Incidence and outcome of antiglomerular basement membrane disease in Chinese

Background: Antiglomerular basement membrane (anti-GBM) disease is an uncommon disease, especially among Asian population. Many reports and studies on this condition in the Caucasian population are available, but little information exists on anti-GBM disease in Asians. To study the incidence and clinical characteristics of anti-GBM disease among Chinese patients, we reviewed our experience of anti-GBM disease in our hospital (Queen Mary Hospital, Hong Kong) from 1992 to 2003. Methods: All patients who were admitted for acute renal impairment, which was caused by crescentic glomerulonephritis associated with linear immunoglobulin G (IgG) staining on immunofluorescence, were included in the analysis. Serum anti-GBM antibodies were detected by either enzyme-linked immunofluorescence or indirect immunofluorescence. Ten patients were treated for anti-GBM disease during this 11-year period, yielding an incidence of approximately 0.6 cases per million population per year. Results: In this cohort, anti-GBM disease predominantly affected older patients (mean age: 58.6 +/- 21.7 years). Eight patients were aged between 60 and 80 years and there was a female preponderance (M:F = 2:8). The 1-year renal and patient survival was 15% (95% CI 0-40%) and 70% (95% CI 42-98%), respectively. Most patients presented with non-specific symptoms as well as impaired renal function. Detection of anti-GBM antibody provided a good screening test for the disease. Antiglomerular basement membrane antibodies were not detected in two patients. All but two patients received steroid, cyclophosphamide and intensive plasmapheresis therapy. Haemoptysis occurred in four patients (40%), and usually lagged behind the renal presentation and commencement of treatment. Six patients required long-term dialysis after the acute disease. Three patients died from the disease, two died from pulmonary complications and one died suddenly after a partial recovery of renal function. Conclusion: Antiglomerular basement membrane disease is uncommon among the Chinese population. It predominantly affects older patients, and prognosis is poor. Long-term preservation of renal function after the initial attack is unusual.