Table 3.
Sensitivity, specificity, PPV, and NPV of clinical case definitions for cholera, Haiti, 2012–2013*
| Case definition† | No. of patients in cell‡ | Sensitivity % (95% CI) | Specificity % (95% CI) | PPV % (95% CI) | NPV % (95% CI) | |||
|---|---|---|---|---|---|---|---|---|
| A | B | C | D | |||||
| WHO case definitions | ||||||||
| Age ≥ 5 years | 1062 | 396 | 101 | 300 | 91.3 (89.6–92.8) | 43.1 (39.5–46.8) | 72.8 (70.5–75.1) | 74.8 (70.3–78.8) |
| Age ≥ 5 years and severe dehydration | 641 | 160 | 375 | 461 | 63.1 (60.1–66.0) | 74.2 (70.7–77.5) | 80.0 (77.1–82.7) | 55.1 (51.8–58.5) |
| Moderate and severe dehydration | ||||||||
| Severe dehydration | 695 | 248 | 333 | 374 | 67.6 (64.7–70.4) | 60.3 (56.2–63.9) | 73.7 (70.8–76.4) | 52.9 (49.2–56.6) |
| Moderate or severe dehydration | 1003 | 595 | 25 | 27 | 97.6 (96.4–98.4) | 4.3 (3.0–6.2) | 62.8 (60.4–65.1) | 51.9 (38.7–64.9) |
| Age ≥ 5 years and moderate or severe dehydration | 901 | 325 | 115 | 296 | 88.7 (86.6–90.5) | 47.7 (43.8–51.6) | 73.5 (71.0–75.9) | 72.0 (67.5–76.1) |
| Nausea | ||||||||
| Nausea | 807 | 339 | 359 | 281 | 69.2 (66.5–71.8) | 45.3 (41.4–49.3) | 70.4 (67.7–73.0) | 43.9 (40.1–47.8 |
| Age ≥ 5 years and nausea | 738 | 250 | 413 | 367 | 64.1 (61.3–66.8) | 59.5 (55.6–63.3) | 74.7 (71.9–77.3) | 47.1 (43.5–50.6) |
| Age ≥ 5 years and severe dehydration and nausea | 458 | 107 | 547 | 440 | 45.6 (42.5–48.7) | 80.4 (76.9–83.6) | 81.1 (77.6–84.1) | 44.6 (41.5–47.7) |
| Vomiting | ||||||||
| Vomiting | 1045 | 487 | 133 | 207 | 88.7 (86.8–90.4) | 29.8 (26.5–33.3) | 68.2 (65.8–70.5) | 60.9 (55.6–65.9) |
| Age ≥ 5 years and vomiting | 947 | 308 | 216 | 383 | 81.4 (79.1–83.6) | 55.4 (51.7–59.1) | 75.5 (73.0–77.8) | 63.9 (60.0–67.7) |
| Age ≥ 5 years and severe dehydration and vomiting | 592 | 140 | 424 | 478 | 58.3 (55.2–61.3) | 77.4 (73.9–80.5) | 80.9 (77.9–83.6) | 53.0 (49.7–56.2) |
| Muscle pain | ||||||||
| Muscle pain | 317 | 109 | 842 | 461 | 27.4 (24.9–30.0) | 80.9 (77.5–83.9) | 74.4 (70.1–78.3) | 35.4 (32.8–38.0) |
| Age ≥ 5 years and muscle pain | 294 | 96 | 850 | 472 | 25.7 (23.3–28.3) | 83.1 (79.8–86.0) | 75.4 (70.9–79.4) | 35.7 (33.2–38.3) |
| Age ≥ 5 years and severe dehydration and muscle pain | 140 | 41 | 860 | 465 | 14.0 (12.0–16.3) | 91.9 (89.2–94.0) | 77.4 (70.7–82.8) | 35.1 (32.6–37.7) |
| Number of stools in last 24 hours | ||||||||
| ≥ 5 stools | 773 | 428 | 21 | 50 | 97.4 (96.0–98.3) | 10.5 (8.0–13.5) | 64.4 (61.6–7.0) | 70.4 (59.0–79.8) |
| ≥ 10 stools | 622 | 215 | 172 | 263 | 78.3 (75.3–81.1) | 55.0 (50.5–59.4) | 74.3 (71.2–77.2) | 60.5 (55.8–64.9) |
| ≥ 15 stools | 431 | 128 | 363 | 350 | 54.3 (50.8–57.7) | 73.2 (69.1–77.0) | 77.1 (73.4–80.4) | 49.1 (45.4–52.8) |
| ≥ 20 stools | 281 | 59 | 513 | 419 | 35.4 (32.1–38.8) | 87.7 (84.4–90.3) | 82.7 (78.3–86.3) | 45.0 (41.8–48.2) |
| ≥ 25 stools | 112 | 26 | 682 | 452 | 14.1 (11.9–16.7) | 94.6 (92.1–96.2) | 81.2 (73.8–86.8) | 39.9 (37.1–42.7) |
| Age ≥ 5 years and ≥ 5 stools | 698 | 253 | 90 | 223 | 88.6 (86.2–90.6) | 46.9 (42.4–51.3) | 73.4 (70.5–76.1) | 71.3 (66.0–76.0) |
| Age ≥ 5 years and ≥ 10 stools | 580 | 171 | 208 | 305 | 73.6 (70.5–76.6) | 64.1 (59.7–68.3) | 77.2 (74.1–80.1) | 59.5 (55.2–63.6) |
| Age ≥ 5 years and ≥ 15 stools | 406 | 107 | 382 | 369 | 51.5 (48.0–55.0) | 77.5 (73.6–81.0) | 79.4 (75.4–82.4) | 49.3 (45.6–52.7) |
| Age ≥ 5 years and ≥ 20 stools | 268 | 51 | 520 | 425 | 34.0 (30.8–37.4) | 89.3 (86.2–91.8) | 84.0 (79.6–87.6) | 45.0 (41.8–48.2) |
| Age ≥ 5 years and ≥ 25 stools | 105 | 23 | 683 | 453 | 13.3 (11.1–15.9) | 95.2 (92.9–96.8) | 82.0 (74.5–87.7) | 39.9 (37.1–42.8) |
| Age ≥ 5 years and severe dehydration and ≥ 5 stools | 423 | 100 | 251 | 323 | 62.8 (59.1–66.3) | 76.4 (72.1–80.2) | 80.9 (77.3–84.0) | 56.3 (52.2–60.3) |
| Age ≥ 5 years and severe dehydration and ≥ 10 stools | 355 | 76 | 319 | 347 | 52.7 (48.9–56.4) | 82.0 (78.1–85.4) | 82.4 (78.5–85.7) | 52.1 (48.3–55.9) |
| Age ≥ 5 years and severe dehydration and ≥ 15 stools | 215 | 44 | 459 | 379 | 31.9 (28.5–35.5) | 89.6 (86.3–92.2) | 83.0 (78.0–87.1) | 45.2 (41.9–48.6) |
| Age ≥ 5 years and severe dehydration and ≥ 20 stools | 122 | 19 | 552 | 404 | 18.1 (15.4–21.2) | 95.5 (93.1–97.1) | 86.5 (79.9–91.2) | 42.3 (39.2–45.4) |
| Age ≥ 5 years and severe dehydration and ≥ 25 stools | 23 | 2 | 651 | 423 | 3.4 (2.3–5.1) | 99.5 (98.3–99.9) | 92.0 (75.0–97.8) | 39.4 (36.5–42.3) |
NPV = negative predictive value; PPV = positive predictive value.
*
Missing values excluded.
†
All case definitions include acute watery diarrhea.
‡
Refer to Figure 3.