Although multimorbidity is recognised as a risk factor for falls and fractures, most studies are retrospective or cross-sectional, and few have explored the relationships between co-occurring morbidities. In 5011 participants of the Busselton Healthy Ageing Study aged 46-70 years at baseline, we evaluated the associations of multimorbidity count and patterns with incident fall- and fracture-related hospitalisations.
Twenty-one morbidities were assessed at baseline through objective measures and a self-reported questionnaire and four classes with distinct multimorbidity profiles were identified: relatively healthy, predominantly respiratory, predominantly cardiometabolic, and mental health/musculoskeletal. Fall- and fracture-related hospitalisations were captured through the Western Australian Data Linkage System from baseline visit (2010-2015) until the end of follow-up (31st December 2020). Associations were examined using Cox regression adjusting for sex, baseline age and lifestyle factors, and prior falls/fracture.
The mean number of chronic conditions at baseline was 2.8 (SD 1.8). During the follow-up incident fall- and fracture-related hospitalisations were recorded in 183 (3.6%) and 200 (3.9%) participants, respectively. A one-unit increase in multimorbidity count was associated with a 16% (95% CI: 7.5-24%) increased risk of fall-related hospitalisations. The relationship between multimorbidity count and fracture-related hospitalisations was non-linear with the risk increased exponentially for having 9 morbidities and above (9 vs 0 chronic conditions: HR 2.13 [95% CI: 1.12-4.06]). Compared with the “relatively healthy” class, multimorbidity classes with a cardiometabolic or mental health/musculoskeletal predominance were associated with an increased risk of fall-related hospitalisations (HR 2.73 [1.69-4.40] and 1.75 [1.21-2.55], respectively). For fracture-related hospitalisations, an elevated risk was observed for the “predominantly cardiometabolic” class (HR 1.71 [0.99-2.94]), albeit with limited precision.
In middle-aged adults we showed that multimorbidity count as well as certain patterns were associated with higher risk for fall- and fracture-related hospitalisations, suggesting that co-occurring morbidities should be considered when assessing a patient’s risks of falls and fractures.