RESUMO
BACKGROUND: The Migraine Disability Assessment (MIDAS) is widely used. However, there are limited data on how much a reduction in the MIDAS score indicates a change that matters to the patient. METHODS: Data from the DMKG (i.e. German Migraine and Headache Society) Headache Registry were used to determine the minimal important difference (MID) of the MIDAS, using the Patient Global Impression of Change (PGIC) as anchor and applying average change and receiver operating characteristic curve methods. RESULTS: In total, 1218 adult migraine patients (85.6% female, 40.2 ± 12.8 years, baseline MIDAS 44.2 ± 47.4, follow-up MIDAS 36.5 ± 45.3) were included. For patients with baseline MIDAS >20 (MIDAS grade IV, n = 757), different methods using PGIC "somewhat improved" as anchor yielded percent change MIDs of the MIDAS between -29.4% and -33.2%. For baseline MIDAS between 6 and 20 (grades II and III, n = 334), using PGIC "much improved" as anchor, difference change MIDs were between -3.5 and -4.5 points. CONCLUSIONS: Based on the above results, we estimated the MID of the MIDAS at -30% for patients with a baseline MIDAS >20, and at -4 points for those with a baseline MIDAS of 6-20, for a tertiary headache care population. TRIAL REGISTRATION: The DMKG Headache Registry is registered with the German Clinical Trials Register (DRKS 00021081).
RESUMO
OBJECTIVE: This study is part of the ODIN-migraine (Optimization of Diagnostic Instruments in migraine) project. It is a secondary, a priori analysis of previously collected data, and aimed to assess the psychometric properties and factor structure of the Cogniphobia Scale for Headache Disorders (CS-HD). We aimed to construct a German-language version and a short version. BACKGROUND: Cogniphobia is the fear and avoidance of cognitive exertion, which the patient believes triggers or exacerbates headache. High cogniphobia may worsen the course of a headache disorder. METHODS: The 15-item CS-HD was translated into German and back translated in a masked form by a professional translator. Modifications were discussed and carried out in an expert panel. A cross-sectional online survey including the CS-HD and further self-report questionnaires was conducted in a sample of N = 387 persons with migraine (364/387 [94.1%] female, M = 41.0 [SD = 13.0] years, migraine without aura: 152/387 [39.3%], migraine with aura: 85/387 [22.0%], and chronic migraine: 150/387 [38.8%]). RESULTS: Exploratory factor analysis resulted in two clearly interpretable factors (interictal and ictal cogniphobia). Confirmatory factor analysis yielded an acceptable to good model fit (χ2(89) = 117.87, p = 0.022, χ2/df = 1.32, RMSEA = 0.029, SRMR = 0.055, CFI = 0.996, TLI = 0.995). Item response theory-based analysis resulted in the selection of six items for the short form (CS-HD-6). Reliability was acceptable to excellent (interictal cogniphobia subscale: ω = 0.92 [CS-HD] or ω = 0.77 [CS-HD-6]; ictal cogniphobia subscale: ω = 0.77 [CS-HD] or ω = 0.73 [CS-HD-6]). The pattern of correlations with established questionnaires confirmed convergent validity of both the CS-HD and the CS-HD-6. CONCLUSION: Both the CS-HD and the CS-HD-6 have good psychometric properties and are suitable for the assessment of cogniphobia in migraine.