Indicators of dehydration and haemoconcentration are associated with the prevalence and severity of coronary artery disease.

1. The vascular endothelium is injured by blood flow abnormalities exacerbated by different risk factors, including markers of haemoconcentration. The aim of the present study was to assess the association between markers of haemoconcentration and dehydration and the prevalence and severity of coronary artery disease (CAD). 2. Subjects in the present study (189 men and 126 women) were classified as either CAD cases or controls according to the results of coronary angiography. The severity of CAD was scored on the basis of the number and the extent of lesions on coronary arteries. Serum electrolytes, osmolality and haematological parameters were measured. 3. Compared with control subjects, patient with CAD had increased levels of serum osmolality, calculated osmolality, tonicity, sodium, glucose and blood urea nitrogen (BUN). Significant differences were also observed in the haematocrit and haemoglobin concentration, but not in erythrocyte counts and total serum protein. On multiple logistic regression analysis adjusting for major risk factors, serum osmolality, glucose and BUN exhibited significant associations with CAD, but the correlations were lessened by diabetes. Analysis using anova showed a significant correlation between serum osmolality, sodium, glucose and BUN and the severity of CAD. The area under the receiver operating characteristic curves, as a relative measure of the test's efficiency, was the highest and significant for serum osmolality, BUN and glucose. 4. The results indicate that some of the markers of dehydration and haemoconcentration are associated significantly with the prevalence and severity of CAD, but the independence of these correlations is questioned. These markers may play a role in the pathogenesis of atherosclerosis.