A recent update of the Mortality Probability Model (MPM)-III found 14% of intensive care patients had age as their only MPM risk factor for hospital mortality. This subgroup had a low mortality rate (2% vs 14% overall), and pronounced differences were noted among elderly patients. This article is an expanded analysis of age-related mortality rates in patients in the ICU.
Project IMPACT data from 135 ICUs for 124,885 patients treated from 2001 to 2004 were analyzed. Patients were stratified as elective surgical, emergency/unscheduled surgical, and medical and then further stratified by age and whether additional MPM risk factors were present or absent.
Mortality rose with advancing age within all patient categories. Elective surgical patients without other risk factors were the least likely to die at all ages (0.4% for patients aged 18-29 years to 9.2% for patients aged ≥ 90 years), whereas medical patients with one or more additional risk factors had the highest mortality rate (12.1% for patients aged 18-29 years to 36.0% for patients aged ≥ 90 years). In these two subsets, mortality rates approximately doubled in the elective surgical group among patients aged in their 70s (2.4%), 80s (4.3%), and 90s (9.2%) but rose less dramatically in the medical group (27.0%, 30.7%, and 36.0%, respectively).
Although mortality increased with age, the risk differed significantly by patient subset, even among elderly patients, which may reflect a selection bias. Advanced age alone does not preclude successful surgical and ICU interventions, although the presence of serious comorbidities decreases the likelihood of survival to discharge for all age groups.