Spondyloarthritis is associated with higher healthcare utilization and complication rates after primary total knee or total hip arthroplasty

Our objective was to assess healthcare utilization and complication rates after primary total knee/hip arthroplasty (TKA/THA) in people with spondyloarthritis (SpA) compared with people without SpA. We performed multivariable-adjusted logistic regression using the 1998–2014 US National Inpatient Sample (NIS), adjusted for age, race/ethnicity, gender, income, Deyo-Charlson comorbidity index, insurance payer, and the underlying diagnosis. The primary THA cohort consisted of 4,116,484 THAs (1.7% with SpA) and primary TKA cohort of 8,127,282 TKAs (1% with SpA). Compared with people without SpA, people with SpA had higher odds ratio (OR (95% confidence interval (CI)) of the following post-THA and post-TKA, respectively: (1) discharge to care facility, 1.16 (1.12, 1.21) and 1.14 (1.11, 1.18); (2) hospital stay > 3 days, 1.15 (1.11, 1.20) and 1.05 (1.01, 1.10); and (3) transfusion, 1.16 (1.12, 1.21) and 1.10 (1.05, 1.14); but lower odds of (1) mortality, 0.78 (0.64, 0.96) and 0.40 (0.19, 0.84); and (2) hospital charges above the median, 0.49 (0.46, 0.53) and 0.48 (0.45, 0.51). SpA was associated with higher odds of implant infection, 3.02 (2.27, 4.03) post-TKA, not post-THA. In-hospital revision rate did not differ. People with SpA utilize more healthcare services and have more complications post-THA/TKA. Interventions to reduce complications and associated utilization are needed.Key Points• People with spondyloarthritis utilized more healthcare services and had a higher risk of transfusion post-THA/TKA, compared with people without spondyloarthritis.• Spondyloarthritis was associated with lower in-hospital mortality rates after THA/TKA.• Spondyloarthritis was associated with a higher risk of implant infection after TKA, but not THA.• A pre-operative discussion with people with spondyloarthritis of possibly higher implant infection after TKA could lead to a more informed consent.