Predictors for immediate and global responses to chiropractic manipulation of the cervical spine.

OBJECTIVE: Patients with nonspecific musculoskeletal disorders may vary in their response to treatment. This study set out to identify the predictors for either improvement or worsening in symptoms for which cervical spine manipulation is indicated.

METHOD: A large prospective study recorded details on patients, their presenting symptoms, and type of treatment. At the end of the consultation, any immediate improvement or worsening in presenting symptoms was noted. At the follow-up visit, information was collected on the patients' self-reported improvement.

RESULTS: Data were collected from 28,807 treatment consultations (in 19,722 patients) and 13,873 follow-up treatments. The presenting symptoms of "neck pain," "shoulder, arm pain," "reduced neck, shoulder, arm movement, stiffness," "headache," "upper, mid back pain," and "none or one presenting symptom" emerged in the final model as significant predictors for an immediate improvement. The presence of any 4 of these predictors raised the probability for an immediate improvement in presenting symptoms after treatment from 70% to approximately 95%. With regard to immediate worsening, "neck pain," "shoulder, arm pain, "headache," "numbness, tingling upper limbs," "upper, mid back pain," and "fainting, dizziness, light-headedness" emerged as predictors; and the presence of any 4 of these raised the probability for immediate worsening from 4.4% to approximately 12%. For global improvement, only 2 predictors were identified; but these did not enhance the postprediction probability.

CONCLUSIONS: This study is the first attempt to identify variables that can predict immediate outcomes in terms of improvement and worsening of presenting symptoms, and global improvement, after cervical spine manipulation. The predictor variables were strongest for immediate improvement.