Erythrocyte hyperaggregation in obesity: determining factors and weight loss influence

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.

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 MA1, which determines EA at stasis (EA0) and at a low shear of 3 seconds(-1) (EA1), and the Sefam aggregometer, which determines aggregation index at 10 seconds(-1) (IA10), aggregation time (Ta), and disaggregation threshold (gammaD). Insulin resistance (IR) was calculated by homeostasis model assessment.

Obese patients showed higher Fbg levels, EA0, EA1, IA10, and gammaD values, and lower Ta values. Differences between obese patients and control group for EA0, EA1, Ta, IA10, and gammaD 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 EA0 and EA1 values. After weight loss, EA1 showed a significant improvement.

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.