National Incidence of Reportable Quality Metrics in the Knee Arthroplasty Population

Abstract

Background: The Centers for Medicare and Medicaid Services (CMS) characterizes adverse quality events in the inpatient setting as patient safety indicators (PSI). The incidence of PSI has not been quantified in the total knee arthroplasty (TKA) population.

Methods: All patients in the Nationwide Inpatient Sample who underwent primary TKA during an inpatient episode in 2013 were identified using International Classification of Disease, Ninth Revision, Clinical Modification codes. The incidence of PSI was determined using the International Classification of Disease, Ninth Revision diagnosis code algorithms used by CMS. Multivariable logistic regression was used to determine significant associations between patient level covariates (demographics, comorbidities, and hospital characteristics) and the risk of experiencing one or more PSI after TKA.

Results: We identified 132,453 primary TKA patients in the Nationwide Inpatient Sample in 2013. We estimated the national incidence rate of experiencing one or more PSI as 0.98%. After adjusting for patient demographics and hospital characteristics, we found that relative to Medicaid/self-pay patients, neither Medicare nor privately insured patients faced significantly different risk of experiencing one or more PSI after TKA. However, alcohol abuse, deficiency anemia, congestive heart failure, coagulopathy, and electrolyte imbalance were associated with increased risk of experiencing one or more PSI after TKA.

Conclusion: The national incidence of PSI among TKA patients was lower than has been reported in other surgical populations. CMS uses the incidence of adverse quality events (measured using PSI) in part to determine hospital reimbursement. As value-based payment becomes more widely adopted in the United States, initiatives designed to eliminate and reduce PSI incidence can benefit vulnerable patient populations, physicians, and hospital systems.

Keywords: Agency for Healthcare Research and Quality; NIS; patient safety; total knee arthroplasty; value-based purchasing.