3032 — Racial Differences in hospital Mortality among Veterans with COPD Are Not Explained by Differences in ICU admission or use of ventilatory support

Cannon KT (VA Iowa City Health Care System; Division of General Internal Medicine, The University of Iowa Carver College of Medicine, Iowa City, Iowa), Vaughan Sarrazin M (VA Iowa City Health Care System; Division of General Internal Medicine, The University of Iowa Carver College of Medicine, Iowa City, Iowa), Kaldjian LC (VA Iowa City Health Care System; Division of General Internal Medicine, The University of Iowa Carver College of Medicine, Iowa City, Iowa), Rosenthal GE (VA Iowa City Health Care System; Division of General Internal Medicine, The University of Iowa Carver College of Medicine, Iowa City, Iowa)

Objectives:
Few studies have examined racial differences in hospital mortality for chronic obstructive pulmonary disease (COPD), a common reason for admission among veterans. The objective of this study was to compare mortality in black and white patients and determine the potential impact of differences in intensive care unit (ICU) admission, mechanical ventilation (MV) and non-invasive ventilation (NIV).

Methods:
The Patient Treatment File (PTF) was used to identify all black (n=5,479) and white (n=31,537) patients admitted to VHA facilities during FY2003-05 with COPD exacerbation. 30-day mortality rates were determined using the PTF and the VA Vital Status File. Hierarchical logistic regression was used to compare mortality in black and white patients, controlling for demographic and clinical factors and accounting for hospital-level variation.

Results:
Black patients were more likely to be admitted to ICUs (17.4% v. 15.4%, respectively;p < .001) and to receive MV (4.1% v. 3.0%;p < .001), although NIV use was similar (7.0% v. 6.9%;p=.73). Blacks had lower unadjusted 30-day mortality than whites (5.1% v. 6.6%;p < .001). In stratified analyses, mortality was lower in blacks among patients admitted to ICUs (12.6% v. 15.6%;p=.02) and non-ICU wards (3.5% v. 4.9%;p < .001). Mortality was also lower in blacks among patients receiving NIV only (10.2% v. 14.3%;p=.04) or no ventilation (3.9% v. 5.4%;p < .001), but was similar among patients receiving MV (24.2% v. 25.1%;p=.78). In hierarchical logistic regression analyses, the odds of death were lower in blacks, relative to whites, in analyses adjusting for clinical and demographic factors (OR=0.72, 95%CI 0.61-0.85;p < .001), and in analyses that further adjusted for ICU admission and the use of MV or NIV (OR=0.69, 95%CI 0.58-0.81;p < .001).

Implications:
Among veterans admitted for COPD exacerbation, mortality was lower in black patients than white patients, even after adjusting for higher ICU admission rates and higher use of ventilatory support in black patients.

Impacts:
The lower risk-adjusted mortality in black veterans with COPD was not explained by several markers of more aggressive care and may reflect greater unmeasured disease severity in whites or racial differences not accounted for in the dataset, such as patient preferences. Identifying such factors may provide insight into racial differences in the treatment of COPD and other common chronic conditions.