The second myocardial infarction: Higher risk factor burden and earlier second myocardial infarction in women compared with men. The Northern Sweden MONICA study.

BACKGROUND: Several studies have examined various parameters and experiences when patients suffer their first myocardial infarction (MI), but knowledge about when they suffer their second MI is limited.

AIM: To compare risk factors for MI, that is, diabetes, hypertension and smoking, for the first and second MI events in men and women affected by two MIs and to analyse the time intervals between the first and second MIs.

METHODS: A retrospective cohort study of 1017 patients aged 25-74 years with first and second MIs from 1990 through 2009 registered in the Northern Sweden MONICA registry.

RESULTS: More women than men have diabetes and hypertension and are smokers at the first MI. Similar differences between the genders remain at the time of the second MI for diabetes and hypertension, although both risk factors have increased. Smoking decreased at the second MI without any remaining difference between genders. Women suffer their second MI within a shorter time interval than men do. Within 16 months of their first MI, 50% of women had a second MI. The corresponding time interval for men was 33 months.

CONCLUSION: Patients affected by an MI should be made aware of their risk of recurrent MI and that the risk of recurrence is highest during the first few years after an MI. In patients affected by two MIs, women have a higher risk factor burden and suffer their second MI earlier than men do and thus may need more aggressive and more prompt secondary prevention.