Validation of the multiple organ dysfunction (MOD) score in critically ill medical and surgical patients

Objective. To validate the Multiple Organ Dysfunction (MOD) score externally. Design. Prospective observational cohort study. Setting. Mixed medical/surgical ICU in a tertiary referral university hospital. Patients and participants. Thousand eight hundred and nine patients admitted to ICU for more than 24 h over a 3-year period. Interventions. None. Measurements and results. The MOD score was calculated daily for all patients. The criterion validity of the individual organ scores, the maximal MOD score and the change in MOD score were assessed by examining the relationship between increasing scores and ICU mortality. Increased maximal MOD scores and each of the six individual organ scores, and change in MOD scores were associated with increased mortality. Conclusions. Maximal and individual organ scores have criterion validity when tested in a different ICU from that in which the scores were derived, indicating that the scoring systems are reproducible. The association of change in MOD score with mortality indicates that the score is responsive. These data, combined with previous data establishing concept and content validity, indicate that the MOD score is a valid measure of multi-organ dysfunction.