I think that Rod Jackson has hit the nail on the head. What the HOT study
may tell us is that in the subgroup of diabetic hypertensives taking calcium
channel blockers, and ignoring the usual recommendations to use ace
inhibitors or diuretics as first line therapy, a lower target for DBP (<80)
may be appropriate. However the recent FACET and ABCD trials add evidence
that Calcium Channel Blockers are either harmful, or not as helpful as ace
inhibitors. Is there any justification for using calcium channel blockers
at all in diabetics?
References
Tatti P, Pahor M, Byington RP, Di Mauro P, Guarisco R, Strollo G, Strollo F.
Outcome results of the Fosinopril Versus Amlodipine Cardiovascular Events
Randomized Trial (FACET) in patients with hypertension and NIDDM. Diabetes
Care 1998 Apr;21(4):597-603
RESULTS
...The patients receiving fosinopril had a significantly lower risk of the
combined outcome of acute
myocardial infarction, stroke, or hospitalized angina than those receiving
amlodipine (14/189 vs. 27/191; hazards ratio = 0.49, 95% CI = 0.26-0.95).
CONCLUSIONS: Fosinopril and amlodipine had similar effects on biochemical
measures, but the patients randomized to fosinopril had a significantly
lower risk of major vascular events, compared with the patients randomized
to amlodipine.
Quoting from the Journal of Family Practice Journal Club, "The prospectively
defined aggregate outcome of myocardial infarction, stroke, or angina
requiring hospitalization was significantly less frequent in patients
assigned to fosinopril (14/189) as opposed to amlodipine (27/191). This
corresponds to a 'number needed to harm' of 14 over the 3 years of the
study; there would be one bad outcome for every 14 people who took
amlodipine instead of fosinopril for three years. Using the Cox
proportionate hazards model this corresponds to 2.6 versus 5.0 events per
100 person-years (hazard ratio 0.49, 95% CI 0.26 to 0.95)"
The Appropriate Blood Pressure Control in Diabetes (ABCD) Trial
Estacio RO, Jeffers BW, Hiatt WR, Biggerstaff SL, Gifford N, Schrier RW. The
effect of nisoldipine as compared with enalapril on cardiovascular outcomes
in patients with non-insulin-dependent diabetes and hypertension. N Engl J
Med 1998 Mar 5;338(10):645-652
RESULTS: Analysis of the 470 patients in the trial who had hypertension
(base-line diastolic
blood pressure, > or = 90 mm Hg) showed similar control of blood pressure,
blood glucose and lipid concentrations, and smoking behavior in the
nisoldipine group (237 patients) and the enalapril group (233 patients)
throughout five years of follow-up. Using a multiple logistic-regression
model with adjustment for cardiac risk factors, we found that nisoldipine
was associated with a higher incidence of fatal and nonfatal myocardial
infarctions (a total of 24) than enalapril (total, 4) (risk ratio, 9.5; 95
percent confidence interval, 2.7 to 33.8). CONCLUSIONS: In this population
of patients with diabetes and hypertension, we found a significantly higher
incidence of fatal and nonfatal myocardial infarction among those assigned
to therapy with the calcium-channel blocker nisoldipine than among those
assigned to receive enalapril. Since our findings are based on a secondary
end point, they will require confirmation.
After five years of follow-up, on the advice of the Data and Safety
Monitoring Committee, the ABCD investigators stopped the study in the
patients with hypertension who had been assigned to nisoldipine because of a
marked difference in the number of myocardial infarctions (25 in the
nisoldipine group vs. 5 in the enalapril group)
David Brown, MD
Assistant Professor
Department of Family Practice
University of Hawaii
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