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Efficacy and safety of paracetamol for spinal pain and osteoarthritis: systematic review and meta-analysis of randomised placebo controlled trials

BMJ 2015; 350 doi: https://doi.org/10.1136/bmj.h1225 (Published 31 March 2015) Cite this as: BMJ 2015;350:h1225

Rapid Response:

Methodological flaws invalidate findings of meta-analysis on the efficacy and safety of paracetamol for spinal pain and osteoarthritis

Dear Editor,

On 2015 Mar 31, Machado et al. published a systematic review and meta-analysis of the effectiveness of paracetamol (aka acetaminophen) for spinal pain and osteoarthritis [1]. Three randomized controlled trials (RCT) were included in the meta-analysis [2-4]. There are significant limitations to this analysis that undermine the manuscript and invalidate the conclusions.

Of note, the Machado et al. meta-analysis included a retracted study [2,5]. Dr. Kietaibl (formerly Kozek-Langenecker) did not consent to manuscript publication and demanded retraction after discovering deceptive practices by some co-authors that resulted in fraudulent data [5,6]. Although Machado et al. may not have been aware of the retraction at the time of manuscript preparation, in my opinion, they should have become aware later but they seem not to have notified The BMJ as evidenced by subsequent inclusion of the same retracted article in another meta-analysis despite recognizing its retracted status in the text [7]. Including a retracted study in a meta-analysis means transferring major errors from a single study into the highest level of evidence, thereby compromising and invalidating the meta-analysis results. Doing so knowingly raises larger ethical concerns.

The results of this analysis are not valid, and readers should be cautioned against applying them in clinical practice.

References
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. Brit Med J. 2015;350.
2. Wetzel L, Zadrazil M, Paternostro-Sluga T, Authried G, Kozek-Langenecker S, Scharbert G. 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(1):35-40.
3. Williams CM, Maher CG, Latimer J, et al. Efficacy of paracetamol for acute low-back pain: A double-blind, randomised controlled trial. Lancet. 2014;384(9954):1586-1596.
4. Prior MJ, Harrison DD, Frustaci ME. A randomized, double-blind, placebo-controlled 12 week trial of acetaminophen extended release for the treatment of signs and symptoms of osteoarthritis. Curr Med Res Opin. 2014;30(11):2377-2387. https://www.ncbi.nlm.nih.gov/pubmed/25121804. doi: 10.1185/03007995.2014.949646.
5. [No Authors Listed]. Intravenous non opioid analgesic drugs in chronic low back
pain patients on chronic opioid treatment: A crossover, randomised, double-blinded, placebo-controlled study: Retraction. Eur J Anaesthesiol. 2015;31(1):287.
6. Kietaibl S. Personal Communication: Reasons for manuscript retraction. 2018 Nov 19-21.
7. Saragiotto BT, Machado GC, Ferreira ML, Pinheiro MB, Abdel Shaheed C, Maher CG. Paracetamol for low back pain. Cochrane Database Syst Rev. 2016(6):CD012230.

Competing interests: No competing interests

27 November 2018
Andrew C. Miller
Associate Professor; Chief, Division of Research; Department of Emergency Medicine
East Carolina University Brody School of Medicine
Mail Stop 625 Emergency Medicine 600 Moye Blvd., Greenville, NC, USA 27858-1103