The Association of Comorbidities With Total Knee Arthroplasty Health Care Utilization

Background: Patients undergoing total knee arthroplasty (TKA) tend to have comorbidities such as obesity, hypertension, and cancer, which are associated with advanced age. This study aimed to elucidate the associations of these comorbidities with hospital charge (HC), hospital costs (HCos), and length of stay (LOS). Methods: A national database was queried for patients who underwent primary TKA from 2012 to 2020. There were 30 comorbidities classified using the Elixhauser comorbidity index. For each comorbidity of interest, patients were matched to another patient by age, sex, and all other comorbidities except the comorbidity of interest. Matched cohorts were analyzed via multivariable regression analyses controlled for age, sex, procedure year, hospital location, and comorbidities to predict increases in HC, HCo, and LOS. A total of 1,014,831 patients were included. Results: Mean HC, HCo, and LOS were $64,097, $17,299, and 2.5 days, respectively. Weight loss, blood loss anemia, coagulopathies, and fluid and electrolyte disorders were associated with the largest increases in HC, with 6, 5, 5, and 5% increases, respectively (P < 0.05). Pulmonary hypertension, non-metastatic tumors, paralysis, and obesity were associated with increased HCo, with 6, 4, 4, and 4% increases, respectively (P < 0.05). All comorbidities except hypothyroidism were associated with increased LOS. Pulmonary hypertension, weight loss, paralysis, fluid and electrolyte disorders, and human immunodeficiency virus/acquired immunodeficiency syndrome were associated with were associated with 53, 21, 15, 14, and 12%, respectively, increased odds of having LOS greater than or equal to 4 days’ increase (P < 0.05). Conclusion: This study offers targets for the reduction of HC, HCo, and LOS for patients with these ailments through protocol change. Optimization programs targeting malnourished patients, patients with pulmonary hypertension, and other comorbidities are encouraged. These results also provide clinicians with a quantifiable way to communicate financial burden and recovery time after TKA to patients’ unique problem lists.