Strength Of Evidence

A number of types of clinical investigation are described in this chapter, and elsewhere in the book. When making clinical decisions about a course of therapeutic action, it is obviously relevant to judge the strength of evidence generated by different types of study. This has been summarised as follows, in rank order.38

1. Systematic reviews and meta-analysis

2. Randomised controlled trials with definitive results (confidence intervals that do not overlap the threshold of the clinically significant effect)

3. Randomised controlled trials with nondefinitive results (a difference that suggests a clinically significant effect but with confidence intervals overlapping the threshold of this effect)

4. Cohort studies

5. Case-control studies

6. Cross-sectional surveys

7. Case reports.


Fig. 4.4 Oscillations in the development of a drug.41

38 Guyatt G H et al 1995 Journal of the American Medical Association 274:1800.

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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