Model | AUROC (95% CI) | Sensitivity | Specificity | PPV | NPV | NNS |
Original RUBY score | 0.698 (0.662 to 0.733) | 0.485 | 0.785 | 0.424 | 0.822 | 2.4 |
Extended RUBY model 1 | 0.756 (0.722 to 0.791) | 0.588 | 0.794 | 0.484 | 0.855 | 2.1 |
Extended RUBY model 2 | 0.778 (0.744 to 0.812) | 0.635 | 0.805 | 0.516 | 0.871 | 1.9 |
NCDRS | 0.648 (0.609 to 0.687) | 0.603 | 0.693 | 0.389 | 0.843 | 2.6 |
Optimal risk cut-offs: original RUBY score (12 out of 30), extended RUBY model 1 (risk threshold, 29.4%), and extended RUBY model 2 (risk threshold, 29.5%) for predicting AGT were determined by the Youden Index. NCDRS with cut-off points 27 for predicting pre-diabetes and diabetes based on ADA criteria. Extended RUBY models used corresponding absolute risk in percentage as the optimal risk cutoffs while NCDRS and original RUBY score provided risk score.
ADA, American Diabetes Association; AGT, abnormal glucose tolerance; AUROC, area under receiver operating characteristics; NCDRS, New Chinese Diabetes Risk Score; NNS, number needed to screen; NPV, negative predictive value; PPV, positive predictive value; RUBY, Risk-Understanding-By-Yourself.