Mortality and years of potential life loss in systemic lupus erythematosus: a population-based cohort study

Abstract

Multiple sources were used to identify 325 systemic lupus erythematosus (SLE) patients within the city of Oslo during 1999–2009 who met ≥4 of the American College of Rheumatology (ACR) criteria. The survival, standard mortality rate (SMR), years of potential life loss before 60 years of age (YPLL60) and causes of death of these patients were examined and compared to a matched control population. Only inception cases (127) were studied in the calculation of survival. The analysis includes underlying, immediate and contributing causes of death. The five- and 10-year survival was 95% and 90%, respectively, which was significantly reduced when compared to the general population. A total of 50 SLE patients died during the study period. Overall SMR was 3.0 (95% confidence interval (CI) 2.2–3.8) with the highest SMR found for female patients aged 16–39 years old. SLE patients had a 10 times higher rate of YPLL60 compared to the control group. YPLL emphasizes active disease and reduces the importance of cancer as a cause of death in SLE. This study demonstrates that YPLL gives additional and useful information for the prognosis of SLE, supplementing traditional methods of measuring mortality.