Table 4.

Sensitivity, specificity, PPV, NPV, and accuracy of likelihood of treatment response based on the duration of PHN

PHN duration a	Moderate-to good pain relief, n	Poor pain relief, n	Sensitivity	Specificity	PPV	NPV	Accuracy
≤11 months	16	13	84.2%	43.5%	55.2%	76.9%	61.9%
>11 months	3	10

Note: ^aWe sought to establish the optimum cutoff point for PHN duration that would be predictive of moderate-to-good pain relief at 12 weeks.

Abbreviations: NPV, negative predictive value; PHN, postherpetic neuralgia; PPV, positive predictive value.