The Influence of Race on Plasma Thrombin Generation In Healthy Subjects In Singapore

Race is touted as an independent risk factor for venous thromboembolism (VTE), although the basis for this is varied and contentious. Comparison of plasma thrombin generation (TG) using calibrated automated thrombogram (CAT) across races offers a modality that objectively measures global hemostatic function to evaluate this influence. Direct comparative data across races are currently not available. Aim is to establish the influence of race on plasma TG. Sixty normal participants, matched for age and gender, equally representing 4 races-Caucasian, Chinese, Indian, and Malay-were recruited. Thrombin generation parameters (lag time, time to peak, peak, and endogenous thrombin potential [ETP]) in platelet-poor plasma were measured using CAT. The mean ETP (standard deviation) for the different races were Caucasians: 1338.18 (194.19) nM·min; Chinese, 1318.91 (108.90) nM·min; Indians, 1389.81 (182.61) nM·min; and Malays, 1436.21 (184.24) nM·min. Caucasians had the longest mean lag time of 2.59 ± 0.37 seconds; Indians had the highest mean peak of 284.22 ± 30.74 nM, and Malays had the longest mean time to peak of 5.47 ± 0.59 seconds. Analysis based on race did not demonstrate any significant difference for all TG parameters. The greatest mean difference of ETP between any 2 races (Malays and Chinese) was 117.30 nM·min (95% confidence interval: -45.86 to 280.46 nM·min) which was within the predefined limit of equivalence. In a cohort of healthy participants, TG mediated by plasma factors is not influenced by race and does not explain the reported racial differences in VTE incidence. For the 4 racial groups studied, the use of separate normal ranges for plasma TG might not be essential.