Effectiveness of bone density screening for osteoporosis – adapted from the British Medical Journal 1996;312;1254-9 – Tips from Other Journals
The World Health Organization has estimated that 30 percent of all post-menopausal women have osteoporosis, as defined by bone mineral density more than 2.5 standard deviations below the mean for young healthy adult women. Postmenopausal osteoporosis leads to significant mortality, morbidity, and millions of dollars in health care and other costs. Therefore, a screening test to identify those at greatest risk of serious outcome could be a significant advance. Marshall and colleagues conducted a meta-analysis of prospective cohort studies to determine if bone density measurements could predict later fractures in postmenopausal women.
A search of both formal and informal data sources identified 11 studies published from 1985 to 1994 that met scientific criteria and were included in the study. These prospective cohort studies covered approximately 90,000 women-years of follow-up and more than 2,000 fractures. Eight case-control studies of hip fractures published between 1990 and 1994 were also included for comparative purposes.
Compared with other bone density measurements, measurements of the spine and hip appeared to have better ability to predict future fractures at those sites, but overall this measurement did not appear suitable for a population screening tool. The authors believe that using bone density measurements alone to predict fractures is comparable with using blood pressure measurements to predict stroke (that is, abnormal measurements can predict risk but cannot identify individuals who will progress to the catastrophic outcome). The wide area of overlap in the bone densities of patients who suffer a fracture and those who do not make bone density measurement suitable at best for very selective screening.
The authors conclude that firm recommendations cannot be made about selective screening because too little is known about the practical aspects of screening programs, including compliance rates for treatment and for attending a screening program, as well as the efficacy of treatments. (Marshall D, et al. Meta-analysis of how well measures of bone mineral density predict occurrence of osteoporotic fractures. BMJ 1996;312:1254 9.)
COPYRIGHT 1996 American Academy of Family Physicians
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