Performance of Clinical and Biochemical Parameters in Identifying Renal Histopathology and Predictors of One-Year Renal Outcome in Lupus Nephritis-A Single Centre Study from India

Objectives: To assess the performance of clinical and biochemical parameters in identifying renal histopathology. To assess the performance of a combination of demographic, clinical, serological and histopathological parameters in determining renal response at one year. Methods: Data of biopsy-proven (ISN/RPS-2003 criteria) Lupus Nephritis (LN) were extracted from the institute database. Demographic, clinical and biochemical parameters at the time of biopsy were noted, and their associations with histopathological class, activity and chronicity scores were evaluated. Follow-up data at one year were collected. Complete, partial or no response (CR, PR, NR) for renal outcomes at one year and the predictors of NR were assessed. Results: Out of the 333 renal biopsies, 240 (71.8%) were Class III/IV. More patients with Class III/IV LN had hypertension (52.1%) and low eGFR (p < 0.001). Among Class III/IV, AS correlated weakly with UPCR (r = 0.31, p < 0.01), eGFR (r = -0.172; p < 0.01) and CS with eGFR (r = -0.212; p < 0.01). The presence of either hypertension, UPCR > 0.5 g/day, active urinary sediments or serum creatinine >1.3 g/dL had a sensitivity of >96% and specificity of <9% in detecting proliferative LN, crescents, interstitial inflammation and chronicity. NR was higher in males (aOR:3.9, 95% CI:1.4-11.0, p < 0.001), those with abnormal baseline creatinine (aOR: 1.9, 95% CI: 1.1-3.2, p < 0.001), higher renal SLEDAI (p < 0.05), higher AS, CS (p < 0.001) and interstitial inflammation (p < 0.005). In the binary logistic regression, the combination of male sex, baseline creatinine, UPCR and CS performed best in predicting NR (AUC: 0.762; 95% CI: 0.684-0.840, p < 0.001). Conclusions: Clinical and biochemical parameters alone have a poor specificity in identifying renal histopathology. A combination of demographic, clinical and histopathology parameters can better predict renal outcomes at one year.