RESUMO
The objective of this study was to test the validity, in the Chinese population, of the Lifting The Burden diagnostic questionnaire for the purpose of a population-based survey of the burden of headache in China. From all regions of China, a population-based sample of 417 respondents had completed the structured questionnaire in a door-to-door survey conducted by neurologists from local hospitals calling unannounced. They were contacted for re-interview by telephone by headache specialists who were unaware of the questionnaire diagnoses. A screening question ascertained whether headache had occurred in the last year. If they had, the specialists applied their expertise and ICHD-II diagnostic criteria to make independent diagnoses which, as the gold standard, were later compared with the questionnaire diagnoses. There were 18 refusals; 399 interviews were conducted in 202 women and 197 men aged 18-65 years (mean age 44.4±12.6 years). In comparison to the specialists' diagnoses, the sensitivity, specificity, positive predictive value, negative predictive value and Cohen's kappa (95% CI) of the questionnaire for the diagnosis of migraine were 0.83, 0.99, 0.83, 0.99 and 0.82 (0.71-0.93), respectively; for the diagnosis of tension-type headache (TTH), they were 0.51, 0.99, 0.86, 0.92 and 0.59 (0.46-0.72), respectively. In conclusion, the questionnaire was accurate and reliable in diagnosing migraine (agreement level excellent), less so, but adequate, for TTH (sensitivity relatively low, false negative rate relatively high and agreement level fair to good). The non-specific features of TTH do not lend themselves well to diagnosis by questionnaire.