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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

From: The validity and reliability of the Patient Health Questionnaire-9 for screening depression in primary health care patients in Botswana

Cut-off PointsN(%)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
≥5179 (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
≥6166 (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
≥7145 (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
≥8132 (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
≥9112 (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
≥10103 (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
≥1191 (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
≥1279 (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
≥1369 (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
≥1454 (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
  1. LR + Positive likelihood ratio, LR– Negative likelihood ratio, PPV Positive predictive value, NPV Negative predictive value; (a) Youden’s Index = [Sensitivity + Specificity-1]