Effect of headache-free days on disability, productivity, quality of life, and costs among individuals with migraine

BACKGROUND: The functional impairment associated with migraine can cause physical, emotional, and economic ramifications that can affect occupational, academic, social, and family life. Understanding the relationship between headache-free days (HFDs) and the disease burden of migraine may help with decisions regarding treatment and management of migraine. OBJECTIVE: To determine the relationship between burden of disease measures and HFDs among individuals with migraine experiencing ≥4 headache days in the previous 30 days. METHODS: The 2016 U.S. National Health and Wellness Survey (N=97,503) was self-administered to a nationally representative sample of adults. Respondents with a migraine diagnosis who reported ≥4 headache days a month were included in the analysis. The primary independent variable was the number of HFDs assessed as both a continuous (HFDs in the previous 30 days) and categorical (0-10, 11-20, and 21-26 HFDs) measure. HFDs were used to predict outcomes using separate generalized linear models. Outcomes included effect on functional status and well-being, measured by the 6-item Headache Impact Test (HIT-6) score; number of days of work and/or household activities missed due to migraine; annualized indirect costs due to work productivity loss (assessed via the Work Productivity and Activity Impairment questionnaire); and annualized direct costs due to health care resource use (health care provider visits, emergency room visits, and hospitalizations). RESULTS: The survey included 372 respondents with diagnosed migraine and ≥4 headache days per month. Using HFDs as a continuous variable, each additional HFD was associated with a 0.15-point reduction in HIT-6 scores, a 5% reduction in both number of work days and household activities missed, and a 4% reduction in indirect costs; thus, a 5-day increase in HFDs would lead to a 0.75-point reduction in HIT-6 scores, 25% reduction in days of work or household activities missed, and 20% reduction in indirect costs. Analyzing HFDs as a categorical variable, respondents experiencing 21-26 HFDs had lower HIT-6 total scores than those with 0-10 HFDs (adjusted means: 66.59 vs. 63.91; P=0.001) or those with 11-20 HFDs (65.66 vs. 63.91, P=0.015). Respondents experiencing 21-26 HFDs missed fewer work days than those with 0-10 HFDs (4.44 vs. 1.46, P=0.002) or those with 11-20 HFDs (3.36 vs. 1.46, P=0.009). Similarly, respondents with 11-20 HFDs (22.99 vs. 9.72, P<0.001) and those with 21-26 HFDs (22.99 vs. 7.34, P=0.001) were associated with fewer days of household activities missed due to migraine compared with respondents with 0-10 HFDs. Respondents with 21-26 HFDs per month had significantly lower indirect costs ($16,975 vs. $6,919, P=0.025) than those with 0-10 HFDs. CONCLUSIONS: A higher number of HFDs is associated with decreased headache-related disability among those with migraine. Interventions that increase the total number of HFDs may reduce the burden and cost associated with migraine.