Taisei Kobayashi (Corporal Michael J Crescenz, Veterans Affairs Medical Center, Philadelphia, USA) and others report in JAMA Cardiology that—after adjustment for demographics, comorbidities and procedural characteristics—black patients do not have a significantly higher rate of one-year mortality after percutaneous coronary intervention (PCI) than do white patients. Previous studies have suggested that black patients have higher intermediate- and long-term adjusted mortality after PCI.
Kobayashi et al comment that while earlier studies have already compared outcomes of black patients who have undergone PCI with those of white patients, these studies reviewed data from non-Veteran Affairs health system hospitals and such comparisons have not been performed with data from Veteran Affairs health system hospitals. “The Veteran Affairs health system represents a unique nationalised, single-payer healthcare system within the USA,” they add. Therefore, the authors reviewed data from patients (black and white) treated at Veteran Affairs hospitals across the USA.
They hypothesised that black patients would have worse adjusted one-year mortality after PCI than their white counterparts but that these differences would be “at least partially mediated by variations in procedural and post-procedural care, including stent type choice, access site, completeness of revascularisation, and post-PCI medication prescription”. The primary outcome was one-year mortality, which was calculated as a dichotomous variable denoted as death during the hospitalisation or within one-year after hospital discharge from the index PCI.
Of 42,391 patients (from 69 Veteran Affairs cardiac catheterisation laboratories), 13.3% were black. Kobayashi et al found that black patients tended be younger, have lower socioeconomic status, have a higher burden of several medical comorbidities, and were more likely to present with acute coronary syndrome. Furthermore, they were significantly more likely to undergo PCI under urgent or emergent conditions: 43.2% vs. 36.6% for white patients (p<0.01).
According to the unadjusted analysis, one-year mortality was significantly higher among black patients: 7.1% vs. 5.9%, respectively; p<0.001. However, after adjustment, there were no longer any significant differences between groups. Furthermore, there were no significant differences between black and white patients in the secondary outcomes (after adjustment)—including 30-day all-cause readmission rates, 30-day blood transfusion, and one-year readmission rates for myocardial infarction.
The authors report: “Post-hoc analyses revealed that adjustment for comorbidities and presentation or anatomic factors attenuated most of the difference in the unadjusted primary outcome, with socioeconomic status and the proportion of black patients having minimal influence on the attenuation after accounting for the previous factors.” They add that reducing racial disparities “relating to the prevention and treatment of chronic comorbidities may lead to improved absolute outcomes among black veterans undergoing PCI”.
Kobayashi et al also reviewed differences in procedural and post-procedural care between black and white patients. With this analysis, after adjustment, black patients were more likely to receive a bare metal stent than were white patients but were less likely to be prescribed beta-blockers. There were no other significant differences in procedural or post-procedural care between groups. “Prior analyses of veterans have demonstrated reduced efficacy of beta-blockers as an antihypertensive agent for black patients. Results of these seminal studies could be influencing post-PCI prescription patients,” the authors observe. Additionally, they note beta-blockers do not “clearly improve mortality in patients with stable coronary artery disease”.
As to why their study did not find a difference in one-year mortality between black and white patients whereas other studies have suggested significant differences in intermediate- and long-term outcomes, Kobayashi et al state that sample size—larger in a previous Medicare study—may have been a factor. They also say: “The Veteran Affairs system is an integrated health system that provides primary and specialty care, inpatient services, and outpatient pharmaceuticals. Integrated health systems have been associated with reduced racial outcome disparities in some medical conditions.”
Ten days prior to the Kobayashi et al study (published online 19 July), a study published in Circulation (published online 10 July) indicated that black men have twice the risk of having a first fatal cardiac event than do white men. However, authors Lisandro Colantonio (University of Alabama, Birmingham USA) and others found that—similar to Kobayashi et al—this risk attenuated after adjustment for cardiovascular risk factors and socioeconomic factors. Senior author Monika Safford (John J Kuiper Professor of Medicine and Chief of General Internal Medicine at Weill Cornell Medical College, New York, USA) comments: “Our concern is that blacks may not be seeking medical attention for important symptoms that could signal heart problems. Greater public awareness of heart attack symptoms would benefit everyone. Many people think that heart attacks are only present if they have severe chest pain. In fact, many heart attacks cause only mild symptoms and people may mistakenly think they are having a bout of indigestion.”