LONG-TERM EFFECTS OF REDUCED RENAL MASS IN HUMANS

The long-term risks of kidney donation have not been well defined. We carried out a meta-analysis of investigations that examined the long-t erm effects of reduced renal mass in humans. We used multiple linear r egression to combine studies and adjust for differences in the duratio n of follow-up, the reason for reduced renal mass, the type of control s, age and gender. We analyzed 48 studies with 3124 patients and 1703 controls. Unilateral nephrectomy caused a decrement in glomerular filt ration rate (-17.1 ml/min; 95% confidence interval -20.2 to -14.0 ml/m in) that tended to improve with each 10 years of follow-up (1.4 ml/min /decade; 0.3 to 2.4 ml/min/decade). Patients with single kidneys had s mall, progressive increases in proteinuria (76 mg/day/decade; 52 to 10 1 mg/day/decade), but proteinuria was negligible after nephrectomy for trauma or kidney donation. Nephrectomy did not affect the prevalence of hypertension, but there was a small increase in systolic blood pres sure (2.4 mm Hg; -0.3 to 5.1 mm Hg, P > 0.05) which rose further with duration of follow-up (1.1 mm Hg/decade; 0.0 to 2.2 mm Hg/decade). Dia stolic blood pressure was higher after nephrectomy (3.1 mm Hg; 1.8 to 4.4 mm Hg), but this increment did not change with duration of follow- up. Thus, in normal individuals, unilateral nephrectomy does not cause progressive renal dysfunction, but may be associated with a small inc rease in blood pressure.