Determining appropriate inclusion criteria for reviews of public health interventions: Skin cancer prevention as a case study

Article type
Authors
McDaid C1, Sowden A1, Paton F1
1Centre for Reviews and Dissemination, UK
Abstract
Background: We undertook a systematic review to evaluate the effects of provision of sun protection resources (e.g. shade, sunscreen) combined with information provision in the prevention of skin cancer, commissioned by Centre for Public Health Excellence at NICE. Broad inclusion criteria were applied; studies were included regardless of design or quality. Due to limitations in the included studies it was difficult to determine the contribution of various intervention components to outcome. This raised the question of whether it is appropriate to adopt broad inclusion criteria for answering a policy relevant question.

Objectives: To assess the impact on review conclusions of varying the inclusion criteria where the intervention includes multiple components.

Methods: We used a completed systematic review as a case study. We investigated the inclusion of studies according to three sets of criteria: i) studies with appropriate assessment of the sun protection resource and information components; ii) studies where the main intervention components were of at least equal importance and iii) the original criteria. Narrative synthesis was undertaken. We assessed whether choice of criteria influenced the number of studies included and the overall conclusions.

Results: Applying the narrowest inclusion criteria resulted in a single included study; the second set resulted in five included studies; 27 studies were included in the original synthesis, using the broadest criteria. The overall review conclusions remained the same, irrespective of criteria applied. The review would have been less resource intensive with tighter inclusion criteria, although the commissioner would not have had access to the same breadth of evidence, regardless of its limitations.

Conclusions: Careful consideration should be given to the inclusion criteria selected for reviews in public health as decisions will affect the number of studies included, the amount of data to be extracted, quality assessed and synthesised, without necessarily impacting on the conclusions reached.