title: Blood pressure and hematocrit in diabetes and the role of endothelial responses in the variability of blood viscosity.
abstract: OBJECTIVE
  To investigate the relationship between mean arterial blood pressure and hematocrit in a population of treated diabetic patients and a control population of healthy individuals.
  
  
  METHODS
  Data on hematocrit and blood pressure were obtained from 129 diabetic subjects (87 women and 42 men) and 103 healthy subjects (76 women and 27 men) enrolled in a cross-sectional study. Alcohol consumption, ischemic heart disease, stroke, neoplasia, renal, hepatic, and chronic inflammatory disease were exclusion criteria.
  
  
  RESULTS
  The hematocrit of diabetic patients ranged from 0.35 to 0.52, and blood pressure had a bimodal distribution described by a second-order polynomial (P < 0.001), whereby elevated pressures correlated with low and high hematocrit, while the minimum average pressure was at hematocrit 0.43. Hematocrit of normal control subjects (range 0.28-0.55) was uncorrelated to blood pressure (averaged 99.7 +/- 9.7 mmHg). High blood pressure, low hematocrit diabetic subjects up to the minimum average hematocrit of 0.43 had a negative correlation (P < 0.0001) between these variables.
  
  
  CONCLUSIONS
  Our findings are compatible with the hypothesis that diabetic patients present normal responses to hematocrit variation and therefore blood viscosity and shear stress in mediating the release of vasodilators and lack the ability to autoregulate blood pressure relative to differences in hematocrit by comparison to nondiabetic subjects. These findings also suggest that the treatment of diabetes should target maintaining an optimal hematocrit in order to lower cardiovascular risk.
authors.affiliation: Medical Research Unit, Mexican Social Security Institute, 34000 Durango, Dgo, México.
authors.forename: Beatriz Y
authors.initials: BY
authors.lastname: Salazar-Vazquez
authors.forename: Marcos
authors.initials: M
authors.lastname: Intaglietta
authors.forename: Martha
authors.initials: M
authors.lastname: Rodríguez-Morán
authors.forename: Fernando
authors.initials: F
authors.lastname: Guerrero-Romero
mesh_terms: D000328:Adult; D001794:Blood Pressure; D001809:Blood Viscosity; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000503:physiopathology*; D004730:Endothelium, Vascular / Q000502:physiology*; D005260:Female; D006400:Hematocrit; D006801:Humans; D008297:Male; D008875:Middle Aged