Is survival better at hospitals with higher "end-of-life" treatment intensity?

Abstract

Background: Concern regarding wide variations in spending and intensive care unit use for patients at the end of life hinges on the assumption that such treatment offers little or no survival benefit.

Objective: To explore the relationship between hospital "end-of-life" (EOL) treatment intensity and postadmission survival.

Research design: Retrospective cohort analysis of Pennsylvania Health Care Cost Containment Council discharge data April 2001 to March 2005 linked to vital statistics data through September 2005 using hospital-level correlation, admission-level marginal structural logistic regression, and pooled logistic regression to approximate a Cox survival model.

Subjects: A total of 1,021,909 patients > or =65 years old, incurring 2,216,815 admissions in 169 Pennsylvania acute care hospitals.

Measures: EOL treatment intensity (a summed index of standardized intensive care unit and life-sustaining treatment use among patients with a high predicted probability of dying [PPD] at admission) and 30- and 180-day postadmission mortality.

Results: There was a nonlinear negative relationship between hospital EOL treatment intensity and 30-day mortality among all admissions, although patients with higher PPD derived the greatest benefit. Compared with admission at an average intensity hospital, admission to a hospital 1 standard deviation below versus 1 standard deviation above average intensity resulted in an adjusted odds ratio of mortality for admissions at low PPD of 1.06 (1.04-1.08) versus 0.97 (0.96-0.99); average PPD: 1.06 (1.04-1.09) versus 0.97 (0.96-0.99); and high PPD: 1.09 (1.07-1.11) versus 0.97 (0.95-0.99), respectively. By 180 days, the benefits to intensity attenuated (low PPD: 1.03 [1.01-1.04] vs. 1.00 [0.98-1.01]; average PPD: 1.03 [1.02-1.05] vs. 1.00 [0.98-1.01]; and high PPD: 1.06 [1.04-1.09] vs. 1.00 [0.98-1.02]), respectively.

Conclusions: Admission to higher EOL treatment intensity hospitals is associated with small gains in postadmission survival. The marginal returns to intensity diminish for admission to hospitals above average EOL treatment intensity and wane with time.

Figure 1

Sample selection. Four years of hospital discharge data included over 7 million admissions among more than 3 million individual patients. After restriction of the sample to in-state residents over age 65 and subjecting the data to cleaning, verification, and weighting, the analytic sample included over 2 million admissions among over 1 million patients.

Figure 2

Panels A–D. Adjusted odds ratio 30- and 180-day postadmission mortality, by hospital treatment intensity among admissions with a high probability of dying. The figures represent the adjusted odds ratio for death at 30 days (A, B) and 180 days (C, D) postadmission, given treatment in a hospital with a particular end-of-life treatment intensity compared with if the patient had been admitted instead to a hospital with the average intensity. Adjustment covariables included patient demographics and clinical characteristics, hospitalization history, and hospital characteristics. Panels A and C depict a patient with an average predicted probability of death (PPD) upon admission (4.6% predicted probability of inpatient death; black line with 95% confidence interval in shaded gray), panels B and D depict patients at lowest (0% predicted probability of inpatient death; blue line with 95% confidence interval in shaded blue) and highest (41% predicted probability of inpatient death; red line with 95% confidence interval in shaded red) PPD upon admission (confidence interval overlap in shaded purple) (note: as the length of follow-up increases, the odds ratio cannot be interpreted as the risk ratio because the event rate exceeds 5%).