length of stay in hospitals and treatment outcome : Evidence from Japanese AMI patients

s contain over 100 comorbid diseases and severity measures that collectively summarize all the major associated diseases and functional status impairments. Moreover, the abstracts include AMI severity measures following the CCP’s expert advisory panel, which influence the appropriateness of major AMI treatment decisions and health outcomes (Noguchi et al., 2008). Table 1 presents the frequency of Rokuyo days at admission and discharge as well as ALOS. The data demonstrates that Rokuyo days are random at admission (Column 1) and the ALOS is comparable regardless on which Rokuyo day a patient was admitted (Column 2). Table 2 presents the test statistics from the Kolmogorov–Smirnov test for equality of distribution of LOS by Rokuyo on admission and discharge days. As the table clearly shows, there is no significant difference in the distribution of LOS across Rokuyo on admission. On the contrary, the Rokuyo day of discharge is concentrated more on Taian, (21.9 percent) and less on Butsumetsu (13.2 percent) (Column (3) in Table 1). The pattern follows the ALOS by Rokuyo on discharge days (Column 4). The gap in the ALOS between Taian and Butsumetsu is 2.3 days. Further, Table 2 reveals that the distribution of LOS differs among some Rokuyo. In particular, the distribution of LOS on Taian is statistically different from that on Butsumetsu, Sensho, and Senpu. Further, that of Senpu is statistically different from Tomobiki in addition to Taian. These observations demonstrate that the Rokuyo day of admission and the subsequent LOS are random. This is natural because a patient who has a heart attack needs to be hospitalized immediately and cannot wait to choose a suitable Rokuyo day for admission. In contrast, it is evident that discharge is more frequent on Taian and less so on Butsumetsu. The non-random variation stems from the fact that a patient can choose (or wait for) a good Rokuyo day for discharge even if he/she no longer requires hospitalization. According to modern science, Rokuyo is a superstition and the choice of Rokuyo does not affect the treatment outcome for 13 According to the guideline for AMI treatments, a doctor must make a diagnosis within 10 minutes after a patient arrives at the hospital, describe the treatment with the risks and benefits to the patient and family members, and begin treatment within 30 minutes (Uematsuse, 2002).