Predictors of renal and patient outcomes in anti-GBM disease: clinicopathologic analysis of a two-centre cohort.

BACKGROUND

Patients with anti-glomerular basement membrane (GBM) disease are at increased risk of morbidity and mortality from renal failure, pulmonary haemorrhage or complications of treatment. One-third also have circulating anti-neutrophil cytoplasmic antibodies (ANCA). The aim of this study was to determine the clinicopathologic predictors of patient and renal outcomes in anti-GBM disease with or without ANCA.

METHODS

Retrospective review of 43 patients diagnosed with anti-GBM disease over 20 years in two centres, including nine with dual anti-GBM and ANCA positivity. Renal biopsies from 27 patients were scored for the presence of active and chronic lesions.

RESULTS

Dual-positive patients were almost 20 years older than those with anti-GBM positivity alone (P = 0.003). The overall 1-year patient and renal survivals were 88 and 16%, respectively. Oligoanuria at diagnosis was the strongest predictor of mortality; none of the 16 patients without oligoanuria died. In a Cox regression model excluding oligoanuria, age was the only other independent predictor of survival. Pulmonary haemorrhage and dialysis dependence did not influence mortality. Thirty-five of the forty-three (81%) patients required dialysis at presentation, including all nine dual-positive patients. Of them, only two (5.7%) regained renal function at 1 year. By logistic regression, oligoanuria at diagnosis and percentage of crescents were independent predictors of dialysis independence at 3 months. However, in biopsied patients, the presence of crescents (>75%) added little to the presence of oligoanuria in predicting dialysis independence. Histological activity and chronicity indices did not predict renal outcome. Two of the nine (22%) dual-positive patients relapsed compared with none of the anti-GBM alone patients. Seven patients received kidney transplants without disease recurrence.

CONCLUSIONS

Oligoanuria is the strongest predictor of patient and renal survival while percentage of glomerular crescents is the only pathologic parameter associated with poor renal outcome in anti-GBM disease. Kidney biopsy may not be necessary in oligoanuric patients without pulmonary haemorrhage.