Table 3.
Sensitivity, specificity, +LR, −LR, PPV, NPV, accuracy for different PHQ-9 cut-off points compared to the gold standard MINI and Youden’s index
| Cut-off Points | N(%) | Sensitivity (95% C.I) | Specificity (95% C.I) | +LR (95% C.I) | -LR (95% C.I.) | PPV (95% C.I) | NPV (95% C.I) | Youden’s Indexa |
|---|---|---|---|---|---|---|---|---|
| ≥5 | 179 (69.6%) | 93.3 (86.7–97.3) | 46.7 (38.6–55.0) | 1.8 (1.5–2.0) | 0.14 (0.07–0.3) | 54.7 (50.8–58.6) | 91 (82.9–95.5) | 0.4004 |
| ≥6 | 166 (64.6%) | 91.4 (84.4–96.0) | 54.0 (45.7–62.1) | 2.0 (1.7–2.4) | 0.16 (0.08–0.3) | 57.8 (53.3–62.2) | 90.1 (82.7–94.5) | 0.4538 |
| ≥7 | 145 (56.4%) | 82.9 (74.3–89.5) | 61.8 (53.6–69.6) | 2.2 (1.7–2.7) | 0.28 (0.2–0.4) | 60 (54.6–65.2) | 83.9 (77.1–89.0) | 0.4470 |
| ≥8 | 132 (51.4%) | 77.1 (67.9–84.8) | 66.5 (58.3–73.9) | 2.3 (1.8–2.9) | 0.34 (0.2–0.5) | 61.4 (55.4–67.0) | 80.8 (74.4–85.9) | 0.4359 |
| ≥9 | 112 (43.6%) | 72.4 (62.8–80.7) | 76.3 (68.7–82.8) | 3.1 (2.2–4.2) | 0.36 (0.3–0.5) | 67.9 (60.8–74.2) | 80 (74.3–84.7) | 0.4870 |
| ≥10 | 103 (40.1%) | 68.6 (58.8–77.3) | 79.6 (72.3–85.7) | 3.4 (2.4–4.7) | 0.39 (0.3–0.5) | 69.9 (62.3–76.5) | 78.6 (73.2–83.1) | 0.4818 |
| ≥11 | 91 (35.4%) | 60.0 (50.0–69.4) | 81.6 (74.5–87.4) | 3.3 (2.3–4.7) | 0.49 (0.4–0.6) | 69.2 (60.9–76.5) | 74.7 (69.8–79.1) | 0.4158 |
| ≥12 | 79 (30.7%) | 53.3 (43.3–63.1) | 84.9 (78.2–90.2) | 3.5 (2.3–5.3) | 0.55 (0.4–0.7) | 70.9 (61.6–78.7) | 72.5 (68.0–76.6) | 0.3820 |
| ≥13 | 69 (26.8%) | 48.6 (38.7–58.5) | 88.2 (81.9–92.8) | 4.1 (2.5–6.6) | 0.58 (0.5–0.7) | 73.9 (63.8–82.0) | 71.3 (67.1–75.1) | 0.3673 |
| ≥14 | 54 (21.0%) | 39.1 (29.7–49.1) | 91.5 (85.8–95.4) | 4.6 (2.6–8.1) | 0.67 (0.6–0.8) | 75.9 (64.0–84.8) | 68.5 (64.9–71.8) | 0.3050 |
LR + Positive likelihood ratio, LR– Negative likelihood ratio, PPV Positive predictive value, NPV Negative predictive value; (a) Youden’s Index = [Sensitivity + Specificity-1]