Poor agreement between self-reported diagnosis and bone mineral density results in the identification of osteoporosis

Osteoporosis is a major health concern, estimated to affect millions worldwide. Bone mineral density (BMD) assessment is not practical for many large-scale epidemiological studies resulting in the reliance of self-report methods to ascertain diagnostic information. The aim of the study was to assess the validity of self-reported diagnosis of osteoporosis in a population-based study. This study examined data collected from 906 men and 843 women participating in the Geelong Osteoporosis Study. Osteoporosis was self-reported and compared against results of BMD scans of the hip and spine. Validity was examined by calculating sensitivity, specificity, positive predictive value, negative predictive value, and kappa statistic. Osteoporosis was self-reported by 118 (6.7%) participants and identified using BMD results for 64 (3.7%) participants. Specificity and negative predictive value were good (95.1% and 96.0%, respectively), whereas sensitivity and positive predictive value were poor (35.9% and 31.4%, respectively). The overall level of agreement (kappa) was 0.29. The results changed only slightly when we included participants with osteopenia and adult fracture as osteoporotic. Reliance on self-report methods to ascertain osteoporosis status is not recommended.