Abstract 13232: Medication Use After Coronary Revascularization in a Large, Community-Based Population

Abstract

Background Medication use after coronary revascularization has been relatively low in older studies, and potential differences in adherence after CABG and PCI have been poorly studied.

Methods We studied adults receiving CABG or PCI for new onset CAD in Kaiser Permanente Northern California, a large integrated health care system caring for >3.3 million members. Longitudinal data on prescriptions in the 12 months post-revascularization were used to calculate: (1) patients who never filled a prescription, and (2) the medication possession ratio (MPR) among patients who filled ≥1 prescription. Drugs of interest were β-blockers, statins, ACE inhibitors (ACEI), and angiotensin receptor blockers (ARBs). Multivariable regression was used to compare the association of CABG and PCI on medication use and MPR, adjusting for demographics, cardiovascular history and risk factors, and comorbid conditions.

Results Between 2000-2007, 8,837 patients received CABG and 14,516 received PCI. CABG patients were older (67.3 vs 64.0 yrs; p<0.01) and less likely to have had a recent MI (11.9% vs 30.3%; p<0.01) than PCI patients. More CABG patients than PCI patients never filled a prescription for a statin (7.1% vs. 4.8%, p<0.01), or for an ACEI/ARB (29.1% vs 22.4%, p<0.01), but similar proportions never filled a prescription for a β-blocker (6.4% vs. 6.1%, p=0.35). Differences were similar in adjusted analyses. Among those who filled a prescription, CABG patients had lower MPRs than PCI patients for ACEI/ARBs (69.4% vs 77.8%, adjusted difference -8.2%, p<0.01), beta-blockers (76.1% vs 80.6%, adj. diff. -3.7%, p<0.01), and statins (82.7% vs 84.2%, adj. diff. -1.0%, p<0.01), although differences were modest. Similar trends but with attenuated differences were found for patients with diabetes or heart failure. Over the study period medication use and MPR increased in both CABG and PCI groups, and differences in use of and MPR for statins and beta blockers narrowed.

Conclusions Patients are generally less likely to use and adhere to secondary preventive medications after CABG than after PCI. Future research should examine the predictors of poor adherence, and test interventions to improve long-term adherence to these proven medication regimens.