The impact of comorbidities on hip fracture mortality: a retrospective population-based cohort study

The impact of comorbidities on hip fracture-related excess mortality was assessed in a population-based age-and sex-matched cohort over 10 years. On average, only 1 out of 12 excess deaths over 10 years was related to pre-fracture life-threatening comorbidities. The presence of life-threatening comorbidities increased the excess risk of death after hip fracture. Purpose This work aimed to estimate the impact of pre-fracture comorbidities on the 10-year excess risk of all-cause death after hip fracture among Estonian men and women >= 50 years of age. Methods Retrospective, population-based 10-year study of people aged >= 50 in two cohorts: those with a hip fracture and an age-and sex-matched random sample from the national health insurance fund for comparison. Results We found that hip fracture was a strong independent risk factor for death. Upon adjustment for Charlson Comorbidities Index (CCI) score, the impact of life-threatening comorbidities on average hip fracture-related excess mortality was modest: only 8% of excess deaths over 10 years were related to comorbidities. Upon stratification by CCI groups, the excess risk of patients in CCI groups >= 3 and 1-2 exceeded that in the CCI 0 group over 5-7 years, indicating that in patients with life-threatening comorbidities, a hip fracture accelerates the chain of lethal events and brings deaths from other conditions forward. The impact of comorbidities was age-and time-dependent: in younger hip fracture patients, the comorbidities almost doubled the excess risk from a fracture in 10 years; in older patients, the effect was shorter and modest. Conclusions The presence of pre-fracture comorbidities increases the risk of excess death in hip fracture patients, but the comorbidity impact on aggregated excess mortality is modest.