How does systemic lupus erythematosus impact the peri-operative complication rates in primary hip arthroplasty? A national inpatient sample-based study

Introduction: With prolonged life expectancy, the number of patients with systemic lupus erythematosus (SLE) undergoing total hip arthroplasty (THA) has substantially increased over the past years. The post-operative outcome and complications in SLE are less clearly understood than other inflammatory diseases, due to limited availability of evidence within the literature. Methods: Using the National Inpatient Sample (NIS) database, patients who underwent THA between 2016 and 2019 were identified (ICD-10 CMP code). Patients were then classified into one of the two groups, namely those with SLE (ICD-10-CM; code710.0) or those without SLE (NSLE). Data regarding demographic details, co-morbidities, details regarding hospital stay, expenditure incurred, and complications encountered were analyzed, and compared between the groups. Results: Overall, among 367,894 patients undergoing THA, 1684 (0.5%) had SLE. Mean age of SLE (57.3 ± 14.5 years) patients undergoing THA was significantly lower than NSLE (65.9 ± 11.4 years) population (p = 0.001). There was a greater proportion of female patients in SLE group [89.6% (SLE) vs 55.8% (NSLE); p = 0.001]. SLE patients had a greater incidence of emergent hospital admissions (p = 0.04), longer hospital stay (p = 0.001), and higher hospital-related expenditure (p = 0.001). Among the peri-operative complications, SLE patients had significantly greater risk of developing post-operative anemia (p = 0.001), need for blood transfusion (p = 0.001), peri-prosthetic mechanical complications (p = 0.04), and prosthetic dislocations (p = 0.001). There was also a greater incidence of peri-prosthetic infections in the SLE group (p = 0.001). Conclusion: The presence of SLE significantly lengthens hospital stay and augments healthcare-related costs in patients undergoing THA. The three main complications which may significantly affect the post-operative course of these patients include higher rates of post-operative anemia, peri-prosthetic infections, and early prosthetic dislocations.