Importance: A high proportion of patients who sustain a fracture have multimorbidity. However, the association of multimorbidity with postfracture adverse outcomes, such as subsequent fractures and premature mortality, has not been widely explored.
Objective: To examine the association of multimorbidity and self-rated health with subsequent fractures and mortality after fracture.
Design, setting, and participants: This prospective cohort study included participants from New South Wales, Australia, in the Sax Institute's 45 and Up Study (n = 267 357). Participants were recruited from July 2005 to December 2009 and followed up from the date of the incident fracture until subsequent fracture, death, or the end of the study (April 2017), whichever occurred first, with questionnaire data linked to hospital admission and medication records. Data analysis was reported between March and September 2023.
Exposures: Charlson Comorbidity Index (CCI) score and self-rated health (SRH).
Main outcomes and measures: The main outcomes were subsequent fracture or mortality after an incident fracture. Associations between SRH measures and subsequent fracture and mortality were also assessed. All analyses were stratified by sex given the different fracture and mortality risk profiles of females and males.
Results: Of 25 280 adults who sustained incident fractures, 16 191 (64%) were female (mean [SD] age, 74 [12] years) and 9089 (36%) were male (mean [SD] age, 74 [13] years). During a median follow-up time of 2.8 years (IQR, 1.1-5.2 years), 2540 females (16%) and 1135 males (12%) sustained a subsequent fracture and 2281 females (14%) and 2140 males (24%) died without a subsequent fracture. Compared with a CCI score of less than 2, those with a CCI score of 2 to 3 had an increased risk of subsequent fracture (females: hazard ratio [HR], 1.16 [95% CI, 1.05-1.27]; males: HR, 1.25 [95% CI, 1.09-1.43]) and mortality (females: HR, 2.19 [95% CI, 1.99-2.40]; males: HR, 1.89 [95% CI, 1.71-2.09]). Those with a CCI score of 4 or greater had greater risks of subsequent fracture (females: HR, 1.33 [95% CI, 1.12-1.58]; males: HR, 1.48 [95% CI, 1.21-1.81]) and mortality (females: HR, 4.48 [95% CI, 3.97-5.06]; males: HR, 3.82 [95% CI 3.41-4.29]). Self-rated health was also significantly associated with subsequent fracture and mortality. Those reporting the poorest health and quality of life had the highest subsequent fracture risks, and their mortality risks were even higher.
Conclusions and relevance: In this cohort study, both CCI and SRH measures were associated with increased risk of subsequent fractures and mortality after fracture, underscoring the importance of managing the care of patients with comorbidities who sustain a fracture.