Levels of evidence
The key recommendations and levels of evidence incorporated in the COPD-X guidelines were originally based largely on the Global Initiative for Chronic Obstructive Lung Disease (GOLD), which used the evidence ranking system of the US National Heart, Lung and Blood Institute (NHLBI) (NHLBI/WHO Workshop Report April 2001). The NHLBI scheme is shown in Box 1. For comparison, the National Health and Medical Research Council (NHMRC) (National Health and Medical Research Council 1998) levels of evidence are also shown, along with the equivalent NHLBI categories.
For this update, the COPD-X Guidelines Committee reclassified NHLBI level A as NHMRC level I and NHLBI level B as NHMRC level II evidence. All citations to NHLBI level C were individually reviewed and reclassified as NHMRC level II, III-2, III-3 or IV evidence. On closer examination, some references originally classified as level C were actually considered level D. As NHLBI level D is not recognised in the NHMRC classification, these levels were removed whilst the bibliographic citations were retained.
a) National Heart, Lung, and Blood Institute (NHLBI) categories
b) National Health and Medical Research Council (NHMRC) Evidence Hierarchy: designations of ‘levels of evidence’ according to type of research question
< Prev Next >