[Clinical relevance of study results].
The critical appraisal process of available evidence includes the evaluation of clinical importance of the study findings. This should coincide with the minimum worthwhile effect expected by the investigators in the study design and planning. In hard outcome studies it can be quantified by the absolute risk difference between groups and its reciprocal, known as number needed to treat to avoid one adverse event, or benefit (NNTB). The number needed to treat to produce harmful consequences of treatment (NNTH) should also be taken into account. Finally these effect measures, like risks and incidence proportions, are usually rough estimates of the true effects, due to non-complete follow-up of the observations under study. Underlying assumptions and design issues are especially important to assess the clinical relevance of any results.
Ravani
P
P
Divisione di Nefrologia e Dialisi, Azienda Istituti Ospitalieri di Cremona, Italy. p.ravani@ospedale.cremona.it
Andrulli
S
S
D002986:Clinical Trials as Topic / Q000706:statistics & numerical data*; D003627:Data Interpretation, Statistical; D006801:Humans