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Table 4 Validity of BMI cut-off for detecting obesity among Ethiopian adults as compared to obesity based on the body fat percentage determined by the air displacement plethysmography (ADP)

From: Performance of newly developed body mass index cut-off for diagnosing obesity among Ethiopian adults

Sex Cut-off values TP (a) FP (b) FN (c) TN (d) Total Sensitivity (%) Specificity (%) PPV (%) NPV (%) Kappa Agreement P
Males BMI ≥ 30 kg/m2 8 1 144 154 307 5.3 99.4 88.9 51.7 0.047 Slight 0.0160
BMI > 22.2 kg/m2a 133 19 19 136 307 87.5 87.7 87.5 87.7 0.752 Substantial < 0.0001
Females BMI ≥ 30 kg/m2 75 0 185 137 397 46.9 100.0 100.0 42.5 0.219 Fair < 0.0001
BMI > 24.5 kg/m2a 208 6 52 131 397 80.0 95.6 97.2 71.6 0.701 Substantial < 0.0001
  1. Sensitivity = a/a + c, specificity = d/b + d, positive predictive value (PPV) = a/a + b, negative predictive value (NPV) = d/c + d. Kappa agreement (0 = no/poor), (0.01–0.20 = slight), (0.21–0.40 = fair), (0.41–0.60 = moderate), (0.61–0.80 = substantial), and (0.81–1.00 = almost perfect) (William et al., 2011). ADP measured body fat percentage > 25 for males and > 35 for females was used as a gold standard [20]. BMI cut-off for obesity ≥ 30 kg/m2 is the WHO cut-off [20]
  2. ADP air displacement plethysmography
  3. aEthiopian sex-specific cut-off for BMI for defining obesity based on the local data