Clinical characteristics and patient-reported outcomes of chronic and episodic migraine patients at a US tertiary headache center: A retrospective observational study

Objective: To describe differences in clinical and demographic characteristics between patients with episodic migraine (EM) or chronic migraine (CM) and determine the effect of migraine subtype on patient-reported outcome measures (PROM). Background: Prior studies have characterized migraine in the general population. While this provides a basis for our understanding of migraine, we have less insight into the characteristics, comorbidities, and outcomes of migraine patients who present to subspecialty headache clinics. These patients represent a subset of the population that bears the greatest burden of migraine disability and are more representative of migraine patients who seek medical care. Valuable insights can be gained from a better understanding of CM and EM in this population. Methods: We conducted a retrospective observational cohort study of patients with CM or EM seen in the Cleveland Clinic Headache Center between January 2012 and June 2017. Demographics, clinical characteristics, and patient-reported outcome measures (3-Level European Quality of Life 5-Dimension [EQ-5D-3L], Headache Impact Test-6 [HIT-6], Patient Health Questionnaire-9 [PHQ-9]) were compared between groups. Results: Eleven thousand thirty-seven patients who had 29,032 visits were included. More CM patients reported being on disability 517/3652 (14.2%) than EM patients 249/4881 (5.1%) and had significantly worse mean HIT-6 (67.3 +/- 7.4 vs. 63.1 +/- 7.4, p < 0.001) and median [interquartile range] EQ-5D-3L (0.77 [0.44-0.82] vs. 0.83 [0.77-1.00], p < 0.001), and PHQ-9 (10 [6-16] vs. 5 [2-10], p < 0.001). Conclusions: There are multiple differences in demographic characteristics and comorbid conditions between patients with CM and EM. After adjustment for these factors, CM patients had higher PHQ-9 scores, lower quality of life scores, greater disability, and greater work restrictions/unemployment.