Reader response: Migraine progression in subgroups of migraine based on comorbidities: Results of the CaMEO Study

I read the article by Lipton et al.1 The sociodemographic model creating subdivisions of migraine into statistically valid subgroups based on comorbidity classes to predict progression from episodic migraine (EM) to chronic migraine (CM)1 does not have any biologic or pathophysiologic basis. The distinction between EM and CM is based on a unique, purely arbitrary symptom-based nosologic template. After the widely split primary headache classification,2—itself absolutely without any biologic or pathophysiologic substance—this statistical subdivision of migraine through comorbidities1 ensures continuous generation of data sans any overarching matrix, thereby indefinitely adding to the extant confusion.