Levels of evidence: further insight on Gugiu and Gugiu

An Application of a New Evidence Grading System to Research on the Chronic Care Model

Methodological quality undergirds all evidence-based medicine because without strong evidence supporting or refuting the efficacy of an intervention, the movement toward basing medical decisions and practice on scientific evidence is not sustainable. Recently, the consensus that had existed regarding the hierarchy of evidence produced by a study design was challenged on the basis that existing guidelines failed to properly define key terms, weight the merits of certain non-randomized controlled trials, and employ a comprehensive list of study design limitations to render evaluative conclusions, to name a few of the challenges. The present study introduces a new grading system that overcomes, or at the very least greatly diminishes, these challenges. This new method is applied to the literature on the Chronic Care Model and the results are then compared to several of the most popular grading guidelines currently in use. These results revealed substantial differences between the guidelines in accordance with previous research that challenged existing methods. Furthermore, the present study lends support to the proposed grading guideline although further research into its validity and reliability is needed.

Evidence-based guidelines for use of probiotics in preterm neonates

BACKGROUND

Current evidence indicates that probiotic supplementation significantly reduces all-cause mortality and definite necrotising enterocolitis without significant adverse effects in preterm neonates. As the debate about the pros and cons of routine probiotic supplementation continues, many institutions are satisfied with the current evidence and wish to use probiotics routinely. Because of the lack of detail on many practical aspects of probiotic supplementation, clinician-friendly guidelines are urgently needed to optimise use of probiotics in preterm neonates.

AIM

To develop evidence-based guidelines for probiotic supplementation in preterm neonates.

METHODS

To develop core guidelines on use of probiotics, including strain selection, dose and duration of supplementation, we primarily used the data from our recent updated systematic review of randomised controlled trials. For equally important issues including strain identification, monitoring for adverse effects, product format, storage and transport, and regulatory hurdles, a comprehensive literature search, covering the period 1966-2010 without restriction on the study design, was conducted, using the databases PubMed and EMBASE, and the proceedings of scientific conferences; these data were used in our updated systematic review.

RESULTS

In this review, we present guidelines, including level of evidence, for the practical aspects (for example, strain selection, dose, duration, clinical and laboratory surveillance) of probiotic supplementation, and for dealing with non-clinical but important issues (for example, regulatory requirements, product format). Evidence was inadequate in some areas, and these should be a target for further research.

CONCLUSION

We hope that these evidence-based guidelines will help to optimise the use of probiotics in preterm neonates. Continued research is essential to provide answers to the current gaps in knowledge about probiotics.

Levels of Evidence: A Reply to Berger and Knoll

Although a randomized controlled trial (RCT) provides the strongest level of evidence when properly conducted, it is by no means the only research design capable of supporting causal claims. As discussed in Gugiu and Gugiu, numerous non-RCTs are able to produce valid and reliable results, providing they can establish approximately equivalent treatment groups at baseline. The purpose of this article is to respond to the issues raised by Berger and Knoll.