Trends and Predictors of Antihypertensive Medication Adherence in Commercially Insured Adults under 65 (2018–2023)

Understanding class‐specific antihypertensive adherence is crucial for optimizing hypertension management. This retrospective cohort study analyzed adherence to antihypertensive medication among commercially insured adults (18–64 years) from 2018 to 2023 using Merative MarketScan data. Adherence was defined as the proportion of days covered (PDC) ≥ 80%. Among 2 770 855 hypertensive patients with single‐pill therapy, the majority were older (43% aged 55–64 years) and predominantly male (53%). The South had the highest prevalence of hypertension (53%). Overall adherence improved significantly from 56.61% in 2018–2019 to 75.55% in 2022–2023 across all medication classes. Patients receiving angiotensin‐converting enzyme inhibitor/angiotensin receptor blocker (ACEi/ARB) combination therapies had the highest adherence rate (79.18%), while diuretics (67.58%) and “Other Drugs” (57.38%) had the lowest in 2022–2023. Logistic regression showed that younger patients (18–34 years) were significantly less adherent than older adults (OR = 0.434, 95% CI: 0.420–0.448). Males were more likely to adhere than females (OR = 1.142, 95% CI: 1.129–1.156). Regional variations were notable, with patients in the Northeast exhibiting 15% higher adherence than those in the West. Insurance types also influenced adherence, with managed care plan enrollees showing better adherence than those in fee‐for‐service plans (OR = 1.165, 95% CI: 1.151–1.179). Surprisingly, prescription refill monitoring reduced adherence, decreasing odds by 52% (OR = 0.482, 95% CI: 0.470–0.490). Monotherapy and combination therapy users differed significantly across all demographics ( p < 0.0001). Higher comorbidity burden correlated with lower adherence, with diabetes being most prevalent among users of diuretics (12.88%), beta‐blockers (12.8%), and other antihypertensives (26.01%). These findings highlight the multifaceted barriers to antihypertensive adherence and emphasize the need for targeted interventions that address medication‐specific and patient‐specific factors.