinical features between the two groups. The original cohort consisted of 975 patients (556 in EBUS-TBB-GS; 419 in EBUS-TBB+GS). GS guidance was more likely to be used with smaller (40 mm versus 44 mm) and middle or lower lobe (60% versus 35%) lesions. After propensity score matching, 720 (360 in each group) patients were included; the diagnostic yields for PPLs were 79% and 78% for EBUS-TBB-GS and EBUS-TBB+GS groups, respectively (p=0.649). The complication rates (5.8% versus 7.2% for bleeding; 0.6% versus 1.9% for pneumothorax) appeared to be lower in the EBUS-TBB+GS group, but the differences did not reach statistical significance. The procedure time was significantly longer in the EBUS-TBB+GS group than in the EBUS-TBB-GS group (29 min versus 24 min; p<0.001). In conclusion, adding a GS to EBUS-TBB did not improve the diagnostic yield for malignant PPLs. GS guidance was seemingly associated with a lower number of complications after TBB but contributed significantly to a longer procedure time.

Impact of household shocks on access to healthcare services in Kenya: a propensity score matching analysis

OBJECTIVE

This study examines the effects of household shocks on access to healthcare services in Kenya. Shocks are adverse events that lead to loss of household income and/or assets.

DESIGN AND SETTING

The study used data from the Kenya Integrated Household Budget Survey 2015/2016, a nationally representative cross-sectional survey. A propensity score matching approach was applied for the analysis.

PARTICIPANTS

The study sample included 16 297 individuals from households that had experienced shocks (intervention) and those that had not experienced shocks (control) within the last 12 months preceding the survey.

OUTCOME MEASURES

The outcome of interest was access to healthcare services based on an individual's perceived need for health intervention.

RESULTS

The results indicate that shocks reduce access to healthcare services when household members are confronted with an illness. We observed that multiple shocks in a household exacerbate the risk of not accessing healthcare services. Asset shocks had a significant negative effect on access to healthcare services, whereas the effect of income shocks was not statistically significant. This is presumably due to the smoothing out of income shocks through the sale of assets or borrowing. However, considering the time when the shock occurred, we observed mixed results that varied according to the type of shock.

CONCLUSIONS

The findings suggest that shocks can limit the capacity of households to invest in healthcare services, emphasising their vulnerability to risks and inability to cope with the consequences. These results provoke a debate on the causal pathway of household economic shocks and health-seeking behaviour. The results suggest a need for social protection programmes to integrate mechanisms that enable households to build resilience to shocks. A more viable approach would be to expedite universal health insurance to cushion households from forgoing needed healthcare when confronted with unanticipated risks.

Is There Any Need for Adjusting 131I Activity for the Treatment of High Turnover Graves' Disease Compared to Normal Turnover Patients? Results from a Retrospective Cohort Study Validated by Propensity Score Analysis

Purpose

To compare ¹³¹I-therapy outcomes in high turnover and normal turnover Graves' disease patients and predict optimal first ¹³¹I activity for high turnover patients.

Methods

Retrospective cohort design (1:2) validated by propensity score analysis. Cohort 1, high turnover (2-h RAIU/24-h RAIU ≥ 1), n = 104, and cohort 2, normal turnover (ratio < 1), n = 208, patients were compared for post ¹³¹I outcome. The cure was defined as a combined euthyroid and stable hypothyroid state following ¹³¹I treatment. Logistic regression analysis was used for identifying prognostic factors. The propensity score was applied; 77 matched pairs (1:1 ratio) of high and normal turnover patients were selected as a validation set.

Results

First ¹³¹I cure rates of 28% in high turnover and 66% in normal turnover groups (p = 0.001) were noted. The therapy cycles (median, 2 vs. 1) and cumulative ¹³¹I activity (median, 15 vs. 7 mCi) were required to cure hyperthyroidism in cohort 1 and cohort 2, respectively. Age (> 44 years), higher grade of goitre, and 2-h RAIU (> 37%) were associated with ¹³¹I therapy failure. The high turnover patients needed a factor of 1.5-2 times more ¹³¹I activity to achieve a similar cure rate compared to the normal turnover patients. The first-dose cure rate was 31% vs. 60% by propensity score analysis (n = 154), no way different (28% vs.66%) from the whole group of 312 patients.

Conclusion

High turnover Graves' disease patients, if administered standard ¹³¹I activity, the outcomes shall be poor. To improve the success rate, ¹³¹I activity should be increased by 1.5 to 2 times in the high turnover patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13139-020-00674-3.

Patients with IVF complicated by moderate-to-critical OHSS experience increased thrombosis, GDM and neonatal NICU admission but slightly shorter gestation compared with matched IVF counterparts: A retrospective Chinese cohort study

BACKGROUND

Ovarian hyperstimulation syndrome (OHSS) is a common disease during controlled ovarian hyperstimulation treatment. However, the obstetric and neonatal outcomes of this group of patients are unknown. The aim of this study was to explore the effects of late moderate-to-critical OHSS on obstetric and neonatal outcomes.

METHODS

This prospective observational study included 17,537 patients who underwent IVF/ICSI-fresh embryo transfer (ET) between June 2012 and July 2016 and met the inclusion criteria, including 7,064 eligible patients diagnosed with clinical pregnancy. Ultimately, 6,356 patients were allocated to the control group, and 385 patients who were hospitalized and treated at the center for late moderate-to-critical OHSS were allocated to the OHSS group. Then, propensity score matching analysis was performed, matching nine maternal baseline covariates and the number of multiple gestations; 385 patients with late moderate-to-critical OHSS were compared with a matched control group of 1,540 patients. The primary outcomes were the live birth rate, preterm delivery rate, miscarriage rate, gestational age at birth (weeks), obstetric complications and neonatal complications.

RESULTS

The duration of gestation in the matched control group was significantly higher than that in the OHSS group. The live birth delivery rate did not significantly differ between the OHSS and matched control groups. The incidence rates of the obstetric complications venous thrombosis (VT) and gestational diabetes mellitus (GDM), neonatal complications and the number of neonates admitted to the NICU were significantly higher in the OHSS group than in the matched control group.

CONCLUSIONS

Pregnant women undergoing IVF with fresh ET whose course is complicated by late moderate-to-critical OHSS appear to experience shortened gestation and increased obstetrical and neonatal complications compared with matched controls whose course is not complicated by OHSS. However, the live birth rate, average neonatal weight, and incidence rates of premature delivery, miscarriage, early abortion, hypertensive disorder of pregnancy (HDP), placenta previa (PP), intrahepatic cholestasis of pregnancy (ICP), and low neonatal birth weight (LBW) did not differ significantly between the two groups.

Efficacy and Safety in Combining Primary Palatoplasty and Myringotomy in Patients with Cleft Palate

Patients born with a cleft lip and palate undergo multiple surgical procedures, increasing the infants’ exposure to anesthesia and potential risk of neurocognitive delays. In addition, these numerous procedures lead to greater use of hospital resources. This study analyzes the differences in anesthetic exposure and perioperative characteristics between performing combined versus separate primary palatoplasty (PP) and placement of bilateral myringotomy tubes (BMT).

Endoscopic sphincterotomy to prevent post-ERCP pancreatitis in patients with biliary neoplasms: a multicenter retrospective cohort study

Background and aims  Treatment of biliary neoplasms often involves multiple endoscopic retrograde cholangiopancreatography (ERCP)-related procedures. Endoscopic sphincterotomy (ES) may prevent post-ERCP pancreatitis (PEP). This retrospective, multicenter cohort study aimed to investigate the effectiveness of ES for prevention of PEP in patients with biliary neoplasm. Methods  Patients with biliary duct neoplasm who underwent ERCP between January 2006 and December 2016 were enrolled. The frequency of PEP was compared between the ES and non-ES groups using propensity score analysis. The effectiveness of ES in subgroups of patients who underwent biliary duct stent placement, intraductal ultrasound (IDUS), and transpapillary biliary duct biopsy was analyzed by logistic regression. Results  Of the 362 patients enrolled, 84 (23.2 %) developed PEP. Propensity score matching for PEP risk factors in 172 ERCP procedures showed that the frequency of PEP in the ES group was lower than that in the non-ES group (19.7 % vs. 33.7 %). Non-ES was also an independent risk factor for PEP in patients who underwent intraductal ultrasound and transpapillary biliary duct biopsy (RR = 4.54 and 5.26), but was not an independent risk factor for PEP in patients with biliary duct stents. In addition, there was no evidence that the frequency of PEP was statistically different between patients with plastic stents and metal stents in the ES and non-ES groups ( P  = 0.14 and 0.10). Conclusions  ES is an effective technique to prevent PEP in patients with biliary neoplasms. In particular, ES is a safe technique to prevent PEP when performing IDUS and transpapillary biliary duct biopsy.

Effectiveness of endoscopic ultrasound-guided drainage for noncapsulated postoperative pancreatic collection

BACKGROUND

Postoperative pancreatic collection (POPC) is a frequent complication after pancreatectomy. Although percutaneous drainage (PD) has been the treatment of choice for POPC with encapsulation, endoscopic ultrasound-guided transmural drainage (EUS-TD) was recently reported effective for this condition. The main aim of this retrospective study was to compare EUS-TD and PD in terms of effectiveness and safety as the first procedure in patients with noncapsulated POPC.

METHODS

Consecutive patients who underwent pancreatectomy and developed noncapsulated POPC requiring EUS-TD or PD between April 2003 and May 2018 were enrolled. Noncapsulated POPC was defined as pancreatic collection appearing within 28 days postoperatively and lacking a thick encapsulating inflammatory wall on contrast-enhanced computed tomography. The effectiveness of drainage was compared between the two groups before and after propensity-score matching of patient characteristics. Outcomes of interest included re-intervention rate, number of re-interventions, immediate complication, remote complication, and time to clinical resolution after the procedure.

RESULTS

A sum of 81 patients were included: 14 underwent EUS-TD, and 67 underwent PD. There were significant differences between groups in POPC size and type of surgery. Propensity-score matching selected 13 patients who underwent EUS-TD and 28 who underwent PD. Re-intervention rate (p = 0.045), and number of re-interventions (p = 0.026) were significantly lower in the matched EUS-TD group than in the matched PD group. There were no significant between-group differences in immediate complication and remote complication. The time to clinical resolution after the procedure was significantly shorter in the matched EUS-TD than in the matched PD group (14 versus 26 days; p < 0.0001).

CONCLUSION

EUS-TD is more effective than PD for drainage of noncapsulated POPC. EUS-TD should be considered as the first treatment of choice for noncapsulated POPC visible on EUS.

Effects of Statins to Reduce All-Cause Mortality in Heart Failure Patients: Findings from the EPICAL2 Cohort Study

INTRODUCTION

The addition of statins to standard care in heart failure (HF) patients remains controversial in clinical practice. Large-scale clinical trials failed to show mortality benefits, but uncertainty persists in real-world settings.

OBJECTIVE

We evaluated whether the prescription of statins at hospital discharge is associated with a reduction in all-cause mortality at up to 1 year of follow-up in HF patients.

METHODS

We analyzed data from Epidémiologie et Pronostic de l'Insuffisance Cardiaque Aiguë en Lorraine (EPICAL2) cohort study of 2254 hospitalized acute HF patients who were admitted to 21 hospitals located in northeast France for acute HF between October 2011 and October 2012 and who received statins at discharge compared with patients who did not. We used propensity score matching and instrumental variable analyses to estimate the treatment effects of statins, and a multivariable Cox proportional-hazards model to examine survival with statin use, adjusting for patient demographics, HF characteristics, medical history, comorbidities, drug treatment and other known potential confounders. We plotted Kaplan-Meier survivor curves, and used log-rank test to determine the equality of survivor functions.

RESULTS

We included 2032 patients in this investigation: 919 (45%) in the statin-treated group and 1113 (55%) in the control group. The estimated average statin-treatment effects for all-cause mortality in HF failed to demonstrate a significant effect on mortality [Z = - 1.73, 95% confidence interval (CI) - 0.11 to 0.007, p value = 0.083, and Z = - 0.95, 95% CI - 1.34 to 0.46, p value = 0.34] for propensity score matching and instrumental variable analyses, respectively. Moreover, the Cox proportional-hazards model showed that statin prescription was not significantly associated with the rate of death (hazard ratio = 0.85, 95% CI 0.66-1.11, p value = 0.26), adjusted for all confounders.

CONCLUSION

In patients with HF (and reduced or preserved ejection fraction), the prescription of statins did not appear to be associated with better survival after 1 year of follow-up in the EPICAL2 cohort. We cannot exclude that a subpopulation of HF patients may have some benefits compared with the whole HF population or that there might be a lack of power to show such effect.

CLINICAL TRIAL REGISTRATION

NCT02880358.

Association between intravenous contrast media exposure and non-recovery from dialysis-requiring septic acute kidney injury: a nationwide observational study

PURPOSE

This study aimed to examine the association between the use of intravenous contrast and non-recovery from dialysis-requiring acute kidney injury (AKI-D) and in-hospital mortality among patients with sepsis.

METHODS

This was a retrospective observational study using the Japanese Diagnosis Procedure Combination inpatient database between January 2011 and December 2016. We identified patients with septic AKI who began continuous renal replacement therapy (RRT) within 2-days of admission and underwent computed tomography. We compared patients with AKI-D with and without the use of intravenous contrast for computed tomography and performed propensity score matching to adjust for confounders for the association between exposure to intravenous contrast and outcomes, including a composite outcome of in-hospital mortality and RRT dependence at discharge and RRT duration.

RESULTS

From 3782 and 6619 patients with septic AKI-D with and without intravenous contrast exposure, respectively, 3485 propensity score-matched pairs were generated. No significant differences were found in the outcomes between the propensity score-matched groups: a composite outcome of in-hospital mortality and RRT dependence, 49.6% vs. 50.2% (odds ratio (OR) 0.98; 95% CI (confidence interval) 0.88, 1.07); in-hospital mortality, 45.3% vs. 46.1% (OR 0.97; 95% CI 0.87, 1.06); RRT dependence, 4.4% vs 4.1% (OR 1.08; 95% CI 0.85, 1.31); and median (interquartile range) of RRT duration, 4 [2-11] days vs. 4 [2-11] days (P = 0.58).

CONCLUSIONS

This large observational study did not support an association between intravenous contrast media and adverse in-hospital outcomes in patients with septic AKI-D. Further studies are warranted to assess the generalizability.

Effectiveness of Sequential Compression Devices in Prevention of Venous Thromboembolism in Medically Ill Hospitalized Patients: A Retrospective Cohort Study

Objective:

To evaluate the effectiveness of sequential compression devices (SCDs) for venous thromboembolism (VTE) prevention in medically ill hospitalized patients.

Materials and Methods:

Adult patients admitted to a teaching hospital from April 2015 to March 2016 were included. Patients on anticoagulants with or without SCDs were excluded. We analyzed VTE risk, length of hospital stay, and other comorbidities among propensity score-matched patients on SCDs and those without thromboprophylaxis (NONE).

Results:

Among 30,824 patients, 67 patients (0.22%) developed VTE during their hospital stays, with deep vein thrombosis (DVT) in 55 cases and pulmonary embolism (PE) in 12. VTE was seen in 47 out of 20,018 patients on SCDs (41 DVT, 6 PE) and 20 out of 10,819 patients without SCDs (14 DVT, 6 PE). Risk-adjusted analysis showed no significant difference in VTE incidence in the SCD group compared to NONE (odds ratio 0.99, 95% confidence interval 0.57-1.73, p=0.74).

Conclusion:

Compared to the NONE group, SCDs are not associated with decreased VTE incidence during hospital stay.

The impact of racism on the future health of adults: protocol for a prospective cohort study

BACKGROUND

Racial discrimination is recognised as a key social determinant of health and driver of racial/ethnic health inequities. Studies have shown that people exposed to racism have poorer health outcomes (particularly for mental health), alongside both reduced access to health care and poorer patient experiences. Most of these studies have used cross-sectional designs: this prospective cohort study (drawing on critical approaches to health research) should provide substantially stronger causal evidence regarding the impact of racism on subsequent health and health care outcomes.

METHODS

Participants are adults aged 15+ sampled from 2016/17 New Zealand Health Survey (NZHS) participants, sampled based on exposure to racism (ever exposed or never exposed, using five NZHS questions) and stratified by ethnic group (Māori, Pacific, Asian, European and Other). Target sample size is 1680 participants (half exposed, half unexposed) with follow-up survey timed for 12-24 months after baseline NZHS interview. All exposed participants are invited to participate, with unexposed participants selected using propensity score matching (propensity scores for exposure to racism, based on several major confounders). Respondents receive an initial invitation letter with choice of paper or web-based questionnaire. Those invitees not responding following reminders are contacted for computer-assisted telephone interview (CATI). A brief questionnaire was developed covering current health status (mental and physical health measures) and recent health-service utilisation (unmet need and experiences with healthcare measures). Analysis will compare outcomes between those exposed and unexposed to racism, using regression models and inverse probability of treatment weights (IPTW) to account for the propensity score sampling process.

DISCUSSION

This study will add robust evidence on the causal links between experience of racism and subsequent health. The use of the NZHS as a baseline for a prospective study allows for the use of propensity score methods during the sampling phase as a novel approach to recruiting participants from the NZHS. This method allows for management of confounding at the sampling stage, while also reducing the need and cost of following up with all NZHS participants.

Adjuvant chemotherapy following stereotactic body radiotherapy for early stage non-small-cell lung cancer is associated with lower overall: A National Cancer Database Analysis

OBJECTIVES

Adjuvant chemotherapy is routinely offered post-surgical resection for early stage non-small-cell lung cancer (NSCLC) ≥4 cm; however, its role following definitive stereotactic body radiotherapy (SBRT) has not been well defined. We investigated the association between receipt of adjuvant chemotherapy post-SBRT and overall survival (OS) for patients with T1-T3N0M0 NSCLC in the National Cancer Database (NCDB).

MATERIALS AND METHODS

The NCDB was queried for patients with T1-T3N0M0 NSCLC treated with definitive SBRT from 2004 to 2014. The association between non-randomized receipt of adjuvant chemotherapy and OS was analyzed for all patients (n = 24,011) and a propensity-matched cohort (n = 608) using Kaplan-Meier methods and Cox proportional hazard models. A subset analysis was performed for patients with tumors ≥4 cm (n = 2,323).

RESULTS

There were 24,011 patients in the cohort with a median follow-up of 32.5 months. Of these, 322 (1.3%) received adjuvant chemotherapy. Three-year OS was 41.3% with adjuvant chemotherapy compared to 50.6% without adjuvant chemotherapy (p = 0.001). On multivariate analysis, adjuvant chemotherapy was independently associated with higher overall mortality (hazard ratio:1.22, 95% confidence interval:1.06-1.40, p = 0.005). For tumors ≥4 cm, 3-year OS was 38.2% with adjuvant chemotherapy (n = 80) compared to 33.0% without adjuvant chemotherapy (p = 0.81). After propensity-score matching, there was a persistent association between lower OS and adjuvant chemotherapy with those receiving adjuvant chemotherapy (n = 322) having 3-year OS of 41.3% compared to 60.9% without adjuvant chemotherapy (p < 0.0001).

CONCLUSION

Adjuvant chemotherapy following definitive SBRT for T1-3N0M0 NSCLC is associated with lower OS and is not associated with a survival benefit for patients with tumors ≥4 cm.

Organ damage in patients treated with belimumab versus standard of care: a propensity score-matched comparative analysis

Objectives

The study (206347) compared organ damage progression in patients with systemic lupus erythematosus (SLE) who received belimumab in the BLISS long-term extension (LTE) study with propensity score (PS)-matched patients treated with standard of care (SoC) from the Toronto Lupus Cohort (TLC).

Methods

A systematic literature review identified 17 known predictors of organ damage to calculate a PS for each patient. Patients from the BLISS LTE and the TLC were PS matched posthoc 1:1 based on their PS (±calliper). The primary endpoint was difference in change in Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI) score from baseline to 5 years.

Results

For the 5- year analysis, of 567 (BLISS LTE n=195; TLC n=372) patients, 99 from each cohort were 1:1 PS matched. Change in SDI score at Year 5 was significantly lower for patients treated with belimumab compared with SoC (−0.434; 95% CI –0.667 to –0.201; p<0.001). For the time to organ damage progression analysis (≥1 year follow-up), the sample included 965 (BLISS LTE n=259; TLC n=706) patients, of whom 179 from each cohort were PS-matched. Patients receiving belimumab were 61% less likely to progress to a higher SDI score over any given year compared with patients treated with SoC (HR 0.391; 95% CI 0.253 to 0.605; p<0.001). Among the SDI score increases, the proportion of increases ≥2 was greater in the SoC group compared with the belimumab group.

Conclusions

PS-matched patients receiving belimumab had significantly less organ damage progression compared with patients receiving SoC.

Utilization and Effectiveness of Home Treatment for People With Acute Severe Mental Illness: A Propensity-Score Matching Analysis of 19 Months of Observation

Treatment guidelines recommend home treatment (HT) as an effective alternative to inpatient treatment for individuals with severe, acute mental illness (SAMI). Nevertheless, HT is largely unfamiliar in German-speaking countries. Here we examined the utilization and effectiveness of HT services newly implemented in a large hospital setting in Switzerland. We used a naturalistic observational study design including patients (n = 201, 18-65 years, 65.7% females) with SAMI who received HT between June 2016 and December 2017. HT patients were compared with a crude inpatient sample (n = 1078) and a matched inpatient sample (n = 201). Propensity-score matching was used to control for personal characteristics. Treatment outcomes were compared between HT patients and the matched inpatients based on routinely obtained medical data. The results showed that the HT sample consisted of more females (+21%), older (+4 years), and better educated (+10%) patients with more affective disorders (+13%) and less substance use disorders (-15%) as compared with the crude inpatient sample. The severity of symptoms was the same. After matching, there were no significant differences in the proportion of readmissions (36%), the duration until readmission and scores of the Health of the Nation Outcome Scales (HoNOS). The treatment duration of HT patients was significantly longer and, post-treatment, scores on the Global Assessment of Functioning scale (GAF) were significantly better. We conclude that HT is an effective treatment option for patients with SAMI also in Switzerland concerning the reduction of hospital days, the improvement of symptoms and functioning and readmission rates. HT cannot fully replace hospital admissions in all cases and HT may be beneficial for particular groups of patients (e.g., females and individuals with affective disorders). The study further shows the potential value of propensity-score matching in health care service research.

Treatment effects of renin-angiotensin aldosterone system blockade on kidney failure and mortality in chronic kidney disease patients

BACKGROUND

Chronic kidney disease (CKD) is a leading cause of death before and after onset of end-stage renal disease (ESRD). Knowing treatments that can delay disease progression will lead to reduced mortality. We therefore aimed to estimate the effectiveness of renin angiotensin aldosterone system (RAAS) blockade on CKD progression.

METHODS

We conducted a retrospective CKD cohort at Ubon Ratchathani province, Thailand from 1997 to 2011. ESRD was defined as estimated glomerular filtration rate (eGFR) <15 ml/min/1.73 m2, dialysis, or kidney transplantation. All-cause mortality was verified until December 31, 2011. A counterfactual-framework was applied to estimate the effectiveness of RAAS blockade on outcomes, i.e., ESRD, death before and after ESRD. RAAS blockade was categorized according to duration of use <0.25 year, 0.25-1 year (RAAS1), and >1 year (RAAS2). An augmented inverse-probability weighting (AIPW) method was used to estimate potential-outcome mean (POM) and average treatment-effect (ATE). Multi-logit and Poisson regressions were used for treatment and outcome models, respectively. Analyses were stratified by ESRD, death before/after ESRD for diabetic and non-diabetic groups. STATA 14.0 was used for statistical analyses.

RESULTS

Among 15,032 diabetic patients, 2346 (15.6%), 2351 (18.5%), and 1607 (68.5%) developed ESRD, died before ESRD, and died after ESRD, respectively. Only RAAS2 effect was significant on ESRD, death before and after ESRD. The ESRD rates were 12.9%, versus 20.0% for RAAS2 and non-RAAS, respectively, resulted in significant risk differences (RD) of -7.2% (95% CI: -8.8%, -5.5%), and a numbers needed-to-treat (NNT) of 14. Death rates before ESRD for these corresponding groups were 14.4% (12.9%, 15.9%) and 19.6% (18.7%, 20.4%) with a NNT of 19. Death rates after ESRD in RAAS2 was lower than non-RASS group (i.e., 62.8% (55.5%, 68.9%) versus 68.1% (65.9%, 70.4%)) but this was not significant. RAAS2 effects on ESRD and death before ESRD were persistently significant in non-diabetic patients (n = 17,074) but not for death after ESRD with the NNT of about 15 and 16 respectively.

CONCLUSIONS

Receiving RAAS blockade for 1 year or longer could prevent both CKD progression to ESRD and premature mortality.

Risk of nonsteroidal anti-inflammatory drug-associated renal dysfunction among neonates diagnosed with patent ductus arteriosus and treated with gentamicin

OBJECTIVE

To evaluate the risk of nonsteroidal anti-inflammatory drug (NSAID) therapy-associated acute kidney injury (AKI) among neonates diagnosed with patent ductus arteriosus (PDA) who are treated with gentamicin.

STUDY DESIGN

Multicenter retrospective observational study of patients ⩽44 postmenstrual weeks of age diagnosed with PDA who received gentamicin during hospitalization between January 2006 and December 2014. Patients with and without NSAID exposure were matched on covariates associated with AKI and NSAID therapy. The primary end point, AKI, was defined according to Kidney Disease Improving Global Outcomes neonatal criteria.

RESULTS

The rate of AKI for the entire cohort (n=594) was 12% (n=71). Among neonates receiving NSAIDS, 14.8% (n=44) experienced an AKI as compared to 9.1% (n=27) for those who were not exposed (relative risk, 1.6; 95% confidence interval, 1.0 to 2.6). Therefore, the attributable risk of NSAID use was 5.7% (95% confidence interval, 0.5 to 11.0).

CONCLUSION

Among neonates with PDA and receiving gentamicin, NSAID therapy increases the risk of AKI by about 6%.

Acute Kidney Injury After Computed Tomography: A Meta-analysis

STUDY OBJECTIVE

Computed tomography (CT) is an important imaging modality used in the diagnosis of a variety of disorders. Imaging quality may be improved if intravenous contrast is added, but there is a concern for potential renal injury. Our goal is to perform a meta-analysis to compare the risk of acute kidney injury, need for renal replacement, and total mortality after contrast-enhanced CT versus noncontrast CT.

METHODS

We searched MEDLINE (PubMed), the Cochrane Library, CINAHL, Web of Science, ProQuest, and Academic Search Premier for relevant articles. Included articles specifically compared rates of renal insufficiency, need for renal replacement therapy, or mortality in patients who received intravenous contrast versus those who received no contrast.

RESULTS

The database search returned 14,691 articles, inclusive of duplicates. Twenty-six unique articles met our inclusion criteria, with an additional 2 articles found through hand searching. In total, 28 studies involving 107,335 participants were included in the final analysis, all of which were observational. Meta-analysis demonstrated that, compared with noncontrast CT, contrast-enhanced CT was not significantly associated with either acute kidney injury (odds ratio [OR] 0.94; 95% confidence interval [CI] 0.83 to 1.07), need for renal replacement therapy (OR 0.83; 95% CI 0.59 to 1.16), or all-cause mortality (OR 1.0; 95% CI 0.73 to 1.36).

CONCLUSION

We found no significant differences in our principal study outcomes between patients receiving contrast-enhanced CT versus those receiving noncontrast CT. Given similar frequencies of acute kidney injury in patients receiving noncontrast CT, other patient- and illness-level factors, rather than the use of contrast material, likely contribute to the development of acute kidney injury.

Association of tenofovir disoproxil fumarate with primary allograft survival in HIV-positive kidney transplant recipients

BACKGROUND

Tenofovir disoproxil fumarate (TDF) is an antiretroviral agent frequently used to treat human immunodeficiency virus (HIV). There are concerns regarding its potential to cause acute kidney injury, chronic kidney disease, and proximal tubulopathy. Although TDF can effectively suppress HIV after kidney transplantation, it is unknown whether use of TDF-based antiretroviral therapy (ART) after kidney transplantation adversely affects allograft survival.

METHODS

We examined 104 HIV+ kidney transplant (KT) recipients at our center between 2001 and 2014. We generated a propensity score for TDF treatment using recipient and donor characteristics. We then fit Cox proportional hazards models to investigate the association between TDF treatment and 3-year, death-censored primary allograft failure, adjusting for the propensity score and delayed graft function (DGF).

RESULTS

Of the 104 HIV+ KT candidates who underwent transplantation during the study period, 23 (22%) were maintained on TDF-based ART at the time of transplantation, and 81 (78%) were on non-TDF-based ART. Median age of the cohort was 48 years; 87% were male; 88% were black; and median CD4 count at transplantation was 450 cells/mm³ . Median kidney donor risk index was 1.2. At 3 years post transplantation, primary allograft failure occurred in 26% of patients on TDF-based ART and in 28% of patients on non-TDF-based ART (P=.5). TDF treatment was not associated with primary allograft failure at 3 years post transplant after adjusting for DGF and a propensity score for TDF use (hazard ratio 2.12, 95% confidence interval 0.41-10.9).

CONCLUSIONS

In a large single-center experience of HIV+ kidney transplantation, TDF use following kidney transplantation was not significantly associated with primary allograft failure. These results may help inform management for HIV+ KT recipients in need of TDF therapy for adequate viral suppression.

Diabetes mellitus in patients with chronic obstructive pulmonary disease-The impact on mortality

Background

Chronic obstructive pulmonary disease (COPD) is the leading cause of morbidity and mortality worldwide. There is evidence to support a connection between COPD and diabetes mellitus (DM), another common medical disorder. However, additional research is required to improve our knowledge of these relationships and their possible implications. In this study, we investigated the impact of DM on patient outcomes through the clinical course of COPD.

Methods

We conducted a cohort study in patients from the Taiwan Longitudinal Health Insurance Database between 2000 and 2013. Patients with COPD were identified and assessed for pre-existing and incident DM. A Cox proportional hazards model was built to identify factors associated with incident DM and to explore the prognostic effects of DM on COPD patients. A propensity score method was used to match COPD patients with incident DM to controls without incident DM.

Results

Pre-existing DM was present in 332 (16%) of 2015 COPD patients who had a significantly higher hazard ratio (HR) [1.244, 95% confidence interval (CI) 1.010–1.532] for mortality than that of the COPD patients without pre-existing DM. During the 10-year follow-up period, 304 (19%) of 1568 COPD patients developed incident DM; comorbid hypertension (HR, 1.810; 95% CI, 1.363–2.403), cerebrovascular disease (HR, 1.517; 95% CI, 1.146–2.008) and coronary artery disease (HR, 1.408; 95% CI 1.089–1.820) were significant factors associated with incident DM. Survival was worse for the COPD patients with incident DM than for the matched controls without incident DM (Log-rank, p = 0.027).

Conclusions

DM, either pre-existing or incident, was associated with worse outcomes in COPD patients. Targeted surveillance and management of DM may be important in clinical care of the COPD population.

A systematic review of propensity score methods in the acute care surgery literature: avoiding the pitfalls and proposing a set of reporting guidelines

BACKGROUND

Propensity score methods are techniques commonly employed in observational research to account for confounding when estimating the effects of treatments and exposures. These methods have been increasingly employed in the acute care surgery literature in an attempt to infer causality; however, the adequacy of reporting and the appropriateness of statistical analyses when using propensity score matching remain unclear.

OBJECTIVES

The goal of this systematic review is to assess the adequacy of reporting of propensity score methods, with an emphasis on propensity score matching (to assess balance and the use of appropriate statistical tests), in acute care surgery (ACS) studies and to provide suggestions for improvement for junior investigators.

METHODS

We searched three databases, and other relevant literature (from January 2005 to June 2015) to identify observational studies within the ACS literature using propensity score methods (PROSPERO No: CRD42016036432). Two reviewers extracted data and assessed the quality of the studies retrieved by reviewing the adequacy of both overall reporting and of the propensity score matching methods used.

RESULTS

A total of 49/71 (69%) of studies adequately reported propensity score methods overall. Matching was the most common propensity score method used in 46/71 (65%) studies, with 36/46 (78%) studies reporting matching methods adequately. Only 19/46 (41%) of matching studies reported the balance of baseline characteristics between treated and untreated subjects while 6/46 (13%) used correct statistical methods to assess balance. There were 35/46 (76%) of matching studies that explicitly used statistical methods appropriate for the analysis of matched data when estimating the treatment effect and its statistical significance.

CONCLUSION

We have proposed reporting guidelines for the use of propensity score methods in the acute care surgery literature. This is to help investigators improve the adequacy of reporting and statistical analyses when using observational data to estimate effects of treatments and exposures.

A practical guide to propensity score analysis for applied clinical research

Observational studies are often the only viable options in many clinical settings, especially when it is unethical or infeasible to randomly assign participants to different treatment régimes. In such case propensity score (PS) analysis can be applied to accounting for possible selection bias and thereby addressing questions of causal inference. Many PS methods exist, yet few guidelines are available to aid applied researchers in their conduct and evaluation of a PS analysis. In this article we give an overview of available techniques for PS estimation and application, balance diagnostic, treatment effect estimation, and sensitivity assessment, as well as recent advances. We also offer a tutorial that can be used to emulate the steps of PS analysis. Our goal is to provide information that will bring PS analysis within the reach of applied clinical researchers and practitioners.

A propensity score-matched analysis of the impact of minimum inhibitory concentration on mortality in patients with Pseudomonas aeruginosa bacteraemia treated with piperacillin/tazobactam

The Clinical and Laboratory Standards Institute (CLSI) recently re-examined Pseudomonas aeruginosa minimum inhibitory concentration (MIC) susceptibility breakpoints for piperacillin/tazobactam (TZP). The objectives of this study were to analyse the impact of elevated TZP MICs (32-64 mg/L) versus lower respective MICs on P. aeruginosa bacteraemia patient outcomes. Data were gathered from a Veterans Health Administration national clinical database on P. aeruginosa bacteraemia episodes from 2007 to 2013. Patients treated with TZP were identified, comprising 53 elevated MIC episodes and 301 low MIC episodes. Propensity score matching (1:2 ratio) utilising independent variables associated with 30-day all-cause mortality was conducted to compare the outcomes of 53 elevated MIC episodes with 106 matched low MIC episodes. Independent baseline variables associated with 30-day all-cause mortality for all 354 episodes were hyperkalaemia, elevated blood urea nitrogen, elevated temperature, hypoglycaemia, lack of urinary source and thrombocytopenia. Similar 30-day all-cause mortality was found between the two propensity-matched TZP groups (elevated MIC 24.5% vs. low MIC 22.6%; P = 0.79).

Evaluating community health centers' adoption of a new global capitation payment (eCHANGE) study protocol

Primary care patient-centered medical homes (PCMHs) are an effective healthcare delivery model. Evidence regarding the most effective payment models for increased coordination efforts is sparse. This protocol paper describes the evaluation of an Alternative Payment Methodology (APM) implemented in a subset of Oregon community health centers (CHCs), using a prospective matched observational design. The APM is a primary care payment reform intervention that changed Oregon's Medicaid payment for several CHCs from fee-for-service reimbursement to a per-member-per-month capitated payment. We will implement a difference-in-difference analytic approach to evaluate pre-post APM changes between intervention and control groups, including: 1) clinic-level outcomes, 2) patient-level clinical outcomes, and 3) patient-level econometric outcomes. Findings from the project will be of national significance, as there is a need for evidence regarding how novel payment methods might enhance PCMH capabilities and support their capacity to produce better quality and outcomes. If this capitated payment method is proven effective, study findings will inform dissemination of similar APMs nationwide.

Prognostic value of an increase in post-exercise ankle-brachial index

Prior studies have assessed the prognostic value of a decrease, not an increase, of the post-exercise ankle-brachial index (ABI) among patients with normal resting results. Thus, we sought to evaluate the prognostic significance of an increase in post-exercise ABI among these patients. From a single center vascular laboratory database between September 2005 and January 2010, we retrospectively identified 1437 consecutive patients with a normal resting ABI (1.00-1.40) and available post-exercise results. We classified them into group 1 (normal subjects; post-exercise ABI drop ⩽ 20%, 58%) and group 2 (post-exercise ABI increase, 42%) after excluding those with an ABI drop > 20% (peripheral artery disease) as they had known disease ( n=192). The primary outcome was to assess the risk of ischemic events, defined as a composite of unadjudicated death, stroke, or myocardial infraction (MACE). Associations between groups and outcomes were examined using multivariable Cox proportional hazard and propensity analyses. Both groups had similar prevalence of cardiovascular comorbidities. In unadjusted analysis, group 2 was more likely to have MACE ( p = 0.001). After adjusting for all baseline characteristics, an increase in post-exercise ABI compared to normal subjects was associated with a higher MACE (adjusted HR: 1.70, 95% CI: 1.14-2.53; p=0.009). This association stayed statistically significant after propensity matching (adjusted HR: 1.80, 95% CI: 1.17-2.76; p=0.007). This hypothesis-generating analysis showed that an increase in post-exercise ABI appears to identify a population with a higher risk for MACE. A prospective study of this association and mechanisms of risk should be conducted.

Safety of lumbar puncture in comatose children with clinical features of cerebral malaria

Objective:

We assessed the independent association of lumbar puncture (LP) and death in Malawian children admitted to the hospital with the clinical features of cerebral malaria (CM).

Methods:

This was a retrospective cohort study in Malawian children with clinical features of CM. Allocation to LP was nonrandom and was associated with severity of illness. Propensity score–based analyses were used to adjust for this bias and assess the independent association between LP and mortality.

Results:

Data were available for 1,075 children: 866 (80.6%) underwent LP and 209 (19.4%) did not. Unadjusted mortality rates were lower in children who underwent LP (15.3% vs 26.7% in the no-LP group) but differences in covariates between the 2 groups suggested bias in LP allocation. After propensity score matching, all covariates were balanced. Propensity score–based analyses showed no change in mortality rate associated with LP: by inverse probability weighting, the average risk reduction was 2.0% at 12 hours (95% confidence interval −1.5% to 5.5%, p = 0.27) and 1.7% during hospital admission (95% confidence interval −4.5% to 7.9%, p = 0.60). Undergoing LP did not change the risk of mortality in subanalyses of children with severe brain swelling on MRI or in those with papilledema.

Conclusion:

In comatose children with suspected CM who were clinically stable, we found no evidence that LP increases mortality, even in children with objective signs of raised intracranial pressure.

High Mortality in Severe Sepsis and Septic Shock Patients with Do-Not-Resuscitate Orders in East Asia

BACKGROUND

Severe sepsis is a potentially deadly illness and always requires intensive care. Do-not-resuscitate (DNR) orders remain a debated issue in critical care and limited data exist about its impact on care of septic patients, particularly in East Asia. We sought to assess outcome of severe sepsis patients with regard to DNR status in Taiwan.

METHODS

A retrospective cohort study was conducted in intensive care units (ICUs) between 2008 and 2010. All severe sepsis patients were included for analysis. Primary outcome was association between DNR orders and ICU mortality. Volume of interventions was used as proxy indicator to indicate aggressiveness of care.

RESULTS

Sixty-seven (9.4%) of 712 patients had DNR orders on ICU admission, and these patients were older and had higher disease severity compared with patients without DNR orders. Notably, DNR patients experienced high ICU mortality (90%). Multivariate analysis revealed that the presence of DNR orders was independently associated with ICU mortality (odds ratio: 6.13; 95% confidence interval: 2.66-14.10). In propensity score-matched cohort, ICU mortality rate (91%) in the DNR group was statistically higher than that (62%) in the non-DNR group (p <0.001). Regarding ICU interventions, arterial and central venous catheterization were more commonly used in DNR patients than in non-DNR patients.

CONCLUSIONS

From the Asian perspective, septic patients placed on DNR orders on ICU admission had exceptionally high mortality. In contrast to Western reports, DNR patients received more ICU interventions, reflecting more aggressive approach to dealing with this patient population. The findings in some ways reflect differences between East and West cultures and suggest that DNR status is an important confounder in ICU studies involving severely septic patients.