Clinical variables associated with recovery in patients with chronic tension-type headache after treatment with manual therapy.

The aims of this study were to describe the course of chronic tension-type headache (CTTH) in participants receiving manual therapy (MT), and to develop a prognostic model for predicting recovery in participants receiving MT. Outcomes in 145 adults with CTTH who received MT as participants in a previously published randomised clinical trial (n=41) or in a prospective cohort study (n=104) were evaluated. Assessments were made at baseline and at 8 and 26 weeks of follow-up. Recovery was defined as a 50% reduction in headache days in combination with a score of 'much improved' or 'very much improved' for global perceived improvement. Potential prognostic factors were analyzed by univariable and multivariable regression analysis. After 8 weeks 78% of the participants reported recovery after MT, and after 26 weeks the frequency of recovered participants was 73%. Prognostic factors related to recovery were co-existing migraine, absence of multiple-site pain, greater cervical range of motion and higher headache intensity. In participants classified as being likely to be recovered, the posterior probability for recovery at 8 weeks was 92%, whereas for those being classified at low probability of recovery this posterior probability was 61%. It is concluded that the course of CTTH is favourable in primary care patients receiving MT. The prognostic models provide additional information to improve prediction of outcome.