OBJECTIVES: In 2012, Medicare incorporated medication adherence for oral antidiabetics, renin-angiotensin system (RAS) antagonists, and statins as triple-weighted measures in star rating calculations, and health plans began receiving Quality Bonus Payments for higher star ratings. We assessed how these policy changes affected adherence to medications targeted by star rating measures and to other chronic disease medications.

METHODS: We performed interrupted time series with multivariable segmented linear regression to assess changes in monthly medication adherence from 2010-2016 using Medicare claims from a large pharmacy benefits manager. We conducted two separate sets of analyses: the first examined whether policy changes affected medication adherence for the three targeted classes, and the second assessed how policy changes affected adherence to five chronic disease classes not considered in star ratings (thiazides, beta blockers, calcium channel blockers, non-statin anti-hyperlipidemics, and levothyroxine). We compared adherence among beneficiaries who concomitantly used and did not use star rating medications.

RESULTS: We studied 240,811 Medicare beneficiaries on oral antidiabetics, 500,958 on RAS antagonists, and 471,135 on statins. Monthly medication adherence increased for all star rating and non-star rating medications after 2012 (p<0.001). Adherence for oral antidiabetics, statins, and RAS antagonists was 11.2%, 3.7%, and 8.1% higher than in the absence of policy changes, respectively (p<0.001). Non-star rating anti-hypertensive and anti-hyperlipidemic adherence increased more among those concomitantly on star ratings medications compared with those who were not (p<0.001), while levothyroxine adherence did not differ between these two groups.

CONCLUSIONS: Incentivizing medication adherence was most effective in increasing adherence to drugs targeted by policy changes and non-targeted drugs that treat the same diseases. As policymakers aim to determine the optimal number and type of quality measures without increasing administrative burden, it is important to consider that incentives can improve performance of targeted measures and related outcomes. Our findings inform future approaches to quality measure development.