Antihypertensive efficacy of the losartan/hydrochlorothiazide combination and its effect on plasma B-type natriuretic peptide in hypertensive patients uncontrolled by angiotensin II type 1 receptor antagonist-based therapy: a multicentre prospective observational study.

Background And Objectives: Although strict blood pressure (BP) control is effective in the prevention of cardiovascular events, it is often insufficient in many hypertensive patients. B-type natriuretic peptide (BNP) has been shown to be associated with cardiovascular events. We investigated the effects of the losartan/hydrochlorothiazide combination on BP and plasma BNP in hypertensive patients uncontrolled by an angiotensin II type 1 receptor antagonist (angiotensin receptor blocker [ARB])-based therapy.

Methods: In a multicentre prospective observational study, we enrolled 185 patients aged 36-79 years (mean age 63.8 years) with essential hypertension but without symptoms of heart failure who received an ARB-based therapy for ≥3 months but failed to achieve a target BP recommended by the Japanese Society of Hypertension (JSH). ARBs were switched to losartan (LOS) 50 mg/hydrochlorothiazide (HCTZ) 12.5 mg. The antihypertensive efficacy, safety, and effects of this combination on blood biochemical parameters and plasma BNP were evaluated for 12 months.

Results: Mean ± SD systolic and diastolic BP decreased from 152 ± 13/87 ± 10 mmHg to 128 ± 14/74 ± 10 mmHg, respectively, after 12 months (p < 0.001). Mean ± SD plasma BNP levels decreased significantly from 46.0 ± 83.0 pg/mL to 40.8 ± 68.0 pg/mL (p < 0.05). The percentage of patients who achieved the JSH 2004 target BP was 51% after 12 months; the percentage was 63% in elderly patients aged ≥65 years without complications, and 43% in patients with concomitant diabetes mellitus or chronic kidney disease. No association was found between a decrease in plasma BNP levels and BP, age, body mass index or estimated glomerular filtration rate. There was a significant increase in serum uric acid and a decrease in serum potassium, but both were within the range of normal values. Adverse events were observed in 8.6% of the patients.

Conclusion: Antihypertensive treatment using two types of drugs (LOS/HCTZ) with different mechanisms yielded potent antihypertensive efficacy with safety and decreased plasma BNP levels.