Predictors of response to spinal manipulative therapy, dry needling and exercise in patients with cervicogenic headache

Background and purpose: Spinal manipulative therapy, dry needling, and exercise have been found to reduce pain and disability in individuals with cervicogenic headache (CGH). The purpose of this study was to quantify the impact of several baseline, anthropometric, demographic, and treatment-related factors on the likelihood that patients with CGH would experience a successful outcome following these interventions. Methods: A secondary analysis of data from 142 patients with CGH that received upper cervical spinal manipulative therapy, dry needling, and exercise in a multi-center randomized controlled trial. The primary outcome was headache intensity as measured by the Numeric Pain Rating Scale. Binary logistic regression was performed to assess the impact of nine baseline factors and one treatment-related factor on the likelihood that patients with CGH would experience a successful outcome (i.e., ≥50% improvement from baseline to 3 months). Results: Only two of the independent variables made a unique statistically significant contribution to the model: sex (P = 0.018) and baseline headache intensity (P = 0.003). The strongest predictor of experiencing a successful outcome was sex (odds ratio: 3.906, 95% CI: 1.263, 12.195). The second significant predictor of experiencing a successful outcome was baseline headache intensity (odds ratio: 1.708, 95% CI: 1.203, 2.424). Chronicity of headache symptoms (P = 0.296), headache frequency (P = 0.094), age (P = 0.981), body mass index (P = 0.101), pretreatment medication levels (P = 0.661), headache duration (P = 0.387), disability (P = 0.637), and number of treatment sessions (P = 0.455) did not predict outcome. Conclusions: In patients with cervicogenic headache that received spinal manipulative therapy, dry needling, and exercise, the strongest predictors of experiencing a successful outcome were male sex and baseline headache intensity.