Outcome study of renal biopsy patients in Okinawa, Japan

Here we report a community-based epidemiologic study of patients who received renal biopsy in Okinawa, Japan between 1967 and 1994. The total number of cases was 2832 (1395 men and 1437 women), and the mean (SD) age at biopsy was 30.0 (10.0) years (range 1.0 to 88.0 years). The most common clinical indications for renal biopsy were proteinuria/hematuria (46.7%), nephrotic syndrome (21.2%), acute glomerulonephritis (10.1%), and systemic lupus erythematosus (7.5%). Patients who received renal biopsy between 1985 and 1994 (N= 1480) were much less likely to have acute glomerulonephritis than patients treated between 1967 and 1984 (N= 1352); the rates of proteinuria/hematuria, renal failure, and diabetes mellitus were slightly higher in the later period. Okinawa patients who began dialysis between 1971 and 2000 (N= 5246) were also studied. Among them, a total of 468 patients (260 men and 208 women) began dialysis after renal biopsy. The cumulative incidence of end-stage renal disease (ESRD) among these patients was 17% in 17 years. Half of these patients developed ESRD in the 5.8 years after renal biopsy. Among the dialysis patients, the biopsy rate was 12.6% in chronic glomerulonephritis, 1.7% in diabetes mellitus, 2.6% in nephrosclerosis, and 52.1% in systemic lupus erythematosus. The diagnoses of primary renal diseases were primarily made clinically. The survival rate after starting dialysis therapy was slightly better in those with than in those without renal biopsy but this finding was not statistically significant (adjusted hazards ratio 0.855, 95% CI 0.711-1.028, P= 0.095). The clinical significance of renal biopsy, other than its provision of histologic evidence, remains to be shown.