Prevalence of diabetic cardiomyopathy in low- and middle-income countries: a systematic review protocol

The burden of type 2 diabetes mellitus (T2DM) is rising rapidly in low- and middle-income countries (LMICs). Diabetic cardiomyopathy (DbCM), defined as myocardial dysfunction occurring independently of coronary artery disease, hypertension, or significant valvular disease, is an important complication of T2DM and may progress to overt heart failure if undiagnosed. While well characterised in high-income settings, DbCM prevalence and distribution in LMICs remain poorly defined. This systematic review aims to estimate the pooled prevalence of DbCM among adults with T2DM in LMICs.

This protocol follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) guidelines and the Joanna Briggs Institute (JBI) Manual for Evidence Synthesis. A comprehensive search will be conducted in PubMed, Scopus, Web of Science, Embase, AJOL, and EBSCOhost, supplemented by regional databases and grey literature sources. Observational studies conducted in LMICs that report the prevalence of DbCM among adults with T2DM will be considered. DbCM must be diagnosed using objective cardiac imaging after exclusion of alternative causes of myocardial dysfunction. Two reviewers will independently screen, extract data, and assess risk of bias using a tool adapted for prevalence studies.

Where data are sufficiently comparable, pooled prevalence estimates will be calculated using random-effects meta-analysis. Prevalence proportions will be modelled using generalised linear mixed models with a logit link function to account for within- and between-study variability. Statistical heterogeneity will be assessed using the I² statistic and explored through subgroup analyses by demographic, clinical, and regional characteristics. Where meta-analysis is not appropriate, findings will be synthesised using a structured narrative approach.

This review is expected to report pooled prevalence estimates of DbCM across LMICs and to describe regional variation. Differences in diagnostic approaches, glycaemic control, diabetes duration, age, sex, and geographical region are anticipated to contribute to heterogeneity and will be explored where data permit.

By synthesising available evidence on the prevalence of DbCM in LMICs, this review will clarify the burden of disease and provide evidence to inform health system planning and guide future research and prevention efforts aimed at reducing diabetes-related heart failure.