Pathogenesis and treatment of hypertension associated with diabetes

The pathogenesis of hypertension accompanying diabetes mellitus (DM) may involve abnormalities in at least two major blood pressure (BP)--regulating systems. Exchangeable sodium (Naex) and the cardiovascular pressor responsiveness to norepinephrine are often increased, while blood volume is normal or low, regardless of age, insulin-dependence or non-dependence, or the presence or absence of retinopathy or clinical nephropathy. In hypertensive DM, systolic BP correlated (P less than 0.001) with Naex; diuretic treatment improved norepinephrine responsiveness, Naex and BP, while calcium entry blockade improved cardiovascular responsiveness and BP without changing Naex. Plasma catecholamine, renin and aldosterone levels are usually normal or sometimes low in stable DM. Antihypertensive therapy in DM is based on 3 legs, namely antidiabetic treatment, general measured aimed at reducing BP and associated risk correlates, and if necessary BP-lowering drugs. Due to their metabolic side effects, thiazide-diuretics given in moderate to high doses are not ideal step 1 drugs in DM. Certain beta 1-blockers have fewer, although still some, unwanted side effects. Preliminary data suggest that certain calcium antagonists may often lower BP without causing relevant metabolic impairment. These agents and converting enzyme inhibitors deserve further evaluation in the treatment of DM-associated hypertension.