Background: Older age is associated with less aggressive treatment and higher short-term mortality due to serious illness. It is not known whether less aggressive care contributes to this survival disadvantage in elderly persons.
Objective: To determine the effect of age on short-term survival, independent of baseline patient characteristics and aggressiveness of care.
Design: Secondary analysis of data from a prospective cohort study.
Setting: Five academic medical centers participating in SUPPORT (Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatments).
Patients: 9105 adults hospitalized with one of nine serious illnesses associated with an average 6-month mortality rate of 50%.
Measurements: Survival through 180 days of follow-up. In Cox proportional hazards modeling, adjustment was made for patient sex; ethnicity; income; baseline physical function; severity of illness; intensity of hospital resource use; presence of do-not-resuscitate orders on study day 1; and presence and timing of decisions to withhold transfer to the intensive care unit, major surgery, dialysis, blood transfusion, vasopressors, and tube feeding.
Results: The mean (+/- SD) patient age was 63 +/- 16 years, 44% of patients were female, and 16% were black. Overall survival to 6 months was 53%. In analyses that adjusted for sex, ethnicity, income, baseline functional status, severity of illness, and aggressiveness of care, each additional year of age increased the hazard of death by 1.0% (hazard ratio, 1.010 [95% CI, 1.007 to 1.013]) for patients 18 to 70 years of age and by 2.0% (hazard ratio, 1.020 [CI, 1.013 to 1.026]) for patients older than 70 years of age. Adjusted estimates of age-specific 6-month mortality rates were 44% for 55-year-old patients, 48% for 65-year-old patients, 53% for 75-year-old patients, and 60% for 85-year-old patients. Similar results were obtained in analyses that did not adjust for aggressiveness of care. Acute physiology and diagnosis had much larger relative contributions to prognosis than age.
Conclusions: We found a modest independent association between patient age and short-term survival of serious illness. This age effect was not explained by the current practice of providing less aggressive care to elderly patients.