A pilot methodological validation study for a population-based survey of the prevalences of migraine, tension-type headache and chronic daily headache in the country of Georgia

We report the methodology of an epidemiological survey of the prevalences of migraine, tension-type headache and chronic daily headache in Georgia. Medical residents visited adjacent households in Tbilisi to interview a pre-defined target of 100 biologically unrelated subjects. All respondents reporting headache in the previous year, as well as random 20 non-headache controls, were examined by a neurologist. The response rate was 70%. Of 156 respondents, 93 were biologically unrelated and 45 (48%) reported headache in the previous year. Eight subjects fulfilled all IHS criteria for migraine (1-year prevalence 8.6% [95% CI: 2.9–14.3%]), and 13 had probable migraine, meeting all but the criterion for duration. Nineteen had tension-type headache (20.4% [95% CI: 12.2–28.6%]) and five had chronic daily headache (5.4% [95% CI: 1–10.0%]). In comparisons of diagnoses by questionnaire and neurologist (considered the gold standard), sensitivities for the questionnaire of 89% for migraine and 67% for tension-type headache were calculated (overall kappa=0.74).