COMET - effectiveness and tolerability of methocarbamol versus oral opioid-analgesics as add-on measure in patients with non-specific low back pain refractory to recommended 1st line treatments. A retrospective analysis of depersonalized propensity score matched open-label real-world 4-week data from the German Pain e-Registry.

BACKGROUND

To compare the 4-week effectiveness and tolerability of an add-on treatment with oral high dose methocarbamol (MET) vs long-acting oral opioid analgesics (LAO) in patients with non-specific low back pain (nsLBP) poorly responsive to recommended 1st line treatments.

METHODS

Analysis of anonymized, propensity score-matched real-world data from the German Pain e-Registry, using a sequential non-inferiority superiority approach, for adult outpatients with nsLBP who had initiated treatment with MET or LAO between 1st January 2018 and 31st December 2019 (EUPAS identifier: 38484). The primary effectiveness variable was the absolute change of the average 24-h. pain intensity index (PIX). Safety was assessed by incidence of physician-confirmed drug-related adverse events (DRAEs), and DRAEs leading to discontinuation.

RESULTS

Propensity score-matched data were analyzed for 374 patients treated with MET and 374 patients treated with LAO. Mean ± SD (median) MET dose over the 4-week evaluation period was 2390.4 ± 1980 (3000) mg and 69.6 ± 25.9 (60) mg morphine equivalent for LAO. With 25.8 ± 11.4 (median 26, 95%CI: 24.5-27.1) vs. 11.4 ± 6.8 (median 11; 95%CI: 10.6-12.2) mm VAS, absolute 4-week improvement vs. baseline was superior for MET vs. LAO [ < .001; effect size 1.6; least square mean difference 14.4 (95%CI: 13.4-15.3)]. Percentages of patients with a PIX improvement ≥ MCID was 81.8 vs. 24.6% [ < .001; OR: 13.8 (9.7-19.6), RR: 4.0 (3.2-5.0), NNT: 1.7]. A significantly lower number of patients treated with MET vs. LAO reported DRAEs in response to study medication: 36 (9.6%) vs. 139 (37.2%;  < .001; NNT 4), and 9 patients treated with MET (2.4%) vs. 86 (23.0%) treated with LAO discontinued treatment in response to these DRAEs ( < .001; NNT: 5).

CONCLUSION

4-week add-on treatment with MET in patients with nsLBP who showed an inadequate response to recommended 1 line treatments is superior effective to LAO and significantly better tolerated.KEY MESSAGESLow back pain is the most common musculoskeletal problem worldwide.In the majority of patients, LBP does not have a specific cause and the most prevalently coded form is mechanical, non-specific (ns) LBP associated with muscular tension, restrictions in mobility, and static malposition.Current treatment recommendations for nsLBP are largely "non-specific" as well, limited to symptomatic pain-relieving measures.In our propensity score-matched two cohort analyses of depersonalized real-world data from the German Pain e-Registry, a 4-week treatment with the muscle relaxant methocarbamol proved superior effective and significantly better tolerated than treatment with oral long-acting opioid analgesics in patients who poorly responded to recommended 1st line treatments.