Diabetes and hypertension

Hypertension is about twice as common in diabetics as in non-diabetics. The increased prevalence may relate to insulin resistance and its sequelae. Hypertension is a major risk factor for both large and small vessel disease, contributing to accelerated atherogenesis and progression of diabetic nephropathy and retinopathy. Treating raised blood pressure in diabetics is beneficial in the context of large vessel disease and in slowing progression of overt nephropathy. There is controversy as to whether antihypertensives, and particularly ACE inhibitor drugs, will prevent progression from incipient to overt nephropathy. All the major classes of antihypertensives can be used in diabetics, but the thiazide diuretics and p-blockers have metabolic side-effects which make them less appropriate as first line agents. The calcium antagonists and ACE inhibitors have better metabolic profiles and the latter reduce insulin resistance. ACE inhibitors may also have a renal protective effect in incipient nephropathy although the studies have been fairly short-term and with small patient numbers. Although ACE inhibitors and calcium antagonists are suitable as first line antihypertensives in diabetics, evidence is still lacking that these drugs reduce morbidity and mortality over and above that seen with other antihypertensives. The isolation of insulin in 1922 was for many diabetics life saving and for others health preserving. It was soon realised, however, that those people whose lives were being saved by insulin were starting to succumb to the long-term vascular complications of the disease. 70 years later diabetes is still a major health problem. Coronary artery disease, stroke and peripheral vascular disease are significantly more common in diabetics than non-diabetics.1 Diabetic small vessel disease (microangiopathy) leading to eye and kidney damage also accounts for much morbidity and mortality.