Reliability of the evidence to guide decision-making in foot ulcer prevention in diabetes: an overview of systematic reviews.

Background: Reliable evidence on the effectiveness of interventions to prevent diabetes-related foot ulceration is essential to inform clinical practice. Well-conducted systematic reviews that synthesise evidence from all relevant trials offer the most robust evidence for decision-making. We conducted an overview to assess the comprehensiveness and utility of the available secondary evidence as a reliable source of robust estimates of effect with the aim of informing a cost-effective care pathway using an economic model. Here we report the details of the overview. [PROSPERO Database (CRD42016052324)].

Methods: Medline (Ovid), Embase (Ovid), Epistomonikos, Cochrane Database of Systematic Reviews (CDSR), Database of Abstracts of Reviews of Effectiveness (DARE), and the Health Technology Assessment Journals Library were searched to 17th May 2021, without restrictions, for systematic reviews of randomised controlled trials (RCTs) of preventive interventions in people with diabetes. The primary outcomes of interest were new primary or recurrent foot ulcers. Two reviewers independently extracted data and assessed the risk of bias in the included reviews.

Findings: The overview identified 30 systematic reviews of patient education, footwear and off-loading, complex and other interventions. Many are poorly reported and have fundamental methodological shortcomings associated with increased risk of bias. Most concerns relate to vague inclusion criteria (60%), weak search or selection strategies (70%) and quality appraisal methods (53%) and inexpert conduct and interpretation of quantitative and narrative evidence syntheses (57%). The 30 reviews have collectively assessed 26 largely poor-quality RCTs with substantial overlap.

Interpretation: The majority of these systematic reviews of the effectiveness of interventions to prevent diabetic foot ulceration are at high risk of bias and fail to provide reliable evidence for decision-making. Adherence to the core principles of conducting and reporting systematic reviews is needed to improve the reliability of the evidence generated to inform clinical practice.