Modic Change Edema in Chronic Low Back Pain Treated with Infliximab or Placebo: The BackToBasic Trial.

Abstract

Study design: Randomized trial.

Objective: To assess whether infliximab is superior to placebo in reducing Modic change (MC) edema, and whether MC edema or apparent diffusion coefficient (ADC) values of MCs modify the effect of infliximab on disability or low back pain (LBP).

Summary of background data: In the present BackToBasic trial, infliximab did not reduce disability or LBP at 5-months follow-up in patients with chronic LBP and MC type 1. The effect on MC edema and in edema-defined subgroups is unknown.

Methods: Patients with chronic LBP and type 1 MCs were randomized to receive four infliximab infusions or placebo over 98 days. MC edema was assessed using short tau inversion recovery imaging. Primary edema variables were maximum baseline edema volume (Volmax) ≥25% of vertebral body marrow (yes/no) and reduced edema at 6 months (yes/no). Maximum MC-related ADC value (0-100%) was measured at baseline. Outcomes at 5 months were the Oswestry Disability Index (ODI, 0-100, primary outcome) and LBP intensity (0-10). The analyses included logistic regression and linear mixed-effects models.

Results: 128 patients (mean age 43 years, 84 women) were included, of which78 were treated per protocol (PP). The odds ratio for reduced MC edema at 6 months in the infliximab vs placebo group was 2.2 (95% confidence interval [CI] 0.8, 5.8; P=0.12) in the primary PP analysis and 2.1 (95% CI 1.02, 4.5; P=0.04) in the total sample. Neither MC edema nor ADC values modified the effect of infliximab on ODI or LBP intensity. At 5 months, the effect in the Volmax ≥25% group was -4.2 ODI points (95% CI -11.4, 3.1; primary PP analysis).

Conclusion: Infliximab had no clinically relevant edema reducing effect. MC edema did not modify the effect of infliximab on disability or LBP, nor did the MC-related ADC value.

Level of evidence: Level 2.