November 24, 1993

Mortality Probability Models (MPM II) Based on an International Cohort of Intensive Care Unit Patients

Author Affiliations

From the School of Public Health, University of Massachusetts, Amherst (Drs Lemeshow and Gehlbach and Mss Klar and Avrunin); the Critical Care Division, Baystate Medical Center, Springfield, Mass, and Tufts University School of Medicine, Boston, Mass (Dr Teres); and the Department of Economics, Mount Holyoke College, South Hadley, Mass (Dr Rapoport).

JAMA. 1993;270(20):2478-2486. doi:10.1001/jama.1993.03510200084037

Objective.  —To revise and update models in the Mortality Probability Model (MPM II) system to estimate the probability of hospital mortality among 19124 intensive care unit (ICU) patients that can be used for quality assessment within and among ICUs.

Design and Setting.  —Models developed and validated on consecutive admissions to adult medical and surgical ICUs in 12 countries.

Patients.  —A total of 12610 patients for model development, 6514 patients for model validation. Patients younger than 18 years and burn, coronary care, and cardiac surgery patients were excluded.

Outcome Measure.  —Vital status at hospital discharge.

Results.  —The admission model, MPM0, contains 15 readily obtainable variables. In developmental and validation samples it calibrated well (goodness-of-fit tests: P=.623 and P=.327, respectively, where a high P value represents good fit between observed and expected values) and discriminated well (area under the receiver operating characteristic curve=0.837 and 0.824, respectively). The 24-hour model, MPM24 (developed on 10357 patients still in the ICU at 24 hours), contains five of the admission variables and eight additional variables easily ascertained at 24 hours. It also calibrated well (P=.764 andP=.231 in the developmental and validation samples, respectively) and discriminated well (area under the receiver operating characteristic curve=0.844 and 0.836 in the developmental and validation samples, respectively).

Conclusions.  —Among severity systems for intensive care patients, the MPM0 is the only model available for use at ICU admission. Both MPM0 and MPM24 are useful research tools and provide important clinical information when used alone or together.(JAMA. 1993;270:2478-2486)