Comorbidities and outcomes associated with young adult hip fracture: a systematic review and meta-analysis

Background: The prognosis of hip fracture in younger adults (YAs) aged 18–50 years is unestablished. Large studies that rigorously assess risk factors for hip fracture in YAs, their associated functional outcomes and mortality are lacking. While international guidelines recommend comprehensive bone health assessment and consideration of pharmacotherapy in YAs with major fragility fractures, rates of implementation of these guidelines are unknown. Methods: We systematically reviewed the existing literature on YAs with hip fracture to identify (1) clinical risk factors for hip fracture, (2) functional outcomes beyond 12 months from hip fracture (including employment and mortality) and (3) referral rates for bone health assessment. Results: Forty-four studies were included from 1875 eligible abstracts. Twenty-three studies reported data on question 1. Psychiatric disease (15% [10–23%]), glucocorticoid exposure (5% [2–14%]), psychotropic exposure (12% [3–42%]), alcohol excess (15% [6–38%]) and cigarette smoking (36% [25–49%]) were highly prevalent in YAs with hip fracture. Twenty-six studies contributed data on question 2, including four that provided mortality data. There is either good or excellent functional recovery in ≥80% of YAs by 12 months following hip fracture; however, up to 15% experience poor outcomes at two years. Mortality rates beyond one year were only reported in one study. Only eight studies were designed specifically to investigate risk factors for, or outcomes associated with, YA hip fracture. Three studies reported outcomes of interest by fracture mechanism. The Quality in Prognosis Studies tool was used to assess the risk of bias of included studies. 24/44 (54.5%) were found to have a moderate or high risk of bias. One study reported data on question 3. Conclusion: Psychiatric morbidity, alcohol excess and smoking were the major risk factors associated with hip fracture in YAs. Further research is required to establish the risk factors for minimal trauma hip fracture in YAs. Limited data on mortality in YAs following hip fracture are concerning and deserve further investigation.