Validation of the KKOS scoring system for Screening of Osteoporosis in Thai Elderly Woman aged 60 years and older

Abstract

Background:  Osteoporosis is a major public health problem resulting in disability, deformity, pain and fractures.  The “gold standard” for osteoporosis is the bone mineral density (BMD) measurement; however bone densitometers are not widely available and the cost of measurement is high. As a solution, the “Khon Kaen Osteoporosis Study Scoring System (KKOS)” screening tool for osteoporosis was developed.  A study of the KKOS index indicated a sensitivity and specificity of 70 and 73 percent, respectively.  The receiver operating characteristic (ROC) curve was 0.73.

Objectives: The purpose of this study then was to validate the KKOS scoring index for osteoporosis screening in Khon Kaen province in elderly women age ³ 60 years of age.

Design: Retrospective diagnostic study

Methodology: The data was retrospectively collected from 487  medical records (at the Department of Nuclear Medicine, Srinagarind Hospital) of elderly women  of  ³ 60 years of age who resided in Khon Kaen province between 2004 and 2007.  Body weight, age and BMD were used to calculate the KKOS score.

Results:  Included were 487 menopausal women  of  ³ 60 years of age (mean 75.7±5.3). Mean weight was 51.7 ± 8.8 kg. The prevalence of osteoporosis, as per bone mineral density of the femoral neck by Lunar DPX-IQ densitometer, was 27.10 percent.  The KKOS score was calculated basing on age and weight.  Individuals with a KKOS score <-1 were classified as having a high risk of osteoporosis. The KKOS score at the cut-off of £ -1 had a respective sensitivity and specificity of 98.48 and 11.27 %.  The respective positive and negative predictive value was 29.21 and 34.91 %.  The area under the curve was 0.70.

Conclusion:  Although the KKOS scoring system has very high sensitivity for screening osteoporosis, the specificity and positive predictive value are low.  The index may not be sufficiently definitive for diagnosis but be more useful as a screening tool for detecting osteoporosis before prescribing bone mineral density measurements in elderly women.

Keywords:  Khon Kaen Osteoporosis Study scoring system, Osteoporosis, Elderly woman, Screening