Findings of meta-analysis on the efficacy and safety of paracetamol for spinal pain and osteoarthritis are valid and consistent with current guideline recommendations
The harsh criticisms made by Professor Miller, Dr Manniche and Dr Skousgaard seem out of proportion to the single issue they raised. Our systematic review considered 13 trials, 10 for osteoarthritis and three for spinal pain . The retracted Wetzel et al. trial  was one of the three spinal pain trials and it contributed data for only one of the four spinal pain meta-analyses. This trial had some concerns with risk of bias and if excluded the quality of evidence (GRADE criteria) increases from moderate to high for the one effect estimate it contributed to. Our new conclusion would be that there is high quality evidence that paracetamol is ineffective for improving spinal pain and disability in the immediate and short term. Our results published in 2015 are very consistent with current guidelines which independently of us have come to the same conclusion and changed recommendations of paracetamol for low back pain [3,4].
The retraction of Wetzel et al. paper was mentioned in various BMJ rapid responses soon after our publication in 2015, and this issue was notified to the Cochrane Back & Neck Group prior to manuscript submission and acknowledged in the subsequent published review . The retraction notice from European Journal of Anaesthesiology states that the reason for retracting Wetzel et al. paper was because one of the authors did not consent to its submission and publication; there is no mention of fraudulent data . While it is not entirely clear what happened with the Wetzel et al. trial, what is clear is that its inclusion or deletion from our meta-analysis will not change the key message we should provide to clinicians: they should reconsider the use of paracetamol for osteoarthritis and low back pain.
1. Machado GC, Maher CG, Ferreira PH, et al. Efficacy and safety of paracetamol for spinal pain and osteoarthritis: Systematic review and meta-analysis of randomised placebo controlled trials. BMJ. 2015;350:h1225.
2. Wetzel L, Zadrazil M, Paternostro-Sluga T, et al. Intravenous nonopioid analgesic drugs in chronic low back pain patients on chronic opioid treatment: a crossover, randomised, double-blinded, placebo- controlled study. Eur J Anaesthesiol 2014;31:35–40.
3. Qaseem A, Wilt TJ, McLean RM, et al. Noninvasive treatments for acute, subacute, and chronic low back pain: A clinical practice guideline from the American College of Physicians. Ann Intern Med. 2017;166:514-530.
4. National Guideline Centre. Low back pain and sciatica in over 16s: assessment and management. National Institute for Health and Care Excellence (UK); 2016:NG59.
5. Saragiotto BT, Machado GC, Ferreira ML, et al. Paracetamol for low back pain. Cochrane Database Syst Rev. 2016;6:CD012230.
6. [Retraction]. Intravenous non opioid analgesic drugs in chronic low back pain patients on chronic opioid treatment: A crossover, randomised, double-blinded, placebo-controlled study. Eur J Anaesthesiol. 2015;31(1):287.
Gustavo C Machado (NHMRC Research Fellow, Institute for Musculoskeletal Health, Sydney)
Chris G Maher (Director, Institute for Musculoskeletal Health, Sydney)
Manuela L Ferreira (NHMRC Research Fellow, Institute of Bone and Joint Research, Sydney)
Competing interests: No competing interests