Title:
Healthcare resource utilization and direct costs associated with frequent nausea in episodic migraine: results from the American Migraine Prevalence and Prevention (AMPP) Study.

Abstract:
Nausea is a common migraine symptom that is associated with impaired quality-of-life and functional disability. In this study, population-based data were used to elucidate the relationship between nausea frequency and headache-related healthcare utilization and costs in persons with migraine.
Participants with episodic migraine who completed the 2009 American Migraine Prevalence and Prevention (AMPP) Study survey rated their headache-related nausea as occurring never, rarely, <half the time, or ≥half the time with their headaches, and completed questions on symptom frequency and healthcare resource utilization.
Ordinal logistic regression models were used to assess the association between nausea frequency and headache-related healthcare utilization. Healthcare cost equivalents were calculated.
Among the 6488 respondents with episodic migraine, the number of respondents observed across headache-related nausea frequency strata were 6.9% for never, 14.5% for rarely, 29.1% for <half the time, and 49.5% for ≥half the time. In unadjusted models, the odds of having ≥1 healthcare encounter for headache in the preceding year increased with frequency of nausea for primary care/obstetrics-gynecology visits (OR = 1.41; 95% CI = 1.30-1.52, p < 0.001), nurse practitioner/physician assistant visits (OR = 1.52; 95% CI = 1.25-1.85, p < 0.001), neurology/headache clinic visits (OR = 1.33, 95% CI = 1.18-1.51, p < 0.001), pain clinic visits (OR = 1.31, 95% CI = 1.01-1.71, p < 0.05), emergency department visits (OR = 1.85; 95% CI = 1.56-2.19, p < 0.01), and overnight hospital stays (OR = 1.50, 92% CI = 1.12-2.00, p < 0.01). The odds of having ≥1 lifetime CT scan or MRI also increased with the frequency of nausea (p < 0.001 for both). Results remained significant in these analyses when controlling for sociodemographics and overall symptom severity except in the case of pain clinic visits (p < 0.107). Visits for Mental Health and visits for Chiropractic/Alternative care did not differ significantly by nausea group in unadjusted or adjusted models. Mean estimated direct headache-related healthcare cost equivalents per person per year generally increased with increasing headache-related nausea frequency across categories of healthcare utilization. Average per person healthcare cost for nausea ≥half the time vs nausea never was $179 and $49 yearly for outpatient services, $183 vs $20 yearly for overnight hospital stays, and $314 vs $257 for lifetime diagnostic services/imaging.
Direct costs of migraine increase with increasing frequency of migraine-associated nausea. Both frequency and severity of headache-related nausea should be monitored as part of ongoing care of persons with migraine. Headache-related nausea, like headache pain, should be considered an area of central concern during clinical, diagnostic, and treatment optimization assessments.
This study relied on self-reported headache frequency and healthcare costs which are subject to recall bias and under-reporting; however, reporting bias is unlikely to be different as a function of nausea frequency. In addition, medication use costs and indirect costs (which may be higher than direct costs for migraine) were not assessed.