Antihypertensive effect of zofenopril plus hydrochlorothiazide versus zofenopril monotherapy in patients with essential hypertension according to their cardiovascular risk level: A post hoc analysis

BACKGROUND: International guidelines recommend the use of angiotensin-converting enzyme inhibitors, possibly in combination with other antihypertensive drugs, to treat hypertension with associated risk factors. OBJECTIVE: The aim of this study was to compare the antihypertensive effect of the combination of zofenopril plus hydrochlorothiazide versus zofenopril monotherapy in patients with essential hypertension, according to their cardiovascular risk level. METHODS: This was a post hoc analysis of a previously published efficacy and tolerability study. After a 4-week placebo washout, patients with mild to moderate essential hypertension (diastolic blood pressure [DBP] 95-115 mm Hg), aged 18 to 75 years, were randomized at a ratio of 2:1:1 to treatment with zofenopril 30 mg plus hydrochlorothiazide 12.5 mg or monotherapy with zofenopril 30 mg or hydrochlorothiazide 12.5 mg for 12 weeks in an international, multicenter, double-blind study. This period was followed by 24 weeks of open-label treatment. Systolic BP [SBP] and DBP were measured by mercury sphygmomanometry, and changes associated with treatment were calculated. Patients' cardiovascular risk was computed using the Heart Score algorithm. Patients were classified in quartiles according to distribution of cardiovascular risk level, and comparisons were limited to the zofenopril plus hydrochlorothiazide and zofenopril monotherapy treatment groups. The primary end point was change in office DBP. RESULTS: Two hundred forty-six patients (139 men, 107 women; mean [SD] age, 54 [11] years) were included in the analysis. Mean baseline cardiovascular risk was similar in the zofenopril plus hydrochlorothiazide group and the zofenopril monotherapy group (7% vs 9%). DBP and SBP reductions with treatment were significantly greater (both, P < 0.01) with combination treatment than with monotherapy for each quartile of cardiovascular risk. Cardiovascular risk reduction at the end of the 12 weeks of double-blind treatment was greater in the zofenopril plus hydrochlorothiazide group than in the zofenopril monotherapy group (1.9% vs 0.2%; P < 0.01), particularly in the group of patients with the highest cardiovascular risk at baseline (5.2% vs 2.0%). At the end of the 24-week open-label treatment period, the mean reduction in cardiovascular risk was also significantly greater in the combination treatment group than in the monotherapy group (1.4% vs 0.5%; P < 0.01). CONCLUSIONS: In these hypertensive patients, combination treatment with zofenopril plus hydrochlorothiazide was associated with a significantly greater decrease in BP compared with zofenopril monotherapy, regardless of the patient's cardiovascular risk. The difference between combination treatment and monotherapy was particularly evident for the group of patients at highest risk.