THU0484 ESTIMATION OF PATIENT ACCEPTABLE SYMPTOM STATE FOR PATIENT-REPORTED OUTCOMES BETWEEN 2 POPULATIONS OF PATIENTS WITH NON-SPECIFIC CHRONIC LOW BACK PAIN

Background Clinical relevance of commonly used patient-reported outcomes (PROs) is unclear in people with non-specific chronic low back pain (cLBP) (1). Objectives To estimate and compare patient acceptable symptom state (PASS) at 1 month post-intervention for 4 PROs between 2 populations of patients with non-specific cLBP and to determine which baseline variables contribute to having an acceptable symptom state at 1 month. Methods Overall, we included 256 patients: 135 patients with cLBP and active discopathy participated in a randomized controlled trial assessing the efficacy on pain at 1 month of a single glucocorticoid intradiscal injection compared to contrast alone (2), and 121 patients with cLBP and without active discopathy participated in a randomized controlled trial assessing the efficacy on pain at 4 months of 12 sessions of immersive virtual reality (VR) compared to usual care (3). Using an anchor-based method, PASS estimates for PROs were obtained using the 75th percentile method (4). Logistic regression was used to determine baseline variables contributing to achieving PASS at 1 month. Results At 1 month, 137/256 (53.52%) participants self-rated their health as acceptable. In the whole population, PASS (95% IC) were 47.50 (40.00 to 50.00) for the lumbar-pain VAS, 30.50 (30.00 to 40.00) for the radicular-pain VAS, 39.27 (33.60 to 45.26) for the QUEBEC score, 9.95 (9.16 to 10.00) for the HAD anxiety subscale and 6.70 (6.00 to 8.00) for the HAD depression subscale. The PASS estimates did not differ between the 2 populations of cLBP patients for any of the PRO. The only baseline variable contributing to having an acceptable symptom state at 1 month was symptom intensity. Conclusion PASS estimates at 1 month did not vary across 2 independent samples of people with cLBP and 2 distinct nociceptive sources of cLBP. The main contributor of the PASS was symptom intensity at baseline. Our findings can be useful in interpreting the clinical relevance of PROs values. References [1] Tubach F, Ravaud P, Baron G, Falissard B, Logeart I, Bellamy N, et al. Evaluation of clinically relevant states in patient reported outcomes in knee and hip osteoarthritis: the patient acceptable symptom state. Ann Rheum Dis. 2005;64(1):34-7. [2] Nguyen C, Boutron I, Baron G, Sanchez K, Palazzo C, Benchimol R, et al. Intradiscal Glucocorticoid Injection for Patients With Chronic Low Back Pain Associated With Active Discopathy: A Randomized Trial. Ann Intern Med. 2017;166(8):547-56. [3] Nguyen C, Boutron I, Perrodeau E, Sanchez K, Borderie D, Palazzo C et al. 3D immersive virtual reality in patients with chronic low back pain: a randomized controlled trial. PlosOne (under review). 2017. Disclosure of Interests None declared