This systematic review assessed the effect of spinal manipulative therapy (SMT), the hallmark therapy of chiropractors, on pain and function for chronic low back pain (LBP) using individual participant data (IPD) meta-analyses.
Of the 42 RCTs fulfilling the inclusion criteria, the authors obtained IPD from 21 (n=4223). Most trials (s=12, n=2249) compared SMT to recommended interventions. The analyses showed moderate-quality evidence that SMT vs recommended interventions resulted in similar outcomes on
- pain (MD -3.0, 95%CI: -6.9 to 0.9, 10 trials, 1922 participants)
- and functional status at one month (SMD: -0.2, 95% CI -0.4 to 0.0, 10 trials, 1939 participants).
Effects at other follow-up measurements were similar. Results for other comparisons (SMT vs non-recommended interventions; SMT as adjuvant therapy; mobilization vs manipulation) showed similar findings. SMT vs sham SMT analysis was not performed, because data from only one study were available. Sensitivity analyses confirmed these findings.
The authors concluded that sufficient evidence suggest that SMT provides similar outcomes to recommended interventions, for pain relief and improvement of functional status. SMT would appear to be a good option for the treatment of chronic LBP.
In 2019, this team of authors published a conventional meta-analysis of almost the same data. At this stage, they concluded as follows: SMT produces similar effects to recommended therapies for chronic low back pain, whereas SMT seems to be better than non-recommended interventions for improvement in function in the short term. Clinicians should inform their patients of the potential risks of adverse events associated with SMT.
Why was the warning about risks dropped in the new paper?
I have no idea.
But the risks are crucial here. If we are told that SMT is as good or as bad as recommended therapies, such as exercise, responsible clinicians need to decide which treatment they should recommend to their patients. If effectiveness is equal, other criteria come into play:
Can any reasonable person seriously assume that SMT would do better than exercise when accounting for costs and risks?
I very much doubt it!