In this large cohort of patients with acute ischemic stroke, we found that black patients had lower in-hospital mortality and all-cause mortality for up to 1 year after stroke onset than white patients. The survival difference persisted after we controlled for the observed confounders in propensity score analyses and used a regular risk-adjustment model that included all of the covariates.
These data highlight the difference between stroke mortality and case-fatality rates. Compared with white persons, black persons have excess overall stroke-related mortality because of higher stroke incidence (31
). Conflicting data have been reported on stroke case-fatality by race (6
), but an increasing body of evidence from hospital administrative data (9
) and stroke registries (8
) suggests that patients from racial or ethnic minority groups have a lower risk for all-cause mortality after being hospitalized for stroke than white patients.
We found that black patients with stroke received life-sustaining interventions more often and had longer lengths of stay, higher hospital spending, and a lower hospice admission rate. Our data are consistent with previous research (17
) that shows that black patients more often receive life-sustaining interventions, including gastrostomy, hemodialysis, and intubation and tracheostomy, than nonblack patients. In addition, black patients are less likely to access palliative care services or hospice (16
). Previous research (35
) has shown that early care limitations (such as do-not-resuscitate orders) independently predict death after intracerebral hemorrhage. Therefore, a philosophy of care that involves providing more or less intensive treatment and services may influence short- to intermediate-term survival.
Our data are also consistent with recent research (36
) that shows a better survival rate for up to 180 days at acute-care hospitals in Pennsylvania with higher-intensity end-of-life treatment. Although the racial differences in mortality that we observed (30-day adjusted OR, 0.69 [CI, 0.57 to 0.84]) were greater than those seen between the high- versus average-intensity (30-day adjusted OR, 0.97 [CI, 0.95 to 0.99]) or the low- versus average-intensity Pennsylvania hospitals (30-day adjusted OR, 1.09 [CI, 1.07 to 1.11]), the differences attenuated over time in both studies. However, despite the narrowing mortality gap in our study, the differences persisted through 1 year, which is consistent with the facts that patients with stroke who opt for aggressive treatment may live months or years with continued supportive care and more intensive treatment may produce short or intermediate survival benefit. In a recent study (37
), black Medicare patients with stroke had a short-term (30-day) mortality benefit (4.4%), after which the survival advantage decreased over time (to 0.6% at 1 year) and eventually reversed after 2 years of follow-up (to a 1.2% advantage for white patients).
The mortality differences are unlikely to be due to disparities in the delivery of effective care, because most research suggests that black patients have poorer access to and adherence to evidence-based treatment (11
). Although we had limited information relating to evidence-based process measures, we observed that fewer black patients received thrombolytic therapy, which is consistent with previous studies (11
). In addition, our data emphasize the limitations of using stroke mortality rates as a measure of quality; their indiscriminate use would imply that black patients had better quality of care than white patients (40
). This is a concern because stroke mortality is a common outcome measure used in clinical trials, and inpatient stroke mortality is the most common publicly reported measure used to judge the quality of stroke care. The Centers for Medicare & Medicaid Services is considering including 30-day ischemic stroke mortality as one of its publicly reported measures.
Although we have no information on advance directives or patient or family preferences, our results highlight the potential importance of value-laden end-of-life decisions on survival outcomes in stroke care. This involves the complex process of shared decision-making and deliberation to arrive at treatment decisions with end-of-life implications. More research is required to develop methods for measuring the quality of these preference-sensitive decisions for seriously ill stroke patients. Such methods would need to capture the degree of truly informed patient choice, adequacy of physician communication, attention to health literacy, and respect for individual spiritual beliefs. The quality of these decisions may differ by race, as suggested by a recent study (42
) that found that white patients with cancer received end-of-life care consistent with their preferences more frequently than black patients. The policy push toward patient-centered care will also require us to confront the possibility that well-informed patients who decide to forgo life-prolonging treatments and allow a natural death might receive excellent-quality care but have higher mortality than poorly informed patients who decide to use life-prolonging treatments (43
Because we used administrative data, we could not adjust for admission stroke severity, measure disability, or functional status. We do not believe that a lower severity of initial strokes in black patients (for example, as a result of more small vessel vs. large vessel or cardioembolic disease) explains our findings. First, we used several risk adjustment methods, including the Charlson Comorbidity Index, the Elixhauser Index, the presence of atrial fibrillation, and present-on-admission diagnoses, to improve mortality risk adjustment and provide a more accurate assessment of the relationship between race and mortality risk. Second, after adjusting for the probability of dying in the hospital, the ICU admission and mechanical ventilation rates were similar between black and white patients, which suggests that the groups had similar proportions of severe strokes and need for respiratory support. Third, previous research (3
) has shown that black patients have more severe deficits at presentation, a confounding variable that would increase rather than decrease mortality in black patients. Finally, research (9
) has also shown that black patients 65 years and older have lower adjusted 30-day mortality than white patients after being hospitalized for several conditions, including congestive heart failure, acute myocardial infarction, hip fracture, and gastrointestinal bleeding, which suggests something more systemic than disease-specific confounding. Further research is needed to confirm these findings.
Our study has additional limitations. First, it is descriptive in nature. Although we observed more aggressive end-of-life treatment and lower mortality in black patients, the causal relationship cannot be established with our study design. However, describing this pattern brings the literature closer to identifying the underlying sources of disparities in stroke outcomes. Second, the ICD-9-CM procedure codes might underestimate the prevalence of potential life-sustaining interventions and thrombolytic therapy. However, no data suggest that these procedures would be coded differently by race. Third, we used data from patients who live in urban areas of New York, and the generalizability of our findings, especially to rural areas and to other states, remains to be established. Fourth, because up to 50% of stroke deaths occur outside the hospital setting (44
), a racially disproportionate number of out-of-hospital deaths could have affect mortality rates calculated from hospital records. Fifth, previous studies (5
) have shown excess burden of stroke, particularly among young and middle-aged patients. Because most of our study patients were 65 years or older, survivor bias may exist if older black patients differed from older white patients. However, we stratified our analysis by age group and observed a consistent pattern of lower risk for death among black patients in each age stratum. Finally, propensity score methods can only adjust for observed confounders (22
); unmeasured residual confounders, for which we could not adjust, could have been present.
In conclusion, black patients hospitalized with acute ischemic stroke had lower mortality rates than their white counterparts, an effect which persisted but attenuated over the year after the initial hospitalization. A racial effect, which may be explained by the differential use of intensive treatment in seriously ill patients with stroke, contributes to the mortality difference. Future research should focus on understanding what drives the racial variations in stroke care and developing optimal approaches for promoting patient-centered decision-making, including the ability to recognize, explore, and respect the cultural norms that each patient and family bring to every clinical encounter.