The association between socioeconomic position and infection risk after hip fracture surgery: a nationwide cohort study of 54,853 patients

Abstract

Purpose: We examined the association between socioeconomic position (SEP) and risk of any infection after surgery for hip fracture, and whether markers of poor health modify this.

Methods: Individual-level data on SEP markers (education, liquid assets, marital status, and cohabitation) were obtained from Danish registries for hip fracture patients undergoing surgery (2010-2018). We computed cumulative incidences of any hospital-treated infection within one month after surgery. Using Cox regression we estimated adjusted hazard ratios (aHRs) with 95% confidence intervals. Analyses were stratified by comorbidity clusters based on latent class analysis, body mass index (BMI), pre-fracture mobility, and residence type.

Results: The incidences of infection were: 17% for low vs 16% for high education (aHR 1.10, 1.02-1.18), 19% for low vs 16% for high liquid assets (aHR 1.21, 1.15-1.28), 18% for divorced vs 16% for married (aHR 1.24, 1.15-1.32), and 18% for living alone vs 15% for cohabiting (aHR 1.16, 1.06-1.28). The incidence of infection was highest among patients with diabetic-renal comorbidity, underweight, poor mobility, or nursing home residency. The magnitude and direction of associations were modified by comorbidity clusters, BMI, mobility, and residence type. Conclusion: We observed socioeconomic inequalities in 30-day risk of infection after hip fracture surgery. Health modified the observed inequalities but could not fully explain them.