BOF: Laboratory & Research

Three randomised controlled trials of a new drug have shown non-inferiority in the treatment of idiopathic thrombocytic purpura (ITP). To which level of evidence may this be classified (according to the Oxford Centre for Evidence Based Medicine (CEBM)?

a) Ia

b) Ib

c) II

d) III

e) IV

Answer:

b) Ib

Explanation:

The quality of research data is graded for the purposes of meta-analysis and construction of protocols and guidelines, as summarized below:

Ia Evidence obtained from meta-analysis of randomised controlled trials

Ib Evidence obtained from at least one randomised controlled trial

IIa Evidence obtained from at least one well-designed controlled study without randomisation

IIb Evidence obtained from at least one other type of well-designed quasi-experimental study

III Evidence obtained from well-designed non-experimental descriptive studies, such as comparative studies, correlated studies and case studies

IV Evidence obtained from expert committee reports or opinions and/or clinical experience of respected authorities

Reference:

Oxford Centre For Evidence-Based Medicine