Wendy A Davis1, Emma J Hamilton1,2, David G Bruce1, Timothy M E Davis3. 1. Medical School, The University of Western Australia, Fremantle Hospital, Fremantle, Western Australia, Australia. 2. Department of Endocrinology and Diabetes, Fiona Stanley Hospital, Murdoch, Western Australia, Australia. 3. Medical School, The University of Western Australia, Fremantle Hospital, Fremantle, Western Australia, Australia tim.davis@uwa.edu.au.
Abstract
OBJECTIVE: To develop a type 2 diabetes hip fracture risk tool in community-based patients, to validate it in an independent cohort, and to compare its performance against the only published prediction equation to include type 2 diabetes as a risk factor (QFracture). RESEARCH DESIGN AND METHODS: Hip fracture hospitalizations in 1,251 participants with type 2 diabetes aged 40-89 years from the longitudinal Fremantle Diabetes Study Phase I (FDS1) were ascertained between entry (1993-1996) and end-2012. Competing risk regression modeling determined independent predictors of time to first fracture over 10 years and the coefficients incorporated in a risk model. The model was validated in 286 participants with type 2 diabetes from the Busselton Health Study (BHS). RESULTS: Fifty FDS1 participants (4.0%) experienced a first hip fracture during 10,306 person-years of follow-up. Independent predictors of fracture were older age, female sex, lower BMI, peripheral sensory neuropathy, and estimated glomerular filtration rate <45 mL/min/1.73 m2. The model-predicted mean 10-year incident fracture risk was 3.3% with good discrimination, calibration, and accuracy. For a 3% cutoff, sensitivity was 76.0%, specificity 71.9%, positive predictive value (PPV) 10.1%, and negative predictive value (NPV) 98.6%. Model performance in the small BHS sample was also good (sensitivity 66.7%, specificity 79.8%, PPV 6.2%, and NPV 99.2%). QFracture performed well in FDS1 but required availability of 25 variables. CONCLUSIONS: The FDS1 hip fracture risk equation is a simple validated adjunct to type 2 diabetes management that uses variables that are readily available in routine care.
OBJECTIVE: To develop a type 2 diabetes hip fracture risk tool in community-based patients, to validate it in an independent cohort, and to compare its performance against the only published prediction equation to include type 2 diabetes as a risk factor (QFracture). RESEARCH DESIGN AND METHODS: Hip fracture hospitalizations in 1,251 participants with type 2 diabetes aged 40-89 years from the longitudinal Fremantle Diabetes Study Phase I (FDS1) were ascertained between entry (1993-1996) and end-2012. Competing risk regression modeling determined independent predictors of time to first fracture over 10 years and the coefficients incorporated in a risk model. The model was validated in 286 participants with type 2 diabetes from the Busselton Health Study (BHS). RESULTS: Fifty FDS1 participants (4.0%) experienced a first hip fracture during 10,306 person-years of follow-up. Independent predictors of fracture were older age, female sex, lower BMI, peripheral sensory neuropathy, and estimated glomerular filtration rate <45 mL/min/1.73 m2. The model-predicted mean 10-year incident fracture risk was 3.3% with good discrimination, calibration, and accuracy. For a 3% cutoff, sensitivity was 76.0%, specificity 71.9%, positive predictive value (PPV) 10.1%, and negative predictive value (NPV) 98.6%. Model performance in the small BHS sample was also good (sensitivity 66.7%, specificity 79.8%, PPV 6.2%, and NPV 99.2%). QFracture performed well in FDS1 but required availability of 25 variables. CONCLUSIONS: The FDS1 hip fracture risk equation is a simple validated adjunct to type 2 diabetes management that uses variables that are readily available in routine care.