Chronic daily headache with analgesic overuse -: Epidemiology and impact on quality of life

Objective: To analyze the prevalence and demography of chronic daily headache (CDH) with analgesic overuse. Methods: A population of 9,984 inhabitants aged 14 or older living in Santona, Spain, was studied. The authors personally interviewed 4,855 subjects, using a quota sampling approach. Those with headache for greater than or equal to 10 days/month and some analgesic use were asked to fill in a diary over the course of 1 month. Then, subjects were classified into CDH with or without analgesic overuse subtypes. Quality of life ( Short Form-36 Health Survey [SF-36]) was also assessed in this second interview. Results: Headache for greater than or equal to 10 days/month with analgesic consumption was reported by 332 subjects. Seven had secondary headache. Seventy-four ( standardized prevalence 1.41%, 95% CI 1.1 to 1.8) fulfilled criteria for CDH with analgesic overuse. Prevalence in women ( 2.6%, 2.0 to 3.3) was much higher than in men (0.19%, 0.006 to 0.52). Mean age was 56 years ( range 19 to 82 years). As recalled by the subjects, the mean age at onset of CDH was 38 years ( range 9 to 82 years), whereas the mean age at onset of CDH with frequent analgesic consumption was 45 years ( range 19 to 80 years) and that of primary headache was 22 years ( range 5 to 60 years). CDH subjects showed a significant decrease in each SF-36 health-related score as compared with healthy control subjects. Transformed migraine was diagnosed in 49 ( prevalence 0.9%), chronic tension-type headache in 20 (0.4%), and new daily persistent headache in 5 (0.1%). Thirty-five percent of patients overused simple analgesics, 22% ergotics, 12.5% opioids, and 2.7% triptans; the remaining 27.8% were overusing different combinations. Conclusion: CDH with analgesic overuse is a common disorder in the general population, mainly in women in their fifties, in whom 5% meet its diagnostic criteria.