Increased all-cause mortality following proximal humerus fractures in Danish adults: a register-based matched cohort study of 93,952 fracture cases and 469,760 controls.

Unlabelled: Mortality after proximal humerus fractures (PHF) has received less attention compared to hip fractures. We found higher all-cause mortality among PHF patients in Denmark compared to matched controls, with the highest rates within 30 days post-fracture, especially in men. Further research is needed to identify factors associated with this increased mortality.

Purpose: To assess all-cause mortality among adults with PHFs in Denmark, compared to age- and sex-matched controls from the general population.

Methods: This population-based matched cohort study retrieved data from the Danish National Patient Register and the Danish Civil Registration System from 1998-2018. Adults with a PHF were included and matched 1:5 on age and sex. Outcomes were death at 30 and 90 days, one and two years. Poisson regression analysis accounting for interactions was performed, and age- and sex-specific mortality rates (MRs) per 1,000 persons were calculated for PHFs and controls. Mortality rate-ratios (MRRs) were calculated for all age groups.

Results: We included 93,952 PHF patients and 469,760 age- and sex-matched controls. Across all time periods, MRs were higher among PHF patients, with MRs consistently higher for men than women. MRs increased with age in both PHF patients and controls. For individuals aged ≥ 60 years, the MRRs among PHF patients and controls were highest within the first 30 days post-fracture, particularly for the age group 60-69 years, where the MRR was 16.32 (95% CI: 14.47-18.40) for males and 7.82 (95% CI: 7.15-8.54) for women. Between 31 and 90 days, the MRR decreased to 6.75 (95% CI: 6.07-7.52) for men and 3.87 (95% CI: 3.58-4.19) for women. After one year, the MRR stabilized and remained relatively unchanged throughout the two-year follow-up.

Conclusion: Danish patients with PHF demonstrated substantially higher all-cause MRs than their controls, with the highest rates within the first 30 days after the fracture, especially among men.