Can hospital discharge diagnoses be used for intensive care unit administrative and quality management functions?

Objective: To determine whether hospital discharge diagnoses can be used for intensive care unit (ICU)-related activities. Design: Comparison between the diagnoses coded by physicians at the time of ICU admission and those diagnoses coded by medical records personnel. Setting: University hospital adult surgical ICU. Patients: Consecutive ICU admissions (n = 622). Interventions: None. Measurements and Main Results: The ICU admission and hospital discharge codes were compared in two ways. Initially, each discharge code was subtracted from the corresponding ICU admission code. There was no difference in 150 (24%) cases. In 216 (35%) patients, the codes differed by ±10. In 221 (36%) instances, the codes differed by >200. The secondary discharge diagnoses were also compared with the ICU admission diagnoses. In 56 patients, the ICU admission diagnosis was one of the secondary diagnoses. The second comparison involved having two physicians not associated with the study examine each pair of codes to determine if the two diagnoses were medically different. Review of the codes by physicians not involved in the study found that in 318 (48%) patients, the two diagnoses were not different, i.e., the codes were either the same or the codes were so similar as not to functionally change the actual diagnosis. Conclusions: The primary discharge diagnosis often failed to reflect the reason for ICU admission, making it impossible to consistently establish the reason for ICU admission from the discharge data. The reason for ICU admission was also frequently not included among the secondary discharge diagnoses. Administrative data are therefore not useful for ICU quality management and other functions. Intensivists need to establish their own databases.