The algorithms presented in these chapters are based on available evidence.
The degree of evidence available to support the decision tree in the algorithm
is rated according to the following scale:
No rating: there are no published studies with original data to
investigate a direct relationship between an intervention and outcome.
One star (*): There is qualitative (directional) evidence but insufficient
quantitative evidence to establish a statistical relationship between
intervention and outcome. Suggestive evidence refers to data from descriptive
studies, case reports, and other study designs/reports that include original
Two stars (**): Quantitative data indicate a statistically significant
relationship between an intervention and an outcome, and qualitative data
are supportive and concur. Supportive evidence refers to data from randomized
and controlled non-randomized comparative studies.