Impact of availability of hospital-based invasive cardiac services on racial differences in the use of these services.

BACKGROUND: Reports indicate that black patients are less likely than white patients to receive invasive cardiac services after hospitalization for acute myocardial infarction (AMI). There is still uncertainty as to why racial differences exist and how they affect patient outcomes. This is the first study to focus on the availability of invasive cardiac services and racial differences in procedure use. Study objectives were to (1) document whether racial differences existed in the use of invasive cardiac procedures, (2) study whether these racial differences were related to availability of hospital-based invasive cardiac services at first admission for AMI, and (3) determine whether there were racial differences in long-term mortality rates.
METHODS: A historical cohort study was conducted with discharge records from all acute care hospitals in New Jersey for 1993 linked to death certificate records for 1993 and 1994. There were 13,690 black and white New Jersey residents hospitalized with primary diagnosis of AMI. Use of cardiac catheterization within 90 days, revascularization within 90 days (percutaneous transluminal coronary angioplasty [PTCA] or coronary artery bypass graft surgery [CABG]), and death within 1 year after admission for AMI were the main outcome measures. Patterns for PTCA and CABG as separate outcomes were also studied. Hospital-based cardiac services available were described as no invasive cardiac services, catheterization only, or PTCA/CABG. To account for payer status and comorbidity differences, patients 65 years and older with Medicare coverage were analyzed separately from those younger than 65 years.
RESULTS: Black patients aged 65 and older were generally less likely to receive catheterization and revascularization than white patients, regardless of facilities available at first admission. For patients younger than 65 years, the greatest differences between black and white patients in catheterization and PTCA/CABG use within 90 days after AMI occurred when no hospital-based invasive cardiac services were available. However, use of invasive cardiac procedures within 90 days after AMI was substantially increased if the first hospital offered catheterization only or PTCA/CABG services, among all patients, especially among blacks younger than age 65. No significant racial differences or interactions with available services were found in 1-year mortality rates.
CONCLUSIONS: Availability of invasive cardiac services at first hospitalization for AMI was associated with increased procedure use for both races. However, use of invasive cardiac procedures was generally lower for black patients than for white patients, regardless of services available. Long-term mortality rates after hospitalization for AMI did not differ between blacks and whites.