Publications by authors named "Sengwee Toh"

Clinical guidelines recommend continuation of sodium-glucose cotransporter-2 inhibitor (SGLT2i) treatment when renal function deteriorates among patients with type 2 diabetes. However, the recommendation is not currently supported by research specifically designed to compare continuation versus discontinuation of SGLT2is for patients who have received the treatment for a while before experiencing renal function deterioration. Using linked Taiwanese databases with claims and clinical data and a target trial emulation framework, we conducted a nationwide cohort study to investigate the association between SGLT2i continuation and major cardiorenal outcomes after renal function declined.

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We evaluated neural tube defect (NTD) risk associated with prescription opioid analgesic use during early pregnancy. We conducted a cohort study of liveborn singletons during 2001-2014 among nine U.S.

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Signal management, defined as the set of activities from signal detection to recommendations for action, is conducted using different data sources and leveraging data from spontaneous reporting databases (SRDs), which represent the cornerstone of pharmacovigilance. However, the exponentially increasing generation and availability of real-world data collected in longitudinal healthcare databases (LHDs), along with the rapid evolution of artificial intelligence-based algorithms and other advanced analytical methods, offers a wide range of opportunities to complement SRDs throughout all stages of signal management, especially signal detection. Integrating information derived from SRDs and LHDs may reduce their respective limitations, thus potentially enhancing post-marketing surveillance.

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Background: Pregnant women are at high risk for developing severe illness related to COVID-19. We adapted the "COVID-19 infectiOn aNd medicineS In pregnancy" (CONSIGN) study protocol as part of an international collaboration to examine medication use patterns among pregnancies in the US.

Methods: We identified eligible women aged 12-55 years with documented live-birth deliveries in the Sentinel Distributed Database who had at least one qualifying diagnosis for COVID-19 or a positive-confirmed test for SARS-CoV-2, by trimester of COVID-19 infection.

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Multiple imputation (MI) models can be improved with auxiliary covariates (AC), but their performance in high-dimensional data remains unclear. We aimed to develop and compare high-dimensional MI (HDMI) methods using structured and natural language processing (NLP)-derived AC in studies with partially observed confounders. We conducted a plasmode simulation with acute kidney injury as outcome and simulated 100 cohorts with a null treatment effect, incorporating creatinine labs, atrial fibrillation (AFib), and other investigator-derived confounders in the outcome generation.

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Introduction: This real-world study assessed the effectiveness of bebtelovimab (BEB) versus nirmatrelvir/ritonavir (NR) among outpatients with COVID-19 during the Omicron variant era.

Methods: We conducted a cohort study evaluating patients treated with BEB or NR from February to August 2022 (study period). Follow-up began the day after treatment and continued for 30 days.

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Article Synopsis
  • The study addresses the challenges of missing data in confounding variables when using real-world data, specifically in pharmaceutical research comparing cardiovascular outcomes between two types of diabetes medications in older adults.
  • Utilizing the Structural Missing Data Investigations (SMDI) toolkit, researchers analyzed the missingness patterns of important health metrics like HbA1c and BMI from electronic health records.
  • Results indicated significant missing data (63.6% for HbA1c and 16.5% for BMI) and demonstrated that missingness could be predicted and managed through statistical techniques, leading to improved estimates of medication effects.
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Article Synopsis
  • Most drug repurposing studies focus on validating existing ideas, but this study aimed to generate new hypotheses for sodium-glucose cotransporter-2 inhibitors (SGLT2i) using advanced statistical methods.
  • The researchers created a matched cohort of SGLT2i users and dipeptidyl peptidase-4 inhibitors (DPP4i) to analyze a large dataset of patient outcomes, identifying potential associations.
  • They found 18 notable signals that could indicate new uses for SGLT2i, including significant links to chronic kidney disease and anemia, which align with recent approvals but need further research for confirmation.*
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Epidemiologic studies frequently use risk ratios to quantify associations between exposures and binary outcomes. When the data are physically stored at the sites of multiple data partners, it can be challenging to perform individual-level analysis if data cannot be pooled centrally due to privacy constraints. Existing methods either require multiple file transfers between each data partner and an analysis center (eg, distributed regression) or only provide approximate estimation of the risk ratio (eg, meta-analysis).

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Background: Antidepressants are among the most commonly prescribed medications, but evidence on comparative weight change for specific first-line treatments is limited.

Objective: To compare weight change across common first-line antidepressant treatments by emulating a target trial.

Design: Observational cohort study over 24 months.

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While many pregnant individuals use prescription medications, evidence supporting product safety during pregnancy is often inadequate. Existing electronic healthcare data sources provide large, diverse samples of health plan members to allow for the study of medical product utilization during pregnancy, as well as pregnancy, maternal, and infant outcomes. The Sentinel System is a national medical product surveillance system that includes administrative claims and electronic health record databases from large national and regional health insurers.

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Objective: Partially observed confounder data pose challenges to the statistical analysis of electronic health records (EHR) and systematic assessments of potentially underlying missingness mechanisms are lacking. We aimed to provide a principled approach to empirically characterize missing data processes and investigate performance of analytic methods.

Methods: Three empirical sub-cohorts of diabetic SGLT2 or DPP4-inhibitor initiators with complete information on HbA1c, BMI and smoking as confounders of interest (COI) formed the basis of data simulation under a plasmode framework.

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Purpose: Our objective is to describe how the U.S. Food and Drug Administration (FDA)'s Sentinel System implements best practices to ensure trust in drug safety studies using real-world data from disparate sources.

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Article Synopsis
  • Researchers faced challenges in using claims data for studying bariatric surgery because they often didn't have body mass index (BMI) measurements.
  • They created a new scoring system, called B3S3, using machine learning to predict pre-operative BMI based on claims data and health records from patients who had bariatric surgery.
  • The B3S3 scoring system performed really well in testing and is a helpful tool for researchers to better understand the effects of obesity on bariatric surgery outcomes.
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Article Synopsis
  • Lasso regression is a common method for estimating propensity scores in large healthcare studies, but undersmoothing can lead to improved confounding control while risking non-overlap in covariate distributions.
  • The study explores how to choose the right level of undersmoothing for Lasso PS models using simulations and a technique called collaborative-controlled targeted learning.
  • Findings indicate that this approach can effectively reduce bias in treatment effect estimates and highlight the importance of cross-fitting to maintain covariate overlap when using undersmoothed models.
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Objectives: Partially observed confounder data pose a major challenge in statistical analyses aimed to inform causal inference using electronic health records (EHRs). While analytic approaches such as imputation are available, assumptions on underlying missingness patterns and mechanisms must be verified. We aimed to develop a toolkit to streamline missing data diagnostics to guide choice of analytic approaches based on meeting necessary assumptions.

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Objectives: Automated phenotyping algorithms can reduce development time and operator dependence compared to manually developed algorithms. One such approach, PheNorm, has performed well for identifying chronic health conditions, but its performance for acute conditions is largely unknown. Herein, we implement and evaluate PheNorm applied to symptomatic COVID-19 disease to investigate its potential feasibility for rapid phenotyping of acute health conditions.

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Biological plausibility suggests that fluoroquinolones may lead to mitral valve regurgitation or aortic valve regurgitation (MR/AR) through a collagen degradation pathway. However, available real-world studies were limited and yielded inconsistent findings. We estimated the risk of MR/AR associated with fluoroquinolones compared with other antibiotics with similar indications in a population-based cohort study.

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