Increased long-term mortality of patients with prosthetic joint infection after primary total hip arthroplasty - a large observational cohort study.

Objective Evaluate long-term mortality and the role of causative pathogens in periprosthetic joint infection (PJI) following total hip arthroplasty (THA).Methods Retrospective nationwide cohort study of adults undergoing THA (2012-2022) using data from the Swiss Joint Registry, Center for Infection Prevention and civil registry. Primary outcome was up to 10-year survival with or without PJI. Adjusted hazard ratios (aHR) were estimated via Gompertz regression, controlling for sex, age, BMI, and ASA. Pathogen-specific mortality hazard was analyzed.Results Of 215 678 patients, 89 709 met inclusion criteria (51.3% women; median age 69 years). PJI occurred in 745 (0.8%) patients, 2 752 (3.1%) underwent aseptic revision. PJI was associated with increased mortality (aHR 2.15; 95% CI, 1.79-2.57; p<0.001) compared to no PJI/revision, aseptic revisions were not (aHR 0.92; 95% CI, 0.80-1.06; p=0.27). Pathogens associated with increased mortality included Enterobacterales (aHR 3.17; 95% CI, 2.09-4.83, p<0.001), Staphylococcus aureus (aHR 2.32; 95% CI, 1.65-3.27; p<0.001), Cutibacterium acnes (aHR 2.31; 95% CI, 1.20-4.45; p=0.01), and coagulase-negative staphylococci (aHR 1.65; 95% CI, 1.16-2.35; p=0.006). Streptococcal infections showed no significant association (aHR 1.24; 95% CI, 0.62-2.49; p=0.54).Conclusion PJI following THA was associated with an approximately twofold increase in long-term mortality hazard. C. acnes presented an unexpectedly high mortality hazard.