Association between organ damage and mortality in systemic lupus erythematosus: a systematic review and meta-analysis

OBJECTIVE: At least half of patients with systemic lupus erythematosus (SLE) develop organ damage as a consequence of autoimmune disease or long-term therapeutic steroid use. This study synthesised evidence on the association between organ damage and mortality in patients with SLE. DESIGN: Systematic review and meta-analysis. METHODS: Electronic searches were performed in PubMed, Embase, Cochrane Library and Latin American and Caribbean Health Sciences Literature for observational (cohort, case-control and cross-sectional) studies published between January 2000 and February 2017. Included studies reported HRs or ORs on the association between organ damage (measured by the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI) score) and mortality. Study quality was assessed using the modified Newcastle-Ottawa assessment. Pooled HRs were obtained using the DerSimonian and Laird random-effects model. Heterogeneity was assessed using the Cochrane Q (Q) and I(2) statistics. RESULTS: The search yielded 10 420 articles, from which 21 longitudinal studies were selected. Most studies (85%) were of high quality. For 10 studies evaluating organ damage (SDI) as a continuous variable and reporting HR as a measure of association, a 1-unit increase in SDI was associated with increased mortality; pooled HR was 1.34 (95% CI: 1.24 to 1.44, p<0.001; Q p=0.027, I(2)=52.1%). Exclusion of one potential outlying study reduced heterogeneity with minimal impact on pooled HR (1.33 (95% CI: 1.25 to 1.42), p<0.001, Q p=0.087, I(2)=42.0%). The 11 remaining studies, although they could not be aggregated because of their varying patient populations and analyses, consistently demonstrated that greater SDI was associated with increased mortality. CONCLUSIONS: Organ damage in SLE is consistently associated with increased mortality across studies from various countries. Modifying the disease course with effective therapies and steroid-sparing regimens may reduce organ damage, improve outcomes and decrease mortality for patients with SLE.