Progress report on the first sub-Saharan Africa trial of newer versus older antihypertensive drugs in native black patients

Abstract

Background: The epidemic surge in hypertension in sub-Saharan Africa is not matched by clinical trials of antihypertensive agents in Black patients recruited in this area of the world. We mounted the Newer versus Older Antihypertensive agents in African Hypertensive patients (NOAAH) trial to compare, in native African patients, a single-pill combination of newer drugs, not involving a diuretic, with a combination of older drugs including a diuretic.

Methods: Patients aged 30 to 69 years with uncomplicated hypertension (140 to 179/90 to 109 mmHg) and ≤2 associated risk factors are eligible. After a four week run-in period off treatment, 180 patients have to be randomized to once daily bisoprolol/hydrochlorothiazide 5/6.25 mg (R) or amlodipine/valsartan 5/160 mg (E). To attain blood pressure <140/<90 mmHg during six months, the doses of bisoprolol and amlodipine should be increased to 10 mg/day with the possible addition of up to 2 g/day α-methyldopa.

Results: At the time of writing of this progress report, of 206 patients enrolled in the run-in period, 140 had been randomized. At randomization, the R and E groups were similar (P ≥ 0.11) with respect to mean age (50.7 years), body mass index (28.2 kg/m(2)), blood pressure (153.9/91.5 mmHg) and the proportions of women (53.6%) and treatment naïve patients (72.7%). After randomization, in the R and E groups combined, blood pressure dropped by 18.2/10.1 mmHg, 19.4/11.2 mmHg, 22.4/12.2 mmHg and 25.8/15.2 mmHg at weeks two (n = 122), four (n = 109), eight (n = 57), and 12 (n = 49), respectively. The control rate was >65% already at two weeks. At 12 weeks, 12 patients (24.5%) had progressed to the higher dose of R or E and/or had α-methyldopa added. Cohort analyses of 49 patients up to 12 weeks were confirmatory. Only two patients dropped out of the study.

Conclusions: NOAAH (NCT01030458) demonstrated that blood pressure control can be achieved fast in Black patients born and living in Africa with a simple regimen consisting of a single-pill combination of two antihypertensive agents. NOAAH proves that randomized clinical trials of cardiovascular drugs in the indigenous populations of sub-Saharan Africa are feasible.

Figure 1

Trial profile based on data available on 14 April 2011.

Figure 2

Number of patients screened, enrolled and randomized on 14 April 2011. The horizontal dotted line indicates the number of patients to be randomized.

Figure 3

Systolic blood pressure (A), diastolic blood pressure (B) and the proportion of patients controlled (C) during the course of the trial. For this analysis the two treatment groups were combined and all available data were used. Blood pressure control is a level below 140 mmHg systolic and 90 mmHg diastolic.

Figure 4

Systolic blood pressure (A), diastolic blood pressure (B) and the proportion of patients controlled (C) during the course of the trial. For this cohort analysis the two treatment groups are combined and the number of patients was constant in each of the data points (n = 49). Blood pressure control is a level below 140 mmHg systolic and 90 mmHg diastolic.