Critical appraisal of reports of randomised controlled trials is a core element of evidence-based practice. When considering whether to use an intervention with a patient, clinicians are encouraged to consider the estimate of the size of the treatment effect of the intervention. Confidence intervals can be used to estimate of the effect of an intervention. Most often the 95% confidence interval is used, this is the interval within which we can be 95% confident that the true average effect of the intervention actually lies. But how commonly are 95% confidence intervals used in published reports of randomised controlled trials evaluating physiotherapy interventions? A recent observational study has answered this question. The study evaluated 200 trials randomly selected from the Physiotherapy Evidence Database: 50 from each of the years 1986, 1996, 2006, and 2016. The primary outcome was the prevalence of the between-group difference presented with 95% confidence intervals. The overall prevalence of use of confidence intervals was 29%. There was a consistent increase in reporting of confidence intervals between 1986 (2%) and 2016 (42%). While the majority of trials of physiotherapy interventions do not report confidence intervals, use of confidence intervals is increasing steadily. Increased reporting of confidence intervals will assist physiotherapists to use the results of randomised controlled trials to inform clinical practice.
Freire APCF, et al. Use of 95% confidence intervals in the reporting of between-group differences in randomized controlled trials: analysis of a representative sample of 200 physical therapy trials. Braz J Phys Ther 2019;23(4):302-10