BackgroundClinical guidelines recommend epidural steroid injection (ESI) for severe sciatica but there is uncertainty of effectiveness. The POiSE study aims to identify factors, routinely collected in clinical practice that predict outcome in patients who have ESI. This presentation describes characteristics and early clinical outcomes of POiSE participants.MethodsProspective cohort study in 19 NHS spinal services in England, inviting patients with sciatica listed for an ESI. Participant baseline characteristics and 6-week follow-up outcomes are presented. Outcomes include pain intensity (0–10 NRS), disability (Oswestry Disability Index 0–100) and global change in symptoms.ResultsOver 24 months, 693 patients were invited to participate and 353 (51%) completed baseline questionnaires. Mean (SD) age 49.0 years (14.4), 60% female, and 46% (n=101) of those in work had certified time-off for sciatica. Mean pain intensity was 7.2 (2.0) and 6.2 (2.7) for leg and back pain respectively and mean disability (ODI) was 46.5 (18). 60% (n=210) had leg pain for >6 months. Average confidence at baseline (0 to 10) that the ESI would help symptoms was 5.7 (2.4).Of 217 patients reaching 6-week follow-up, mean leg and back pain intensity is 5.0 (2.8) and 4.9 (2.9) respectively and ODI 36.6 (20.4), with 57% reporting improvement (completely recovered/much better/better). Follow-up data collection at 6, 12 and 24-weeks post-ESI is ongoing.ConclusionInterim analysis shows only just over half of patients are reporting improvement at 6 weeks post ESI. The POiSE cohort study will help better identify the patients with sciatica who are most likely to benefit from this treatment.Conflicts of interestNoneSources of fundingThis study is supported by Health Education England and the National Institute for Health and Care Research (HEE/ NIHR ICA Programme Clinical Lectureship, Dr Siobhan Stynes, NIHR300441). The views expressed are those of the authors and not necessarily those of the NHS, the National Institute for Health Research or the Department of Health and Social Care