medwireNews: Results of a systematic review and meta-analysis suggest that treatment with DMARDs does not offer clinically significant pain relief for patients with osteoarthritis (OA).
“The literature is scattered with hypotheses and hopes for a positive effect” of DMARDs in OA, but “this is interspersed with reports of treatment failures,” and whether or not they are effective remains controversial, say Weiya Zhang and colleagues, from the University of Nottingham in the UK.
The researchers included 11 placebo-controlled randomized trials of DMARDs in OA patients, involving a total of 1205 participants, in their meta-analysis. Six trials investigated conventional DMARDs, including methotrexate and hydroxychloroquine, while the remaining five involved biologic DMARDs such as adalimumab, infliximab, and anakinra.
Overall, DMARDs produced a statistically significant improvement in pain outcomes relative to placebo, with a Hedges’ effect size (ES) of 0.18.
However, the ES was “far below” the minimal clinically important difference threshold of 0.5, indicating that “[n]o clinically significant pain relief is offered by DMARDs (compared with placebo) in OA,” say Zhang and team.
They note that the estimated ES was associated with a moderate degree of inconsistency, but a sensitivity analysis including only high-quality trials as indicated by allocation concealment demonstrated no statistically or clinically significant difference in pain relief among patients treated with DMARDs versus placebo.
Moreover, subgroup analyses by treatment type indicated that neither conventional nor biologic DMARDs offered significant improvements in pain compared with placebo, and when biologic DMARDs were analyzed by type, neither interleukin-1 inhibitors nor tumor necrosis factor inhibitors demonstrated efficacy.
And further subgroup analyses by patient characteristics, including hand versus knee OA and erosive versus non-erosive phenotype, confirmed these findings.
“This poor efficacy indicates that inflammation may not be a prime driver for OA pain,” write the researchers in Rheumatology.
They acknowledge, however, that the subgroup analyses “were based on relatively small numbers of trials, which may limit the power of this meta-analysis to detect differences within the subgroups.”
And the team concludes: “Better understanding of pain mechanisms and the role of inflammation in OA is required in order to identify and develop more effective treatments.”
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