Disease-Related Factors Associated with Acupuncture Response in Patients with Chronic Tension-Type Headache: A Secondary Analysis of A Randomized Controlled Trial

Objective To explore the demographic and disease-related factors associated with acupuncture response in patients with chronic tension-type headache (CTTH). Methods Using data from a randomized clinical trial (218 cases) consisting of 4 weeks of baseline assessment, 8 weeks of treatment, and 24 weeks of follow-up, participants were regrouped into responders (at least a 50% reduction in monthly headache days at week 16 compared with baseline) and non-responders. Twenty-three demographic and disease-related factors associated with acupuncture response in 183 participants were analyzed by multivariable logistic regression. Results One hundred and nineteen (65.0%) participants were classified as responders. Four factors were significantly independently associated with acupuncture response, including treatment assignment, headache intensity at baseline, and 2 domains [general health (GH) and social functioning (SF)] from the 36-Item Short Form Health Survey quality of life questionnaire. Treatment assignment was associated with non-response: participants receiving true acupuncture were 3-time more likely to achieve a CTTH response than those receiving superficial acupuncture [odds ratio (OR) 0.322, 95% confidence interval (CI) 0.162 to 0.625, P =0.001]. Compared with patients with mild-intensity headache, patients with moderate-intensity headache were twice as likely to respond to acupuncture (OR 2.001, 95% CI 1.020 to 4.011, P =0.046). The likelihood of non-response increased by 4.5% with each unit increase in the GH grade (OR 0.955, 95% CI 0.917 to 0.993, P =0.024) while decreased by 3.8% with each unit increase in the SF grade (OR 1.038, 95% CI 1.009 to 1.069, P =0.011). Conclusions Greater headache intensity, lower GH score, and higher SF score were associated with better acupuncture responses in CTTH patients. These 3 factors require independent validation as predictors of acupuncture effectiveness in CTTH.