Importance of hematological parameters for micro- and macrovascular outcomes in patients with type 2 diabetes: the Rio de Janeiro type 2 diabetes cohort study

BACKGROUND: The prognostic importance of several hematological parameters has been scarcely investigated in type 2 diabetes. So, we aimed to evaluate their prognostic importance for development of complications in a cohort of type 2 diabetes. METHODS: In a prospective study, 689 individuals with type 2 diabetes had blood red cell, platelet and leukocyte parameters obtained at baseline. Multivariate Cox analyses examined the associations between several hematological parameters (including neutrophyl-to-lymphocyte, lymphocyte-to-monocyte, platelet-to-lymphocyte, and monocyte-to-HDL ratios) and the occurrence of microvascular (retina, renal and peripheral neuropathy) and cardiovascular complications (total cardiovascular events [CVEs], and major adverse CVEs [MACEs]), and all-cause and cardiovascular mortality. Improvements in risk discrimination were assessed by C-statistics and Integrated Discrimination Improvement (IDI) index. RESULTS: During a median follow-up of 10.5 years, 212 patients had a CVE (174 MACEs), 264 patients died (131 cardiovascular deaths); 206 had a renal, 161 a retinopathy and 179 patients had a neuropathy outcome. In multivariate-adjusted analyses, the lymphocytes count and lymphocyte-to-monocyte ratio were protective (hazard ratios [HRs]: 0.77 and 0.72, respectively), whereas the neutrophyl-to-lymphocyte and platelet-to-lymphocyte ratios were associated with increased risks (HRs: 1.19 and 1.17) for all-cause mortality. For cardiovascular mortality, the monocytes count, the neutrophyl-to-lymphocyte and monocyte-to-HDL ratios were associated with increased risks and the lymphocyte-to-monocyte ratio was protective. Higher lymphocyte-to-monocyte ratio was protective for renal failure outcome. However, none of them improved risk discrimination. CONCLUSIONS: Low lymphocytes count and leukocyte ratios that mainly included lymphocytes were predictors of macrovascular complications and mortality in individuals with type 2 diabetes. However, they did not improve risk prediction over traditional risk factors.