Major determinants of prolonged remission in systemic lupus erythematosus: retrospective study over a 41+ year period.

OBJECTIVES: To investigate predictors of sustained complete remission (CR) for 3 and 5 years, minimum.

METHODS: Retrospective observational study from January 1978 to December 2019, including systemic lupus erythmatosus (SLE) patients who attended the Lupus Clinic in a tertiary hospital, for at least 3 years. We used the BILAG score and serological profile to classify patients into CR, serologically active clinically quiescent (SACQ) and serological remission (SR). Multivariable Cox regression analysis was performed to investigate predictors of CR and Kaplan-Meier curves were obtained.

RESULTS: We included 564 patients; 15% achieved CR, 7% SACQ and 15% SR. Some 63% attained no remission. In the CR group, 73% sustained the remission for 5 years or more. Patients who did not reach any kind of sustained remission died significantly earlier (P < 0.001). Cumulative survival figures at 5, 10, 20 and 30 years were 100, 100, 94 and 90%, respectively, for CR patients and 96, 93, 77 and 58%, respectively, for patients in the no-remission group. Significant predictors of CR were White ethnicity [adjusted hazard ratio (HR) 2.16 (95% CI 1.30-3.59); P = 0.003]; older age at diagnosis (>32 years) [HR 1.92 (1.24-2.97); P = 0.003]; absence of renal involvement [HR 2.55 (1.39-4.67); P = 0.002]; and of antiphospholipid syndrome (APS) [HR 4.92 (1.55-15.59); P = 0.007].

CONCLUSION: Patients not achieving any kind of sustained remission have a higher risk of early mortality. White ethnicity, older age at diagnosis, absence of renal involvement and of APS were significantly associated with CR. Predictors for sustained CR do not change whether a 3-year or 5-year period is applied.