The associations of multimorbidity with fall- and fracture-related hospitalisations: the Busselton Healthy Ageing Study.

Unlabelled: In middle-aged adults, we evaluated the associations between multimorbidity count and patterns with fall- and fracture-related hospitalisations. Falls risk increased linearly with multimorbidity count, and certain multimorbidity patterns were associated with increased risks of falls and fractures. Multimorbidity count and pattern should therefore be considered when risk stratifying patients.

Purpose: Although multimorbidity is recognised as a risk factor for falls and fractures, most studies are retrospective, and few have explored these relationships through statistically derived multimorbidity patterns. Our prospective cohort study with 4991 participants of the Busselton Healthy Ageing Study aged 45-69 years evaluated the associations of multimorbidity count and classes with incident fall- and fracture-related hospitalisations.

Methods: Twenty-one morbidities were assessed at baseline, and four multimorbidity classes were identified using latent class analysis. Fall- and fracture-related hospitalisations were captured through the Western Australian Data Linkage System over a median follow-up of 7.9 years. Associations were examined using Cox regression models adjusting for sex, baseline age, lifestyle factors, and prior falls/fractures.

Results: During follow-up, incident fall- and fracture-related hospitalisations were recorded for 177 (3.5%) and 197 (3.9%) participants, respectively. Each one-unit increase in multimorbidity count was associated with a 16% (95% CI, 7.8-25%) increased risk of fall-related hospitalisations. Multimorbidity scores of 9 and above (HR 2.32 [1.22-4.42]) showed an increased risk of fractures. Compared with the relatively healthy class, the cardiometabolic or mental health and musculoskeletal classes were associated with an increased risk of fall-related hospitalisations (HR 2.84 [1.76-4.59] and 1.78 [1.23-2.59], respectively). The cardiometabolic class was associated with an increased risk of fracture-related hospitalisations (HR 1.79 [1.04-3.07]).

Conclusion: In middle-aged adults, we showed that multimorbidity count and certain multimorbidity patterns were associated with increased risk for fall- and fracture-related hospitalisations. Multimorbidity should therefore be considered when assessing a patient's risk of falls and fractures.