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

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 five months follow-up in patients with chronic LBP and MC type 1. The effect on MC edema and in edema-defined subgroups is unknown.

MATERIALS AND 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 six months (yes/no). Maximum MC-related ADC value (0%-100%) was measured at baseline. Outcomes at five 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

One hundred twenty-eight patients (mean age 43 yr, 84 women) were included, of which 78 were treated per protocol (PP). The odds ratio for reduced MC edema at six months in the infliximab versus placebo group was 2.2 (95% 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 five months, the effect in the Volmax ≥25% group was -4.2 ODI points (95% CI: -11.4 to 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 II.