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

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.