Danish registries were used to compare 30-day post-operative infection after hip fracture surgery (2004-21, n=100,335) with an age- and sex-matched general-population cohort (n=498,943), stratified by recorded mental health diagnoses (F00-F48). Hospital-treated infection reached 18.1% among hip fracture patients with mood disorders, and hospital- or community-treated infection reached 43.0% among those with dementia, against 18.4% in comparators with dementia. The two conditions interacted on both absolute and relative scales, raising infection risk by more than 30%, with the strongest synergy in psychoactive substance use.
Why it is interesting: Quantifies, on national registry data, how far recorded mental illness compounds the short-term infection risk after hip fracture surgery.