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Table 3 Discriminative properties of four ΔCCQ total score cut off points for unrecovered exacerbations

From: Detecting exacerbations using the Clinical COPD Questionnaire

  Δ CCQ total score in unrecovered exacerbations
  Cut off
0.1 points
Cut off
0.2 points
Cut off
0.3 points
Cut off
0.4 points
Sensitivity, % 72.9
(60.5 - 82.8)
62.5
(50.3 - 73.4)
47.9
(36.4 - 58.9)
39.6
(29.2 - 49.1)
Specificity, % 69.1
(66.1 - 71.3)
82.0
(79.3 - 84.4)
87.6
(85.0 - 90.0)
93.1
(90.8 - 95.2)
PPV, % 34.3
(28.5 - 39.0)
43.5
(35.0 - 51.0)
46.0
(35.0 - 56.6)
55.9
(41.3 - 69.3)
NPV, % 92.0
(88.4 - 94.9)
90.8
(87.8 - 93.5)
88.4
(85.8 - 90.8)
87.4
(85.3 - 89.4)
Overall accuracy, % 69.8
(65.3 - 73.4)
78.5
(74.1 - 82.4)
80.4
(76.2 - 84.4)
83.4
(79.6 - 86.8)
True positive, n 35 30 23 19
False positive, n 67 39 27 15
Unreported,
n (% of TP)
26 (74) 22 (73) 16 (70) 13 (68)
Exacerbation type I,
n (% unreported)
8 (31) 5 (23) 4 (25) 4 (31)
Exacerbation type 2,
n (% unreported)
11 (42) 10 (45) 6 (37.5) 5 (38)
Exacerbation type 3,
n (% unreported)
7 (27) 7 (32) 6 (37.5) 4 (31)
  1. Overall accuracy = (number of true-positives+ true negatives)/(number of true positives + true negatives + false positives + false negatives). PPV: Positive Predicted Value. NPV: Negative Predicted Value. TP: True Positive. Data are presented as value or ratio (95% confidence interval).