Table 6.

Receiver operating characteristic curve analyses for cough severity VAS score thresholds predictive of PGIC scores.

VAS change score threshold, mm	Sensitivity	Specificity	PPV	NPV	Youden index
PGIC score of 1, 2, or 3
⩽-10	0.76	0.64	0.83	0.54	0.41
⩽-15	0.68	0.76	0.87	0.50	0.44
⩽-18	0.64	0.81	0.89	0.49	0.46
⩽-20	0.61	0.86	0.91	0.48	0.47
⩽-30	0.48	0.89	0.91	0.42	0.37
⩽-40	0.38	0.93	0.93	0.39	0.31
⩽-50	0.24	0.99	0.98	0.35	0.22
⩽-60	0.12	1.00	1.00	0.32	0.12
PGIC score of 1 or 2
⩽-10	0.83	0.47	0.48	0.82	0.29
⩽-20	0.76	0.70	0.59	0.83	0.45
⩽-30	0.66	0.79	0.65	0.80	0.45
⩽-40	0.55	0.86	0.71	0.77	0.42
⩽-50	0.37	0.95	0.80	0.72	0.31
⩽-60	0.17	0.97	0.79	0.67	0.15
⩽-70	0.07	1.00	1.00	0.65	0.07

NPV, negative predictive value; PGIC, patient global impression of change; PPV, positive predictive value; VAS, visual analog scale.