Table 1

 Performance indexes associated with different cut off values of (A) crude and (B) relative change in pain VAS assessment

(A) Cut off value for crude change in pain VAS between day 0 and day 20
−40 mm−30 mm−20 mm−10 mm
Sensitivity56.4 (39.6 to 72.2)76.9 (60.7 to 88.9)87.2 (72.6 to 95.7)92.3 (79.1 to 98.4)
Specificity91.7 (77.5 to 98.2)80.6 (64.0 to 91.8)69.4 (51.9 to 83.7)58.3 (40.8 to 74.5)
Accuracy*73.3 (61.9 to 82.9)78.7 (67.7 to 87.3)78.7 (67.7 to 87.3)76.0 (64.7 to 85.1)
(B) Cut off value for relative change in pain VAS between day 0 and day 20
−60%−50%−40%−33%
Results are expressed as point estimates (95% confidence intervals).
*Accuracy is defined as the proportion of patients for whom treatment was correctly classified as success or failure.
Sensitivity76.9 (60.7 to 88.9)87.2 (72.6 to 95.7)87.2 (72.6 to 95.7)89.7 (75.8 to 97.1)
Specificity88.9 (73.9 to 96.9)80.6 (64.0 to 91.8)69.4 (51.9 to 83.7)69.4 (40.8 to 74.5)
Accuracy*82.7 (72.2 to 90.4)84.0 (73.7 to 91.4)78.7 (67.7 to 87.3)80.0 (69.2 to 88.4)