Primary glomerulonephritis: an update on renal survival and determinants of progression

Abstract

Background: Few epidemiological studies have investigated the long-term outcome of primary glomerulonephritis (GN) and its determinants in the decade since angiotensin-converting enzyme inhibitors entered widespread use.

Aim: To study several traditional and less traditional risk factors for kidney disease progression in a cohort of patients with primary GN.

Design: Retrospective cohort study.

Methods: We included 536 patients with primary GN first diagnosed between 1994 and 2001: 283 IgA nephropathy (IgA), 129 membranous nephropathy (MN), and 124 focal and segmental glomerulosclerosis (FSGS). Adjusted hazard ratios (HR) or dialysis or preemptive transplantation for end-stage renal disease (ESRD) according to various characteristics were estimated with Cox proportional-hazard models.

Results: At diagnosis, mean patient age was 43 +/- 17 years, 74% were men, and the mean estimated glomerular filtration rate (eGFR) was 69 +/- 31 mL/mn/1.73m(2). After a mean follow-up of 7-years, 104 patients had started ESRD treatment and 14 had died before reaching ESRD. The 7-year renal survival rate was 69% for FSGS, 88% for MN, and 82% for IgAN (p < 0.01). In patients with FSGS, younger age was associated with a higher risk of ESRD. Baseline proteinuria, diabetes, and haemoglobin (Hb) concentration were strongly associated with shorter time to ESRD independent of baseline eGFR, but gender, hypertension and smoking were not. Adjusted HRs for ESRD were 2.6 [95% confidence interval, 1.2-5.8] for diabetes and 2.4 [1.3-4.5] for the lowest and 1.9 [1.0-3.6] for the intermediate Hb tertiles versus the highest.

Discussion: In patients with primary GN, renal survival is clearly lower for FSGS than for IgAN and MN. Independent predictors for progression were baseline diabetes and anaemia, as well as proteinuria, for all GN types, and younger age, for FSGS.