Impact of Diabetes on 90-Day Episodes of Care After Elective Total Joint Arthroplasty Among Medicare Beneficiaries

Background: In an effort to improve quality and reduce costs, reimbursement for total knee arthroplasty (TKA) and total hip arthroplasty (THA) in the United States is being based on the value of care provided, with adjustments for some qualifying comorbidities, including diabetes in its most severe form and excluding many diabetes codes. The aims of this study were to examine the effects of diabetes on elective TKA or THA complications and readmission risks among Medicare beneficiaries.

Methods: Complication (n = 521,230) and readmission (n = 515,691) data were extracted from Medicare files in 2013 and 2014. Diabetes status (no diabetes, controlled-uncomplicated diabetes, controlled-complicated diabetes, and uncontrolled diabetes) was identified with ICD-9 (International Classification of Diseases, 9th Revision) codes. TKA or THA complications and readmission odds based on diabetes status were estimated using logistic regression and adjusted for sociodemographic and clinical characteristics, including comorbidities.

Results: Compared with no diabetes, the odds ratio (OR) of TKA complications was significantly higher for uncontrolled diabetes (1.29, 95% confidence interval [CI] = 1.06 to 1.57). The OR of THA complications was significantly higher for controlled-complicated diabetes (1.45, 95% CI = 1.17 to 1.80). The OR of readmission was significantly higher for all diabetes groups (1.21 to 1.48 for TKA, 1.20 to 1.70 for THA).

Conclusions: Readmission odds were higher in all diabetes categories. The uncontrolled-diabetes group had the greatest TKA readmission and complication odds. The controlled-complicated diabetes group had the greatest THA readmission and complication odds. The findings suggest that including diabetes and associated systemic complications in cost adjustments in alternative payment models for arthroplasty should be considered.

Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.