Clinical usefulness of a prognostic score in histological analysis of renal biopsy in patients with lupus nephritis.

Objective: To evaluate active and chronic lesions in association with renal outcome according to the International Society of Nephrology/Renal Pathology Society classification in patients with lupus nephritis.

Methods: A retrospective analysis of 99 biopsy-proven subjects with lupus nephritis from 1990 to 2006 was performed in our center using the new classification. Each histological lesion was evaluated by multivariate survival analysis as predictive factor for renal insufficiency in patients with lupus nephritis, and independent predictors were graded to develop the prognostic score based on the regression coefficient. A receiver operating-characteristic curve based on the prognostic score was plotted to determine the most appropriate cutoff point.

Results: In class IV, the IV-G group tended to exhibit a worse renal outcome compared with the IV-S group, but the difference was not significant (log-rank test, p = 0.4330). Independent histological predictors of poor renal outcome were extracapillary proliferation, glomerular sclerosis, and fibrous crescents analyzed by Cox proportional hazards model, while predictors of favorable renal outcome were hyaline thrombi and fibrous adhesions. By the prognostic score, renal outcome was significantly worse in the group with the higher score (> or = 0.25) than in the group with the lower score (< 0.25) in class IV patients (log-rank test, p < 0.001).

Conclusion: These results demonstrate the advantage of our prognostic score compared to subclasses in predicting the renal outcome of class IV patients [University Hospital Medical Information Network (UMIN) clinical trials registry, number UMIN 000001943].