Prognosis of apparent treatment-resistant hypertension and poor adherence: a nationwide cohort study

Large-scale studies of the prognosis of resistant hypertension in Asian populations are limited, and the impact of poor adherence on clinical prognosis in patients with apparent treatment-resistant hypertension has not been studied. A nationwide cohort analysis was done utilizing the National Health Insurance Service database in Korea, covering patients who participated in health examinations from 2013 to 2018. A total of 935,002 patients were classified into apparent treatment-resistant (N = 69,372) or nonresistant (N = 865,630) hypertension based on blood pressure control and antihypertensive medication use. Medication adherence was assessed using the proportion of days covered. The primary composite outcome included all-cause mortality, myocardial infarction, stroke, and heart failure. Other outcomes were the development of atrial fibrillation and progression to end-stage renal disease (ESRD). The median follow-up duration was 6.0 (interquartile range [IQR], 4.1-7.0) years. Patients with apparent treatment-resistant hypertension were at a higher risk for the primary composite outcome than those with nonresistant hypertension (hazard ratio [HR], 1.32; 95% confidence interval [CI], 1.29-1.35). The incidence rates of ESRD were notably higher in the resistant hypertension group (HR, 3.02; 95% CI, 2.85-3.20). Among participants with resistant hypertension, 3852 (5.7%), 11,667 (17.3%), and 51,879 (77%) had poor, suboptimal, and optimal adherence, respectively. Poor medication adherence in apparent treatment-resistant hypertension was associated with a higher risk of the primary composite outcome compared to optimal adherence (HR, 1.49; 95% CI, 1.36-1.63). Apparent treatment-resistant hypertension is associated with significant cardiovascular risks in the Korean population. Poor adherence to antihypertensive medication significantly elevates the risk of adverse clinical outcomes in patients with apparent treatment-resistant hypertension, underscoring the need for stringent management of these patients.