Socioeconomic disparity and multimorbidity are associated with an increased mortality risk, though their interaction on post-fracture mortality remains unclear. We sought to determine their interaction on post-fracture excess deaths.
This nationwide population-based cohort study involved 95,372 men and 212,498 women in Denmark with an incident fracture at an average age of 72 and 75 years, respectively, between 2001 and 2014. Fracture was identified using ICD-10 codes from the National Hospital Discharge Register. Socioeconomic disparity was examined using individual-based measures (i.e., personal income, educational attainment, occupation or marital status) and the area-based measure of residential area closest to fracture time. Multimorbidity was defined using Charlson’s comorbidity index (CCI). Relative survival analysis was used to quantify excess mortality attributable to the combination of socioeconomic disparity and multimorbidity, accounting for sex, aging, and time-related mortality changes in the general population.
During a median follow-up of 6.5 years (IQR: 3-11), 41,017 men and 81,727 women died post-fracture. All individual-based socioeconomic measures, but not residential area, and CCI were independent predictors of post-fracture excess mortality in both sexes. The combination of socioeconomic disparity and multimorbidity compounded the association with post-fracture excess mortality, conferring much greater mortality risk than either alone. The 1-year post-fracture excess mortality for men in the poorest income quintile and CCI³5 was 37.4% (95% CI: 32.0%-43.2%), significantly greater than excess mortality among the poorest fracture patients with CCI of zero (17.0%; 16.1%-17.9%), and fracture patients in the richest income quantile with CCI of either zero (1.6%; 1.3%-2.0%) or ³5 (24.4%; 20.2%-29.2%). This compound excess mortality was more pronounced among patients with a hip fracture (Figure).
These data strongly suggest that socioeconomic disparity and multimorbidity compounded post-fracture excess mortality. This important finding underscores the urgent need for implementing more holistic patient-centred strategies for fracture patients who face economic challenges and multiple health issues.