Effect of Sleep Quality on Headache-Related Impact in Primary Headache Disorders

BACKGROUND AND PURPOSE: Sleep disturbance is common in patients with primary headache disorders. We were interest in whether poor sleep quality affects patients directly or via increases in the frequency and severity of headaches. To that end, we investigated the direct and indirect effects of sleep quality on the headache-related impact among patients with primary headache disorders. METHODS: We analyzed migraine and tension-type headache (TTH) in patients included in the headache registry of our headache clinic from October 2015 to May 2018. We collected information on the headache frequency, severity, and psychological status. Sleep quality and headache-related impact were measured using the Pittsburgh Sleep Quality Index and Headache Impact Test-6, respectively. We performed path analyses with headache frequency and severity as covariates to determine the direct effect of sleep quality on the headache-related impact, and the indirect effects mediated by increases in the headache frequency and severity. RESULTS: This study included 915 patients: 784 with migraine and 131 with TTH. Worse sleep quality was independently associated with greater headache-related impact in both patients with migraine and those with TTH. Path analysis revealed a direct effect (β=0.207, p<0.001) of sleep quality and an indirect effect mediated by headache frequency and severity (β=0.067, p=0.004) on the headache-related impact in migraine. In TTH, only direct effects of sleep quality on the headache-related impact were significant (β=0.224, p=0.004). CONCLUSIONS: We suggest that poor sleep quality can directly increase the headache-related impact in both patients with migraine and TTH as well as indirectly by increasing the headache frequency and severity in patients with migraine.