Prognostic relevance of clinical and histological features in IgA nephropathy treated with steroid and angiotensin receptor blockers.

BACKGROUND: The prognostic relevance of clinical and histological features on renal outcome has not been assessed in patients with IgA nephropathy (IgAN) treated with the combination therapy of steroid and angiotensin receptor blockers (ARB).
METHODS: A prospective trial of a combination of steroid and ARB was performed in 50 patients with IgAN, proteinuria and serum creatinine levels < 2 mg/dl.
RESULTS: Over a mean follow-up period of 4 years, the combination therapy reduced proteinuria and hematuria and improved renal function in most patients. The mean change in estimated GFR (eGFR) was + 0.30 +/- 0.74 ml/min/1.73 m2/month. Forty-three patients (86%) exhibited stable renal function and 7 patients (14%) reached the primary end point of a (3) 20% decrease in eGFR from baseline levels. Between the nonprogressive and progressive patients, there were significant differences in the levels of urine protein/ creatinine excretion ratio (PCR) at baseline and throughout the follow-up period as well as baseline eGFR and degree of glomerular crescents (p < 0.05). Forty (80%) and 24 patients (48%) had a urine PCR < 1 and < 0.3 g/g, respectively, at their last follow-up. Renal survival was better in patients who had initial urine PCR < 3 g/g as well as final PCR < 1 g/g. Regression analysis revealed that the final urine PCR and age were critical determinants of slope of the eGFR by both univariate and multivariate analyses. However, eGFR, pathologic findings, systolic BP, proteinuria, and body mass index at the initial presentation were not predictive of slope.
CONCLUSION: Our results indicate that achieving a low urinary protein excretion is the main determinant for the good outcome in patients treated with combination therapy.