Effect of carvedilol and metoprolol on the mode of death in patients with heart failure.

BACKGROUND: In the COMET study, carvedilol improved survival compared to metoprolol tartrate in 3029 patients with NYHA II-IV heart failure and EF <35%, followed for an average of 58 months. AIMS: To evaluate whether the effect on overall mortality was specific for a particular mode of death. This may help to identify the mechanism of the observed difference. METHODS: Of the 1112 total deaths, 972 were adjudicated as cardiovascular, including 480 sudden, 365 circulatory failure (CF) and 51 stroke deaths. For each mode of death, the effect of pre-specified baseline variables was assessed, including sex, age, NYHA class, aetiology, heart rate, systolic blood pressure, EF, atrial fibrillation, previous myocardial infarction or hypertension, renal function, concomitant medication, and study treatment allocation. RESULTS: In multivariate Cox regression analyses, compared to metoprolol, carvedilol reduced cardiovascular (RR 0.80, CI 0.7-0.91, p=0.0009), sudden (RR 0.77, CI 0.64-0.93, p=0.0073) and stroke deaths (RR 0.37, CI 0.19-0.71, p=0.0027) with a non-significant trend for CF death (RR 0.83, CI 0.66-1.04, p=0.07). Treatment benefit with carvedilol did not differ between modes of death, except for a greater reduction in stroke death with carvedilol (competing risk analysis, p=0.0071 vs CF death). There were no interactions between treatment allocation and baseline characteristics. CONCLUSION: Mortality reduction with carvedilol compared to metoprolol appears relatively non-specific and could be consistent with a superior effect of carvedilol on cardiac function, arrhythmias or, in view of the greater reduction in stroke deaths, on vascular events.

Prognostic importance of plasma NT-pro BNP in chronic heart failure in patients treated with a beta-blocker: results from the Carvedilol Or Metoprolol European Trial (COMET) trial.

BACKGROUND: Plasma levels of N-terminal pro-brain natriuretic peptide (NT-pro BNP) are increased in patients with chronic heart failure (CHF). Beta-blockers (BB) may influence these levels but it is unclear whether changes in NT-pro BNP reflect concomitant changes in prognosis. OBJECTIVES: To assess the prognostic importance of NT-pro BNP at baseline and during follow-up, in patients in whom beta-blocker therapy is initiated. METHODS: In COMET, 3029 patients with CHF in NYHA class II-IV and EF<35% were randomised to carvedilol or metoprolol tartrate and were followed for an average of 58 months. Blood samples were collected for the measurement of NT-pro BNP at baseline (n=1559) and during follow-up (n=309). RESULTS: Baseline plasma concentrations of NT-pro BNP above the median (1242 pg/ml) were associated with higher all-cause mortality (RR 2.77; 95% CI 2.33-3.3, p<0.001). Patients who achieved NT-pro BNP levels<400 pg/ml during follow-up had a lower subsequent mortality (RR 0.32; 95% CI 0.15-0.69, p=0.004). CONCLUSIONS: The plasma concentration of NT-pro BNP is a powerful predictor of mortality in patients with CHF. Patients who achieve an NT-pro BNP of <400 pg/ml subsequent to treatment with a beta-blocker have a favourable prognosis.

Carvedilol protects better against vascular events than metoprolol in heart failure: results from COMET.

OBJECTIVES: We explored whether vascular protection by carvedilol could contribute to its superior effects in the treatment of heart failure (HF) compared with metoprolol tartrate in the COMET (Carvedilol Or Metoprolol European Trial) study. BACKGROUND: Full adrenergic blockade by carvedilol and additional (e.g., antioxidative) properties may lead to vascular protection relative to beta-1 blockade alone, and contribute to its efficacy in HF treatment. METHODS: Three thousand twenty-nine patients with HF due to ischemic (51%) or idiopathic cardiomyopathy (44%) were randomized double-blind to carvedilol (n = 1,511) or metoprolol (n = 1,518) and followed for 58 months. Vascular end points were cardiovascular death, stroke, stroke death, myocardial infarction (MI), and unstable angina. RESULTS: The effect of carvedilol on cardiovascular death improved consistently in subgroups with prespecified baseline variables. Myocardial infarctions were reported in 69 carvedilol and 94 metoprolol patients (hazard ratio [HR] 0.71, 95% confidence interval [CI] 0.52 to 0.97, p = 0.03). Cardiovascular death or nonfatal MI combined were reduced by 19% in carvedilol (HR 0.81, 95% CI 0.72 to 0.92, p = 0.0009 vs. metoprolol). Unstable angina was reported as an adverse event in 56 carvedilol and in 77 metoprolol patients (HR 0.71, 95% CI 0.501 to 0.998, p = 0.049). A stroke occurred in 65 carvedilol and 80 metoprolol patients (HR 0.79, 95% CI 0.57 to 1.10). Stroke or MI combined occurred in 130 carvedilol and 168 metoprolol patients (HR 0.75, 95% CI 0.60 to 0.95, p = 0.015), and fatal MI or fatal stroke occurred in 34 carvedilol and in 72 metoprolol patients (HR 0.46, 95% CI 0.31 to 0.69, p = 0.0002). Death after a nonfatal MI or stroke occurred in 61 of 124 carvedilol and in 106 of 160 metoprolol patients (HR 0.66, 95% CI 0.48 to 0.90, p = 0.0086). CONCLUSIONS: Carvedilol improves vascular outcomes better than metoprolol. These results suggest a ubiquitous protective effect of carvedilol against major vascular events.

Effects of metoprolol and carvedilol on pre-existing and new onset diabetes in patients with chronic heart failure: data from the Carvedilol Or Metoprolol European Trial (COMET).

BACKGROUND: Beta blocker treatment may worsen glucose metabolism. OBJECTIVE: To study the development of new onset diabetes in a large cohort of patients with heart failure treated with either metoprolol or carvedilol. DESIGN: Prospective and retrospective analysis of a controlled clinical trial. SETTING: Multinational multicentre study. PATIENTS: 3029 patients with chronic heart failure. INTERVENTIONS: Randomly assigned treatment with carvedilol (n = 1511, target dose 50 mg daily) or metoprolol tartrate (n = 1518, target dose 100 mg daily). RESULTS: Diabetic events (diabetic coma, peripheral gangrene, diabetic foot, decreased glucose tolerance or hyperglycaemia) and new onset diabetes (clinical diagnosis, repeated high random glucose level or glucose lowering drugs) were assessed in 2298 patients without diabetes at baseline. Diabetic events occurred in 122/1151 (10.6%) patients in the carvedilol group and 149/1147 (13.0%) patients in the metoprolol group (hazard ratio (HR) = 0.78; 95% confidence interval (CI) 0.61 to 0.99; p = 0.039). New onset diabetes was diagnosed in 119/1151 (10.3%) v 145/1147 (12.6%) cases in the carvedilol and metoprolol treatment groups (HR = 0.78, CI 0.61 to 0.997; p = 0.048), respectively. Patients with diabetes at baseline had an increased mortality compared with non-diabetic subjects (45.3% v 33.9%; HR = 1.45, CI 1.28 to 1.65). Both diabetic and non-diabetic subjects at baseline had a similar reduction in mortality with carvedilol compared with metoprolol (RR = 0.85; CI 0.69 to 1.06 and RR = 0.82; CI 0.71 to 0.94, respectively). CONCLUSION: A high prevalence and incidence of diabetes is found in patients with heart failure over a course of 5 years. New onset diabetes is more likely to occur during treatment with metoprolol than during treatment with carvedilol.