Predictive ability of the STarT Back Tool: An ancillary analysis of a cluster randomised controlled trial from Danish general practice

BACKGROUND: Low back pain (LBP) is a common cause of contact with the primary healthcare sector. In some patients, symptoms quickly resolve, but others develop long-lasting pain and disability. To improve the care pathway for patients with LBP, the STarT Back Tool (STarT) questionnaire has been developed. It helps initial decision-making by subgrouping patients on the basis of their prognosis and helps to target treatment according to prognosis. An assumption behind the use of STarT is the ability to predict functional improvement. This assumption has never been tested in a population that consists exclusively of patients enrolled when consulting a Danish general practitioner for LBP. The aim of this study was to investigate STarT's ability to predict a 30% improvement in the Roland Morris Disability Questionnaire (RMDQ) score. METHODS: This was an ancillary analysis using data from a Danish guideline implementation study (registered at ClinicalTrials.gov NCT01699256). An inclusion criterion was age 18 to 65 years of age. Exclusion criteria were pregnancy, fractures, and signs of underlying pathology. Patient-reported STarT score and the Roland Morris Disability Questionnaire were administered at baseline and again after 4, 8, and 52 weeks. RESULTS: Between January 2013 and July 2014, 475 patients from the original trial participated with questionnaires. From this subpopulation, 441 (92.8%) patients provided information regarding STarT. Baseline and eight-week RMDQ data were available for 304 (64.0%) patients. After 8 weeks, 61 (65.6%) in the low-risk group, 67 (54.9%) in the medium-risk group, and 33 (37.1%) in the high-risk group had achieved a 30% improvement in the RMDQ score. After 8 weeks, high-risk patients were at 61% (95% CI: 20-125%, P < 0.001) higher risk of not achieving a 30% improvement in the RMDQ score compared with patients in either the low-risk group or the medium-risk group. CONCLUSION: STarT was predictive for functional improvement in patients from general practice with LBP.