Medication adherence, costs, and ER visits of nurse practitioner and primary care physician patients: Evidence from three cohorts of Medicare beneficiaries

Abstract

Objective: To compare medication adherence, cost, and utilization in Medicare beneficiaries attributed to nurse practitioners (NP) and primary care physicians (PCP). Data: Medicare Part A, B, and D claims and beneficiary summary file data, years 2009-2013. Study Design: We used propensity score-weighted analyses combined with logistic regression and generalized estimating equations to test differences in good medication adherence (proportion of days covered (PDC >0.8); office-based and specialty care costs; and ER visits. Data Extraction: Beneficiaries with prescription claims for anti-diabetics, renin-angiotensin system antagonists (RASA), or statins. Principal Findings: There were no differences in good medication adherence (PDC >0.8) between NP and PCP attributed beneficiaries taking anti-diabetics or RASA. Beneficiaries taking statins had a slightly higher probability of good adherence when attributed to PCPs (74.6% vs 75.5%; P < 0.05). NP attributed beneficiaries had lower office-based and specialty care costs and were less likely to experience an ER visit across all three medication cohorts (P < 0.01). Conclusions: Examining the impact of NP and PCP provided care on outcomes beyond the primary care setting is important to the Medicare program in general but will also help practices seeking to meet benchmarks under alternative payment models that incentivize higher quality and lower costs.