Background: Systematic reviews of prevalence aim to summarise data from individual studies so as to inform healthcare planning and resource allocation, and to assist policy makers and funding models. It is often challenging to judge the overall quality of research evidence in systematic reviews about prevalence due to the nature of the observational studies. Standards aimed at improving the quality of prevalence studies on health conditions have been created, but these standards are often not adequately applied, thus causing confusion as to how to judge the evidence.
Methods: This paper presents an adaptation of the Hoy framework, developed to rate the quality of evidence from prevalence studies included in a systematic prevalence review. The modification evaluates the potential impact of individual factors on the quality of evidence using a scoring system. The proposed system was evaluated against a number of studies by independent reviewers to establish reliability and robustness.
Results: We developed a scoring system that can rate the quality of evidence in such a way so as to have a clear judgement of the risk of bias in prevalence studies. We present illustrative examples from systematic reviews from Africa in support of the proposed modifications to the Hoy framework for use in prevalence systematic reviews.
Conclusions: The scoring system, based on the Hoy framework, presents potential for evaluating the impact of individual factors on the quality of evidence when conducting a review of prevalence, including a narrative synthesis or a meta-analysis. These recommendations require further investigation and testing.