RENIN LEVEL AND HYDRATION STATUS IN ELDERLY HYPERTENSIVE PATIENTS

Abstract

Objective: The aim of our study was to evaluate renin level, the hydration status in elderly hypertensive patients and efficacy of amlodipine/indapamid-retard combination therapy. Design and method: 40 patients (age 62 years, male 20%, AH duration 9 years, obesity 63%, dyslipidemia 53%) with uncomplicated AH were enrolled to open single-center study. All patients were drug-naïve or have 2-day wash-out period from non-effective monotherapy. Bioimpedance was measured using a 50 KHz single-frequency bioimpedance vector analyzer (BIVA), (Medass, Russia). Hydration was evaluated based on the impedance vector constructed in the coordinates of the active resistance, reactance and patients height. Direct renin plasma concentration was measured by immunoassay analysis. All patients were treated with combination of amlodipine (5 mg) and indapamide-retard (1,5 mg) for 12 weeks. If BP was >140/90 mmHg after 4 weeks up-titration of amlodipine to 10 mg was done. All methods were performed twice - at screening and after 12-week treatment period. Results: baseline systolic BP was 165 [148; 171] mmHg and diastolic BP was 98 [80; 107] mmHg. 33% of patients has isolated systolic AH. Mean pulse pressure was 67 [49; 71] mmHg. 55% of patients has renin less than lower normal limit, 43% - within normal ranges, 2% had high-renin hypertension. Active resistance by BIVA was 455 [385; 529] Om, phase angle - 6.3 [5.3; 7.2]. Hyperhydration was confirmed in 58% of study population. After 4 weeks up titration was done in 10% of patients. After 12-week treatment SBP reduced by 31 mmHg (17% from baseline, p-value 0.01), DBP reduced by 17 mmHg (18% from baseline, p-value 0.02). 93% of patients achieved target blood pressure. Significant changes in renin level were not found. Mean active resistance increased to 475 [413; 525] and phase angle - to 6.9 [5.7; 7.4], so overhydrated status was observed in 38% of patients. Conclusions: prevalence of low-renin AH in elderly patients is very high, the combination of two anti-volume drugs (calcium channel blocker and thiazide diuretic) is effective in 93% of patients. BIVA could be considered as instrument for hydration status evaluation.