Prevalence and Risk Factors of Diabetic Macular Edema in Type 1 Diabetes: A Systematic Review and Meta-Analysis

Abstract

Topic: This systematic review and meta-analysis investigates the prevalence, natural history, clinical risk factors, and distinctive characteristics of diabetic macular edema (DME) in type 1 diabetes mellitus (T1D), highlighting comparisons with type 2 diabetes mellitus (T2D). Clinical relevance: DME is the most common vision-threatening complication of diabetic retinopathy, significantly impacting quality of life. Despite extensive research in T2D populations, evidence for T1D remains scarce, limiting targeted prevention and management approaches. Given the increasing longevity of individuals with T1D, understanding the unique epidemiological and clinical aspects of DME in this population is critical to refine screening and treatment guidelines. Methods: This systematic review and meta-analysis was prospectively registered (PROSPERO: CRD420251011398) and performed according to PRISMA guidelines. A comprehensive literature search was performed in MedLine (via PubMed), Scopus, and Web of Science databases through July 15, 2024. Eligible studies included original observational studies explicitly reporting prevalence, incidence, natural history, or risk factors of DME in T1D patients. Studies not differentiating T1D from T2D were excluded. The risk of bias was assessed using the NIH criteria. Meta-analysis and meta-regression were used for data synthesis. Results: Of the 63 studies included in the qualitative synthesis, 27 were eligible for meta-analysis, encompassing 40 distinct populations (470 effect-size estimates). The pooled prevalence of DME among patients with T1D was 11.1% (95% CI: 7.9-14.3%, random-effects model). Disease duration and glycemic control (HbA1c levels) emerged as significant predictors of DME prevalence in meta-regression analyses, with longer disease duration and poorer glycemic control markedly increasing the risk. Other factors, including hypertension, dyslipidemia, and diabetic nephropathy, were also associated with an increased DME risk. Conclusions: DME prevalence in T1D is substantial, with a strong dependency on disease duration and glycemic control. These findings highlight the need for personalized screening intervals and early intervention strategies. Future research should focus on refining diagnostic criteria, integrating emerging biomarkers, and evaluating the impact of novel diabetes management technologies.