Insulin resistance represents a common metabolic abnormality leading to 
cardiovascular disease, the major cause of morbidity and mortality in most parts 
of the world. Insulin resistance is also associated with an increased risk of 
type 2 diabetes which is strongly associated with obesity. The insulin 
resistance of obese people and subjects with type 2 diabetes is characterised by 
defects at many levels, affecting insulin receptor concentration, glucose 
transport mechanisms and the activities of intracellular enzymes. Around 25% of 
western populations show some features of the insulin resistance syndrome (often 
referred to as syndrome X or the metabolic syndrome) ie, a clustering of 
metabolic, atheromatous risk factors, including hypertriglyceridaemia, 
hyperinsulinaemia, hyper-tension, hypercholesterinaemia and obesity. However, 
the known metabolic cardiovascular risk factors associated with the insulin 
resistance syndrome do not sufficiently explain the excess vascular risk 
attributed to this syndrome. The observation, that increased plasma plasminogen 
activator inhibitor 1 (PAI-1) levels were associated with insulin resistance and 
atherothrombosis added for the first time a pathological basis for an 
association of the insulin resistance syndrome not only with metabolic, 
atheromatous (atherosclerotic) risk but also with atherothrombotic risk. It is 
very likely that not only PAI-1, but also other abnormalities in haemostatic 
variables contribute to this excess vascular risk. Knowledge of how haemostatic 
variables cluster with classical metabolic risk factors associated with the 
insulin resistance syndrome could help to better understand the pathogenesis of 
cardiovascular diseases. Indeed, many coagulation and fibrinolytic proteins have 
been shown to be associated with features of the insulin resistance syndrome and 
these associations suggest that some coagulation and fibrinolytic proteins have 
a role in atherothrombotic disorders, principally through an association with 
other established metabolic (atheromatous) risk factors in the presence of 
underlying insulin resistance. Interestingly, new therapeutic approaches in the 
prevention and treatment of insulin resistance do show some influence on 
coagulation and fibrinolysis. The newest drugs are the thiazolidinediones, a 
totally novel class of insulin sensitisers. They have the potential to offer 
improvements both in glycaemic control and in cardiovascular events.