부산대학교 도서관

Objective To develop and test incident drug user designs for assessing cost savings from statin use in diabetics. Data Source Random 5 percent sample of Medicare beneficiaries, 2006-2008. Study Design Seven-step incident user design to assess impact of statin initiation on subsequent Medicare spending: (1) unadjusted pre/post initiation test; (2) unadjusted difference-in-difference ( DID) with comparison series; (3) adjusted DID; (4) propensity score ( PS)-matched DID with static and dynamic baseline covariates; (5) PS-matched DID by drug adherence strata; (6) PS-matched DID for high adherers controlling for healthy adherer bias; and (7) replication for ACE-inhibitor/ ARB initiators. Data Collection/Extraction Methods Subjects with prevalent diabetes and no statin use (January-June 2006) and statin initiation (July 2006-January 2008) compared to nonusers with a random 'potential-initiation' month. Monthly Medicare spending tracked 24 months pre- and post-initiation. Principal Findings Statistically significant savings in Medicare spending were observed beginning 7 months post-initiation for statins and 13 months post-initiation for ACEIs/ ARBs. However, these savings were only observed for adherent patients in steps 5 and 6. Conclusions Drug initiator designs are more robust to confounding than prevalent user designs in assessing cost-offsets from drug use but still require other adjustments and sensitivity analysis to ensure proper inference. [ABSTRACT FROM AUTHOR]