Objective: To examine the disease flare rate in lupus nephritis (LN), focusing on renal flares, and the factors associated with relapse risk in recent years.

Methods: We analyzed data on 139 Chinese patients with class III/IV ± V LN diagnosed from January 1983 to December 2013. We also compared data before and after 1998, when maintenance immunosuppression was changed from azathioprine (AZA) to mycophenolic acid (MPA).

Results: Over 112.5 ± 88.4 months, 135 episodes of renal flare occurred, giving a flare rate of 0.108 episodes per patient-year. The renal relapse-free survival rate was 96%, 90%, 86%, 80%, 69%, and 57% after 1, 2, 3, 4, 5, and 10 years, respectively, calculated from the start of induction treatment. Reduced risk of flare was associated with MPA maintenance (OR 0.314, 95% CI 0.099-0.994, p = 0.049), complete remission after induction immunosuppression (OR 0.329, 95% CI 0.133-0.810, p = 0.016), and diagnosis after 1998 (OR 0.305, 95% CI 0.133-0.700, p = 0.005). Relapse-free survival was significantly better in patients treated with prednisolone and MPA as maintenance immunosuppression (91% after 5 yrs and 83% after 10 yrs, respectively) compared with prednisolone and AZA (70% and 52%, respectively, p = 0.044). LN diagnosed in 1998-2013 showed 5-year and 10-year relapse-free survival rates of 93% and 86%, respectively, compared with 81% and 66%, respectively (p = 0.017) for LN that presented in 1983-1997.

Conclusions: Our data show a relatively low flare rate for LN in the more recent era, attributed to effective induction of immunosuppression and MPA as maintenance treatment.