Myocardial infarction: diabetes increased the risk of one year mortality.

Clinical bottom line (level 1b)

  1. A third of patients with acute myocardial infarction had died at 12 months.
  2. Patients who had an MI were at increased risk of death at 12 months if they were diabetic (RR 1.38 to 1.86).
  3. Female diabetics were at greater risk of death than male diabetics.
Miettinen et al: Diabetes Care 1998; 21 (1): 69-75
Expires March 2003

The study

Prospective cohort study with objective outcomes, adjusted for confounding factors, not validated in an independent set of patients.

Setting: population based, Finland

4065 patients (aged mean 56 years, 77% male) patients residing in the study areas and either hospitalised due to suspected myocardial infarction or died because of coronary heart disease

Excluded if
  • <25 or >64 years old



Factors studied:
  • 12 month mortality
  • male and diabetic
  • female and diabetic




Multivariate regression was used to adjust for some confounding factors (thrombolytic therapy, smoking, prehospital delay, type of hospital, peak CK, age, geographic area).

100% followed for 12 months
Outcomes studied:
  • mortality

  • Diabetic men were significantly older than nondiabetic men. Diabetic men and women smoked less than nondiabetic patients.

The evidence

outcome time to outcome number of patients/total number %
(95% CI)
mortality 12 months 1310/4065 32.2%
(30.8% to 33.7%)

prognostic factor for
mortality 		time to outcome adjusted RR
(95% CI)		 NNF+
(95% CI)
male and diabetic 12 months 1.38
(1.18 to 1.61) 		10
(6 to 22)
female and diabetic 12 months 1.86
(1.40 to 2.46) 		5
(3 to 10)

Comments

  1. There was limited adjustment for confounding factors in the RR used. Further analysis of the data controlling fro the other variables 'did not significantly affect the results' but we are not given the data.

Citation

  1. Miettinen H, Haffner SM, Lehto S, et al: Impact of diabetes on mortality after the first myocardial infarction. Diabetes Care 1998; 21 (1): 69-75
Contributor: Clare Wotton and Bob Phillips, February 2000
Reviewer:

Clinical Question.
    Patient myocardial infarction
    Intervention or Exposure diabetes
    Comparison no diabetes
    Outcome mortality