Clinical risk factors as predictors of postmenopausal osteoporosis in general practice

Background. Case-finding strategies to identify women with high risk for os teoporotic fractures have recently been proposed, but little information ab out such an approach in general practice known. Aim: To study the validity of the proposed case-finding for osteoporosis. Design of study: Survey using case-finding strategy. Setting: Seven hundred and twelve women aged between 55 and 84 years, rando mly selected from a general practice in The Netherlands. Method: Of the 712 randomly selected women, 449 women participated. Informa tion was obtained from a questionnaire, direct questioning, and computerise d patients files. Bone mineral density of the femoral neck was measured by dual energy x-ray absorptiometry and vertebral morphometry was performed on lateral X-rays of the spine. Osteoporosis was defined by a bone mineral de nsity T-score of less than 2.5 and/or the presence of severe vertebral defo rmities. Sensitivity,specificity and predictive values were calculated for the whole set of risk factors; those significantly associated with osteopor osis and in logistic models. Results: Clinical risk factors were present in 55% of the women and identif ied 68% of the women with osteoporosis. Three risk factors - a low body mas s index, fragility fractures, and severe kyphosis and/or loss of height - w ere associated significantly with osteoporosis; they were present in 33% of the women and identified 60% of those with osteoporosis. A logistic model based on age and fragility fractures selected 32% of the women and identifi ed 76%. Conclusion: No single risk factor could assist in identifying women with os teoporosis. A simplified case-finding strategy using only three risk factor s, that is suitable for primary care, reduces, the number of women to be ev aluated by two-thirds; however, this is at the cost of missing the diagnosi s in 40% of the women with osteoporosis. Addition of spine radiographs to t he case-finding approach helped to obtain a better risk profile of the wome n and had also practical consequences for the management of some. We propos e that radiographs should be included in any case-finding strategy.