Determinants of renal functional outcome in lupus nephritis: a single centre retrospective study

Lupus nephritis (LN) is a rare disease but is the strongest predictor of poor outcome in patients with Systemic Lupus Erythematosis (SLE). It is associated with significant morbidity, with 10-20% of patients developing end stage renal failure. As there is a paucity of randomized clinical trial data in LN, and no consistent literature regarding baseline factors that predict renal outcome, we were prompted to analyse our centre's complete experience of managing LN.

A retrospective analysis was undertaken of all patients presenting to our renal centre with biopsy proven LN from 1979-2003. Patients were divided into two categories, those with stable or deteriorating renal function over time. Baseline parameters were correlated with renal outcome.

Complete clinical records were available for 45 (40 female) patients. Mean (SD) age of onset of SLE was 32 +/- 14 years, and mean age onset of LN was 36 +/- 13 years. Patients were followed up for an average of 74 +/- 56 months. Four patients (9%) had WHO Class II LN, 11 (24%) WHO Class III and there were 15 (33%) each in Class IV and V, respectively on renal biopsy. Five (11%) patients presented with acute renal failure and all had proliferative changes on biopsy. The chief arbiters of renal functional deterioration over follow up were longer time to development of LN (P = 0.04), a high platelet count and worse baseline renal function (both P = 0.05). There was a trend relating low haemoglobin or membranous histology to poor renal outcome, and Class IV histology to better outcome.

The study has identified that longer time to development of LN, high platelet count and poorer renal function at baseline suggest a worse renal outcome in LN. The study was small but LN is a rare condition. A combination of factors is likely to influence renal outcome in LN and larger prospective trials are required to ascertain consistent baseline prognostic markers.