CM was highly disabling in our population: mean MIDAS score was 66.6 and mean HIT-6 score 63.7.
Considering all patients, the mean score for MIDAS was 61.5 ± 68.8, the mean HIT-6 score was 62.8 ± 9.8 and the mean score for the "General Health SF-36" questionnaire was 51.8 ± 20.9.
The difference in mean HIT-6 score between chronic and episodic migraine was smaller (2.3) than the difference in mean MIDAS scores (21.6).
However, the observed decrease in mean HIT-6 score was of a similar size whether migraine sufferers had consulted or not (Fig. 1).
Similar results were evident also when comparing the mean HIT-6 score between the 195 U and the 155 U treated groups.
In the whole group of migraine sufferers who completed the HIT-6 questionnaire at the end of the conferences and 3 months later, mean HIT-6 score decreased significantly from 66.9 ± 5.9 to 63.4 ± 8.3 (P < 0.05).
After two years of treatment the mean HIT-6 score was ≤55 (some impact, little or no impact) in 68.2 % of patients and ≤49 (little or no impact) in 40.9 % of patients (data not shown).
Mean HIT-6 score was 66.9 ± 5.9 (range 49 76) and significantly higher for the migraine sufferers who were medically follow-up (67.8 ± 5.5 vs. 65.2 ± 6.4 for those without medical follow-up; P < 0.05).
A reduction in migraine disability was demonstrated by the mean HIT-6 score being significantly improved from baseline (67.2 ± 0.7) to the end of the nVNS treatment period (64.1 ± 0.7; P < 0.001) (Fig. 4).
The mean HIT-6 score decreased significantly during the period of treatment from the first to the last injection (pre 67.9 ± 4.2, post 49 ± 6.7; p < 0.001), and the proportion of patients with severe (≥60) HIT-6 score decreased as well (pre 95.8 %, post 15.4%%) (Additional file 1: Table S1).
