Efficacy of antihypertensive therapy in decreasing renal and cardiovascular complications in diabetes mellitus

The mechanism underlying the pathogenesis of microangiopathy and macroangio pathy in diabetes mellitus is hypothesized to be chronic hyperglycaemia. Ho wever, the values of blood glucose at which chronic diabetic complications develop at the renal and cardiac level are quite different. It is not clear whether this is due to different responses of kidney and heart tissues to the metabolic challenge of diabetes, or to the simultaneous role of other m echanisms contributing differently to the pathogenesis of chronic diabetic complications in renal and cardiac tissues. One of these mechanisms could b e the simultaneous occurrence of arterial hypertension along with hyperglyc aemia in diabetic patients. We reviewed the available evidence in the recent medical literature and pro vide information on the relationships between hyperglycaemia and cardiovasc ular and renal complications in insulin-dependent diabetes mellitus (IDDM) and non-insulin-dependent diabetes mellitus (NIDDM). The majority of report s indicate that the values of blood glucose appearing to be at threshold le vel for the development of cardiovascular complications are significantly l ower than those determining renal complications (5.4 vs 10.0 mmol/l blood g lucose concentrations 2 h after an oral glucose tolerance test). This was t he case both in cross-sectional and prospective studies and also in interve ntion studies aimed at decreasing blood glucose concentrations by using str ict metabolic control methods (The Diabetes Control and Complications Trial Research Group), which succeeded in delaying the rate of occurrence of mic roangiopathic complications at the kidney and retinal level but not so effe ctively at the cardiac level. Therefore, alternative therapeutic or supplem entary strategies to blood glucose control should be adopted in diabetes to prevent diabetic complications. To date, the most effective approach, from our point of view, is antihypertensive therapy in order to prevent endstag e renal disease. We extensively reviewed the available literature which rep orted comparisons between angiotensin-converting enzyme inhibitors (ACE inh ibitors) and calcium channel blockers (CCBs) in the treatment of arterial h ypertension in diabetes. Intensified antihypertensive therapy achieving a b lood pressure level below 130/85 mmHg has been shown to be useful in decrea sing the rate of occurrence of chronic diabetic complications in diabetes m ellitus. Both ACE inhibitors and CCBs have been shown to significantly impr ove the course of renal function in diabetic patients with incipient and ov ert nephropathy.