Low CD34⁺ cells, high neutrophils and the metabolic syndrome are associated with an increased risk of venous thromboembolism

The relationship between MetS (metabolic syndrome), levels of circulating progenitor/immune cells and the risk of VTE (venous thromboembolism) has not yet been investigated. We studied 240 patients with previous VTE and 240 controls. The presence of MetS was identified according to NCEP ATP III guidelines and flow cytometry was used to quantify circulating CD34⁺ cells. VTE patients showed higher BMI (body mass index), waist circumference, triacylglycerol (triglyceride) levels, blood glucose, hs-CRP (high-sensitivity C-reactive protein) and lower HDL-C (high-density lipoprotein cholesterol) levels. The prevalence of MetS was significantly higher in VTE (38.3%) than in control individuals (21.3%) with an adjusted OR (odds ratio) for VTE of 1.96 (P=0.002). VTE patients had higher circulating neutrophils (P<0.0001), while the CD34⁺ cell count was significantly lower among patients with unprovoked VTE compared with both provoked VTE (P=0.004) and controls (P=0.003). Subjects were also grouped according to the presence/absence of MetS (MetS⁺ or MetS⁻) and the level (high/low) of both CD34⁺ cells and neutrophils. Very high adjusted ORs for VTE were observed among neutrophils_high/MetS⁺ (OR, 3.58; P<0.0001) and CD34⁺_low/MetS⁺ (OR, 3.98; P<0.0001) subjects as compared with the neutrophils_low/MetS⁻ and CD34⁺_high/MetS⁻ groups respectively. In conclusion, low CD34⁺ blood cell count and high circulating neutrophils interplay with MetS in raising the risk for venous thromboembolic events.