Longitudinal associations between treatment adherence patterns and blood pressure control among rural hypertensive patients in Central China: a real-world retrospective cohort study.

Background: Hypertension remains a major public health challenge in rural China, where sustained blood pressure (BP) control is often suboptimal. Although antihypertensive medication use is central to hypertension management, real-world evidence integrating treatment strategies, medication adherence, and longitudinal BP control in rural primary care settings remains limited. Time in target range (TTR) has emerged as an indicator of sustained blood pressure (BP) control, particularly relevant in community-based settings with infrequent follow-up, yet its application in routine rural primary care management remains insufficiently characterized. Methods: This real-world retrospective cohort study included 5,029 adults (≥35 years) with diagnosed hypertension who completed four consecutive quarterly follow-up visits in 2024 under China's National Basic Public Health Service Program in rural Hubei Province. BP control (<140/90 mmHg) was assessed at each visit, and annual TTR was calculated as the proportion of visits meeting the BP target (satisfactory control: TTR ≥ 75%). Medication use (none, monotherapy, combination therapy) and medication adherence (adherent, partially adherent, non-adherent) were integrated into a composite treatment-adherence exposure. Generalized estimating equation models were used to examine longitudinal associations between treatment-adherence patterns and BP control, adjusting for demographic factors, comorbidities, lifestyle variables, and time effects. Results: Among all participants, 22.1% were not taking antihypertensive medication, 58.5% were on monotherapy, and 19.4% were on combination therapy. Overall BP control rates increased modestly over four quarterly visits. Compared with no medication use, medication use with good adherence was associated with a higher likelihood of BP control [odds ratio (OR) = 1.547, 95% confidence interval (CI): 1.388-1.725], whereas medication use with poor adherence was associated with a lower likelihood of control (OR = 0.847, 95% CI: 0.735-0.975)-suggesting it may be less effective than no treatment, possibly due to irregular intake or unmeasured confounding factors. Longitudinal trends showed stable improvement in BP control among patients with good adherence, while control declined among those not receiving medication. Sex-specific analyses indicated that poor adherence was more adversely associated with BP control among men than women. Conclusion: In this rural primary care population, sustained antihypertensive medication adherence was consistently associated with better longitudinal BP control, whereas irregular or absent treatment was linked to unstable or declining control. These findings suggest that expanding medication coverage alone may be insufficient for improving hypertension outcomes in rural settings. Routine adherence assessment and targeted strategies for high-risk subgroups, particularly men and patients with diabetes, may help inform community-based hypertension management programs.