Socioeconomic status and mortality after acute hip fracture surgery in Sweden: a registry-based nationwide epidemiologic study.

BACKGROUND: The relationship between socioeconomic status and outcomes after hip fracture surgery remains unclear. We aimed to assess the association between individual-level socioeconomic status indicators and mortality after acute hip fracture surgery in Sweden. METHODS: Cross-linked registry-based cohort study of patients undergoing acute hip fracture surgery in Sweden 2015-20. Co-primary outcomes were 30-day and 2-yr all-cause mortality. Socioeconomic status was defined using four indicators: level of education, income, residential area, and receipt of social services. Attributable fractions were calculated to illustrate the potential population-level distribution of mortality differences across SES categories. RESULTS: There were 58 641 patients included (median age 83 [interquartile range 75-89] yr, 66.1% women). Crude 30-day and 2-yr mortalities were 7.9% (95% confidence interval [CI] 7.7-8.1) and 35.3% (95% CI 34.9-35.7). Level of education showed the strongest association, with a stepwise gradient most pronounced for 2-yr mortality: adjusted odds ratio 1.16 (95% CI 1.08-1.24) for 10-12 yr, 1.20 (95% CI 1.09-1.32) for 9 yr, and 1.25 (95% CI 1.16-1.34) for <9 yr vs >12 yr (all P<0.001). The attributal fraction for 2-yr mortality was 14.0% (standard error 0.022), with an increase in absolute risk of 6.3% (95% CI 4.3-8.2) for >12 yr vs <9 yr of education. Other socioeconomic status factors, except residential area, were also associated with mortality, although less substantially. CONCLUSIONS: Individual socioeconomic status was associated with short- and long-term death after acute hip fracture surgery in Sweden, with education showing the strongest relationship. These findings support consideration of individual-level socioeconomic factors in perioperative hip fracture care at the population level.