Background: Whereas studies have shown higher mortality rates in patients with do-not-resuscitate (DNR) orders, most have not accounted for confounding factors related to the use of DNR orders and/or factors related to the risk of death.
Objective: To determine the relationship between the use of DNR orders and in-hospital mortality, adjusting for severity of illness and other covariates.
Design: Retrospective cohort study.
Patients: There were 13,337 consecutive stroke admissions to 30 hospitals in 1991 to 1994.
Measures: To decrease selection bias, propensity scores reflecting the likelihood of a DNR order were developed. Scores were based on nine demographic and clinical variables independently related to use of DNR orders. The odds of death in patients with DNR orders were then determined using logistic regression, adjustment for propensity scores, severity of illness, and other factors.
Results: DNR orders were used in 22% (n = 2,898) of patients. In analyses examining DNR orders written at any time during hospitalization, unadjusted in-hospital mortality rates were higher in patients with DNR orders than in patients without orders (40% vs. 2%, P<0.001); the adjusted odds of death was 33.9 (95% CI, 27.4-42.0). The adjusted odds of death remained higher in analyses that only considered orders written during the first 2 days (OR 3.7; 95% CI, 3.2-4.4) or the first day (OR 2.4; 95% CI, 2.0-2.9). In stratified analyses, adjusted odds of death tended to be higher in patients with lower propensity scores.
Conclusion: The risk of death was substantially higher in patients with DNR orders after adjusting for propensity scores and other covariates. Whereas the increased risk may reflect patient preferences for less intensive care or unmeasured prognostic factors, the current findings highlight the need for more direct evaluations of the quality and appropriateness of care of patients with DNR orders.