A Risk Prediction Tool for Hip Fracture in Type 2 Diabetes

According to study results published in Diabetes Care, a hip fracture risk tool for patients with type 2 diabetes (T2D) performed well in predicting incident hip fractures using readily available variables such as age, sex, body mass index, neuropathy measurements, and renal function.

Although there are validated risk calculating tools for fracture risk, further research on tools to predict fractures in populations with diabetes is needed given their higher risk for fractures, potentially as a result of neuropathy and retinopathy. Researchers used data from the Fremantle Diabetes Study Phase 1 cohort to validate a newly developed T2D hip fracture risk tool and compare its capabilities with QFracture, the only published prediction equation that includes T2D as a risk factor. 

Data capturing incident hip fractures were collected through hospital or public records. The risk assessment tool was used to evaluate the risk factors and outcomes of 1251 patients with T2D (average age, 65 years). Competing risk regression modeling determined independent predictors of time to incident hip fracture.

In total, 50 participants (4%) had ≥1 hip fracture during follow-up. The tool was able to determine that common independent predictors of fracture were being older at study entry and diabetes diagnosis, being female, and having lower body mass index, a history of peripheral sensory neuropathy, and an estimated glomerular filtration rate of <45 mL/min/1.73 m².

The model predicted a mean 10-year fracture risk of 3.3% across all participants, with what the researchers determined to be good discrimination, calibration, and accuracy. For a 10-year predicted incident hip fracture cutoff of 3%, sensitivity was 76%, specificity was 71.9%, the positive predictive value was 10.1%, and negative predictive value was 98.6%.

QFracture, which performed well at predicting risk in the same population, required 25 variables; however, the risk equation developed for patients with T2D produced similar results with 5 variables that are readily available from routine medical care.

Certain limitations were noted for this study, including that results might have been biased because of missing data on some variables.

The researchers said their hip fracture risk calculator is “a useful addition to the suite of similar tools because it is the only one that has been developed and validated in people with type 2 diabetes….It can be readily implemented as part of the routine assessment of the person with type 2 diabetes.”

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Reference

Davis WA, Hamilton EJ, Bruce DG, Davis TME. Development and validation of a simple hip fracture risk prediction tool for type 2 diabetes: the fremantle diabetes study phase 1 [published online November 19, 2018]. Diabetes Care. doi:10.2337/dc18-1486