Current issues of ACP Journal Club are published in Annals of Internal Medicine


Prognosis

Review: Hyperglycemia after myocardial infarction increases the risk for death in patients with and without diabetes mellitus

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ACP J Club. 2000 Nov-Dec;133:116. doi:10.7326/ACPJC-2000-133-3-116


Source Citation

Capes SE, Hunt D, Malmberg K, Gerstein HC. Stress hyperglycaemia and increased risk of death after myocardial infarction in patients with and without diabetes: a systematic overview. Lancet. 2000 Mar 4;355:773-8. [PubMed ID: 10711923]


Abstract

Question

Is stress hyperglycemia associated with an increased risk for in-hospital death and congestive heart failure (CHF) after myocardial infarction (MI) in patients with and without diabetes mellitus?

Data sources

Studies were identified by searching MEDLINE (1966 to October 1998) with the terms blood glucose, myocardial infarction, hyperglycemia, euglycemia, hypoglycemia, incidence, mortality, follow-up studies, cohort studies, prognosis, natural history, course, and predict; searching Science Citation Index (1980 to September 1998); scanning bibliographies of relevant papers; and contacting experts in the field.

Study selection

English-language studies were selected if original data were reported, the design was a cohort study or clinical trial, an inception cohort of patients with acute MI was used, ≥ 70% of patients had follow-up to hospital discharge, baseline blood glucose levels were measured within 24 hours of admission, and outcomes (in-hospital death, CHF, or cardiogenic shock) were reported in relation to blood glucose levels at admission.

Data extraction

Data were extracted for study characteristics; patient characteristics, including diabetes status (diabetes or no diabetes) and presence of stress hyperglycemia on admission; and outcomes.

Main results

14 articles that included 15 cohort studies met the selection criteria. 11 studies (mean age range 50 to 68 y) were included in the meta-analysis; 4 studies were excluded because they only reported mean glucose levels associated with outcome. Among patients with diabetes (n = 688, 4 studies), those with stress hyperglycemia after MI had a greater risk for in-hospital death than did those without hyperglycemia (Table). Similarly, among patients without diabetes (n = 1856, 7 studies), those with stress hyperglycemia after MI had a greater risk for in-hospital death than did those without hyperglycemia (Table). Presence of stress hyperglycemia on admission was associated with an increased risk for CHF or cardiogenic shock after MI in patients without diabetes (relative risk range 1.51 to 8.82, 4 studies) but not in those with diabetes (1 study).

Conclusions

Stress hyperglycemia after myocardial infarction is associated with an increased risk for in-hospital death in patients with and without diabetes; an increased risk for congestive heart failure or cardiogenic shock is also seen in patients without diabetes.

Source of funding: No external funding.

For correspondence: Dr. S.E. Capes, Department of Medicine, McMaster University, 1200 Main Street West, Hamilton, Ontario L8N 3Z5, Canada. FAX 905-521-4971.


Table. Weighted relative risk (RR) for the association between stress hyperglycemia and in-hospital {or at 1 month}* death after myocardial infarction

Patients Definition of hyperglycemia† (mmol/L) Weighted RR (95% CI)
With diabetes Range ≥ 10 to ≥ 11 1.7 (1.2 to 2.4)
Without diabetes Range ≥ 6.1 to ≥ 8 3.9 (2.9 to 5.4)

*Information supplied by author.
†Definition differs according to the study.


Commentary

This systematic review by Capes and colleagues supports previous findings that hyperglycemia on admission is associated with increased in-hospital mortality after MI in patients with and without diabetes.

Elevated glucose levels may simply be a noncausal secondary marker of the severity of the hormonal stress response. Alternatively, higher glucose levels on admission may represent a greater preinfarction level of insulin resistance with increased hypercoagulability, decreased fibrinolysis, and poorer endothelial function, all of which might be causal in worsening the outcome after an MI.

Many trials using intravenous glucose-insulin-potassium or glucose-insulin infusions in acute MI have shown that supplying intravenous insulin may improve the outcome. The Swedish trial of insulin-glucose infusion, Diabetes Insulin-Glucose in Acute Myocardial Infarction (DIGAMI), showed a 1-year mortality decrease from 26% to 19% (P < 0.05) in patients with diabetes after an MI (1). A 30-year overview of 9 randomized, placebo-controlled trials of combined glucose-insulin-potassium therapy in acute MI among 1932 patients with and without diabetes showed that hospital mortality decreased from 21% to 16% (P = 0.004) (2).

A recent randomized trial done in South America of intravenous glucose-insulin-potassium infusion within 24 hours of an acute MI in 407 patients (16% with diabetes) decreased in-hospital death, severe CHF, and nonfatal ventricular fibrillation from 20.1% to 11.9% (P = 0.03) (3).

These data suggest that modifying the glucose-insulin metabolism is important to the outcome of MI. Further studies are needed to evaluate the magnitude of the effect of intravenous glucose-insulin and to encourage its use as part of the management of MI.

Donald A. Smith, MD, MPH
Mount Sinai Medical Center
New York, New York, USA


References

1. Malmberg K, Ryden L, Hamsten A, et al. Effects of insulin treatment on cause-specific one-year mortality and morbidity in diabetic patients with acute myocardial infarction. DIGAMI Study Group. Diabetes Insulin-Glucose in Acute Myocardial Infarction. Eur Heart J. 1996;17:1337-44.

2. Fath-Ordoubadi F, Beatt KJ. Glucose-insulin-potassium therapy for treatment of acute myocardial infarction: an overview of randomized placebo-controlled trials. Circulation. 1997;96:1152-6.

3. Diaz R, Paolasso EA, Piegas LS, et al. Metabolic modulation of acute myocardial infarction. The ECLA (Estudios Cardiologicos Latinoamerica) Collaborative Group. Circulation. 1998;98:2227-34.