Plain X-rays often suggest osteoporosis in patients with diabetes-related foot complications (DFC). This study investigated the prevalence of osteoporosis in individuals with DFC and whether bone deficits are worsened during their treatment. Consecutive patients presenting to the Royal Melbourne Hospital Diabetic Foot Unit, with a diagnosis of diabetes, a DFC for no more than 6 weeks, and who required pressure off-loading treatment, were recruited. Following informed consent, participants completed an osteoporosis risk factor questionnaire, had blood taken to assess other risk factors for bone loss, and had dual-energy X-ray absorptiometry (DXA) of the lumbar spine and both hips and peripheral quantitative computed tomography (pQCT) of the trabecular bone (4%) and cortical bone (66%) of both tibias. Densitometry was repeated 6 months later. Preliminary data in 26 participants (81% male; mean age +/- SD = 61 +/-14 years) revealed: mean 25-hydroxyvitamin D level 51 +/- 21 nmol/L and osteoporosis or osteopenia on initial DXA scan in 59%. The mean total hip bone mineral density (BMD) Z-score, tibial cortical density, and leg muscle cross-sectional area ipsilateral to the DFC declined from baseline to follow-up (0.205 vs 0.097; P=0.04; 1088 mg/ccm vs 643 mg/ccm; P<0.001; and 8325 mm2 vs 7701 mm2; P=0.015; respectively). The mean stress-strain index and tibial trabecular density ipsilateral to the DFC increased from baseline to follow-up (1776 mm3 vs 1850 mm3; P=0.014; and 240 mg/ccm vs 275 mg/ccm; P<0.001; respectively). The mean total hip BMD Z-score of the contralateral side showed little change from baseline to follow-up (0.309 vs 0.267, respectively; P=0.352), while the lumbar spine BMD Z-score increased (1.407 vs 1.655, respectively; P<0.001). Diabetes-related foot complications are associated with low BMD at presentation and bone loss at the ipsilateral hip and tibial cortex, indicating high fracture risk in these patients. Increasing BMD at some sites requires further investigation.
Disclosure: Eli Lilly provided a grant-in-aid supporting this study