Can a back pain screening tool help classify patients with acute pain into risk levels for chronic pain?

Background The 9‐item STarT ‐ B ack screening tool was developed in primary care patients with low back pain ( LBP ) to identify those at greatest risk for chronic pain and requiring targeted treatment. We conducted a secondary data analysis study to examine the performance of comparable questionnaire items in a sample of primary care patients with well‐defined acute   LBP . Methods In a prospective cohort study, 605 primary care patients with LBP of less than 30 days answered a questionnaire with 6 items identical and 3 items analogous to the 9‐item STarT ‐ B ack. Participants were followed up at 6 months and 2 years. STarT ‐ B ack rules were applied to classify participant's risk of chronic LBP , and the performance of the screening items in predicting outcomes was assessed using likelihood ratios. Results The proportion of patients with chronic pain at follow‐up was considerably lower (6 months: 22%; 2 years: 25%) than in the STarT ‐ B ack validation cohort (40%) of patients with pain of any duration. The probability of developing chronic pain given a high‐risk designation by items similar to the STarT ‐ B ack increased the pre‐test probability to 31% and 35%. Likelihood ratios were close to 1. Conclusions A risk classification schema using the recommended cut‐off scores with items similar to the STarT ‐ B ack in a primary care population with strictly defined acute   LBP had limited ability to identify persons who progressed to chronic pain. The results suggest caution when applying the STarT ‐ B ack in patients with acute   LBP and a need to consider a modification of its cut‐offs.