Background: Simple and effective methods are needed to identify patients at risk for osteoporosis or osteoporosis-related fracture so that they can be screened with use of dual x-ray absorptiometry and counseled for treatment. Currently, we use a cumbersome survey assessing thirty-two risk factors. A much simpler score based on the Osteoporosis Self-Assessment Screening Tool (OST score) has been established as highly sensitive and specific in women, but similar data are lacking for men. This score is calculated by subtracting the age of the patient in years from the weight in kilograms and multiplying the result by 0.2. Our goal was to test the hypothesis that the OST score is more sensitive and specific than our extensive risk-assessment survey in men.
Methods: Using axial dual x-ray absorptiometry analysis, we evaluated a cohort of men who had either responded to our newspaper advertisement or were seen as patients in our orthopaedic clinic. Patients filled out the risk-assessment survey at the time of scanning. Osteoporosis was defined as a T-score of -2.5 or less in the lumbar spine, hip, or femoral neck.
Results: Twenty-seven (17%) of 158 white men, with a mean age of 67.5 years and a mean weight of 85.3 kg, had osteoporosis. After analysis of the thirty-two risk factors, two remained as significant independent predictors in the final multivariable model (p = 0.042 and p = 0.015). This model had an area under the receiver operating characteristic curve of 0.68 (>0.70 is considered to provide acceptable discrimination). The OST scores ranged from -6 (greatest risk) to 16 (least risk). With use of the OST score to predict osteoporosis, the area under the receiver operating characteristic curve was 0.76. The cutoff of an OST score of <2 provided the largest area under the receiver operating characteristic curve (0.74), with test characteristics for an OST score of <2 including a sensitivity of 85%, specificity of 64%, positive predictive value of 31%, and negative predictive value of 96%.
Conclusions: The Osteoporosis Self-Assessment Screening Tool score is superior to a broad risk-factor analysis in the identification of men at risk for osteoporosis or osteoporotic fractures. We have found it simple to use in our clinic to determine which patients should undergo dual x-ray absorptiometry screening.
Level of evidence: Diagnostic Level I. See Instructions to Authors for a complete description of levels of evidence.