Whereas individual research papers about
antihypertensive treatment in diabetics might be somewhat confusing, the weight of the evidence strongly suggests that: 1) In patients with
type 1 diabetes, it is advantageous to use
angiotensin-converting enzyme (
ACE) inhibitors as primary treatment. 2) In type 2 diabetics, aggressive blood pressure (BP) lowering is warranted and, the
calcium antagonist controversy notwithstanding, all drugs appear to be similarly useful in reducing cardiovascular mortality. Specifically, in the
Systolic Hypertension in Europe study, compared with placebo, a
calcium antagonist dramatically reduced cardiovascular (CV) events in elderly diabetics. The
Hypertension Optimal Treatment study showed that, using a
calcium antagonist-based regimen, the degree of BP lowering determines the degree of CV event reduction. Furthermore, the United Kingdom Prospective Diabetes Study (UKPDS) did not find a difference in CV events reduction in patients treated with beta-blockers or with
ACE inhibitors. In the UKPDS, the effect of BP lowering on reduction in CV events was more substantial than the degree of CV reduction by
blood sugar lowering. 3) Both the
CAPtopril Prevention Project (CAPPP) and the Heart Outcomes Prevention Evaluation (HOPE) studies found that treatment with an
ACE inhibitor may be useful in reducing the incidence of new-onset
type 2 diabetes mellitus. 4) Finally,
insulin resistance, a precursor of
diabetes mellitus and a strong predictor of future CV disease, is differentially affected by
antihypertensive treatment. beta-Blockers and
diuretics worsen
insulin resistance, whereas
alpha-adrenergic blockers and central
imidazoline binding agents increase
insulin sensitivity. The effect of
ACE inhibitors and
angiotensin blockers may also positively affect
insulin resistance, but the results are not uniformly positive. It stands to reason that the differential effect of various drugs on
insulin resistance and primary CV events may be clinically relevant particularly in the course of the long-term prevention of mild
hypertension. All current trials investigate the effect of the treatment on
secondary prevention of CV events among patients with advanced complicated diabetes and
hypertension.