Opportunistic Hip Fracture Risk Prediction in Men from X-ray: Findings from the Osteoporosis in Men (MrOS) Study

Osteoporosis is a common disease that increases fracture risk. Hip fractures, especially in elderly people, lead to increased morbidity, decreased quality of life and increased mortality. Being a silent disease before fracture, osteoporosis often remains undiagnosed and untreated. Areal bone mineral density (aBMD) assessed by dual-energy X-ray absorptiometry (DXA) is the gold-standard method for osteoporosis diagnosis and hence also for future fracture prediction (prognostic). However, the required special equipment is not broadly available everywhere, in particular not to patients in developing countries. We propose a deep learning classification model (FORM) that can directly predict hip fracture risk from either plain radiographs (X-ray) or 2D projection images of computed tomography (CT) data. Our method is fully automated and therefore well suited for opportunistic screening settings, identifying high risk patients in a broader population without additional screening. FORM was trained and evaluated on X-rays and CT projections from the Osteoporosis in Men (MrOS) study. 3108 X-rays (89 incident hip fractures) or 2150 CTs (80 incident hip fractures) with a 80/20 split (training/validation) were used. We show that FORM can correctly predict the 10-year hip fracture risk with a validation AUC of 81.44% ± 3.11%/81.04% ± 5.54% (mean ± STD) including additional information like age, BMI, fall history and health background across a 5-fold cross validation on the X-ray and CT cohort, respectively. Our approach significantly (p < 0.01) outperforms previous methods like Cox Proportional-Hazards Model and with 70.19 ± 6.58 and 74.72 ± 7.21 respectively on the X-ray cohort. Our model outperform on both cohorts hip aBMD based predictions (validation AUC 82.67% ± 0.21% vs. 71.82% ± 0.50% and 78.41% ± 0.33 vs. 76.55% ± 0.89%). We are confident that FORM can contribute on improving osteoporosis diagnosis at an early stage.