COPD Patient's Outcomes following Total Knee Arthroplasty-An Analysis of the National Inpatients Sampling (2016-2020)

Total knee arthroplasty (TKA) is a common elective procedure aimed at improving patients' quality of life. Patients undergoing this procedure can have a wide variety of comorbidities, including chronic obstructive pulmonary disease (COPD). Several studies demonstrated a higher risk of postoperative complications for this patient population. In this study, we examined the mortality risk of this group of patients, as well as the length of stay (LOS) and general costs. This study is a retrospective, case-control study. Using the National Inpatients Sampling (NIS) database, we defined a cohort of adults who received their inpatient primary TKA between 1 January 2016 and 31 December 2020. Preoperative variables include age, sex, race, primary payer, hospital location, and hospital type. Outcomes examined in this study include overall patient mortality as a primary outcome. Secondary outcomes include total LOS (in days) and inpatient costs in the United States (in USD). A total of 2,835,499 patients who underwent TKA procedure in the United States were included. A total of 173,230 (6.1%) COPD patients were included in the COPD group. The mortality rate in the COPD group (0.1%) was more than three times higher than the control group (0.03%, -value < 0.001). Patients in the COPD group had a longer in-hospital length of stay (2.76) compared to the control group (2.31, -value < 0.001) and a higher treatment cost (average value of treatment per patient) (USD 69,386) compared to the control group (USD 64,446, -value < 0.001). We also found higher mortality risk for patients older than 60 and patients of white ethnicity. COPD patients undergoing TKA have a higher mortality rate and this issue should be addressed in order to improve patient care and outcomes.