Time since prior fracture affects mortality at the time of clinical assessment: a registry-based cohort study

Fractures are associated with increased long-term mortality in patients surviving to undergo baseline DXA. Notably, excess mortality risk does not decline with increasing time since prior hip or humerus fractures, even after accounting for comorbid medical conditions and other risk factors.

Mortality risk increases following most types of fracture. In routine clinical practice, patients with prior fractures seen for dual-energy X-ray absorptiometry scan (DXA) are "survivors;" whether they remain at increased mortality risk is unknown. We tested the association between prior fracture and all-cause mortality, stratified by time since fracture, in patients undergoing baseline DXA.

We conducted a DXA registry-based cohort study and linked to population-based health services data for the Province of Manitoba, Canada. We identified women and men ≥ 40 years with minimum 10 years of prior healthcare coverage undergoing baseline DXA and ascertained prior fracture codes since 1984 and mortality to 2017. Time since prior fracture was calculated between the clinical encounter for the fracture and baseline DXA (index date). Cox proportional hazards models estimated hazard ratios for all-cause mortality in those with compared to those without prior fracture adjusted for (1) age and sex, and (2) age, sex, comorbidities, and other covariates.

The study cohort consisted of 74,474 individuals (mean age 64.6 years, 89.7% female). During mean follow-up 9.2 years, we ascertained 14,923 (20.0%) deaths. Except for forearm fractures, all fracture sites were associated with increased mortality risk compared to those without prior fracture, even after multivariable adjustment. Excess mortality risk tended to decline slightly with time since fracture and was no longer significant > 10 years after vertebral fracture. However, excess mortality persisted > 10 years following hip or humerus fracture.

Prior fractures are associated with increased long-term mortality in patients surviving to undergo baseline DXA. Excess mortality risk does not decline with time since prior hip or humerus fractures, after accounting for potential confounders. Fracture prevention may have important long-term benefits preserving life expectancy.