A propensity score matched study is conducted comparing outcomes of surgical versus medical management of stable CAD. What is the primary purpose of propensity score matching in this context?
- A To increase the sample size of the observational study
- B To balance measured confounders between treatment groups, mimicking randomisation ✓
- C To eliminate unmeasured confounding and selection bias entirely
- D To determine causality with the same certainty as a randomised trial
Correct answer: B. To balance measured confounders between treatment groups, mimicking randomisation
Explanation
Propensity score methods estimate each patient's probability of receiving treatment based on measured baseline covariates; matching on this score creates treatment and control groups with similar distributions of measured confounders, approximating a randomised experiment. However, propensity score methods cannot control for unmeasured confounders (unlike true randomisation), which remains the fundamental limitation of all observational designs.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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