Azithromycin in Acute Coronary Syndrome - AZACS

Description:

The goal of Azithromycin in Acute Coronary Syndrome (AZACS) was to evaluate whether short-term treatment with azithromycin, a microlide antibiotic, can prevent death or further cardiac problems after unstable angina or acute myocardial infarction (MI) in patients with prior infection by chlamydia pneumoniae.

Hypothesis:

The rationale behind AZACS was that vascular inflammation leading to plaque disruption and acute coronary syndrome (ACS) may be, in part, due to infection.

Study Design

Study Design:

Patients Screened: 7,100
Patients Enrolled: 1,439
Mean Follow Up: Six months
Mean Patient Age: Mean age of 65 years
Female: 28%

Patient Populations:

Age ≥18 years and admitted with unstable angina or acute MI.

Exclusions:

Q-wave MI within the past 28 days of the current admission; pregnant or breastfeeding; deemed unreliable as study participant; participating in another clinical study; had known hypersensitivity to azithromycin, erythromycin, or any macrolide antibiotic; or had other important diseases or comorbidities (e.g., terminal cancer, life-threatening infection) that could compromise the patient’s safety or participation in the study.

Primary Endpoints:

Composite of death, nonfatal MI, and recurrent ischemia necessitating revascularization.

Secondary Endpoints:

Worsening of ischemic symptoms or congestive heart failure requiring admission.

Drug/Procedures Used:

The randomized, double-blind, placebo-controlled trial tested a strategy of short-term azithromycin therapy on the occurrence of clinical events in patients with ACS. A total of 1,439 patients with ACS were randomized to azithromycin (n=716), 500 mg for one day followed by 250 mg/day for four days, or matching placebo (n=723). The primary end point was a composite of death, nonfatal MI, and recurrent ischemia necessitating revascularization at six months.

Principal Findings:

Mean time from qualifying diagnosis to randomization was 2.9 days. The primary composite end point occurred in 14.3% of placebo recipients and 14.9% of azithromycin-treated patients (hazard ratio [HR] 0.94, p=0.664). There was no difference in any of the individual components of the composite end point by treatment group. There was also no difference in patients presenting with acute MI (n=826) (14% vs. 14%, HR 1.03, p=0.860) or those with serological evidence of prior C pneumonia infection (n=939; 15% azithromycin vs. 14% placebo, HR 1.06, p=0.230). There was also no difference in the secondary end point of ischemia or congestive heart failure (CHF) requiring admission, which occurred in 9% of patients in the azithromycin arm and 8% in the placebo arm (HR 1.07, p=0.707).

Interpretation:

Among patients with acute MI or unstable angina, short-term treatment with azithromycin was not associated with a reduction in the recurrence of ischemic events or death during follow-up for six months. The results of this trial, while negative, are not generalizable to other antibiotics or other anti-inflammatory agents. Whether differing agents, duration of therapy, and follow-up in other patients with atherosclerotic vascular disease will reveal beneficial effects remains to be determined in upcoming larger randomized trials such as PROVE-IT and ACES. Trials to date have shown conflicting results. The WIZARD trial showed a nonsignificant reduction of the primary end point in patients treated with long-term azithromycin therapy, while the STAMINA trial showed a significant reduction in the primary end point of event-free survival in patients treated with short-term use of amoxicillin or azithromycin.

References:

Cercek B, Shah PK, Noc M, et al. Effect of short-term treatment with azithromycin on recurrent ischaemic events in patients with acute coronary syndrome in the Azithromycin in Acute Coronary Syndrome (AZACS) trial: a randomised controlled trial. Lancet. 2003;361:809-13.

Clinical Topics: Acute Coronary Syndromes, Heart Failure and Cardiomyopathies, Acute Heart Failure

Keywords: Inflammation, Myocardial Infarction, Acute Coronary Syndrome, Pneumonia, Follow-Up Studies, Heart Failure, Azithromycin, Disease-Free Survival, Chlamydophila pneumoniae


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