Migraine chronification as an allostatic disorder: a proof-of-concept study

Objective: The underpinning biologics of migraine chronification are not well understood. We aim to investigate the role of the cumulative burden of stress, namely the allostatic load, in migraine chronification. Methods: This was a cross-sectional study. The allostatic load was measured with a composite multi-system score (BALI: Bologna Allostatic Load Index), evaluating 20 biomarkers representing four physiological systems: immune, metabolic, cardiovascular, and neuroendocrinological systems. BALI score was subdivided into high score and low score based on the distribution in controls. Migraine patients were included and subclassified into low-frequency episodic migraine group (low-EM group), high-frequency episodic migraine group (high-EM group), and chronic migraine group (CM group). Results: The distribution of BALI high-score increased in parallel with headache attacks monthly frequency: 16% in low-EM group (n = 10), 24% in high-EM group (n = 12), and 40% in CM group (n = 21) (p = 0.017). In a multivariable analysis, the odds ratio of having a high-score BALI in CM patients (vs. low-EM patients) was 2.78 (95% CI 1.07–7.22; p = 0.036). Individual BALI biomarkers values which were significantly different among migraine subgroups included systolic blood pressure (p = 0.018), diastolic blood pressure (p < 0.001), and heart rate (p = 0.019). Conclusion: Our study substantiates this emerging concept of migraine chronification as an allostatic disorder.