P2Y12 Inhibitors Refill Gap Predicts Death in Medicare Beneficiaries on Chronic Dialysis

Background Oral P2Y12 inhibitors(P2Y12-I) are commonly used antiplatelet drugs in patients with end-stage kidney disease on chronic dialysis(ESKD). Although gaps in prescription refills are quite common in ESKD patients, it remains unclear whether P2Y12-I prescription refill patterns are associated with adverse clinical outcomes. Methods We used the United States Renal Data System(USRDS) registry for ESKD patients to capture new P2Y12-I prescriptions from 2011-2015 with the primary exposure being prescription refill patterns and the primary outcome was all-cause death. Results Of the 31,243 patients with new P2Y12-I prescription, median age 64 years, 54% male, 39% Caucasian, 37% African American, and 18% Hispanic. Observed three P2Y12-I refill patterns: continuous users(45.1%), non-continuous users(3.6%) and users with ≥30days refill gap(51.4%). Prescription refill pattern with ≥30days refill gap (vs continuous use) was associated with all-cause death, adjusted hazard ratio 1.18(95%CI:1.13–1.23). Age and race were the most important risk factors associated with prescription refill pattern-African Americans (vs Caucasians) were more likely to demonstrate ≥30days refill gap, adjusted OR 1.43(95%CI:1.36–1.51). Also, younger patients (vs. older) were more likely to demonstrate ≥30day refill gap, adjusted OR per decade is 0.90(95%CI:0.89–0.92). Conclusion Non-adherence to P2Y12-I prescriptions is quite common, disproportionately affects minorities. Younger individuals with ESKD are independently associated with a higher risk of death. The odds of having a refill gap are decreasing for older patients who are more compliant than younger patients. Future studies should investigate whether phenotyping subgroups of ESKD patients based on prescription refill patterns can help in improving adverse clinical outcomes.