Does treated essential hypertension result in renal impairment? A cohort study.

To determine how frequently essential hypertension results in significant renal impairment we undertook a follow-up study of 176 patients with well documented essential hypertension first seen in 1975-1977. Six patients were Asian, two Negro, and the remainder Europid. Follow-up was achieved in 92% of the cohort at five years and in 87% at 12-14 years. At five years 13 (7%) patients had moved away or were lost, and 15 (9%) patients had died (11 cardiovascular deaths). Treated blood pressure was greater than 160/95 mmHg in 60/148 patients and greater than 200/100 mmHg in 16 patients. Despite this, no significant change in serum creatinine was detected in the group as a whole. Increments in serum creatinine of at least 35 mumol/l occurred in six patients. Over the ensuing 6-9 years serum creatinine had returned to normal in three of these patients and stabilized in two; the sixth patient died from myocardial infarction. No patient reached end-stage renal failure. We conclude that progressive deterioration in renal function in essential hypertension is rarely a significant problem in Caucasian patients. A decline in renal function should prompt a search for underlying primary renal disease.