Prescrire international
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Prescrire international · Oct 2005
Comparative StudyAngiotensin II receptor antagonists and heart failure: angiotensin-converting-enzyme inhibitors remain the first-line option.
(1) Some angiotensin-converting-enzyme inhibitors (ACE inhibitors) reduce mortality in patients with heart failure (captopril, enalapril, ramipril and trandolapril), and in patients with recent myocardial infarction and heart failure or marked left ventricular dysfunction (captopril, ramipril and trandolapril). (2) Angiotensin II receptor antagonists, otherwise known as angiotensin receptor blockers, have haemodynamic effects similar to ACE inhibitors, but differ in their mechanism of action and certain adverse effects. (3) Five clinical trials have evaluated angiotensin II receptor antagonists (candesartan, losartan and valsartan) in terms of their effect on mortality and on the risk of clinical deterioration in patients with symptomatic heart failure, but without severe renal failure, hyperkalemia or hypotension. In these trials, candesartan and valsartan were used at much higher doses than those recommended for the treatment of arterial hypertension. (4) In patients with heart failure who were not taking an angiotensin II receptor antagonist or an ACE inhibitor at enrollment, no significant difference was found between losartan and captopril in terms of mortality or the risk of clinical deterioration. (5) In patients with heart failure who had stopped taking an ACE inhibitor because of adverse effects, candesartan had no effect on mortality as compared with placebo, but it did reduce the risk of clinical deterioration (3 fewer hospitalisations per year per 100 patients). However, candesartan was associated with adverse effects such as renal failure and hyperkalemia, especially in patients who had experienced these same adverse effects while taking an ACE inhibitor. (6) In patients with heart failure who were already taking an ACE inhibitor, adjunctive candesartan or valsartan treatment did not influence mortality in comparison to the addition of a placebo. ⋯ Adding valsartan to ongoing captopril therapy did not reduce mortality or morbidity as compared with placebo, but did increase the risk of adverse effects. (12) Overall, these trials confirm the advantage of angiotensin II receptor antagonists over ACE inhibitors with respect to some adverse effects (cough, skin rash, etc.). However, the two drug classes share certain serious adverse effects such as hyperkalemia, renal failure and hypotension. In one trial, angioedema was less frequent with angiotensin II receptor antagonist therapy (one less case per 500 patients).
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Prescrire international · Oct 2005
Comparative StudyInsulin in type 2 diabetes: a useful alternative despite limited assessment based on surrogate endpoints.
(1) There are few clinical trials comparing combination therapy with a sulphonylurea and metformin after oral antidiabetic monotherapy fails to provide adequate glycaemic control. The UKPDS study suggested that this combination had a negative impact on mortality. (2) The assessment of insulin therapy in patients in whom oral antidiabetic therapy fails is based solely on surrogate endpoints: mainly HbA1c (glycated haemoglobin), bodyweight, and the frequency of hypoglycaemia. (3) In a comparative randomised trial involving patients whose glucose levels were no longer controlled by a sulphonylurea, the addition of metformin or a daily injection of insulin isophane (NPH) was similarly effective in reducing HbA1c levels. However, metformin caused less weight gain. (4) There are no randomised controlled trials comparing the addition of insulin versus a sulphonylurea when ongoing metformin monotherapy is inadequate. (5) Randomised comparative trials show that, when glycaemia is no longer controlled by a sulphonylurea plus metformin, adding a daily insulin injection is more effective in lowering HbA1c levels than the addition of acarbose and as effective as adding a glitazone. ⋯ The two strategies had a similar impact on HbA1c (-1.5% to -2.5%), but patients experienced less weight gain when the oral antidiabetics were continued and a single insulin injection was added. (8) The few available comparative trials fail to show which oral treatment (a sulphonylurea, metformin, or a combination of the two) has the best risk-benefit balance when combined with a bedtime injection of insulin isophane. (9) Insulin isophane is the first-choice insulin for combination therapy with an oral antidiabetic. In comparative trials, when combined with an oral antidiabetic, insulin glargine was no more effective than insulin isophane in terms of HbA1c levels or weight gain. Insulin glargine seems to provoke less hypoglycaemia but, in the absence of adequate follow-up, its long-term adverse effects are not known. (10) When a bedtime insulin injection plus an oral antidiabetic fail to control hyperglycaemia, indirect comparisons support the use of several daily insulin injections plus metformin, or three injections of an ultrarapid insulin analogue plus a sulphonylurea.