Most current reseatch using prognostic scoring systems in critically ill patients have focused o prediction using the first intensive care unit(ICU) day data or daily updated data. Usually the mean ICU length of stay in Korea is longer than in the western world. Consequently, a more cost-effective and practical prognostic parameter is required. The principal aim of this study was to assess the prognostic value of the seventh day(7th day : the average mean ICU length of stay) APACHE III score in a medical intensive care unit.

241 medical ICU patients from July 1997 to April 1998 were enrolled. The 1st and 7th scores were measured by using the APACHE III scoring system and compared between survivors and non-survivors. Logistic regression analysis was performed to determine the relationship between the 1st and 7th APACHE III scores and the mortality risk.

1) The mean length of stay in the ICU was 10.3±13.8 days. 2) The mean 1st and 7th day APACHE III scores were 59.7±30.9 and 37.9±27.7. 3) The mean 1st day APACHE III scores was significantly lower in survivors than in non- survivors(49.9±23.8 vs 86.3±32.3 P<0.0001). 4) The mean 7th day APACHE III scores was significantly lower in survivors than in non- survivors(30.1±18.5 vs 80.1±30.4, P<0.0001). 5) The odds ratios among the 1st and 7th day APACHE III scores and the mortality rate were 1.0507 and 1.0779 respectively.

These results suggest that the seventh day APACHE III scores is as useful in predicting the outcome as is such like the first day APACHE III score. Therefore, in comparison to the daily APACHE III score, measuring the 1st and 7th day APACHE III scores are also useful for predicting the prognosis of critically ill patients in terms of cost-effectiveness. It is suggested that the 7th day APACHE III score is useful for predicting the clinical outcome.