Laboratory data predicts survival post hospitalization

J Clin Epidemiol. 1991;44(12):1387-403. doi: 10.1016/0895-4356(91)90100-n.


From a database of 93,077 in-patient admissions, patients assigned to catastrophic, very severe, moderately severe, and average 30-day mortality risk categories (as defined in Medicare Hospital Mortality Information, 1989 release, from the Health Care Financing Administration (HCFA] were selected for study. These admissions account for 30% of all admissions, but 70% of all deaths up to 1 year post admission. To determine whether laboratory information adds to the predictive power of the information used by HCFA, we compare the performance of 1 year survival predictors (Cox model) that use only diagnostic, demographic, and comorbidity information, with the performance of predictors that also include laboratory information. Using a separate set of patients not used for model definition, we find that laboratory data contain significant prognostic information independent of that already available in non-laboratory data. In HCFA's catastrophic disorders for example, non-laboratory information reduces the average risk of predicting a wrong outcome by 17% relative to considering only catastrophic group membership, and adding laboratory data reduces this risk by a further 21%. These improvements result primarily from considering the outcomes of a small set of routine laboratory tests (maximum BUN, AST, and WBC, and minimum CO2, hematocrit, and sodium).

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Centers for Medicare and Medicaid Services, U.S.
  • Clinical Laboratory Techniques*
  • Comorbidity
  • Diagnosis-Related Groups
  • Evaluation Studies as Topic
  • Humans
  • Medicare
  • Patient Admission*
  • Predictive Value of Tests
  • Prognosis
  • Proportional Hazards Models*
  • Risk Factors
  • San Francisco / epidemiology
  • Severity of Illness Index*
  • Survival Analysis*
  • United States