LAUSR

TO THE EDITOR: We appreciate Graham and colleagues' (1) efforts to conduct a comprehensive study. However, we have 2 concerns about possible confounding factors. We suspect that patients with severe illness may have been transferred from the general medicine department to the intensive care unit, resulting in their condition being drastically underestimated. The only description of disease severity in the study states that patients who were unable to communicate were excluded. We believe that this aspect may have created a serious selection bias. Our second concern relates to functional impairment. A previous study reported that rehospitalization correlated with a decrease in activities of daily living (2), and some effective programs (3) for preventing rehospitalization are relevant to Graham and colleagues' study. Graham and colleagues' article does not mention patients' functional state or the use of antireadmission programs. We thus suspect that functional impairment may be another confounding factor.