Hematological markers such as hematocrit (Hct), hemoglobin (Hb) or red blood cell (RBC) count were reported to be associated with the development of diabetic retinopathy with conflicting results. Moreover, which of these markers is the best to predict incident retinopathy remains unknown. To clarify this, we utilized ICD-10 and medical treatment codes from a nationwide claims database that included 7,182 participants (1,490 women, mean age 50.8 y, HbA1c 6.9%, mean follow-up period 5.5y) classified as having diabetes mellitus or vision-threatening treatment-required diabetic eye diseases (TRDED). Multivariate Cox regression model was used to identify predictors of TRDED. During the study period, 177 patients developed TRDED (4.5/1000 person-years). Cox analysis demonstrated that the lower Hcts were significant predictors TRDED and lower Hcts were more predictive than lower RBC counts. The Hb level was not significantly associated with TRDED. Hazard ratios (HRs) per 1 standard deviation (SD) increase in Hct, RBC count and Hb for incident TRDED were 0.792 (95% confidence interval [CI], 0.666-0.942), 0.874(0.765-0.998), and 0.861 (0.725-1.023) as continuous variables, respectively. The interaction between Hct and RBC count was not statistically significant. Multivariate tertile analysis also revealed that a lower Hct was more predictive of TRDED (HR 2.03 [95% CI, 1.33-3.08] for the bottom [≤43.4%] vs. the top [≥46.7%] tertile [P value = 0.001]) than lower RBC counts (HR 1.54 [95% CI, 0.99-2.38] for the bottom [≤468×104/m3] vs. the top [≥507×104/m3] [P value = 0.054]). These findings demonstrated that lower Hcts were significant predictor of vision-threatening retinopathy for people with diabetes and more useful than the RBC count or Hb. Association of the influence of these three markers on severe retinopathy awaits further investigation.
M. Yamamoto: None. K. Fujihara: None. T. Osawa: None. M. Harada: None. M. Ishizawa: None. H. Suzuki: None. H. Ishiguro: None. H. Seida: None. N. Yamanaka: None. Y. Matsubayashi: None. H. Sone: Research Support; Self; Astellas Pharma Inc., Boehringer Ingelheim Pharmaceuticals, Inc., Daiichi Sankyo Company, Limited, Kowa Pharmaceutical Europe Co. Ltd., Kyowa Hakko Kirin Co., Ltd., Novo Nordisk Inc., Ono Pharmaceutical Co., Ltd., Taisho Pharmaceutical Co., Ltd., Takeda Pharmaceutical Company Limited, Teijin Pharma Limited.