Best Evidence Topics

Randomised control trial

Ronald B. turner et al
An evaluation of Echinacea angustinofolia in Experimental Rhinovirus Infections
New England Journal of Medicine
July 28, 2005, 341-348
  • Submitted by:Scott Bentz - Resident Physician
  • Institution:Grand Rapids MERC
  • Date submitted:9th May 2006
Before CA, i rated this paper: 8/10
1 Objectives and hypotheses
1.1 Are the objectives of the study clearly stated?
  Yes. Evaluate the effect of chemically defned extracts from Echinacea roots on Rhinovirus infections.
2 Design
2.1 Is the study design suitable for the objectives
  Yes, Randomized Control trial.
2.2 Who / what was studied?
  Human volunteers challenged with rhinovirus
2.3 Was this the right sample to answer the objectives?
2.4 Is the study large enough to achieve its objectives? Have sample size estimates been performed?
2.5 Were all subjects accounted for?
2.6 Were all appropriate outcomes considered?
2.7 Has ethical approval been obtained if appropriate?
2.8 Were the patients randomised between treatments?
2.9 How was randomisation carried out?
  Block Randomization
2.10 Are the outcomes clinically relevant?
3 Measurement and observation
3.1 Is it clear what was measured, how it was measured and what the outcomes were?
  Yes. Symptom severity, infection rate, volume of secretions and IL-8 concentrations.
3.2 Are the measurements valid?
3.3 Are the measurements reliable?
3.4 Are the measurements reproducible?
3.5 Were the patients and the investigators blinded?
4 Presentation of results
4.1 Are the basic data adequately described?
4.2 Were groups comparable at baseline?
  Yes, except the 60% extract group had 75% women.
4.3 Are the results presented clearly, objectively and in sufficient detail to enable readers to make their own judgement?
  Yes. Table 1.
4.4 Are the results internally consistent, i.e. do the numbers add up properly?
4.5 Were side effects reported?
  Yes. GI complaints in 5% of treatment group and 4% of placebo group.
5 Analysis
5.1 Are the data suitable for analysis?
5.2 Are the methods appropriate to the data?
5.3 Are any statistics correctly performed and interpreted?
6 Discussion
6.1 Are the results discussed in relation to existing knowledge on the subject and study objectives?
6.2 Is the discussion biased?
7 Interpretation
7.1 Are the authors' conclusions justified by the data?
7.2 What level of evidence has this paper presented? (using CEBM levels)
7.3 Does this paper help me answer my problem?
After CA, i rated this paper: 8/10
8 Implementation
8.1 Can any necessary change be implemented in practice?
  Advise patients that echinacea hasn't been shown to reduce symptoms in rhinovirus infections and they should consider other remidies
8.2 What aids to implementation exist?
  Since the late 1800's echinaccea preparations have been popular as remedies for the common cold.
8.3 What barriers to implementation exist?
  Given the great variety of echinacea preparations it will be difficult to provide conclusive evidence that echinacea has no role in the treatment of the common cold.