Abstract
BACKGROUND: Diabetes mellitus (DM), a worldwide disease affecting more than 400 million people, is associated with high blood pressure (BP). In addition to macrovascular complications, high BP in DM patients is potentially linked to microvascular complications. More than 70% of DM patients have retinopathy. To our knowledge, no systematic review and meta-analysis has been conducted on the relationship between visit-to-visit variability in blood pressure and diabetic retinopathy risk. METHODS: This systematic review and meta-analysis study was performed on the related articles. The search strategy, screening, and data selection were all checklist-based. A comprehensive search was done in three databases, including PubMed, Google Scholar, and Scopus. The Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) were followed. English clinical studies published up to January 2023 contained diabetic patients as the population, retinopathy as the outcome, and visit-to-visit blood pressure as the intervention. Using the QUIPS technique, two authors independently quantify the risk of bias in included publications. The meta-analysis was conducted using R version 4.4.1. We calculated relative risk (RR) as the effect size, applying the random effect model. Standard deviation (SD) and coefficient of variation (CV), were used as measures of BP variability. RESULTS: A total number of 8 studies with 743,315 participants were covered in this systematic review. After meta-analysis, we concluded that the group with higher SD of BP variability had 2 percent higher risk than the control group (RR = 1.02, 95% CI = 1.01-1.03, I-squared = 41%); however, results of our analysis for CV of BP variability showed no significant contrast with control group thus no increased risk was reported (RR = 1.04, 95% CI = 0.94-1.15, I-squared = 32%, P-value = 0.23). CONCLUSION: In conclusion, an increased SD of BP variability significantly increased the relative risk for the development of retinopathy.