Using the STarT Back Tool: Does timing of stratification matter?

It is likely that individuals with nonspecific LBP (nsLBP) constitute a heterogenic group and targeting treatment appropriately to those most likely to respond is of major relevance. The STarT Back Tool (SBT) has been developed to stratify patients into risk groups to aid management choices. However, there is controversy over its generalisability and uncertainty as to the timing of use. This study investigated whether SBT categorisation early in a course of treatment would prove more prognostic than categorising patients at baseline. Seven hundred and forty nine patients over the age of 16 were recruited at 11 chiropractic clinics within the UK. The SBT was used to categorise these patients at presentation and 2 days following initial treatment with patient characteristics and condition specific markers also collected at baseline. The primary outcome was the Patient Global Impression of Change (PGIC) collected at 14, 30 and 90 days following the initial visit. In this population undergoing chiropractic care, patients had similar outcomes irrespective of their STarT back risk ranking. Multivariate prognostic models included only the post initial visit SBT as an independent predictor of favourable outcome for the medium risk group but only at 30 days. Follow up improvement was dominated by previous improvement in 30 and 90-day models. Over one third of patients swapped SBT risk groups in the 2 day period between initial stratification and post initial visit although there was little difference in eventual improvement at follow-up. Understanding the impact of timing of SBT stratification is indicated.