Predictor variables for identifying patients with chronic tension-type headache who are likely to achieve short-term success with muscle trigger point therapy.

To date, no studies have investigated the predictive validity of variables from the initial examination to identify patients with tension-type headache pain who are likely to benefit from muscle trigger point (TrP) therapy. The purpose of this study was to develop a preliminary clinical prediction rule (CPR) to identify chronic tension-type headache (CTTH) patients who are likely to experience a successful response from TrP therapy. Consecutive patients with CTTH underwent a standardized examination and then received six sessions of TrP therapy over 3 weeks (two sessions per week). They were classified as having experienced a successful outcome at short-term (1 week after discharge) and 1-month follow-up based on a 50% reduction on at least one headache parameter (intensity, frequency or duration) and self-report perceived recovery. Potential predictor variables were entered into a stepwise logistic regression model to determine the most accurate set of variables for identifying treatment success. Data from 35 patients were included, of which 19 (55%) experienced a successful outcome. A CPR with four variables for short-term (headache duration < 8.5 h/day, headache frequency < 5.5 days/week, bodily pain < 47 and vitality < 47.5) and a CPR with two variables for 1-month (headache frequency < 5.5 days/week and bodily pain < 47) follow-up were identified. At short-term follow-up, if three of four variables [positive likelihood ratio (LR) 3.4] were present, the chance of experiencing a successful outcome improved from 54% to 80%, and if all the variables (positive LR 5.9) were present, the probability of success was 87.4%. At 1-month follow-up, if one of two variables (positive LR 2.2) was present, the probability of success increased from 54% to 72%, and if both variables (positive LR 4.6) were present, the probability of success was 84.4%. The present CPR provides the potential to identify CTTH patients who are likely to experience short-term and 1-month follow-up success with a muscle TrP therapy approach. Future studies are necessary to validate the CPR.