The relationship between age and the use of DNR orders in critical care patients. Evidence for age discrimination

To determine whether a relationship exists between the use of do-not-resuscitate (DNR) orders in the intensive care unit and the age of the patient after controlling for the severity of illness.

Patients from the Mortality Probability Model database, which includes 6103 patients in 4 large hospitals, and from a second database, which includes 3226 additional patients in 25 hospitals, were analyzed through logistic regression seeking a relationship between age and DNR use. Adult medical and surgical intensive care units from 27 hospitals in the United States were included.

In the Mortality Probability Model database, 11.4% of the patients had DNR orders written. In the group of patients younger than 65 years, 8% had DNR orders. This percentage climbed rapidly with age. For age ranges of 65 to younger than 75 years, 75 to younger than 85 years, and 85 years or older, the percentage of patients who had a DNR order was 11.2%, 18.9%, and 32.6%, respectively. Similar results were found in the second database: 5.4% of patients had DNR orders and, again, the rise in the use of DNR orders was associated with increased age. For patients younger than 75 years, 4.2% had DNR orders. For the older groups, 75 to younger than 85 years and 85 years and older, the rates were 8.8% and 15.4%, respectively. Logistic regression was used to control for severity of illness; when compared with patients younger than 65 years, patients 75 to younger than 85 years were 50% more likely to have DNR orders written and patients 85 years or older were 140% more likely to have DNR orders written.

Older patients (> or = 75 years old) are significantly more likely than younger patients to have DNR orders written even after the severity of illness is controlled as a confounding variable. This association suggests age discrimination and becomes stronger as patient age increases.