Use of aspirin combinations with caffeine and increasing headache frequency: a prospective population-based study

Combinations of analgesics with caffeine have been discussed as bearing a risk for headache chronicity. We investigated whether aspirin with caffeine (ASA+) increases headache frequency compared with aspirin alone in migraine, tension-type headache (TTH), and migraine + TTH (MigTTH). The population-based German Headache Consortium Study, which included participants aged 18 to 65 years, collected information about headache and analgesics at baseline (2003-2007, t(0), response rate: 55.2%), first follow-up after 1.87 +/- 0.39 years (t(1), 37.2%), and second follow-up after 3.26 +/- 0.60 years (t(2), 38.8%). We included participants with headache at t(0), aspirin intake, ASA+ or no analgesics at t(0) and t(2), and known headache frequency. Linear regression was used to estimate changes of headache frequency (Delta t(2)-t(0)) and 95% confidence intervals depending on analgesic intake, stratified by headache subtypes, adjusting for sex, age, analgesics at t(1), changes of headache frequency at t(1), drinking, smoking, body mass index, education, headache frequency at t(0). Of 509 participants (56.0% women, 42.0 +/- 11.8 years [mean +/- SD]), 45.2% reported aspirin intake (41.3 +/- 10.9 years, 59.6% women, headache days at t(0): 2.8 +/- 3.1 d/mo, t(2): 3.6 +/- 4.1 d/mo), 11.8% ASA+ intake (46.0 +/- 9.8 years, 73.3%, t(0): 4.8 +/- 6.1 d/mo, t(2): 5.3 +/- 5.1 d/mo), and 43.0% no analgesics (41.6 +/- 13.1 years, 47.5%, t(0): 3.8 +/- 6.2 d/mo, t(2): 5.3 +/- 6.6 d/mo). There was no increase in headache frequency in participants with ASA+ intake compared with aspirin (adjusted, all headache: -0.34 d/mo [95% confidence intervals: -2.50 to 1.82], migraine: -1.36 d/mo [-4.76 to 2.03], TTH: -0.57 d/mo [-4.97 to 3.84], MigTTH: 2.46 d/mo [-5.19 to 10.10]) or no analgesics (all headache: -2.24 d/mo [-4.54 to 0.07], migraine: -3.77 d/mo [-9.22 to 1.68], TTH: -4.68 d/mo [-9.62 to 0.27]; MigTTH: -3.22 d/mo [-10.16 to 3.71]). In our study, ASA+ intake did not increase headache frequency compared with aspirin or no analgesics.