Does duration of pain at baseline influence longer-term clinical outcomes of low back pain patients managed on an evidence-based pathway?

Study Design: Non-randomised longitudinal observational study. Objective: To evaluate the association between baseline pain duration and medium-to-long term clinical outcomes, in low back pain (LBP) patients enrolled on the North East of England Regional Back Pain and Radicular Pain Pathway (NERBPP). Summary of Background Data: The NERBPP is based upon National Institute for Health and Care Excellence (NICE) guidelines. These guidelines no longer differentiate management of LBP patients based on pain duration. Medium-to-long term data from the NERBPP is lacking. Methods: Between May 2015 and December 2019, 786 and 552 LBP patients from the NERBPP returned 6-month and 12-month follow-up outcome measures, respectively. Outcomes included pain (Numerical rating scale), function (Oswestry Disability Index) and quality-of-life (EuroQol five-dimension, five-level questionnaire), analysed using a series of covariate-adjusted models. Patients were categorized into four groups based upon baseline pain duration: <3 months, ≥3 to <6 months, ≥6 months to <12 months, ≥12 months. Results: Patients with <3 months duration demonstrated clinically important improvements on all outcomes, at both follow-ups. The improvements in outcomes from this group were larger than those in the ≥12 month’s duration group (p<0.05), these group differences in change, in some cases, surpassed our threshold for clinical relevance. Functional improvements in those with ≥12 month’s duration were not clinically relevant at either follow-up. All patients, regardless of baseline pain duration, reported similar levels of readiness to self-manage at the 12-month follow-up. Conclusions: Baseline pain duration would appear to be of clinical importance. Patients with shorter baseline pain duration demonstrated better outcomes. Those with ≥12 month’s duration of pain may need additional support during their management to achieve clinically relevant functional improvements in the medium-to-long term. These findings raise questions about the decision by NICE to move away from duration of pain to differentiate management of LBP patients.