Duration of initial antihypertensive prescription and medication adherence: A cohort study among 203,259 newly diagnosed hypertensive patients

•Duration of initial anti-HT prescription and medication adherence was evaluated.•A large sample of Chinese patients were followed up to up to five years.•Shorter duration of first anti-HT prescriptions related to poorer adherence.•Longer duration of prescriptions might be better for medication-naïve patients.

BackgroundOptimal adherence with antihypertensive medications is crucial to prevent hypertension-related complications. This study evaluated whether the duration of initial antihypertensive prescription is associated with better medication adherence in a large sample of Chinese hypertensive patients.Methods and resultsFrom a validated clinical database which consists of all patients in the public healthcare sector in Hong Kong, all patients on their first-ever antihypertensive agent from 2001 to 2005 (N = 203,259) were included and followed-up for 12 months (and up to 5 years in separate analyses). The average age was 58.7 years (SD 17.3), and the overall rate of optimal adherence (as measured by having the Proportion of Days Covered ≥ 0.80) was 32.4%. The proportion of patients whose initial prescriptions lasted for ≤ 6 days; 7-14 days; 15-28 days and ≥ 29 days was 23.7%, 24.3%, 15.1% and 37.0%, respectively. The corresponding proportion of optimal adherence was 18.1%, 20.1%, 31.0% and 50.3%. The binary logistic regression analysis showed that after controlling for age, sex, socioeconomic status, service type, drug class, and district of residence, those whose initial prescription was 7-14 days (adjusted odds ratio [AOR] = 1.17, 95% C.I. 1.12-1.22); 15-28 days (AOR = 1.90, 95% C.I. 1.82-1.99) and ≥ 29 days (AOR = 4.13, 95% C.I. 3.96-4.31) were significantly more likely to be adherent than those who were prescribed for ≤ 6 days (all p < 0.001). These findings remained significant in separate analyses where the period of follow-up was extended to 5 years.ConclusionsShorter duration of first antihypertensive prescriptions was associated with poorer medication adherence, and this practice should be avoided if possible.