Association between red cell distribution width and its ratio with albumin and diabetic nephropathy/retinopathy: A systematic review and meta-analysis

Abstract

Objective: Red cell distribution width (RDW) and RDW-albumin ratio (RAR) have been used as biomarkers for various illnesses. We reviewed published literature to assess if RDW and RAR can be predictors of predictors of diabetic nephropathy (DN) and diabetic retinopathy (DR).

Methodology: As per PRISMA guidelines, observational studies published on the databases of PubMed, Embase, Scopus and Web of Science till 20th December 2024 were included. We determined the pooled odds ratio (OR) for the association between RDW/RAR and DN/DR.

Results: Nine studies on RDW and three studies (four cohorts) on RAR were included. Studies on RDW and RAR included 6347 and 5005 patients respectively. Meta-analysis showed that high RDW was associated with higher odds of DN (OR: 1.70 95% CI: 1.39, 2.07 I2=43%) but not DR (OR: 1.18 95% CI: 0.97, 1.44 I2=35%). Association between RDW and DN did not change in sensitivity and subgroup analyses. Meta-analysis also found that high RAR was significantly associated with higher odds of DN (OR: 2.74 95% CI: 1.30, 5.74 I2=92%). Data from one study found no relationship between RAR and DR.

Conclusions: Higher RDW and RAR are associated with higher odds of DN. However, both the markers may not be associated with DR. In view of limited data, results must be interpreted with caution till further studies are available.