BACKGROUND; Previous studies reported the increased prevalence of cardiovascular disease (CVD) in patients with rheumatoid arthritis (RA) compared to the general population. However, the predictors for the development of CVD in patients with RA were not clearly established, and the role of thrombosis mechanisms was inconsistently characterized in these patients. The aim of this study was to evaluate the platelet histogram indices, as markers of platelet activation, in patients with RA with or without CVD.
In 64 pts with RA (mean age: 58.0 +/- 12.7 yrs) we performed the standard clinical evaluation and biochemical workup with platelet histogram, including mean platelet volume (MPV) and platelet distribution width (PDW) as markers of platelet activation. We divided the study population into two groups: A - 41 patients with RA without CVD and B - 23 patients with RA and CVD (ischemic heart disease, peripheral artery disease or cerebrovascular disease). The values of MPV and PDW were also analyzed in an age- and sex-mached control group of 20 subjects without RA and CVD and in a group of 62 patients with CVD without RA (stable angina).
The platelets number was similar in both groups, but the platelet histogram showed higher values for MPV (9.6 vs. 8.6 fL, p < 0.01) and PDW (16.1 vs. 14.0, p < 0.01) in patients with RA and CVD, reflecting greater platelet activation in these patients. MPV values were lower in patients with RA, but the values of PDW were higher in these patients comparing to control. Patients with RA with CVD have higher values of PDW than patients with CVD, but without RA, showing an increased platelet activation in RA. The PDW values correlate with fibrinogen (0.63; p = 0.003) but not with CRP or ESR, while the MPV was not correlated with the inflammatory markers in patients with RA.
The pathogensis of CVD in patients with RA may be linked to an increased prothrombotic activity which might be evaluated by platelet histogram indices.