The assessment of disability in children and adolescents with headache: Adopting PedMIDAS in an epidemiological study

Objective: The study aimed at the assessment of disability in children with headache (n = 1585, 11-14 yrs) from a randomly drawn population based sample. We explored the suitability of the PedMIDAS in epidemiological research by various indicators of response quality. Furthermore, predictors of disability were examined, as well as its association with measures of health care behaviour. Methods: The PedMIDAS measures functional interference in different domains of life by asking the children for the number of days that their headache partially or totally interfered with their activities. Results: The examination of response behaviour revealed a marked attrition of responses (missing, invalid) in two items. As a consequence, the total score for disability could not be obtained for about 25% of the children. Analysis of homogeneity of the PedMIDAS items revealed low item/total correlations in two items. The grading of disability resulted in 81.2% of all children with headache showing no or low disability. Only 1.4% was "severely" disabled. Disability was predicted by frequency, type and intensity of headache. From all psychological variables only dysfunctional stress coping was significantly associated with disability. Disability itself was significantly associated with medical consultation. Conclusions: Suitability of the PedMIDAS for epidemiological research was supported, however with a caveat and recommendations for item revision. Severe disability due to headache was rare in the studied unselected sample when defined by behavioural interference. It is suggested to explore the construct of disability by a multi-method approach, including further instruments assessing headache related distress, (respectively) quality of life. (C) 2010 European Federation of International Association for the Study of Pain Chapters. Published by Elsevier Ltd. All rights reserved.