Variations in the use of an innovative technology by payer: The case of drug-eluting stents

Background: Despite receiving identical reimbursement for treating heart disease patients with bare metal stents (BMS) or drug-eluting coronary stents (DES), cardiologists' use of the new technology (DES) may have varied by patient payer type as DES diffused. Payer-related factors that differ between hospitals and/or differential treatment inside hospitals might explain any overall differences by payer type. Objectives: To assess the association between payer and DES use and to examine between-hospital and within-hospital variation in DES use over time. Methods: We conducted a retrospective analysis of 4.1 million hospitalizations involving DES or BMS from 2003 to 2008 Nationwide Inpatient Sample. We estimated hybrid-fixed effects logit models and calculated the adjusted within-quarter, cross-payer differences in DES use. Results: Coronary stent patients with Medicaid or without insurance were significantly less likely to receive DES than were patients with private insurance throughout the study period. The differences fluctuated over time as the popularity of DES relative to BMS increased and decreased. The within-hospital gaps paralleled the overall differences, and were largest in Q3 2003 (Medicaid: 11.9, uninsured: 10.9% points) and Q4 2008 (Medicaid: 12.8, uninsured: 20.7% points), and smallest in Q4 2004 (Medicaid: 1.4, uninsured: 1.1% points). The between-hospital adjusted differences in DES use by payer were small and rarely significant. Conclusions: We found substantial differences in DES use by payer within hospitals, suggesting physicians selected the new technology for patients in a manner associated with patients' payer type.