Better long-term survival in young and middle-aged women than in men after a first myocardial infarction between 1985 and 2006. an analysis of 8630 patients in the Northern Sweden MONICA Study
1 The Northern Sweden MONICA Myocardial Registry, Department of Research, Norrbotten County Council, Luleå, Sweden
2 Department of Nursing, Umeå University, Umeå, Sweden
3 Department of Medicine and Geriatrics, Skellefteå Hospital, Skellefteå, Sweden
4 Department of Medicine, Sunderby Hospital, Luleå, Sweden
5 Department of Cardiology, Heart Centre, University Hospital, Umeå, Sweden
6 Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
7 Department of Research, Norrbotten County Council, Luleå, Sweden
BMC Cardiovascular Disorders 2011, 11:1 doi:10.1186/1471-2261-11-1Published: 5 January 2011
There is conflicting and only scant evidence on the effect of gender on long-term survival after a myocardial infarction (MI). Our aim was to analyse sex-specific survival of patients for up to 23 years after a first MI in northern Sweden and to describe time trends.
The Northern Sweden MONICA Myocardial Infarction Registry was linked to The Swedish National Cause of Death Registry for a total of 8630 patients, 25 to 64 years of age, 6762 men and 1868 women, with a first MI during 1985-2006. Also deaths before admission to hospital were included. Follow-up ended on August 30, 2008.
Median follow-up was 7.1 years, maximum 23 years and the study included 70 072 patient-years. During the follow-up 45.3% of the men and 43.7% of the women had died. Median survival for men was 187 months (95% confidence interval (CI) 179-194) and for women 200 months (95% CI 186-214). The hazard ratio (HR) for all cause mortality after adjustment for age group was 1.092 (1.010-1.18, P = 0.025) males compared to females, i.e. 9 percent higher survival in women. After excluding subjects who died before reaching hospital HR declined to 1.017 (95%CI 0.93-1.11, P = 0.7). For any duration of follow-up a higher proportion of women were alive, irrespective of age group. The 5-year survivals were 75.3% and 77.5%, in younger (<57 years) men and women and were 65.5% and 66.3% in older (57-64 years) men and women, respectively. For each of four successive cohorts survival improved. Survival time was longer for women than for men in all age groups.
Age-adjusted survival was higher among women than men after a first MI and has improved markedly and equally in both men and women over a 23-year period. This difference was due to lower risk for women to die before reaching hospital.