Trends in implantable cardioverter-defibrillator racial disparity: the importance of geography.

OBJECTIVES: The study was designed to determine whether racial disparity in utilization of the implantable cardioverter-defibrillator (ICD) has improved over time, and whether small-area geographic variation in ICD utilization contributed to national levels of racial disparity.
BACKGROUND: Although racial disparities in cardiac procedures have been well-documented, it is unknown whether there has been improvement over time. Low ICD utilization rates in predominantly black geographic areas may have exacerbated national levels of disparity.
METHODS: Discharge abstracts from elderly black and white Medicare beneficiaries hospitalized with ventricular arrhythmias from 1990 to 2000 were analyzed to determine if ICD implantation occurred within 90 days of initial hospitalization. Multivariate logistic regression models were constructed to assess the relationship between ICD implantation, year of admission, and the percentage of black inhabitants in each patient's county of hospitalization while controlling for clinical, hospital, and demographic characteristics.
RESULTS: There was improvement in ICD implantation racial disparity: In the period 1990 to 1992, black patients had an odds ratio of 0.52 (95% confidence interval [CI] 0.42 to 0.64) for receiving an ICD compared with whites. However, by 1999 to 2000, the odds ratio for blacks had risen to 0.69 (95% CI 0.61 to 0.78) (test-for-trend p=0.01). Approximately 20% of this trend could be explained by reduction in geographic variation in ICD use between areas with larger black and predominantly white populations.
CONCLUSIONS: Rates of ICD implants became more equal among whites and blacks during the 1990s, although persistent disparity remained at the decade's end. Geographic equalization in cardiovascular procedure rates may be an essential mechanism in rectifying disparities in health care.