Proteinuria as a modifiable risk factor for the progression of non-diabetic renal disease

Background. Angiotensin-converting enzyme (ACE) inhibitors reduce urine protein excretion and slow the progression of renal disease. The beneficial effect in slowing the progression of renal disease is greater in patients with higher urine protein excretion at the onset of treatment. We hypothesized that the greater beneficial effect of ACE inhibitors on the progression of renal disease in patients with higher baseline levels of proteinuria is due to their greater antiproteinuric effect in these patients. Methods. Data were analyzed from 1860 patients enrolled in I I randomized controlled trials comparing the effect of antihypertensive regimens, including ACE inhibitors to regimens not including ACE inhibitors on the progression of non-diabetic renal disease. Multivariable linear regression analysis was used to assess the relationship between the level of proteinuria at baseline and changes in urine protein excretion during follow-up. The Cox proportional hazards analysis was used to assess the relationship between changes in urine protein excretion during follow-up and the effect of ACE inhibitors on the time to doubling of baseline serum creatinine values or onset of end-stage renal disease. Results. Mean (median) baseline urine protein excretion was 1.8 (0.94) g/day. Patients with higher baseline urine protein excretion values had a greater reduction in proteinuria during the follow-up in association with treatment with ACE inhibitors and in association with lowering systolic and diastolic blood pressures (interaction P