Blood pressure control, microalbuminuria and cardiovascular risk in Type 2 diabetes mellitus

Type 2 (noninsulin-dependent) diabetes mellitus (DM) affects about 3% of the UK population. Diabetes often coexists with a cluster of other potent cardiovascular risk factors, including hypertension, dyslipidaemia and increased tendency for thrombosis, and increases the risk of early death from cardiovascular causes by about threefold. Microalbuminuria or proteinuria also may be present, further increasing the risk of cardiovascular mortality. Cardiovascular risk factors must be treated aggressively in patients with Type 2 diabetes and control of blood pressure at 140/85 mm Hg or lower is a priority. The management of hypertension in patients from some ethnic groups demands special consideration because they have a high incidence of diabetes and hypertensive complications. Patients must be urged to adopt appropriate lifestyle changes in the first instance but additional drug treatment for hypertension is usually required. All the major classes of antihypertensive agents lower blood pressure in Type 2 diabetic patients but have different effects on metabolic risk factors in different ways. Low-dose thiazide diuretics, beta-blockers, calcium channel blockers and angiotensin converting enzyme (ACE) inhibitors have been shown to reduce cardiovascular risk. Individually, the effects of low-dose thiazide diuretics and beta-blockers on glucose and lipid metabolism is clinically insignificant, though in combination much larger metabolic effects are seen. ACE inhibitors and calcium channel blockers have no, or small, beneficial effects on glucose and lipid metabolism, while the greater beneficial effects of alpha1-blockers on lipid profiles may render them especially useful in the Type 2 diabetic patient. Long-acting calcium-channel blockers and ACE inhibitors protect renal function and are suitable as first line therapy in patients with microalbuminuria or proteinuria. Until results from the current batch of randomized, placebo-controlled trials comparing different classes of antihypertensive agents are available, the choice of antihypertensive agent is difficult. Addressing overall cardiovascular risk factors, rather than hypertension alone, is essential in the management of the hypertensive Type 2 diabetic patient.