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. Author manuscript; available in PMC: 2018 Mar 1.
Published in final edited form as: J Acquir Immune Defic Syndr. 2017 Mar 1;74(3):332–338. doi: 10.1097/QAI.0000000000001224

Figure 1. Receiver operating characteristic (ROC) curve showing the 10 and 11.5 cutpoints in the HIV+ group.

Figure 1

In the HIV+ group (n=60), Sensitivity and specificity of the standard raw cutpoint (≤10) were 36% and 75%. Using the cutpoint of ≤11.5 improved the sensitivity to 72% but decreased the specificity to 58%. The positive predictive value (PPV) increased slightly from 68% (≤10) to 72% (≤11.5) and the negative predictive value (NPV) increased from 44% (≤10) to 58% (≤11.5). The overall accuracy for the standard cutpoint (≤10) was 52% while the 11.5 cutpoint provided an overall accuracy of 67%. Youden’s index (J) increased from 0.11 (≤10) to 0.30 (≤11.5); Youden’s index is the vertical distance between the ROC curve and the first bisector (or chance line).

Considering only the participants HIV+ with HAD (n=5) and using 11.5 cut-off, the sensitivity of IHDS was 40% (2 out of 5 got values below 11.5); while three (60%) got a perfect score of 12, but it is a very small number of subjects limiting the ability to test the accuracy.