CAN SELF-REPORTED HEIGHT AND WEIGHT BE USED TO CALCULATE 10 YEAR RISK OF OSTEOPOROTIC FRACTURE

AObjectives: 1) To determine the magnitude of error between self reported height and weight and measured height and weight, 2) To measure what affect this has on calculating 10 year probability of osteoporotic fracture using the World Health Organisation Fracture Risk Assessment Tool (FRAX®). Design: Data collection from a nurse led community osteoporosis clinic. Participants: 214 post-menopausal women with at least one risk factor for osteoporosis. Measurements: Self reported and measured height and weight, risk factors for osteoporosis, demographic details, and 10 year probability of hip fracture or any major osteoporotic fracture as measured by FRAX®. Results: Patients over-reported their height by a mean (95% confidence interval) of 2.8 (2.3 – 3.2) cm and under reported their weight by a mean of 2.1 (1.3 – 2.6) Kg. The resulting underestimation of body mass index was 1.8 (1.3 – 2.0) units. Using self reported height and weight resulted in a significant over-estimation of 10 year risk of hip fracture and any major osteoporotic fracture when compared to measured height and weight; Median 10 probability of hip fracture 3.75% Vs 3.25% (p < 0.001 ), median 10 year probability of any major osteoporotic fracture 15% Vs. 14% (p < 0.001). Conclusion: When calculating 10 year risk of fracture using the FRAX on line assessment tool, measured height and weight should be used instead of self-reported height and weight