Lack of partial renal response by 12 weeks after induction therapy predicts poor renal response and systemic damage accrual in lupus nephritis class III or IV

BACKGROUND Lupus nephritis class III or IV is associated with a poor prognosis for both patient and renal survival. Recommendations for the management of lupus nephritis have recently been established, and changing therapies is recommended for patients who do not respond adequately to induction therapy. However, it remains a major challenge to determine when to switch the treatment. In this study, we identified early prognostic factors capable of predicting poor renal outcome as well as overall damage accrual in patients with lupus nephritis class III or IV. METHODS Eighty patients with biopsy-proven lupus nephritis class III or IV were retrospectively recruited and divided into two groups: those with complete renal response (CR) or non-CR at 3 years after induction therapy. We investigated when clinical responses were obtained at each observational period from baseline to year 3. Clinical responses were divided into three groups: CR, partial renal response (PR), and non-PR. Furthermore, patients were assessed using the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI) and cumulative dose of corticosteroid for 3 years. RESULTS Forty-four patients with CR and thirty-six with non-CR were enrolled. The cumulative CR rate was 85.0%. PR rates of patients with CR were significantly higher than those with non-CR from week 12 (p < 0.01). We identified the achievement of PR at 12 weeks as an independent predictor (OR 3.57, p = 0.03) by multivariate analysis. We next divided all patients into two groups according to PR achievement at week 12. The cumulative CR rate of the patients who achieved PR at week 12 was significantly higher than that of those who did not (96.5% vs 69.2%, p < 0.001). Furthermore, a significantly higher SDI and cumulative dose of corticosteroid were seen in the patients who did not achieve PR at week 12 than in those who did, regardless of their CR status, at year 3. CONCLUSIONS Lack of PR at week 12 predicts a lower likelihood of achieving CR at 3 years and a higher SDI.