Lipoprotein (a) as a predictor of diabetic retinopathy in patients with type 2 diabetes: A systematic review

Background Lipoprotein a (LP(a)), an LDL-like lipoprotein, known as a risk factor for cardiovascular diseases, has a controversial association with diabetic retinopathy in patients with type 2 diabetes—the current systematic review aimed to critically assess the association between LP(a) and diabetic retinopathy. Methods A systematic review of relevant studies was conducted after a thorough search in PubMed, Scopus, and Google Scholar electronic databases. We used English observational, case-control, and prospective cohort studies published up to August 2022, including type 2 diabetic patients as the population, diabetic retinopathy as the outcome, and LP(a) as the intervention. Result 17 relevant studies, including 4688 patients with diabetes, were included in this systematic review. While in 13 studies, Lipoprotein(a) was recognized as a risk factor for diabetic retinopathy, only three studies reported no evidence of a relationship between the two. Also, another study showed a mixed outcome of the relationship between LP(a) and diabetic retinopathy. Conclusion High serum lipoprotein(a) in patients with type 2 diabetes is considered a risk factor for diabetic retinopathy. However, further large-scaled cohort studies are still required to validate this finding.