To the Editor.
—Dr Normand and colleagues1 studied mortality from MI in elderly patients and found that 67% of the variability in 30-day mortality rates remained unexplained after controlling for admission severity. However, mortality from MI is affected by psychosocial factors, as well as biological risk factors. Including these other factors in research might explain part of the variability in mortality rates.Studies show that psychosocial factors contribute to postinfarction prognosis. Frasure-Smith et al2 found that major depression in patients hospitalized following an MI was an independent risk for mortality at 6 months, and its impact was equivalent to that of left ventricular dysfunction (Killip class) and history of previous MI. In another study, Case et al3 found that living alone was an independent prognostic risk factor after MI when compared with other risk factors, and the rate of cardiac disease in those living alone was high (12.4%) and similar