Association of type 2 diabetes with reoperation, adverse events and mortality after hip and knee replacement: a Swedish register-based study including 109 938 hip and 80 897 knee replacements.

objectiveType 2 diabetes mellitus (T2DM) and osteoarthritis (OA) are globally prevalent chronic diseases that affect millions of individuals in ageing populations. Hip and knee replacements are well established and effective treatments in patients suffering from end-stage OA. Understanding how T2DM influences the outcomes of these surgeries is important for optimising patient care and improving surgical results. This study aimed to explore the association of T2DM with reoperation (regardless of the reason), adverse events (AEs) and mortality after primary hip and knee replacement surgery.

designObservational study based on prospectively collected registry data analysed retrospectively. SETTING AND

participantsData from several Swedish national quality registers and health data registers were used to create a study database. 109 938 and 80 897 primary hip and knee replacements due to OA, performed between 2008 and 2019 (hip) and 2009 and 2018 (knee), were included in the study. OUTCOME MEASURES: The risk of complications, such as reoperation, AEs and mortality, was investigated by estimating HRs using Cox regression, and OR using logistic regression, unadjusted and adjusted for confounding factors, such as patient characteristics, socioeconomic status and comorbidities, and mediators, such as surgical factors.

resultsAdjusted multivariable Cox-regression analysis showed no T2DM-associated risk of reoperation after hip or knee replacement, adjusted HR 1.10 (95% CI 0.99 to 1.23) and 1.09 (95% CI 0.96 to 1.24), respectively, while T2DM was associated with increased risk of death after hip and knee replacement, adjusted HR 1.40 (95% CI 1.34 to 1.47) and 1.38 (95% CI 1.31 to 1.45). Adjusted logistic regression analysis showed T2DM-associated increase of reoperation within 90 days (OR 1.23 (95% CI 1.05 to 1.43)) and increased mortality within 90 days (OR 1.42 (95% CI 1.01 to 1.95)) following hip replacement; however, this was not the case after knee replacement, OR 1.08 (95% CI 0.85 to 1.36) for reoperation and OR 1.29 (95% CI 0.84 to 1.94) for mortality. Several factors closely linked with T2DM, such as body-mass index and comorbidities, were identified as important when assessing risk of reoperation and mortality. Regarding AEs within 30 and 90 days, very slight but not statistically significant T2DM-associated increases were seen after either hip replacement, OR 1.01 (95% CI 0.91 to 1.11) and 1.07 (95% CI 0.98 to 1.16) or after knee replacement, OR 1.05 (95% CI 0.93 to 1.17) and 1.08 (95% CI 0.98 to 1.19).

conclusionThe observed risk of reoperation suggests that T2DM alone was not a strong justification to advise against hip or knee replacement in individuals with T2DM deemed eligible for joint replacement. The T2DM-associated increased mortality after hip and knee replacement is challenging to interpret, as T2DM itself without undergoing hip or knee replacement surgery is associated with increased mortality.