Systemic lupus erythematosus, rheumatoid arthritis, and postarthroplasty mortality: a cross-sectional analysis from the nationwide inpatient sample

Abstract

Objective: Systemic lupus erythematosus (SLE) is a disease of considerable morbidity, and this may place patients at greater risk for poor in-hospital postoperative outcomes for procedures such as arthroplasty. Our aim was to test this hypothesis.

Methods: We compared the in-hospital postoperative mortality risk for patients with SLE undergoing hip and knee arthroplasty to those with rheumatoid arthritis (RA) and the general population without either condition, using data from the Nationwide Inpatient Sample (1993-2006). We performed parallel, weighted, multivariable logistic regressions to calculate mortality risk stratified by joint site, type of admission, hospital type, income category, race, length of stay, surgical indication, and medical comorbidities.

Results: The unadjusted mortality rates (per 1000 procedures) for patients with SLE, patients with RA, and controls were 7.4, 3.0, and 6.5, respectively, for nonelective procedures and 2.4, 1.3, and 1.8 for elective procedures. After adjustment for potential confounders, patients with SLE had an OR of 4.0 (95% CI 1.9-8.0) for postoperative mortality with hip replacements and an OR of 1.2 (95% CI 0.2-7.5) for mortality with knee replacements. Mortality risk of patients with RA was not different from that of controls. The adjusted risk estimates for those who underwent arthroplasty before and after 2002 and those who underwent surgery for nonfracture indications were similar.

Conclusion: Arthroplasty, especially of hips, in patients with SLE is associated with relatively higher postoperative mortality risk.