ObjectiveTo assess the association of hemoglobin (Hb) levels with the prevalence of diabetic retinopathy (DR) in patients with type 2 diabetes mellitus (T2DM).MethodsA cross-sectional study. From January 2017 to December 2018, 707 patients with T2DM who were hospitalized in the Department of Internal Medicine of Chu Hsien-I Memorial Hospital & Tianjin Medical University, were included in the study. All patients underwent color photography of the fundus of both eyes with dilated pupils. According to DR diagnostic criteria, patients were divided into DR group and non-DR (NDR) group, with 210 and 497 cases, respectively; DR group was further divided into non-proliferative DR group (NPDR) group and proliferative DR (PDR) group, about 186, 24 cases, respectively. Hb level was detected, single factor analysis of its correlation with DR; logistic regression analysis was used to evaluate the relationship between Hb level and DR risk.ResultsThe Hb levels of the patients in the NDR group and the DR group were 140.58±17.26 and 132.35±23.48 g/dl; compared with the NDR group, the Hb level of the DR group was significantly lower, and the difference was statistically significant (t=5.107, P=0.000). In the NDR group, NPDR group, and PDR group, Hb levels of male patients were 149.3±1.01, 142.6±2.35, 132.9±8.44 g/dl, respectively; Hb levels of female patients were 131.7±0.90, 124.0±2.09, 116.8±5.23 g/dl. With the progress of DR, Hb levels of different sexes decreased significantly, and the difference was statistically significant (P＜0.000 1). The results of correlation analysis showed that Hb reduction was an independent risk factor for DR (odds ratio=4.437, 95% confidence interval 2.590-7.603, P＜0.000 1).ConclusionThe reduction of Hb in T2DM patients is positively correlated with the severity of DR.