Strong recommendations in WHO 2014 guidelines are often based on lower quality evidence than indicated in GRADE approach
Polly Clayden, HIV i-Base
In an article in the Journal of Clinical Epidemiology, 6 January 2014, researchers from the United States and Canada write that WHO guidelines frequently make strong recommendations, based on low or very low confidence estimates.
They note that guideline panelists can be reluctant to offer weak/conditional/contingent recommendations despite GRADE guidance warning against strong recommendations when confidence in effect estimates is low or very low.
The researchers conducted a study to evaluate the strength of recommendations and confidence in estimates in WHO guidelines that used the GRADE approach and graded both strength and confidence. They reviewed WHO guidelines from January 2007 to December 2012 for this study. After identifying those that used GRADE, they looked at the classifications of strong and weak alongside the associated confidence in estimates: high, moderate, low, and very low.
The researchers identified 116 published WHO guidelines of which 43 (37%) used GRADE. From these there were 456 recommendations, of which 289 (63.4%) were strong and 167 (36.6%) were conditional/weak.
They found that 95 of the 289 strong recommendations (33.0%) were based on evidence “warranting low confidence in estimates” and 65 (22.5%) on evidence “warranting very low confidence in estimates”. Overall, they said 55.5% of strong recommendations were based on low or very low confidence in estimates.
They concluded that: “Further study to determine the reasons for such high uncertainty recommendations is warranted”.
Alexander PE et al. World Health Organisation recommendations are often strong based on low confidence in effect estimates. Journal of Clinical Epidemiology. Published online 6 January 2014.