15-year follow-up of renin and blood pressure in reflux nephropathy.

BACKGROUND

Beginning in 1978 a cohort of patients with reflux nephropathy first seen at a London Childrens hospital have had 5-yearly follow-ups. This is the fourth (15-year) report from that series.

METHODS

Of the original 100 normotensive children with reflux nephropathy 78 were traced for the 15-year study in 1994. Five patients were excluded because of nephrectomy, ten for other reasons, and eight refused to take part, leaving 55. 26 were on oral contraceptives. Supine blood pressure and plasma renin activity (PRA) were measured, and daily sodium excretion was assessed on a sample of overnight urine.

FINDINGS

Of the 55 patients (15 male, 40 female, median age 27 years, range 20-31), five had systolic and two had diastolic hypertension. Compared with the 10-year (1988) follow-up there was no change in blood pressure standard deviation scores (SDS) in this cohort. PRA showed an increasing dissociation from controls after 15 years of age and was significantly above that of controls by age 25. Exclusion of the patients on oral contraceptives did not significantly alter the results. The PRA values in 1988 were not individually predictive of the development of hypertension over the ensuing 5 years.

INTERPRETATION

Previously, in the long-term study of reflux nephropathy, blood pressure SDS had progressively increased with age. By 15 years blood pressure had levelled out and the PRA, though raised, did not predict the development of hypertension. Oral contraceptive use did not significantly modify the results.