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Increased urinary albumin loss in patients with Type 1 diabetes is associated with accelerated atherosclerosis. Prothrombotic factors known to be associated with cerebrovascular and coronary artery disease in the general population, antithrombotic factors, were studied in 52 patients with Type 1 diabetes and varying urinary albumin loss and 24 non-diabetic control subjects. Fibrinogen increased from 2.5 g l-1 (95% confidence interval 2.3-2.8) in control subjects and 2.8 g l-1 (2.6-3.0) in diabetic patients without microalbuminuria to 3.1 g l-1 (2.7-3.5) with microalbuminuria (p < 0.005 vs control; p < 0.001 vs without microalbuminuria). Factor VIIc increased from 81% (75-86% in non-diabetic control subjects and 84% (78-90%) in diabetic patients without microalbuminuria to 103% (89-117%) with microalbuminuria (p < 0.005 vs control; p < 0.05 vs without microalbuminuria) and 118% (86-150%) with albuminuria (p < 0.005 vs control and p < 0.001 vs without microalbuminuria). Levels of the antithrombotic factors protein C, protein S, and antithrombin III also rose in the diabetic patients with evidence of renal damage. Elevation of prothrombotic factors has been associated with increased risk of microvascular disease, whereas elevation of antithrombotic factors has no known protective effect. Therefore, this pattern of alteration of haemostatic factors in diabetic renal disease may contribute to the increased risk of vascular disease associated with both microalbuminuria and albuminuria.

SummaryVenous thromboembolism is rare in Chinese. To determine the incidence and disease profile of thrombophilia in Chinese patients with thrombosis, 52 unselected Chinese patients with documented venous thrombosis were studied for the presence of thrombophilia. Levels of antithrombin III (AT III), protein C (PC) and protein S (PS) as well as the presence of acquired lupus anticoagulant (LA) and anticardiolipin antibody (ACA) were investigated. Thirty patients were found to be abnormal. These consisted of 5 AT III deficiencies, 9 PC deficiencies, 10 PS deficiencies, 1 combined PC & PS deficiency (all in the heterozygous range), and 5 patients with LA and/or ACA. When the patients with LA and/or ACA are excluded, the incidence of hereditary thrombophilia is 25/47 i.e. 53.2%' which is much higher than those reported in studies of Caucasian patients selected under strict criteria. Family studies performed in 16 cases ot hereditary thrombophilia revealed involvement in 11 cases (68.7%); a total of 36 heterozygous family members were affected, most of which remain asymptomatic. Although 35 events predisposing to thrombosis (27 pregnancies, 1 oral contraceptive consumption and 7 surgical operations) were identified among these index patients, and the heterozygous family members, thrombosis was observed on only 6 occasions (17.1%). The data suggest that pregnancy and surgery do not carry the same degree of thrombotic risk in Chinese as in the Caucasian population with heterozygous AT III, PC and PS deficiency.

Diabetes mellitus is associated with a two to threefold increase in cardiovascular mortality [1]. The mechanism whereby diabetes increases cardiovascular risk is probably multifactorial. Recent studies suggest that this may in part be attributed to an increase in thrombotic tendency [2] including an increase in circulating level of factor VII, a key enzyme in the initiation of coagulation. A positive correlation between increased factor VII activity and cardiovascular mortality has been shown in the Northwick Park Heart Study [3]. A similar trend Diabetologia (1998) In both diabetic and control subjects the allele frequencies of the R (M1) and Q (M2) alleles were 0.96 and 0.04; the corresponding reported frequencies in Caucasians being 0.90 and 0.10: VIIc were 21 % lower in Chinese control subjects and Type I diabetic patients with R/Q, compared with R/R subjects (p < 0.001 and p < 0.05). The corresponding difference was 4 % for Type II diabetc patients (p = NS). Type II diabetic patients had higher mean VIIc levels than control subjects and Type I diabetic patients (p < 0.01); they were also older, and had higher serum creatinine and triglyceride (all p < 0.01). They also had higher VIIc levels than an age-matched older control group (p < 0.01; n = 182) in whom the genotype effect was clearly seen. On stepwise linear regression analysis, the significant independent determinants of VIIc were serum triglyceride (contributing 20 % and 25 % to variance in control subjects and diabetic patients), the R/Q353 genotype (contributing to 12 % of the variance in control subjects but only 1 % in diabetic patients), age and total cholesterol in all subjects, and in the diabetic patients female sex, urinary albumin excretion rate and serum creatinine. VIIc was higher in diabetic patients with macroangiopathy and retinopathy (both p < 0.0001). We conclude that compared with Caucasians, the Q allele frequency is significantly lower in these Chinese subjects. Plasma VIIc is determined by both genetic and environmental influences such that in Chinese Type II diabetic patients, the effect of environmental factors predominates, almost negating the influence of the R/Q353 genotype. High VIIc may contribute to the increased cardiovascular risk in Type II diabetic patients. [Diabetologia (1998) 41: 760±766]

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