INCREASED MORTALITY FOLLOWING PERIPROSTHETIC JOINT INFECTION AFTER TOTAL HIP ARTHROPLASTY: A MICROBIOLOGICALLY VERIFIED NATIONWIDE COHORT OF 1,611 PJI REVISIONS

Aim Periprosthetic Joint Infection (PJI) following Total Hip Arthroplasty (THA) is a serious complication with potential implications for patient mortality. We evaluated mortality related to PJI revisions compared to major aseptic revisions using a microbiologically verified population-based, nationwide cohort. Method We utilized data from the Danish Hip Arthroplasty Register and the Danish Microbiology Database. We included patients who underwent PJI revisions between January 1, 2010, and November 9, 2023, and compared them with patients undergoing major aseptic revisions in the same period. The follow-up period was until April 4, 2024. We calculated mortality using Kaplan-Meier method. To balance measured confounding, we used Inverse Probability of Treatment Weighting (IPTW) method to calculate adjusted hazard ratios with 95% confidence intervals (CI) comparing PJI and aseptic revisions in terms of mortality. Confounders included in the weighting were age, sex, weight, Charlson Comorbidity Index (CCI) and marital status. Results We identified 1,611 PJI revisions and 2,586 major aseptic revisions following primary THA. The mean follow-up time was 6.8 years for PJI revisions and 7.7 years for aseptic revisions. The PJI cohort had a higher proportion of men, were slightly younger, had a greater prevalence of obesity and comorbidity measured with CCI. The PJI cohort had a crude mortality rate of 5.3 deaths per 100 person-year and major aseptic revision cohort had a crude mortality rate of 4.4 deaths per 100 person-year. The adjusted Kaplan-Meier 10-year cumulative mortality was 43.9% (CI 40.5 – 47.1) for PJI and 34.9 (CI 32.6 – 37.1) for aseptic revisions. Cox proportional hazards analysis revealed an adjusted hazard ratio of 1.33 (CI: 1.20 – 1.48, p<0.001) for PJI-associated mortality. Conclusions PJI following THA is associated with a significantly higher mortality risk compared to major aseptic revisions.