Longitudinal change in migraine headache-days and indirect cost consequences.

OBJECTIVES: To determine whether change in headache-days over 1-year is associated with change in lost productive time (LPT) among a population sample of migraineurs.

METHODS: Data are from migraine sufferers who participated in at least two consecutive annual American Migraine Prevalence and Prevention surveys between 2005 and 2008. LPT was estimated using two questions from the validated Migraine Disability Assessment survey about missed workdays and number of days at work.

RESULTS: The reduction in LPT (ie, missed workdays + reduced productive time) from 1 year to the next had a nonlinear relationship with reduction in headache-days. The relationship was directly linear, however, when change in employment status was considered in the regression model.

CONCLUSION: A reduction in headache days over time translates into a linear reduction in LPT, including an increased likelihood of employment.