Further research should focus on (external) validation of the
presented prognostic models with appropriate study methodology,
rather than developing new ones. With further testing the practical
value of the models can be properly established (Moons et al.,
2009a). The impact for the clinician is that the current thought
suggests a more complex interaction between factors rather than
singular prognostic factors that influence the patient through time.
There is clearly a need to investigate how prognostic factors work
together in their usefulness and feasibility in clinical practice