HIT-6 and MIDAS as measures of headache disability in a headache referral population

The objective of this study was to compare the headache impact test (HIT-6) and the migraine disability assessment scale (MIDAS) as clinical measures of headache-related disability.

The degree of headache-related disability is an important factor in treatment planning. Many quality of life and headache disability measures exist but it is unclear which of the available disability measures is the most helpful in planning and measuring headache management.

We compared HIT-6 and MIDAS scores from 798 patients from the Canadian Headache Outpatient Registry and Database (CHORD). Correlation and regression analyses were used to examine the relationships between the HIT-6 and MIDAS total scores, headache frequency and intensity, and Beck Depression Inventory (BDI-II) scores.

A positive correlation was found between HIT-6 and MIDAS scores (r = 0.52). The BDI-II scores correlated equally with the HIT-6 and the MIDAS (r = 0.42). There was a non-monotonic relationship between headache frequency and the MIDAS, and a non-linear monotonic relationship between headache frequency and the HIT-6 (r = 0.24). The correlation was higher between the intensity and the HIT-6 scores (r = 0.46), than MIDAS (r = 0.26) scores. Seventy-nine percent of patients fell into the most severe HIT-6 disability category, compared with the 57% of patients that fell into the most severe MIDAS disability category. Significantly more patients were placed in a more severe category with the HIT-6 than with the MIDAS (McNemar chi-square = 191 on 6 d.f., P < .0001).

The HIT-6 and MIDAS appear to measure headache-related disability in a similar fashion. However, some important differences may exist. Headache intensity appears to influence HIT-6 score more than the MIDAS, whereas the MIDAS was influenced more by headache frequency. Using the HIT-6 and MIDAS together may give a more accurate assessment of a patient's headache-related disability.