Prevalence of osteoporosis and related risk factors in UK women in the seventh decade: osteoporosis case finding by clinical referral criteria or predictive model?

Abstract

The objectives of the study were: to determine the prevalence of osteoporosis in women in their seventh decade; to determine the number of women who conformed to at least one of the current East Yorkshire Clinical Referral Criteria for Osteoporosis; and to determine the sensitivity and specificity of these referral criteria in the diagnosis of osteoporosis and to compare this with the receiver operating characteristic (ROC) curve of a logistic regression model incorporating variables that were significantly associated with the risk of osteoporosis. An observational study was carried out at the Centre for Metabolic Bone Disease, Hull Royal Infirmary, on women in their seventh decade from three general practices. Densitometric assessment of lumbar spine and femoral neck was carried out using dual-energy X-ray absorptiometry (DXA) and a detailed medical history taken. The main outcome measures were prevalence of osteoporosis in women in their seventh decade and efficacy of agreed clinical referral criteria at osteoporosis case finding. Of 823 Caucasian women who underwent DXA, 24% proved to have osteoporosis at hip, spine or both according to WHO criteria. A further 49% had osteopenia detected at hip, spine or both. At least one of the referral criteria was present in 47% of the women assessed. The sensitivity of the clinical referral criteria for detection of osteoporosis was 58% with a corresponding specificity of 60%. This point lies below the ROC curve (area under fitted curve, Az = 0.73) of a logistic regression model incorporating weight, age at menopause and current use of hormone replacement therapy. In conclusion, osteoporosis according to WHO criteria was found in almost 25% of women in their seventh decade. A simple logistic regression model provided a more sensitive method of osteoporosis case finding than the selective screening component of the clinical referral criteria employed in our practice.