Prognostic value of the Oxford classification and the Oxford score in IgA nephropathy: A Tunisian study

Abstract

Immunoglobulin A nephropathy is the most common primary glomerular disease. The main challenge in this disease is the evaluation of prognostic factors for end-stage renal disease. The aim of our study was to describe the characteristics of immunoglobulin A nephropathy, to evaluate the histological data according to Oxford classification, and to identify factors associated with renal survival. This was a retrospective study, including adults with primary immunoglobulin A nephropathy. The study was conducted over a period of 10 years. Renal biopsies were scored according to Oxford classification. Oxford score, based on the sum of the different histological lesions of Oxford classification, was calculated for each patient. We included 50 patients with a gender ratio (male:female) of 2.8. The average age was 35.6 ± 10.6 years. Fifty-eight percent of the patients had hypertension (HTN). The median proteinuria was 1.9 g/day. The median of the glomerular filtration rate was 47.6 mL/min/1.73 m2. According to Oxford classification, mesangial proliferation, endocapillary proliferation, glomerulosclerosis, interstitial fibrosis, and/or tubular atrophy and crescents were present in 40%, 38%, 88%, 36%, and 22% of the cases, respectively. The median Oxford score was 2. The median follow-up duration was 30 months. Ten patients (20%) reached end-stage renal disease. At univariate analysis, HTN, glomerular filtration rate, proteinuria, tubular involvement, and Oxford score >3 were associated with progression to end-stage renal disease (ESRD). Tubular involvement was an independent risk factor for ESRD. Our study confirms the prognostic value of the Oxford classification in immunoglobulin A nephropathy.