Background:
Prevalence systematic reviews and meta-analysis is an emerging methodology in the field of evidence synthesis. The number of published reviews has increased more than ten folds over the last ten years. These reviews can provide useful information for healthcare professionals and policymakers on the burden of disease, show changes and trends over time in disease, and inform geographical distributions of disease and conditions. The estimates also can be used to inform the absolute impact in health outcomes, from association measures from clinical studies (e.g. relative risk) and be used for estimating costs through the development of economic models.

Objectives:
The objective of this oral is report on the work of the Prevalence Estimates Reviews – Systematic Review (PERSyst) Methodology Group, including an overview of the current state of prevalence reviews and developments planned for the future.

Methods:
A methodological working group was formed to create guidance for conducting systematic reviews of studies reporting prevalence. As part of the groups work, a methodological cross-sectional study evaluating how systematic reviews of prevalence have been conducted was performed.

Results:
The evaluation of how prevalence systematic reviews are conducted displayed substantial variability in methods for searching, study selection, risk of bias, analysis and reporting. This work has led to the group drafting a program of work and ways forward to advance the state of systematic reviews of prevalence.

Conclusions:
Prevalence reviews are increasingly being performed to inform policy and decision making. To improve the conduct of such reviews further work is required to develop reporting guidelines, establish the certainty in estimates of prevalence, for risk of bias and for analysis of prevalence information.

Patient or healthcare consumer involvement:
Systematic reviews of prevalence are important to inform priority of problems and baseline risk, which is important for shared decision making.