Antihypertensive medication persistence and adherence among non-Hispanic Asian US patients with hypertension and fee-for-service Medicare health insurance

Background Less than 50% of non-Hispanic Asian adults taking antihypertensive medication have controlled blood pressure. Methods We compared non-persistence and low adherence to antihypertensive medication between non-Hispanic Asian and other race/ethnicity groups among US adults >= 66 years who initiated antihypertensive medication between 2011 and 2018 using a 5% random sample of Medicare beneficiaries (non-Hispanic Asian, n = 2,260; non-Hispanic White, n = 56,000; non-Hispanic Black, n = 5,792; Hispanic, n = 4,212; and Other, n = 1,423). Non-persistence was defined as not having antihypertensive medication available to take in the last 90 of 365 days following treatment initiation. Low adherence was defined as having antihypertensive medication available to take on <80% of the 365 days following initiation. Results In 2011-2012, 2013-2014, 2015-2016 and 2017-2018, the proportion of non-Hispanic Asian Medicare beneficiaries with non-persistence was 29.1%, 25.6%, 25.4% and 26.7% (p-trend = 0.381), respectively, and the proportion with low adherence was 58.1%, 54.2%, 53.4% and 51.6%, respectively (p-trend = 0.020). In 2017-2018, compared with non-Hispanic Asian beneficiaries, non-persistence was less common among non-Hispanic White beneficiaries (risk ratio 0.74 [95%CI, 0.64-0.85]), non-Hispanic Black beneficiaries (0.80 [95%CI 0.68-0.94]) and those reporting Other race/ethnicity (0.68 [95%CI, 0.54-0.85]) but not among Hispanic beneficiaries (1.04 [95%CI, 0.88-1.23]). Compared to non-Hispanic Asian beneficiaries, non-Hispanic White beneficiaries and beneficiaries reporting Other race/ethnicity were less likely to have low adherence to antihypertensive medication (relative risk 0.78 [95%CI 0.72-0.84] and 0.84 [95%CI 0.74-0.95], respectively); there was no association for non-Hispanic Black or Hispanic beneficiaries. Conclusions Non-persistence and low adherence to antihypertensive medication were more common among older non-Hispanic Asian than non-Hispanic White adults.