High-dimensional propensity scores for empirical covariate selection in secondary database studies: Planning, implementation, and reporting

Comparative effectiveness of robot-assisted vs. open prostatectomy: a real-life nationwide study

OBJECTIVES

To compare long-term progression-free survival (PFS) and overall survival (OS) between patients undergoing robot-assisted radical prostatectomy (RARP) and open radical prostatectomy (ORP).

MATERIALS AND METHODS

A cohort study was designed in the French nationwide claims database with a follow-up of 5 to 8 years. All men undergoing surgery for prostate cancer between 2012 and 2015 were selected. RARP cohort included all men (n = 10,040) from hospitals using a robot for at least 95% of their surgeries. ORP cohort included all men (n = 17,911) from hospitals without robot equipment. PFS and OS were compared using Cox proportional hazards model for 1:1 matched patients on high-dimensional propensity score (hdPS), and for all patients adjusted on inverse probability treatment weighting (IPTW) using the hdPS.

RESULTS

5,677 men could be matched with a median follow-up of 6.7 years. PFS and OS were longer with RARP compared to ORP (HR = 0.85 [95%CI: 0.79-0.91, p < 0.001] and 0.79 [0.68-0.92, p = 0.003], respectively). Index hospitalisation duration was shorter for RARP (6.7 ± 4.0 days vs. 9.9 ± 5.0 days, p < 0.01). At follow-up, care for urinary incontinence and erectile dysfunction were less frequent with RARP (29.7% vs. 37.3%; p < 0.01 and 52.1% vs. 56.3%; p < 0.01, respectively). Results were similar with all patients after IPTW adjustment except no difference for erectile dysfunction care.

CONCLUSION

Compared to ORP, RARP performs better with respect to long-term survival outcomes and urinary complications.

TRIAL REGISTRATION

ENCePP (EUPAS33290).

CLINICALTRIALS

gov (NCT04587284).

Risk of New-Onset Diabetes Before and During the COVID-19 Pandemic: A Real-World Cohort Study

BACKGROUND

Studies of new-onset diabetes as a post-acute sequela of SARS-CoV-2 infection are difficult to generalize to all socio-demographic subgroups.

OBJECTIVE

To study the risk of new-onset diabetes after SARS-CoV-2 infection in a socio-demographically diverse sample.

DESIGN

Retrospective cohort study of electronic health record (EHR) data available from the OneFlorida + clinical research network within the National Patient-Centered Clinical Research Network (PCORnet).

SUBJECTS

Persons aged 18 or older were included as part of an Exposed cohort (positive SARS-CoV-2 test or COVID-19 diagnosis between 1 March 2020 and 29 January 2022; n = 43,906), a contemporary unexposed cohort (negative SARS-CoV-2 test; n = 162,683), or an age-sex matched historical control cohort (index visits between 2 Mar 2018 and 30 Jan 2020; n = 40,957).

MAIN MEASURES

The primary outcome was new-onset type 2 diabetes ≥ 30 days after index visit. Hazard ratios and cases per 1000 person-years of new-onset diabetes were studied using target trial approaches for observational data. Associations were reported by sex, race/ethnicity, age, and hospitalization status subgroups.

KEY RESULTS

The sample was 62% female, 21.4% non-Hispanic Black, and 21.4% Hispanic; mean age was 51.8 (SD, 18.9) years. Relative to historical controls (cases, 28.2 [26.0-30.5]), the unexposed (HR, 1.28 [95% CI, 1.18-1.39]; excess cases, [5.1-10.3]), and exposed cohorts (HR, 1.64 [95% CI, 1.50-1.80]; excess cases, 17.3 [13.7-20.8]) had higher risk of new-onset T2DM. Relative to the unexposed cohort, the exposed cohort had a higher risk (HR, 1.28 [1.19-1.37]); excess cases, 9.5 [6.4-12.7]). Findings were similar across subgroups.

CONCLUSION

The pandemic period was associated with increased T2DM cases across all socio-demographic subgroups; the greatest risk was observed among individuals exposed to SARS-CoV-2.

How Effective Are Machine Learning and Doubly Robust Estimators in Incorporating High-Dimensional Proxies to Reduce Residual Confounding?

BACKGROUND

Residual confounding presents a persistent challenge in observational studies, particularly in high-dimensional settings. High-dimensional proxy adjustment methods, such as the high-dimensional propensity score (hdPS), are widely used to address confounding bias by incorporating proxies for unmeasured confounders. Extensions of hdPS have integrated machine learning, such as LASSO and super learner (SL), and doubly robust estimators, such as targeted maximum likelihood estimation (TMLE). However, the comparative performance of these methods, especially under different learner configurations and high-dimensional proxies, remains unclear.

METHOD

We conducted plasmode simulations to evaluate the performance of standard methods, SL, TMLE, and double cross-fit TMLE (DC-TMLE) under varying exposure and outcome prevalence scenarios. Learner libraries included: 1 learner (logistic regression), 3 learners (logistic regression, MARS, and LASSO), and 4 learners (adding XGBoost, a non-Donsker learner). Metrics included bias, coverage, and variability.

RESULTS

Methods without proxies exhibited the highest bias and poorest coverage, highlighting the critical role of proxies in confounding adjustment. Standard methods incorporating high-dimensional proxies showed robust performance, achieving low bias and near-nominal coverage. TMLE and DC-TMLE reduced bias but exhibited worse coverage compared to standard methods, particularly with larger learner libraries. Notably, DC-TMLE, expected to address under-coverage issues, failed to perform adequately in high-dimensional settings with non-Donsker learners, further emphasizing the instability introduced by complex libraries.

CONCLUSION

Our findings underscore the utility of high-dimensional proxies in standard methods and the importance of tailoring learner configurations in SL and TMLE to ensure reliable confounding adjustment in high-dimensional contexts.

Association Between Use of WATCHMAN Device and 1-Year Mortality Using High-Dimensional Propensity Scores to Reduce Confounding

BACKGROUND

Previous observational studies showed left atrial appendage occlusions with the WATCHMAN device reduced 1-year mortality, which conflicted with evidence generated from randomized controlled trials. We proposed to use the high-dimensional propensity score (hdPS) to assist in nonactive comparator selection (prevalent user of medication) and compared 1-year mortality between patients with atrial fibrillation who received the WATCHMAN device (percutaneous left atrial appendage occlusion device [pLAAO]) and direct oral anticoagulants in 2 matched cohorts based on (1) traditional propensity score (PS) and (2) integrating traditional PS with information learned from hdPS.

METHODS

Patients entered the cohort once diagnosed with atrial fibrillation in the 15% of Medicare fee-for-service claims database from 2011 to 2018. Patients could enter the study cohort upon receiving WATCHMAN or at an outpatient visit with an atrial fibrillation diagnosis, respectively. We used PS matching with a 1:3 ratio for patients in pLAAO and direct oral anticoagulant groups. In cohort 2, we implemented a multistep approach with information learned from hdPS. The Cox proportional hazards model was used to estimate hazard ratios of outcomes with 95% CIs.

RESULTS

In cohort 1, we identified 1159 and 3477 patients in the pLAAO and direct oral anticoagulant groups with a mean age of 78.1 versus 77.5 years, 44.9% versus 40.8% of women, and a 1-year mortality rate of 8.02 versus 8.97/100 person-years (hazard ratio, 0.87 [95% CI, 0.69-1.09]). With the support of hdPS, in cohort 2, we excluded patients with malignant cancer and added frailty score in the PS model. We identified 953 and 2859 patients in the pLAAO and direct oral anticoagulant groups with a mean age of 78.1 versus 77.9 years, 47.2% versus 46.1% of women, and a 1-year mortality rate of 7.45 and 7.69/100 person-years (hazard ratio, 0.95 [95% CI, 0.73-1.24]).

CONCLUSIONS

No association was found between pLAAO and 1-year mortality, which is consistent with existing evidence from randomized controlled trials. The hdPS approach provides an opportunity to improve nonactive comparator selection in traditional PS analysis.

Nonbenzodiazepine hypnotics and police-reported motor vehicle crash risk among older adults: a sequential target trial emulation

Nonbenzodiazepine hypnotics ("Z-drugs") are prescribed for insomnia but might increase the risk of motor vehicle crash (MVC) among older adults through prolonged drowsiness and delayed reaction times. We estimated the effect of initiating Z-drug treatment on the 12-week risk of MVC in a sequential target trial emulation. After linking New Jersey driver licensing and police-reported MVC data to Medicare claims, we emulated a new target trial each week (July 1, 2007, to October 7, 2017) in which Medicare fee-for-service beneficiaries were classified as Z-drug-treated or untreated at baseline and followed for an MVC. We used inverse probability of treatment and censoring-weighted pooled logistic regression models to estimate risk ratios (RRs) and risk differences with 95% bootstrap confidence limits (CLs). There were 257 554 person-trials, of which 103 371 were Z-drug-treated and 154 183 untreated, giving rise to 976 and 1249 MVCs, respectively. The intention-to-treat RR was 1.06 (95% CL, 0.95-1.16). For the per-protocol estimand, there were 800 MVCs and 1241 MVCs among treated and untreated person-trials, respectively, suggesting a reduced MVC risk (RR, 0.83; 95% CL, 0.74-0.92) with sustained Z-drug treatment. Z-drugs should be prescribed to older patients judiciously but not withheld entirely over concerns about MVC risk. This article is part of a Special Collection on Pharmacoepidemiology.

Body mass index changes and their association with SARS-CoV-2 infection: a real-world analysis

OBJECTIVE

To study body mass index (BMI) changes among individuals aged 18-99 years with and without SARS-CoV-2 infection.

SUBJECTS/METHODS

Using real-world data from the OneFlorida+ Clinical Research Network of the National Patient-Centered Clinical Research Network, we compared changes over time in BMI in an Exposed cohort (positive SARS-CoV-2 test between March 2020-January 2022), to a contemporary Unexposed cohort (negative SARS-CoV-2 tests), and an age/sex-matched Historical control cohort (March 2018-January 2020). BMI (kg/m2) was retrieved from objective measures of height and weight in electronic health records. We used target trial approaches to estimate BMI at start of follow-up and change per 100 days of follow-up for Unexposed and Historical cohorts relative to the Exposed cohort by categories of sex, race & ethnicity, age, and hospitalization status.

RESULTS

The study sample consisted of 249,743 participants (19.2% Exposed, 61.5% Unexposed, 19.3% Historical cohort) of whom 62% were women, 21.5% Non-Hispanic Black, 21.4% Hispanic and 5.6% Non-Hispanic other and had an average age of 51.9 years (SD: 18.9). At start of follow-up, relative to the Unexposed cohort (mean BMI: 29.3 kg/m2 [95% CI: 29.1, 29.4]), the Exposed (0.07 kg/m2 [95% CI; 0.01, 0.12]) had higher mean BMI and Historical controls (-0.20 kg/m2 [95% CI; -0.25, -0.15]) had lower mean BMI. Over 100 days, BMI did not change (0 kg/m2 [95% CI: -0.03, 0.03]) for the Exposed cohort, decreased (-0.04 kg/m2 [95% CI; -0.05, -0.02]) for the Unexposed cohort and increased (0.03 kg/m2 [95% CI; 0.01, 0.04]) for the Historical cohort. Observed differences in BMI at start of follow-up and over 100 days were consistent between Unexposed and Exposed cohorts for most subgroups, except at start of follow-up period among Males and those 65 years or older who had lower BMI among Exposed.

CONCLUSIONS

In a diverse real-world cohort of adults, mean BMI of those with and without SARS-CoV2 infection varied in their trajectories. The mechanisms and implications of weight retention following SARS-CoV-2 infection remain unclear.

Hydrochlorothiazide Use and Risk of Skin Cancer: A Population-Based Retrospective Cohort Study

PURPOSE

Hydrochlorothiazide (HCTZ) exposure has been linked to increased skin cancer in Caucasian (white) populations, especially squamous cell carcinoma (SCC), but not basal cell carcinoma (BCC). This study aimed to evaluate and compare skin cancer risks associated with HCTZ- and other antihypertensives use.

METHODS

This retrospective cohort study utilized Taiwan's National Health Insurance Research Database. We identified patients aged 20 years and older, newly receiving antihypertensive medications between 2004 and 2015. We calculated the medication possession ratio (MPR) for the first 2 years of treatment to determine patient eligibility and treatment classification, whereby only patients with MPR above 80% were included. These were subsequently categorized by the type of antihypertensives they received, namely HCTZ, other thiazide diuretics, non-thiazide diuretics or non-diuretic antihypertensives. Cox proportional hazards model was used to evaluate skin cancer risks, and these were then classified as SCC or BCC.

RESULTS

Our study included 41 086, 27 402, 19 613, and 856 782 patients receiving HCTZ, other thiazide diuretics, non-thiazide diuretics, and non-diuretic antihypertensives, respectively. We found BCC risks were similar when comparing HCTZ with other thiazides (adjusted hazard ratio: 0.84; 95% CI: 0.54-1.33), non-thiazide diuretics (0.93; 0.51-1.67), and non-diuretic antihypertensives (0.91; 0.66-1.26). We observed a higher SCC risk in the HCTZ group, compared to other thiazides (1.24; 0.74-2.08), non-thiazide diuretics (1.32; 0.70-2.51), and non-diuretic antihypertensives (1.23; 0.87-1.73), although the confidence intervals (CIs) were wide and crossed the null.

CONCLUSIONS

We concluded that skin cancer need not be of major concern to physicians when prescribing antihypertensives for an Asian population.

Application of High-Dimensional Propensity Score Methods to the National Health and Aging Trends Study

BACKGROUND

High-dimensional propensity scoring (HDPS) is a method for empirically identifying potential confounders within large healthcare databases such as administrative claims data. However, this method has not yet been applied to large national health surveys such as the National Health and Aging Trends Study (NHATS), an ongoing nationally representative survey of older adults in the United States and important resource in gerontology research.

METHODS

In this Research Practice article, we present an overview of HDPS and describe the specific data transformation steps and analytic considerations needed to apply it to national health surveys. We applied HDPS within NHATS to investigate the association between self-reported visual difficulty and incident dementia, comparing HDPS to conventional confounder selection methods.

RESULTS

Among 7 207 dementia-free NHATS Wave 1 respondents, 528 (7.3%) had self-reported visual difficulty. In an unadjusted discrete time proportional hazards model accounting for the complex survey design of NHATS, self-reported visual difficulty was strongly associated with incident dementia (odds ratio [OR] 2.34, 95% confidence interval [CI]: 1.95-2.81). After adjustment for standard investigator-selected covariates via inverse probability weighting, the magnitude of this association decreased, but evidence of an association remained (OR 1.44, 95% CI: 1.11-1.85). Adding 75 HDPS-prioritized variables to the investigator-selected propensity score model resulted in further attenuation of the association between visual impairment and dementia (OR 0.94, 95% CI: 0.70-1.23).

CONCLUSIONS

HDPS can be successfully applied to national health surveys such as NHATS and may improve confounder adjustment. We hope developing this framework will encourage future consideration of HDPS in this setting.

Phosphodiesterase-5 Inhibitors and Dementia Risk: A Real-World Study

INTRODUCTION

Biological and scarce epidemiological evidence suggested that phosphodiesterase-5 inhibitors (PDE5i) might reduce dementia risk. We aimed to examine the association between PDE5i and dementia using real-world data.

METHODS

Two retrospective cohorts within the database of Clalit, the largest healthcare provider in Israel (2005-2023), were studied. The first cohort included new daily users, older than 50 years of age, of low-dose tadalafil, prescribed for benign prostatic hypertrophy (BPH), propensity-score matched to new-users of alpha-1 blockers, and analyzed using 2-year lag time. The second cohort included patients with erectile dysfunction, with/without any PDE5i treatment, using time-dependent analysis. Individuals in the cohorts were followed through May 2023 for the occurrence of dementia.

RESULTS

The first cohort included 5,204 tadalafil initiators propensity-score matched to 18,565 alpha-1 blockers initiators. There was no association between tadalafil use and dementia risk, HR = 0.99 (95% CI: 0.88-1.12), p = 0.927. Similar results were obtained in a competing risk analysis, and in a sensitivity analysis in which we restricted the cohort to patients older than 60 years at cohort entry. The second cohort of 133,336 patients with erectile dysfunction included new users and nonusers of any PDE5i. In a mean follow-up of 7.9 years, 8,631 patients were newly diagnosed with dementia. In a time-dependent multivariable analysis, PDE5i use was not associated with reduced dementia risk, HR = 0.95 (95% CI: 0.86-1.04). Results were not changed in sensitivity analyses (patients older than 60 years or stratification by PDE5i type).

CONCLUSION

This study suggests that the use of PDE5 inhibitors is not associated with decreased risk of dementia.

Is the long-term poor prognosis of acute myocardial infarction in patients with mental illness mediated through their poor adherence with recommended healthcare?

BACKGROUND

Compared with patients without evidence of psychiatric symptoms, those with mental disorders experience reduced adherence with recommended healthcare and poorer clinical outcomes. This study aimed to evaluate whether the worse prognosis of patients with mental disorders after experiencing acute myocardial infarction could be fully or partially mediated by their reduced adherence to recommended healthcare.

METHODS

In this retrospective cohort population-based study, 103 389 residents in the Italian Lombardy Region who experienced acute myocardial infarction in 2007-19 were identified. Among them, 1549 patients with severe mental illness (SMI) were matched with five cohort members without evidence of mental disorders (references). Recommended healthcare (cardiac medicaments and selected outpatient services) was evaluated in the year after the date of index hospital discharge. The first occurrences of cardiovascular (CV) hospital admissions and any-cause-death were considered as endpoints. Mediation analysis was performed to investigate whether post-discharge use of recommended healthcare may be considered a mediator of the relationship between healthcare exposure and endpoints occurrence.

RESULTS

Compared with references, patients with SMI had lower adherence with recommended healthcare and adjusted risk excesses of 39% and 73% for CV hospitalizations and all-cause mortality. Mediation analysis showed that 4.1% and 11.3% of, respectively, CV hospitalizations and deaths occurred among psychiatric patients was mediated by their worse adherence to specific healthcare.

CONCLUSION

The reduced use of recommended outpatient healthcare by patients with SMI had only a marginal effect on their worse prognosis. Other key factors mediating the prognostic gap between patients with and without mental disorders should be investigated.

Comparing major and mild cognitive impairment risks in older type-2 diabetic patients: a Danish register-based study on dipeptidyl peptidase-4 inhibitors vs. glucagon-like peptide-1 analogues

INTRODUCTION

The prevalence of major and mild cognitive impairment (CI) in type-2 diabetes older patients is 15-25% and 30-60%, respectively, thus affecting quality of life and health outcomes. There is, therefore, the need of head-to-head studies aiming at identifying the optimal treatment for individuals with type-2 diabetes at increased risk of mild and major CI. This study focuses on the risk of developing mild and major CI in Danish patients treated with dipeptidyl peptidase-4 inhibitors (DPP-4i) and glucagon-like peptide-1 analogues (GLP-1a) using administrative and healthcare registers.

METHODS

An active comparator design with a 3-year follow-up period was used. The main outcome was the hospital admission with a diagnosis of mild CI or major CI. Multivariate Cox Regression analysis was performed using the high-dimensional propensity score to obtain adjusted Hazard Ratio (HR) estimates. Inverse probability of treatment weighting (IPTW) and marginal structured model were used to calculate risk differences while accounting for the variations of confounders throughout the follow-up period.

RESULTS

Our results show a significant higher risk of major CI between DPP-4i and GLP-1a in unadjusted [HR (95% CI) = 3.13 (2.45-4.00), p < 0.001] and adjusted analyses [HR (95% CI) = 1.58 (1.22-2.06), p = 0.001]. No statistically significant differences were observed for mild CI. IPTW resulted stable throughout the follow-up period. Marginal structure modeling (β (95% CI) = 0.022 (0.020-0.024), p < 0.001) resulted in a higher risk of major CI for DPP-4i when compared to GLP-1a.

DISCUSSION

DPP-4i was associated with an increased risk of developing major CI when compared to GLP-1a among older individuals with type-2 diabetes.

Risk equations for prosthetic joint infections (PJIs) in UK: a retrospective study using the Clinical Practice Research Datalink (CPRD) AURUM and GOLD databases

BACKGROUND

Prosthetic joint infections (PJIs) are a serious negative outcome of arthroplasty with incidence of about 1%. Risk of PJI could depend on local treatment policies and guidelines; no UK-specific risk scoring is currently available.

OBJECTIVE

To determine a risk quantification model for the development of PJI using electronic health records.

DESIGN

Records in Clinical Practice Research Datalink (CPRD) GOLD and AURUM of patients undergoing hip or knee arthroplasty between January 2007 and December 2014, with linkage to Hospital Episode Statistics and Office of National Statistics, were obtained. Cohorts' characteristics and risk equations through parametric models were developed and compared between the two databases. Pooled cohort risk equations were determined for the UK population and simplified through stepwise selection.

RESULTS

After applying the inclusion/exclusion criteria, 174 905 joints (1021 developed PJI) were identified in CPRD AURUM and 48 419 joints (228 developed PJI) in CPRD GOLD. Patients undergoing hip or knee arthroplasty in both databases exhibited different sociodemographic characteristics and medical/drug history. However, the quantification of the impact of such covariates (coefficients of parametric models fitted to the survival curves) on the risk of PJI between the two cohorts was not statistically significant. The log-normal model fitted to the pooled cohorts after stepwise selection had a C-statistic >0.7.

CONCLUSIONS

The risk prediction tool developed here could help prevent PJI through identifying modifiable risk factors pre-surgery and identifying the patients most likely to benefit from close monitoring/preventive actions. As derived from the UK population, such tool will help the National Health Service reduce the impact of PJI on its resources and patient lives.

A methodological review of the high-dimensional propensity score in comparative-effectiveness and safety-of-interventions research finds incomplete reporting relative to algorithm development and robustness

OBJECTIVES

The use of secondary databases has become popular for evaluating the effectiveness and safety of interventions in real-life settings. However, the absence of important confounders in these databases is challenging. To address this issue, the high-dimensional propensity score (hdPS) algorithm was developed in 2009. This algorithm uses proxy variables for mitigating confounding by combining information available across several healthcare dimensions. This study assessed the methodology and reporting of the hdPS in comparative effectiveness and safety research.

STUDY DESIGN AND SETTING

In this methodological review, we searched PubMed and Google Scholar from July 2009 to May 2022 for studies that used the hdPS for evaluating the effectiveness or safety of healthcare interventions. Two reviewers independently extracted study characteristics and assessed how the hdPS was applied and reported. Risk of bias was evaluated with the Risk Of Bias In Non-randomised Studies - of Interventions (ROBINS-I) tool.

RESULTS

In total, 136 studies met the inclusion criteria; the median publication year was 2018 (Q1-Q3 2016-2020). The studies included 192 datasets, mostly North American databases (n = 132, 69%). The hdPS was used in primary analysis in 120 studies (88%). Dimensions were defined in 101 studies (74%), with a median of 5 (Q1-Q3 4-6) dimensions included. A median of 500 (Q1-Q3 200-500) empirically identified covariates were selected. Regarding hdPS reporting, only 11 studies (8%) reported all recommended items. Most studies (n = 81, 60%) had a moderate overall risk of bias.

CONCLUSION

There is room for improvement in the reporting of hdPS studies, especially regarding the transparency of methodological choices that underpin the construction of the hdPS.

Staging and clean room: Constructs designed to facilitate transparency and reduce bias in comparative analyses of real-world data

PURPOSE

We describe constructs designed to protect the integrity of the results from comparative analyses using real-world data (RWD): staging and clean room.

METHODS

Staging involves performing sequential preliminary analyses and evaluating the population size available and potential bias before conducting comparative analyses. A clean room involves restricted access to data and preliminary results, policies governing exploratory analyses and protocol deviations, and audit trail. These constructs are intended to allow decisions about protocol deviations, such as changes to design or model specification, to be made without knowledge of how they might affect subsequent analyses. We describe an example for implementing staging with a clean room.

RESULTS

Stage 1 may involve selecting a data source, developing and registering a protocol, establishing a clean room, and applying inclusion/exclusion criteria. Stage 2 may involve attempting to achieve covariate balance, often through propensity score models. Stage 3 may involve evaluating the presence of residual confounding using negative control outcomes. After each stage, check points may be implemented when a team of statisticians, epidemiologists and clinicians masked to how their decisions may affect study outcomes, reviews the results. This review team may be tasked with making recommendations for protocol deviations to address study precision or bias. They may recommend proceeding to the next stage, conducting additional analyses to address bias, or terminating the study. Stage 4 may involve conducting the comparative analyses.

CONCLUSIONS

The staging and clean room constructs are intended to protect the integrity and enhance confidence in the results of analyses of RWD.

Body mass index changes and their association with SARS-CoV-2 infection: a real-world analysis

Objective

To study body mass index (BMI) changes among individuals aged 18-99 years with and without SARS-CoV-2 infection.

Subjects/Methods

Using real-world data from the OneFlorida+ Clinical Research Network of the National Patient-Centered Clinical Research Network, we compared changes over time in BMI in an Exposed cohort (positive SARS-CoV-2 test between March 2020 - January 2022), to a contemporary Unexposed cohort (negative SARS-CoV-2 tests), and an age/sex-matched Historical control cohort (March 2018 - January 2020). Body mass index (kg/m2) was retrieved from objective measures of height and weight in electronic health records. We used target trial approaches to estimate BMI at baseline and change per 100 days of follow-up for Unexposed and Historical cohorts relative to the Exposed cohort by categories of sex, race-ethnicity, age, and hospitalization status.

Results

The study sample consisted of 44,436 (Exposed cohort), 164,118 (Unexposed cohort), and 41,189 (Historical cohort). Cumulatively, 62% were women, 21.5% Non-Hispanic Black, 21.4% Hispanic and 5.6% Non-Hispanic Other. Patients had an average age of 51.9 years (SD: 18.9). At baseline, relative to the Exposed cohort (mean BMI: 29.3 kg/m2 [95%CI: 29.0, 29.7]), the Unexposed (-0.07 kg/m2 [95%CI; -0.12, -0.01]) and Historical controls (-0.27 kg/m2 [95%CI; -0.34, -0.20]) had lower BMI. Relative to no change in the Exposed over 100 days (0.00 kg/m2 [95%CI; -0.03,0.03]), the BMI of those Unexposed decreased (-0.04 kg/m2 [95%CI; -0.06, -0.01]) while the Historical cohort's BMI increased (+0.03 kg/m2 [95%CI;0.00,0.06]). BMI changes were consistent between Exposed and Unexposed cohorts for most population groups, except at start of follow-up period among Males and those 65 years or older, and in changes over 100 days among Males and Hispanics.

Conclusions

In a diverse real-world cohort of adults, mean BMI of those with and without SARS-CoV2 infection varied in their trajectories. The mechanisms and implications of weight retention following SARS-CoV-2 infection remain unclear.

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.

Strong instrumental variables biased propensity scores in comparative effectiveness research: A case study in oncology

BACKGROUND AND OBJECTIVES

Some medications require specific medical procedures in the weeks before their start. Such procedures may meet the definition of instrumental variables (IVs). We examined how they may influence treatment effect estimation in propensity score (PS)-adjusted comparative studies, and how to remedy.

STUDY DESIGN AND SETTING

Different covariate assessment periods (CAPs) did and did not include the month preceding treatment start were used to compute PS in the French claims database (Sytème National des Données de Santé-SNDS), and 1:1 match patients with metastatic castration resistant prostate cancer initiating abiraterone acetate or docetaxel. The 36-month survival was assessed.

RESULTS

Among 1, 213 docetaxel and 2, 442 abiraterone initiators, the PS distribution resulting from the CAP [-12; 0 months] distinctly separated populations (c = 0.93; 273 matched pairs). The CAPs [-12;-1 months] identified 765 pairs (c = 0.81). Strong docetaxel treatment predictors during the month before treatment start were implantable delivery systems (1% vs. 59%), which fulfilled IV conditions. The 36-month survival was not meaningfully different under the [-12; 0 months] CAP but differed by 10% points (38% vs. 28%) after excluding month -1.

CONCLUSION

In the setting of highly predictive pretreatment procedures, excluding the immediate pre-exposure time from the CAP will reduce the risk of including potential IVs in PS models and may reduce bias.