Proteinuria after conversion to sirolimus in kidney transplant recipients: impact of pre-existing proteinuria, graft function, and angiotensin-converting enzyme inhibitors/angiotensin-receptor antagonists.

BACKGROUND: Proteinuria is a known side effect of therapy with sirolimus. The effect of angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers (ACEI/ARB ) on sirolimus-associated proteinuria has not yet been assessed.

PATIENTS AND METHODS: A retrospective cohort study of renal transplant patients treated with sirolimus (n = 55) was performed.

RESULTS: Of 55 patients, 24 (44%) had no proteinuria (<0.15 g/d) prior to conversion. Of 24 patients, 11 (46%) showed de novo proteinuria >0.15 g/d after 12 months, only 2 developed proteinuria > 1 g/d. The total number of proteinuria >1 g/d after 12 months including patients with pre-existing proteinuria >1 g/d (n = 3) was seven of 55 patients (13%). Multivariate regression analysis revealed pre-existing proteinuria > 0.15 g/d and reduced glomerular filtration rate as independent predictors for the development of proteinuria after conversion to sirolimus.

CONCLUSION: Reduced glomerular filtration rate and pre-existing proteinuria but not therapy with ACEI/ARB are independent predictors for proteinuria after conversion to sirolimus. Treatment with ACEI/ARB did not reduce pre-existing proteinuria after conversion except in single cases with severe proteinuria.