The Chronic Headache Self-Efficacy Scale: Development and assessment of measurement properties.

Objective: To develop and assess the psychometrics of the Chronic Headache Self-Efficacy Scale (CHASE).

Background: Existing scales assess self-efficacy in coping strategies and management of symptoms and triggers but do not measure other important self-efficacy domains, such as performing daily activities and socializing in patients with chronic daily headache (CDH).

Methods: The study had two phases: (i) Development of the 14-item CHASE, with items derived from patients with CDH and a multidisciplinary healthcare team; (ii) longitudinal observational study for psychometric evaluation. Participants with CDH (N = 79) completed the CHASE, Headache Management Self-Efficacy Scale (HMSE), six-item Headache Impact Test-6 (HIT-6), and 12-item Short Form Health Survey (SF-12) at baseline, 24-72 h after baseline, and 12 weeks after baseline. The Global Rating of Change (GROC) assessed perceived change in symptoms. We assessed internal consistency, day-to-day reliability, convergent and known group discriminant validity, dimensionality, and responsiveness via minimal clinical important difference (MCID).

Results: For day-to-day reliability, the CHASE intraclass correlation coefficient was 0.68 (95% confidence interval 0.49-0.81), with standard error of measurement and minimal detectable change of 10.3% and 24%, respectively. The CHASE had two independent factors (total R² = 54.5%) that can be combined into a single score (Cronbach's alpha internal consistency 0.88). For convergent validity, the CHASE score was related to the HIT-6, HMSE, and SF-12 (R²: 0.17-0.29, all p < 0.001). For known group discriminant validity, individuals with an active headache had a lower CHASE score than those without (mean [standard deviation] 47.7 [17.3]% vs. 57.2 [19.8]%, p < 0.001). Classification and regression tree analysis showed the MCID for meaningful positive symptom change on the GROC was a CHASE change of >8% or CHASE change of 8% with baseline CHASE >67%.

Conclusion: The CHASE is a reliable and valid questionnaire for assessing self-efficacy in performing daily activities, socializing, managing headache symptoms and triggers, and guiding treatment plans for patients with CDH.