Elsevier

American Heart Journal

Volume 152, Issue 4, October 2006, Pages 676-683
American Heart Journal

Clinical Investigation
Acute Ischemic Heart Disease
Underuse of evidence-based treatment partly explains the worse clinical outcome in diabetic patients with acute coronary syndromes

https://doi.org/10.1016/j.ahj.2006.04.002Get rights and content

Background

Diabetes-related differences in treatment and clinical outcome of patients across the entire spectrum of acute coronary syndromes (ACSs) have potential clinical implications but have not been well studied.

Methods

The multicenter, prospective, Canadian ACS Registry enrolled 4578 patients hospitalized for ACS between 1999 and 2001 across 9 provinces in Canada. We compared baseline characteristics, in-hospital and post-discharge treatments, and clinical outcome of diabetic and non-diabetic patients. The impact of diabetes on use of thrombolytic therapy and coronary revascularization; and the independent association between diabetes, treatments, and diabetes-treatment interactions on outcome were examined.

Results

Diabetic patients with ACS had more cardiovascular risk factors and higher-risk clinical presentation. They paradoxically received less evidence-based medications in-hospital, at discharge, and at 1-year. Although diabetes independently predicted higher 1-year mortality (OR 1.47, 95% CI 1.15-1.87; P = .002) after adjustment for validated prognosticators, it was also an independent predictor of not receiving thrombolytic therapy (OR 0.72, 95% CI 0.54-0.95; P = .021) and coronary revascularization (OR 0.69, 95% CI 0.59-0.82; P < .001). These underused therapies were all independently associated with reduced 1-year mortality, with no significant diabetes-related treatment-outcome heterogeneity. Importantly, diabetes remained an independent adverse prognosticator even after further adjustment for these differences in treatment.

Conclusions

Evidence-based therapies are underused in the contemporary management of diabetic patients with ACS, which partly explains their worse outcome. Diabetes should be considered a high-risk feature in ACS risk stratification that encourages more intensive treatments. Continued efforts to promote adherence to existing proven therapies and to develop novel treatment strategies targeting diabetes-specific cardiovascular pathophysiology are imperative to improve their adverse prognosis.

Section snippets

Research design and study population

The Canadian ACS Registry was a prospective, multicenter, observational study designed to examine the epidemiology, the in-hospital and post-discharge management, and the outcome of less selected patients with ACS. A detailed description of patients and methods has been published previously.9

In brief, patients older than 18 years admitted to the hospital with a suspected diagnosis of ACS (defined by symptoms consistent with acute cardiac ischemia with onset less than 24 hours and not

Patient characteristics

A total of 5312 patients were enrolled in the ACS registry. This analysis focuses exclusively on the 4578 subjects with confirmed ACS (86.2% of enrollment) as adjudicated by the final diagnosis of unstable angina (n = 1787) or MI (n = 2791). Of these ACS patients, 1685 (36.8%) presented with ST-elevation ACS and 1149 (25.1%) had diabetes. Their pertinent baseline characteristics and differences in clinical presentation according to diabetic status are summarized in Table I.

In-hospital management

Differences in the

Discussions

This multicenter observational study of ACS patients in the real world demonstrated substantial diabetes-related differences in patient characteristics, treatment, and outcome. Our results add to previous studies3, 4, 5, 6, 8 in various important ways. First, in contrast to predefined subsets of ACS patients,3, 4, 6 our study examined less selected patients across the entire spectrum of ACS—from non–ST- and ST-elevation MI to unstable angina–enrolled from a variety of centers with no specific

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    This research was sponsored by the Canadian Heart Research Centre and Key Pharmaceuticals, Division of Schering Canada Inc. Drs Fitchett, Lauzon, Lai, Langer, and Goodman have received research grant support and speaker/consultant honoraria from Schering Canada Inc. Dr McGuire has received research grant support and speaker/consultant honoraria from Pfizer, GlaxoSmithKline, Wyeth, Sanofi-Aventis, Guilford, and Takeda. Dr Andrew Yan is supported by the Canadian Institutes of Health Research Fellowship Award, the Canadian Heart Research Centre Fellowship, and the Detweiler Travelling Fellowship.

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