Efficacy and safety of the losartan-hydrochlorothiazide combination tablet in patients with hypertension uncontrolled by angiotensin II receptor antagonist therapy: the Aichi Research on Combination therapy for Hypertension (ARCH) Study.

BACKGROUND The guidelines recommend combination therapy for patients who are unable to achieve target BP with monotherapy; some fixed dose therapies including an angiotensin II receptor blocker (ARB) and diuretics are available in Japan. However, to date there have been few reports on this long-term treatment and the patient profiles suited for this combination remain ambiguous. METHOD The Aichi Research on Combination therapy for Hypertension Study was a multicenter, open-label, prospective observational study that investigated the efficacy and safety of 1-year treatment with the losartan-hydrochlorothiazide (HCTZ) combination tablet in patients with hypertension uncontrolled by either ARB monotherapy or combination therapy with a calcium channel blocker (CCB). An ARB was switched to a losartan-HCTZ tablet after a pre-observation period. RESULTS A total of 614 of 648 patients were evaluable (mean age, 66.3 years; 52.8% men; mean baseline blood pressure, BP, 157.7/87.9 mmHg). The BP had decreased significantly to 138.0/78.2 mmHg by month 3 (p<0.001, t-test), and 36.2% of the patients had achieved their target BP. The hypotensive effect lasted for 1 year and was found equally in the losartan-HCTZ arm and the losartan-HCTZ plus CCB arm. A stratified analysis showed significant hypotensive effects in patients with higher baseline BP, women, and patients who did not drink alcohol (p<0.001, unpaired t-test). CONCLUSION The losartan-HCTZ combination tablet was found to have an early hypotensive effect, good tolerability, and stable long-term benefits in patients with hypertension uncontrolled by ARB monotherapy or combination therapy with a CCB.