Impaired RBC deformability is associated with diabetic retinopathy in patients with type 2 diabetes

Aim Red blood cell (RBC) deformability, the ability of RBCs to change shape under stress, is known to be decreased in type 2 diabetes (T2D). However, as yet little is known of the association between RBC deformability and diabetic complications in T2D. For this reason, this study has investigated the association between RBC deformability and diabetic complications. Methods In this cross-sectional study, 452 T2D patients were initially enrolled. RBC deformability was measured using a microfluidic ektacytometer and expressed as an elongation index at 3 Pa (EI@3Pa, %). Results A final total of 373 patients (mean age: 60.04 ± 11.93 years; males: 201) were included in the study. When categorized into quartiles of RBC deformability, the lower EI@3Pa groups had higher glycated haemoglobin (HbA_1c), triglycerides and prevalence of diabetic retinopathy compared with the higher quartiles (P < 0.05 for trend). In particular, the EI@3Pa was significantly lower in patients with retinopathy than in those without retinopathy (30.53 ± 1.95 vs 31.20 ± 1.53, P = 0.001). Between the lowest EI@3Pa quartile (Q1) to the highest (Q4, reference), the odds ratio (OR) for Q1 was 2.81 (95% CI: 1.21–6.49, P = 0.004 for trend), after adjusting for age, gender, presence of hypertension and smoking, duration of diabetes, HbA_1c, glomerular filtration rate and triglycerides. Conclusion In terms of diabetic complications, the lowest EI@3Pa group was closely associated with only the risk of diabetic retinopathy in our study. These results suggest that RBC deformability might be contributory to the development of the microvascular complication.