Cost and predictors of lost productive time in chronic migraine and episodic migraine: Results from the American Migraine Prevalence and Prevention (AMPP) Study

Objective: To quantify the cost differences and predictors of lost productive time (LPT) in persons with chronic migraine (CM) and episodic migraine (EM). Methods: The American Migraine Prevalence and Prevention (AMPP) study is a US national longitudinal survey of severe headache. Cost estimates were obtained via U.S. Census income data. To elucidate the unique predictors of LPT, the optimal distribution for modeling was determined. Zero inflation models for LPT were predicted from sociodemographics, headache features, characteristics and disability, medication use, and depression. The interaction between headache status and age was the primary effect of interest. Results: The eligible sample included 6329 persons with EM and 374 persons with CM. Men with CM aged 45 to 54 years cost employers nearly $200 per week more than do their EM counterparts. Likewise, for women, costs were higher for CM, with the cost differential between EM and CM being $90 per week. After comprehensive adjustment, increases in LPT with age were significantly higher in CM than in EM (rate ratio 1.03; 95% confidence interval 1.01-1.05). When age was recoded to a decade, metric rates of LPT increased 25% more per decade for CM than for EM (rate ratio 1.25; 95% confidence interval 1.004-1.5). Conclusions: LPT is more costly and increases more rapidly for those with CM than for those with EM as age increases.