An audit of bone densitometry practice with reference to ISCD, IOF and NOF guidelines

Abstract

The impact of osteoporosis guidelines on clinical practice has not been fully evaluated. To estimate the positive predictive value (PPV) of the National Osteoporosis Foundation (NOF), the International Osteoporosis Foundation (IOF) and the International Society for Clinical Densitometry (ISCD) guidelines for osteoporosis and compare it to the PPV of clinical judgement alone. All subjects tested for bone mineral density during the fall of 2001 in three teaching hospitals in Beirut were invited to participate. The reference databases used for the calculation of the T-score were the NHANES database for the hip and the manufacturer's database for the spine. The impact of using guidelines was measured by the increment in PPV. Osteoporosis was defined as a T-score < or =-2.5 at either the spine or hip. A total of 307 post-menopausal women were tested with dual-energy X-ray absorptiometry (DXA). In current practice (clinical judgement alone), the PPV for osteoporosis was 42.4%; using NOF guidelines, 236 women would have been tested, and the PPV would have been 46.2%. Similarly, using IOF or ISCD guidelines, 236 women would have been tested, and the PPV would have been 47.1%. Compared to current clinical practice, application of the ISCD, IOF and NOF guidelines may increase the predictive value of a central DXA for osteoporosis.