The prevalence and burden of medication overuse headache in Greece.

OBJECTIVE: To estimate the prevalence and burden of medication overuse headache in a representative sample of the Greek population, aged 18-70 years old. METHODS: This is a cross-sectional descriptive observational study performed by quantitative computer-assisted telephone interviews, using a standardized 37-item questionnaire for headaches. The prevalence of medication overuse headache was estimated in the general population and compared within the groups formed by factors such as age, gender, diagnosis of headache type, prophylactic treatment used, geographical regions, social class, workdays lost and loss of productivity. RESULTS: 1197 (12.0%) participants reported headaches affecting performance out of 10,008 interviewees. The estimated prevalence of medication overuse headache in the general population was 0.7% (95% CI: 0.5-0.9). The female to male ratio was 3.6:1. The proportion of medication overuse headache was largest in the 35-54 age group, followed by the over 55 group. The Aegean islands and Crete were the regions with the highest proportion of medication overuse headache. Among participants with headaches, the proportion of medication overuse headache was 5.8% (95% CI: 4.4%-7.1%); 6.3% (95% CI: 4.7%-7.9%) among females and 4.4% (95% CI: 2.2%-6.6%) among males. In the same headache group, the proportion of medication overuse headache by prophylactic treatment for headache was 19.0% (95% CI: 9.5%-29.1%) for recipients and 5.0% (95% CI: 3.8-6.3) for non-recipients. The mean absenteeism in people with medication overuse headache was 1.0 days/month (95% CI: 0.4-1.6) and the mean presenteeism 6.3 days/month (95% CI: 3.9-8.7). The social class stratification showed a significant effect between the medication overuse headache in the sample of the general population and the C2 class, corresponding to skilled manual labour (OR: 0.7, CI: 0.5-0.9). In people with chronic migraine, and chronic tension type headache, as differentiated by the 37-item questionnaire, the proportion of medication overuse headache in the headache group estimated to be 50.5% (95% CI: 40.8%-60.1%) and 45.9%, (95% CI: 29.9%-62.0%) respectively. The group of people with acute headache medication overuse fulfilling the rest of the diagnostic criteria for medication overuse headache, except from the number of headache days per month (≥15 days/month), had a prevalence of 2.0% (95% CI: 1.75-2.30) and a proportion of 17.0% (95% CI: 14.8%-19.1%) among people with headache. In the episodic types of headache, the proportion of acute headache medication overuse was higher in the subgroup of people with high frequency episodic migraine, 24.9% (95% CI: 18.8%-31.0%), while it was 10.8% (95% CI: 8.2%-13.5%), for the low frequency episodic migraine and 8.5% (95% CI: 5.5%-10.4%), for the episodic tension type headache. CONCLUSION: The prevalence of medication overuse headache in the general population in Greece and its proportion among the people with headache belongs to the lower part of the range of the reported literature, while the 3.6:1 female to male ratio is in agreement with it. In the same line, the impact of absenteeism and presenteeism on the workplace renders the condition alarming socio-economic health problem demanding immediate health policy planning.