Accuracy of body mass index compared to whole-body dual energy X-ray absorptiometry in diagnosing obesity in adults in the Eastern Province of Saudi Arabia: A cross-sectional study

BACKGROUND:
Obesity is a major health concern that requires accurate diagnosis and management. Body mass index (BMI) commonly used to diagnose obesity, has limitations in accurately assessing body fat. Body fat percentage (BF%) from whole-body dual energy X-ray absorptiometry (DEXA) scans is gaining popularity as a more accurate method in diagnosing obesity.


MATERIALS AND METHODS:
This cross-sectional study included 319 adult patients who underwent whole-body DEXA scans in the Eastern Province of Saudi Arabia from May 2016 to December 2021 were recruited from three medical centers, where data for whole-body DEXA were available. Body fat percent was obtained from the whole-body DEXA scan reports and were compared to BMI to evaluate prevalence of obesity. Data was extracted by reviewing patients’ records using a structured data collection tool. BMI was defined using WHO criteria, and diagnostic performance was assessed by estimating specificity, sensitivity, likelihood ratios, and predictive values, and by constructing receiver operating characteristic (ROC) curves for BMI to detect obesity by age group.


RESULTS:
The gender-specific BF% cutoff points revealed a higher prevalence of obesity than BMI cutoff points. BMI misclassified 40.6% of participants, and optimal cutoff points yielding highest area under the curve were 24 kg/m2 and 24.3 kg/m2 for males and females, respectively.


CONCLUSION:
The study underscores the importance of using accurate and comprehensive diagnostic tools such as whole-body DEXA scans to assess obesity.