Clinical significance of insulin resistance.

Insulin resistance has emerged in the last 20 years as a concept familiar to clinicians in many specialties. No easily performed laboratory test is available to assess insulin action in routine clinical practice. Several rare syndromes of severe insulin resistance are recognized but most clinicians will encounter insulin resistance as a manifestation of common diseases. Physiological and treatment induced changes in insulin sensitivity influence insulin doses required in insulin-dependent diabetes mellitus. In non-insulin-dependent diabetes mellitus insulin resistance is fundamental to pathogenesis but it is also influenced by standard dietary and pharmacological treatment, and probably mediated by changes in prevailing glycaemia. Antihypertensive agents appear to have diverse effects on the insulin resistance of essential hypertension though the long term significance of these remains unclear. The importance of insulin as a risk factor for coronary heart disease and the concept of an insulin resistance syndrome as a common precursor of conditions with increased vascular risk remains controversial.