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Performance of time-dependent propensity scores: a pharmacoepidemiology case study
Wayne A Ray1, Qi Liu, Bryan E Shepherd
1Department of Health Policy (WAR), Vanderbilt University School of Medicine, Nashville, TN, USA.
Pharmacoepidemiology and Drug Safety
|November 20, 2014
Summary
Time-dependent propensity scores offer an efficient method for pharmacoepidemiologic studies with time-varying exposures. This approach may provide more precise results than marginal structural models when confounding is minimal.
Area of Science:
- Pharmacoepidemiology
- Biostatistics
- Health Services Research
Background:
- Pharmacoepidemiologic studies of acute drug effects often face challenges with time-dependent confounders.
- Marginal structural models (MSMs) can address these confounders but may lack efficiency if confounding is minimal.
- Time-dependent propensity scores (TDPS) offer a potentially more efficient alternative in such scenarios.
Purpose of the Study:
- To compare the efficiency of TDPS analyses versus MSMs in pharmacoepidemiologic research.
- To evaluate the performance of TDPS in controlling for time-dependent confounding in drug safety studies.
- To provide guidance on selecting appropriate statistical methods for time-varying exposures.
Main Methods:
- A cohort study of Tennessee Medicaid enrollees using propoxyphene and hydrocodone prescriptions (1992-2007).
- Comparison of three analytical approaches: full covariate adjustment, TDPS with inverse probability of treatment weighting, and MSMs.
- Identification and control of 22 key time-dependent covariates.
Main Results:
- Estimates for the hazard ratio of propoxyphene versus hydrocodone were similar across methods: 1.63 (full covariates), 1.65 (TDPS), and 1.64 (MSMs).
- The unadjusted hazard ratio was 0.70, highlighting the impact of confounding.
- Results remained consistent across alternative propensity score methods and MSM estimation techniques.
Conclusions:
- Time-dependent propensity scores are a valuable tool for pharmacoepidemiologic studies with time-varying exposures.
- TDPS may offer improved efficiency over MSMs when confounding along the causal pathway is limited.
- The findings support the use of TDPS for robust drug safety evaluations.
Keywords:
hydrocodonemarginal structural modelsopioidspharmacoepidemiologypropensity scorepropoxyphenetime-dependent covariatesMore Related Videos
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