You would think we should know the answer to this question already. But officially we don’t, and this paper adds absolutely nothing to our understanding.
This single-centre randomised, double-blind trial compared the analgesic efficacy of a combination of ibuprofen (10mg/kg) plus acetaminophen (15mg/kg) to either medication alone for the treatment of mostly acute traumatic pain in children.
The primary outcome was pain scores at 60 minutes.
They concluded that the reduction in pain scores was similar between all groups. No difference...
The study design was quite good. But like a plane with no wings, there was a fatal flaw.
They only included 30 patients in each treatment arm!!!
They provided a crazy power calculation, but it clearly does not pass the sniff test.
30 patients would have only enough power to find large changes in treatment effect making this at high risk for a type II error- or a false negative study. (A quick check of Clinicatrials.gov shows the study was originally intended to enrol 125 patients in each arm.)
I’m surprised the ethics committee approved such a study as it could never adequately answer the research question it proposed. I’m also surprised it got published, albeit in a lesser impact factor journal.
I strongly suspect the peer reviewers snuck the last sentence in to the abstract, “…but the trial was underpowered to demonstrate the analgesic superiority of the combination of oral ibuprofen plus acetaminophen in comparison with each analgesic alone.”
If this was the case, then why was the study conducted?
Motov S, Butt M, Masoudi A, et al. Comparison of oral ibuprofen and acetaminophen with either analgesic alone for pediatric emergency department patients with acute pain. J Emerg Med. 2020;58:725-732.[Link to article]