Validity of the Yellow Flag Risk Form in People Treated for Low Back Pain with Mechanical Diagnosis and Therapy and the Pain Mechanism Classification System

Background: Psychosocial aspects of pain are often associated with chronic low back pain, a condition for which the specific etiology is unknown. Psychosocial risk tools, such as the Yellow Flag Risk Form (YFRF) have been used to identify these factors and sub classify participants into clinically relevant subgroups, which are aligned with a specific intervention. The purpose of this research was to analyze patient outcomes in people with low back pain referred to physical therapists who utilize the YFRF Mechanical Diagnosis and Therapy (MDT), and Pain Mechanism Classification (PMCS) principles. Methods: One hundred seventy-nine people with Low Back Pain (LBP) were referred to a hospital-based physical therapy outpatient clinic in western New York State. Of the 179 participants, 26 met the exclusion criteria and 13 had incomplete data, resulting in an analysis of 140 participants. The participants were examined and classified based on MDT and the PMCS classifications by physical therapists trained in both systems. Participants were administered the YFRF, the Numerical Pain Rating Scale (NPRS), and the Focus on Therapeutic Outcomes (FOTO) tools at initial evaluation, at the 4 th visit, and at discharge. Results: Of the 140 participants, 65% were experiencing chronic duration of symptoms and 60.7% of the sample scored greater than or equal to 50 on the YFRF. Among these participants, 92/140 (65.7% of the sample were classified as responders and 48/140 (34.3%) were classified as non-responders based on a statistically significant change score on either FOTO or the NPRS. A regression analysis of YFRF findings and outcome indicated that the model performed well in classifying patients as responders or non-responders. Conclusion: This research suggests that a high percentage of participants receiving musculoskeletal care may have symptom chronicity and psychosocial risk and still respond to physical therapy intervention. Further, MDT may be an effective musculoskeletal approach for participants classified with a derangement irrespective of psychosocial risk factors as indicated by change in YFRF score as a predictor of patient outcome.