[Renal insufficiency in arterial hypertension in black Africa]

The increased risk of renal disease due to high blood pressure observed in Black Americans would suggest ethnic factors are involved. We examined the clinical features of renal disease in patients hospitalized in Ouagadougou, Burkina Faso for high blood pressure to determine the risk factors in this black population.

From November 1988 to October 1990, 317 patients (mean age 49 +/- 14 years, 62.5% males) under treatment for high blood pressure or with a diastolic pressure > 90 mmHg without antihypertensive therapy were examined at their initial hospitalization. The patients were divided into socio-economic groups according to their professional occupation and level of education. Criteria of renal disease, including raised serum creatinine, proteinuria and blood urea nitrogen, together with factors related to hypertension, including obesity, diabetes mellitus, hypertensive retinopathy, heart failure, coronary artery disease, cerebral vascular events and hypertensive encephalopathy were analyzed.

Severe hypertension, diastolic pressure > 130 mm Hg was observed in 43% of the patients. There was a significant inverse correlation between age and diastolic pressure (r = 0.23, p < 0.0001). Response to initial anti-hypertensive treatment was good in 88% and proportional to severity. Hospital mortality was 18.6% (59 patients) including 39 cases during the first two days. Mortality was not correlated with blood pressure, age, sex or socio-economic conditions. Renal disease was observed in 121 patients and chronic renal failure in 117 (44%). Effect of hypertension on at least one target organ was observed in 73.2% of the patients and on at least three target organs in 38.2%. Subjects with renal disease were younger (p < 0.02) and responded less well to treatment than those without renal disease.

These clinical observations confirm the high prevalence of renal failure and the gravity of high blood pressure in Black Africans. In Burkina Faso, hospitalization for high blood pressure often leads to the discovery of terminal renal failure.