Mortality and prognostic factors among inpatients with systemic lupus erythematosus in China: A 20-year retrospective study

Objective To summarize the causes of death and clinical characteristics of systemic lupus erythematosus (SLE) hospitalized patients in the last 20 years to improve SLE survival rates by detecting critical SLE early. Methods In this case-control study, 218 SLE death cases were retrospectively analyzed from January 2002 to December 2022, with 110 SLE inpatients chosen at random as controls. The clinical symptoms, causes of death, and risk factors in patients with SLE were investigated. Results There were 218 deaths among 9538 patients with SLE, including 188 women and 30 men. The death rate fell steadily from 4.14% in 2002 to 1.96% in 2013 and remained at 1.84% from 2014 to 2022. The standardized mortality ratio (SMR) was 4.98 [95% CI (4.06-5.89)] from 2002 to 2012 and 3.39 [95% CI (2.74-4.04)] from 2013 to 2022. Infection, lupus-induced multiple organ failure syndrome (MODS), and neuropsychiatric lupus (NPLE) were the leading causes of death, accounting for 31.19%, 15.14%, and 11.47% of overall deaths. Age had a significant association with the major causes of death. Logistic regression analysis showed NPLE[OR = 10.772,95% CI (3.350,34.633), p < 0.001], lupus pulmonary involvement (LP)[OR = 3.844,95%CI (1.547,9.552), p = 0.004], pneumonia[OR = 3.439,95%CI(1.552,7.621), p = 0.002], thrombocytopenia[OR = 14.941,95%CI (4.088,54.604), p < 0.001], creatinine>177 μmol/L[OR = 8.644,95%CI (2.831,26.388), p < 0.001], glutamic transaminase(AST) > 60U/L[OR = 5.762,95%CI (2.200,15.088), p < 0.001], total bilirubin > 34 μmol/L[OR = 16.701,95%CI (3.349,83.294), p = 0.001], higher SLE Disease Activity Index (SLEDAI)[OR = 1.089,95%CI (1.032,1.149), p = 0.002] and SLE Damage Index (SDI)[OR = 3.690,95%CI (2.487,5.474), p < 0.001] correlated positively with death. Conclusion From 2002 to 2013, the mortality rate among patients with SLE fell steadily but remained unchanged from 2014 to 2022. Patients with SLE had significantly higher SMR than the general population. Childhood-onset SLE had a poorer prognosis than adult-onset SLE. Infection, MODS, and NPLE were the three leading causes of death. Major organ involvement and high disease activity were risk factors for mortality.