Management of hypertension in diabetes mellitus

Overall, approximately 40% of diabetic patients have hypertension at the time of diagnosis of diabetes and a similar percentage may develop hypertension during their follow-up. Factors contributing to this high prevalance of hypertension in diabetes include obesity, old age, insulin resistance, increased extracelluar volume, diabetic nephropathy and increased arterial stiffness. Well-conducted clinical trials that have been completed in the last decade demonstrated a major impact of hypertension on the micro- and macrovascular complications of diabetes and remarkable benefits of its control. Based on this large trial database, the currently accepted level of blood pressure used in diabetes for definition and target of therapy is 130/80 mmHg. Dietary and behavioral lifestyle modifications should be an intergral part of any management regimen. These include weight reduction, low sodium diet, exercise, moderate alcohol intake and smoking cessation. Effective control of blood pressure to target levels is more important than the drug(s) used. Combination drug therapy is needed frequently to achieve a target blood pressure. Although blockers of the renin-angiotensin-aldosterone system seem to have a favorable effect in diabetes, high-level evidence suggests that low-dose thiazide diuretics, angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers and calcium channel blockers are all good choices, both as initial and add-on therapy. Frequently, more than one drug is needed, and a low-dose thiazide diuretic combined with an angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker is a commonly used effective combination. Other drugs that can be added include calcium channel blockers and β-blockers. In certain clinical situations, specific drug classes are indicated. These include angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers in the case of diabetic nephropathy, β-blockers in the case of ischemic heart disease, and calcium channel blockers and loop diuretics in the case of advanced renal insufficiency, where the use of angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers carries a significant risk of hyperkalemia.