Association of sleep disturbances within 4 weeks prior to incident acute myocardial infarction and long-term survival in male and female patients: an observational study from the MONICA/KORA Myocardial Infarction Registry

BACKGROUND: Sleep-related investigations in acute myocardial infarction (AMI) patients are rare. The aim of this study was to examine sex-specific associations of patient-reported sleep disturbances within 4 weeks before AMI and long-term survival. METHODS: From a German population-based, regional AMI registry, 2511 men and 828 women, aged 28–74 years, hospitalized with a first-time AMI between 2000 and 2008 and still alive after 28 days, were included in the study (end of follow-up: 12/2011). Frequency of any sleep disturbances within 4 weeks before AMI was inquired by a 6-categorical item summarized to ‘never’, ‘sometimes’ and ‘nightly’. Cox regression models were calculated. RESULTS: Over the median follow-up time of 6.1 years (IQR: 4.1) sleep disturbances were reported by 32.3% of male and 48.4% of female patients. During the observation period, 318 men (12.7%) and 131 women (15.8%) died. Men who ‘sometimes’ had sleep disturbances showed a 56% increased mortality risk compared to those without complaints in an age-adjusted model (HR 1.56; 95%-CI 1.21–2.00). Additional adjustment for confounding variables attenuated the effect to 1.40 (95%-CI 1.08–1.81). Corresponding HRs among women were 0.97 (95%-CI 0.65–1.44) and 0.99 (95%-CI 0.66–1.49). HRs for patients with nightly sleep disturbances did not suggest any association for both sexes. CONCLUSIONS: Our study found that nightly sleep disturbances have no influence on long-term survival in male and female AMI patients. Contrary to women, men who reported sometimes sleep disturbances had a higher mortality. Further investigations on this topic taking into account the role of obstructive sleep apnoea are needed.