Understanding factors that impact the length of stay after total hip arthroplasty – A national in-patient sample-based study

Background: Total hip arthroplasty (THA) is increasingly used every year; however, there is currently limited information on factors that impact the length of stay (LOS) following the procedure. Longer LOS following THA is met with an increase in the cost of care, necessitating studies to identify factors that may impact LOS. Methods: In this retrospective study, we used the Nationwide Inpatient Sample (NIS) database from 2016 to 2019 to analyze the preoperative comorbidities and postoperative complications that impact the LOS following THA. We divided our cohort into patients with a LOS greater than two days, and patients with a LOS less than two days. Results: A total of 367,890 patients were identified in the NIS database who underwent THA during the study period. Of this cohort, 112,288 (30.52%) patients were identified as having a LOS greater than two days, while the remaining 255,602 (69.48%) patients were patients who had a LOS less than two days. Multivariate analysis demonstrated several pre-operative factors, such as diabetes, systemic lupus erythematosus, organ transplant, dialysis, the human immunodeficiency virus, chronic kidney disease, and Parkinson's disease, were independently associated with a higher risk of a LOS greater than two days. The subsequent multivariate analysis for post-operative variables demonstrated that acute renal failure, myocardial infarction, blood loss anemia, blood transfusion, pulmonary embolism, deep vein thrombosis, periprosthetic fracture, periprosthetic mechanical complications, periprosthetic infections, and wound dehiscence were all independently associated with a higher risk of a LOS greater than two days. Conclusions: Several pre-operative comorbidities and postoperative complications were found to increase the likelihood of a LOS greater than two days. In addition, the group with a LOS greater than two days incurred a higher cost of care. This information is useful for providers to make informed decisions regarding patient care and resource utilization for patients undergoing THA, potentially reducing LOS.