Marital status shows a strong protective effect on long-term mortality among first acute myocardial infarction-survivors with diagnosed hyperlipidemia - findings from the MONICA/KORA myocardial infarction registry

Background: Reduction of long term mortality by marital status is well established in general populations. However, effects have been shown to change over time and differ considerably by cause of death. This study examined the effects of marital status on long term mortality after the first acute myocardial infarction. Methods: Data were retrieved from the population-based MONICA (Monitoring trends and determinants on cardiovascular diseases)/KORA (Cooperative Health Research in the Region of Augsburg)-myocardial infarction registry which assesses cases from the city of Augsburg and 2 adjacent districts located in southern Bavaria, Germany. A total of 3,766 men and women aged 28 to 74 years who were alive 28 days after their first myocardial infarction were included. Hazard ratios (HR) for the effects of marital status on mortality after one to 10 years of follow-up are presented. Results: The study population included 2,854 (75.8%) married individuals. During a median follow-up of 5.3 years, with an inter-quartile range of 3.3 to 7.6 years, 533 (14.15%) deaths occurred. Among married and unmarried individuals 388 (13.6%) and 145 (15.9%) deaths occurred, respectively. Overall marital status showed an insignificant protective HR of 0.76 (95% confidence interval (CI) 0.47-1.22). Stratified analyses revealed strong protective effects only among men and women younger than 60 who were diagnosed with hyperlipidemia. HRs ranged from 0.27 (95% CI 0.13-0.59) for a two-year survival to 0.43 (95% CI 0.27-0.68) for a 10-year survival. Substitution of marital status with co-habitation status confirmed the strata-specific effect [HR: 0.52 (95% CI 0.31-0.86)]. Conclusions: Marital status has a strong protective effect among first myocardial infarction survivors with diagnosed hyperlipidemia, which diminishes with increasing age. Treatments, recommended lifestyle changes or other attributes specific to hyperlipidema may be underlying factors, mediated by the social support of spouses. Underlying causes should be examined in further studies.