Evidence syntheses to inform healthcare decisions in the field of atrioventricular valves disease

Mitral regurgitation (MR) is among the most common valvular heart diseases, yet its true epidemiological burden remains uncertain due to heterogeneity in diagnostic methods, reporting practices, and population structures. The aim of this doctoral thesis was to provide an updated, comprehensive synthesis of MR prevalence through systematic review and meta-analysis, following PRISMA and Cochrane guidance. The focus was on moderate to severe MR, the severity threshold that is consistently captured in contemporary epidemiological studies and has clear relevance for clinical decision making. A systematic search identified population-based studies with echocardiographic or validated diagnostic data. Using random-effects models with Freeman–Tukey transformation and Restricted Maximum Likelihood (REML) estimation of between-study variance, we quantified pooled prevalence, explored heterogeneity, and performed prespecified subgroup and meta-regression analyses. Supplementary analyses included leave-one-out procedures, cumulative meta-analysis, sensitivity testing with logit and Hartung–Knapp adjustments, and the calculation of prediction intervals. In the selected dataset (17 studies, excluding elderly-only cohorts), the pooled prevalence of moderate-to-severe MR was 0.67% (95% CI 0.33–1.11%), with wide prediction intervals and considerable heterogeneity (I² > 98%). Meta-regression confirmed age as the dominant determinant of variation among studies. In fact, age accounted for over 80% of the heterogeneity observed between studies, whereas sex and study year showed no independent effect. Funnel plots and sensitivity analyses did not reveal significant small study or publication bias, and the results remained robust across various statistical transformations. This work represents the largest and most rigorous synthesis of the prevalence of moderate to severe mitral regurgitation (MR) to date. It demonstrates that MR is a common condition in the community, with prevalence significantly influenced by aging demographics. Reliable, age-stratified prevalence estimates, such as those presented here, are crucial for informing clinical guidelines, health policy planning, and the organization of services for managing valvular heart disease.