Long-term mortality and living arrangements in acute coronary syndrome treated with percutaneous coronary intervention

TO THE EDITOR: We have read with interest the article by Takeuchi et al.1 published in European Heart Journal. We believe it should also be noted that solitary living may not in itself be a prognostic risk factor for long-term mortality as the symptom onset to door time may be a significant confounding factor. Ohama et al.2 studied patients undergoing percutaneous coronary intervention for an ST-elevation myocardial infarction and found that those who live alone, on average, have an increased symptom onset to balloon time when compared to patients living with others. The delay in reperfusion may result in greater damage to the myocardium and subsequent reduction in left ventricular ejection fraction, potentially contributing to the long-term mortality. We would also like to note that the authors have indicated that living alone was a predictive risk factor for younger patients with acute coronary syndrome; however, the baseline characteristics for both cohorts studied do not appear to be stratified for age. There could potentially be significant confounding factors upon this stratification. Christensen et al.3 recently examined loneliness and living status independently, finding a strong association with loneliness and worse outcomes across cardiac diagnoses in both men and women, whereas living alone predicted cardiac events in men only. In the current study, both cohorts are composed of largely male participants and this should be taken into account. As secondary prevention may reduce morbidity and mortality following ACS, it is interesting to note that one of the preventative goals (regular physical activity) is higher in patients who live alone, indicating that living alone may not be a solely negative predictive factor and that further sub-categorization of this cohort should be analysed.4