The threshold specified for an analysis matters when several treatments are compared. This study's carnitine result should not be promoted from a trend to a demonstrated benefit. Primary study
What was studied
Sixty people with multiple sclerosis were assigned to amantadine, modafinil, acetyl-L-carnitine or placebo for one month. Amantadine improved the reported fatigue-impact comparison. Acetyl-L-carnitine had P=0.05 against a corrected threshold of 0.046, so that result did not meet the study's stated significance criterion. Primary report
Our appraisal: “almost significant” does not settle the treatment question
A result near a threshold can be compatible with several effect sizes. It should be interpreted through its estimate and uncertainty rather than assigned a positive label because it appears close. The correction is part of the analysis, not an optional obstacle to remove after seeing the data.
Dividing a modest sample across several arms also limits precision. A neutral result may not rule out a clinically important effect, but it cannot demonstrate one either. The proper response is a calibrated statement of uncertainty and a rationale for a better-powered study if the question remains important.
The brief duration limits what can be inferred about sustained fatigue relief and harms. Review should also inspect baseline fatigue, concomitant therapy, adherence and how missing observations were handled. Different fatigue instruments across studies complicate simple comparisons of which trial was “positive.”
This placebo-controlled pilot is distinct from an earlier active-comparator crossover trial. The two designs address different questions and should not be forced into a single verdict without examining those differences. For this report, the carnitine-specific conclusion remains preliminary and unconfirmed; findings from another treatment arm cannot be reassigned to it.
Frequently asked questions
Was placebo included?
Yes.
How many treatment groups were described?
Four.
Did carnitine meet the corrected threshold?
No.
Does P=0.05 always mean a positive finding?
No; the prespecified criterion and analysis matter.
Was follow-up long term?
No; the treatment period was one month.
Can amantadine's result be credited to carnitine?
No.
What is a fair carnitine conclusion?
A possible signal needing confirmation, not established efficacy.