Comparison of OSTA index and KKOS scoring system for prediction of Osteoporosis in postmenopausal women who attended Siriraj menopause clinic

Abstract

Objective: To compare diagnostic performance of the Osteoporosis Self-Assessment Tool for Asians (OSTA) index and Khon Kaen Osteoporosis Study (KKOS) scoring system with standard measurement of bone mineral density (BMD) by dual energy X-rays absorptiometry (DEXA) for screening osteoporosis and to determine osteoporosis risk factors in postmenopausal women who attended the Siriraj Menopause Clinic, Siriraj Hospital Subjects: Four hundred forty one postmenopausal women who attended the Siriraj menopause clinic, Department of Obstetrics and Gynecology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand and had BMD measurement by DEXA and had a diagnostic test were included in the study. Material and Method: The data were collected from medical records. Subjects who met the inclusion criteria, without exclusion criteria were collected data and calculated for OSTA index and KKOS score. Both indices at ≤ -1 were classified as high risk of osteoporosis. Sensitivity, specificity, PPV, NPV, and AUC of OSTA index, and KKOS score were compared. Risk factors for osteoporosis were analyzed. Results: The prevalence of osteoporosis was 19.7%, 18.8% for osteoporosis of lumbar spine, 2.3% for osteoporosis of femoral neck, and 2% for osteoporosis of total hip. The OSTA index in identifying osteoporosis at least one site of femoral neck, total hip or lumbar spine at original cut point of ≤ -1 had sensitivity and specificity of 51.7% and 77.4% respectively and KKOS at original cut point of ≤ -1 had sensitivity and specificity of 56.3% and 71.8% respectively. Sensitivity of OSTA index was 80% at femoral neck, 77.8% at total hip, and 49.4% at lumbar spine. KKOS had sensitivity at femoral neck, total hip and lumbar spine of 80%, 77.9%, and 54.2% respectively. Specificity of KKOS at femoral neck, total hip and lumbar spine were slightly lower than OSTA index. Age ≥ 65 years, family history of osteoporosis, and history of fracture at age > 45 years found to be risk factors for osteoporosis with odd ratio of 9.0, 2.7, and 5.3 respectively. Conclusion: Both OSTA index and KKOS scoring system had good performance in identifying osteoporosis of femoral neck and total hip but both indices had low sensitivity in identifying osteoporosis of spines. The authors recommend using OSTA index for screening osteoporosis because it is comparable in diagnostic performance and OSTA is more convenient and simpler than KKOS scoring system.