The ASA score predicts infections, cardiovascular complications, and hospital readmissions after hip fracture - A nationwide cohort study

SUMMARY: This study examines the association between the ASA physical status classification score at hip fracture surgery and severe postoperative complications in patients aged 60 and older. Among both men and women, ASA scores consistently predict a wide range of complications including infections, cardiovascular complications, hospital readmissions, and death. INTRODUCTION: Hip fractures are common in aging populations and associated with poor prognosis. This study examines how the American Society of Anaesthesiologists (ASA) physical status classification is related to severe complications among hip fracture patients including infections, cardiovascular diseases, hospital readmissions, and death. METHODS: Based on a linkage of the Swedish National Inpatient Register with the Swedish National Registry for Hip Fractures (RIKSHÖFT), this study includes patients aged 60+ with first hip fracture between 1998 and 2017. We estimated associations between ASA score and complications during the hospital stay and during 1 year after hip fracture using multivariable-adjusted logistic regression and Cox proportional hazard regression. RESULTS: The study population included 170,193 hip fracture patients of which 24% died and 39% were readmitted to hospital within 1 year. The most common complications were urinary tract infections, pneumonia, second hip fractures, and heart failure. Among both men and women, higher ASA scores were consistently associated with higher risks for all complications included in this study. The strongest associations were observed for heart failure, myocardial infarction, pneumonia, and death. CONCLUSION: ASA scores are routinely assessed in clinical practice and predict a wide range of postoperative complications among hip fracture patients. Since many complications may be preventable through adequate drug treatment, rehabilitation, and risk awareness, future studies should examine the mechanisms linking ASA scores to complication risk in order to improve preventive strategies. Particularly, the high risk of cardiovascular complications among patients with high ASA scores deserves clinical and scientific attention. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00198-021-05956-w.