Diabetes mellitus greatly increased the risk for death after first MI
ACP J Club. 1998 Jul-Aug;129:17. doi:10.7326/ACPJC-1998-129-1-017
Miettinen H, Lehto S, Salomaa V, et al., for the FINMONICA Myocardial Infarction Register Study Group. Impact of diabetes on mortality after the first myocardial infarction. Diabetes Care. 1998 Jan;21:69-75.
In patients who have a first myocardial infarction (MI), does diabetes mellitus increase the risk for death?
Inception cohort followed for 1 year.
3 areas of Finland that were part of the World Health Organization Multinational Monitoring of Trends and Determinants of Cardiovascular Disease (WHO MONICA) project.
4065 patients who were 25 to 64 years of age (mean age 56 y, 77% men) and who were hospitalized or died between 1988 and 1992 from a first definite, possible, or probable MI. Diagnosis of MI was confirmed by electrocardiography, enzyme values, and autopsy data (when available). Patients with a history of MI or missing data about previous MI were excluded.
Assessment of prognostic factors
620 patients (15%) had diabetes mellitus. The diagnosis of diabetes mellitus was based on interviewing the patients, reviewing medical records, contacting the patients' physicians, and by routinely measuring blood glucose levels obtained during the patients' hospitalization for MI.
Main outcome measures
All-cause mortality: 1-year mortality, out-of-hospital mortality, 28-day mortality in hospitalized patients, and 1-year mortality in patients who survived to 28 days.
Hazard ratios (HRs) were calculated and adjusted for age and area of the risk for death in diabetic compared with nondiabetic patients. Overall 1-year mortality was greater in diabetic men and women than in nondiabetic men and women (HR for men 1.38, 95% CI 1.18 to 1.61; HR for women 1.86, CI 1.40 to 2.46; P < 0.001 for both). Out-of-hospital mortality was greater in diabetic men than in nondiabetic men (HR 1.25, CI 1.03 to 1.52; P = 0.008); no difference was shown between diabetic and nondiabetic women. 28-day mortality was higher in diabetic men and women than in nondiabetic men and women (HR for men 1.58, CI 1.15 to 2.18; HR for women 2.60, CI 1.71 to 3.95; P ≤ 0.003 for both), as was 1-year mortality in patients who survived to 28 days (HR for men 1.97, CI 1.25 to 3.12; HR for women 4.17, CI 2.05 to 8.51; P < 0.001 for both).
During the year after a first myocardial infarction, diabetic patients were at a higher risk for death than nondiabetic patients.
Source of funding: Not stated.
For correspondence: Dr. H. Miettinen, Kuopio University Hospital, Department of Medicine, Box 1777, 70211 Kuopio, Finland. FAX 358-17-173-993.
The study by Miettinen and colleagues focuses on patient fatality. In all phases of MI, diabetic patients fared worse than nondiabetic patients. Patient fatality was higher in diabetic patients out of hospital (mostly sudden deaths), in hospital, and during the late phase from 1 month to 12 months after MI.
The effect of diabetes mellitus on the community burden of coronary heart disease is even greater than that shown by this well-done study. Middle-aged men with diabetes mellitus have a 3-fold excess risk for MI, and women with diabetes mellitus have a 5-fold excess risk (1). The study by Miettinen and colleagues is restricted to patients with a first MI. However, the risk for recurrent infarction in diabetic patients is 2-fold (1). These components—excess risk for first MI, excess risk for recurrent infarction, and high patient fatality early and late after an MI—make the risk for dying from MI 4-fold higher in diabetic men and 7-fold higher in diabetic women (1).
Prospects for diabetic patients with MI may seem grim. However, improvements are possible. Many diabetic patients with MI, especially those with long-term diabetes and autonomic neuropathy, present atypically (i.e., without severe chest pain). Increased awareness of patients, their families, and the health care staff may allow more diabetic patients with MI to get immediate and appropriate care. Further, a randomized controlled trial involving 620 diabetic patients has shown that in the early phase of MI, aggressive metabolic control using insulin-glucose infusions followed by multiple-dose insulin therapy improves survival rates (2).
Kjell Asplund, MD, PhD
Umeå UniversityUmeå, Sweden
Kjell Asplund, MD, PhD
2. Malmberg K, Ryden L, Efendic S, et al. Randomized trial of insulin-glucose infusion followed by subcutaneous insulin treatment in diabetic patients with acute myocardial infarction (DIGAMI study): effects on mortality at 1 year. J Am Coll Cardiol. 1995;26:57-65.