LONG-TERM CARDIOVASCULAR PROGNOSIS OF RESISTANT HYPERTENSION DEFINED BY ADHERENCE CRITERIA IN KOREAN NATIONAL HEALTH INSURANCE SERVICE - NATIONAL SAMPLE COHORT (NHIS-NSC)

Abstract

Objective: Resistant hypertension (RH) is known to be poor in cardiovascular prognosis. But adherence to treatment was reported to be very important when to diagnose a RH. Moreover there seems to be a chance for a poor adherence itself to be an indicator of hostile factor for patient health. There are few studies to report the prognosis of RH by reflecting the aspect of adherence and comorbidities.

Design and Method: In NHIS-NSC database, based on prescription duration and the pill counts for class of antihypertensive medication (AHM) in 2002, 2535 subjects with proportion of days covered (PDC) > 0.8 and 2257 subjects without clinical cardiovascular diseases were analyzed. RH was defined as casual BP 3 140/90 mmHg with 3 AHMs including diuretics or condition in need of 4 or more AHMs. Primary end points were cardiovascular events and cardiovascular death. Adjusted covariates were age, sex, obesity, antiplatelet, hyperlipidemia, smoking, diabetes, and house income.

Results: Age was 57.7 ± 9.7 year and female was 42.7%. Systolic BP 137.7 ± 19.2 mmHg. Patients taking three or more AHMs were 8.7%. The prevalence of RH was 4.4%. Stroke, heart disease, and chronic kidney disease (CKD) were noted in 1.2%, 9.2%, and 0.8%. For all subjects adherent to AHM, age (HR:2.95) and taking AHMs 33 (HR:1.96), and heart disease history (HR:2.26) were significant factor but RH (HR:0.46, p = 0.0626) was borderline significance for protective effect. For patients in whom stroke, heart disease, and CKD were excluded, age (HR:3.34), diabetes (HR:1.55) were significant factors whereas RH (HR:0.65, p = 0.373) and AHMs 33 (HR:1.54, p = 0.1888) were not significant factor for primary end point. The proportion of the subjects taking AHM 33 were not different according to exclusion of clinical cardiovascular diseases (8.7% vs 8.4%).

Conclusions: Regardless of the exclusion of comorbid clinical cardiovascular diseases, in the subjects with good adherence, RH defined by current criteria was not associated with worse cardiovascular prognosis.