Erythrocyte hyperaggregation in obesity:: Determining factors and weight loss influence

Objective: To compare erythrocyte aggregation (EA) in patients with severe obesity without other cardiovascular risk factors with a control group, using the Myrenne and the Sefam aggregometers, and to evaluate the effect of weight loss on this parameter. Research Methods and Procedures: This was a longitudinal, clinical intervention study of a very low-calorie diet for 4 weeks followed by a low-calorie diet for 2 months. In 67 severely obese patients, an anthropometric and analytical evaluation [plasmatic lipids, fibrinogen (Fbg), and EA] was performed at baseline and 3 months after diet. The same determinations were performed in 67 normal-weight volunteers. EA was measured with the Myrenne MA(1) which determines EA at stasis (EA(0)) and at a low shear of 3 seconds(-1) (EA,), and the Sefarn aggregometer, which determines aggregation index at 10 seconds(-1) (IA(10)), aggregation time (Ta), and disaggregation threshold (gamma D). Insulin resistance (IR) was calculated by homeostasis model assessment. Results: Obese patients showed higher Fbg levels, EA, EA, IA(10), and gamma D values, and lower Ta values. Differences between obese patients and control group for EA(0), EA I, Ta, IA(10), and gamma D disappeared after adjusting for BMI or for homeostasis model assessment but were maintained after adjusting for Fbg or low-density lipoprotein-cholesterol. Obese patients with IR showed higher EA(0) and EA, values. After weight loss, EA, showed a significant improvement. Discussion: Obese patients show increased EA. Erythrocyte hyperaggregation does not seem to be related to a high Fbg level or to an abnormal lipid profile but to IR. Hyperagreggation improves after weight loss.