Comorbidities May Drive PAD Procedural Outcomes in Black Patients

Undertreatment of comorbidities, including diabetes and chronic kidney disease (CKD), contribute to poorer outcomes after peripheral vascular interventions for arterial disease in Black versus white patients, according to a nationwide analysis of Medicare patients.

As prior research has shown, Black patients with PAD tend to have more-advanced vascular disease at the time of an intervention compared with white patients and are much more likely than white patients to undergo amputation.

The new study, led by Anna K. Krawisz, MD (Beth Israel Deaconess Medical Center, Boston, MA), and published online ahead of print in Circulation, found that Black patients had a 34% greater risk of the composite endpoint of major amputation and death within 1 year of a peripheral intervention. After adjusting for comorbid illness, the association between Black adults and adverse outcomes was no longer significant, suggesting that failure to prescribe guideline-directed therapies could account for some of the excess risk after intervention, in addition to the structural racism that perpetuates health disparities.

“The overall rates of use of medical therapy in this sick population was low overall, and it was a bit surprising. I think we would have anticipated that at that point in people's care, there would have been a higher percentage of medical therapy,” Krawisz told TCTMD. “But these patients who were being referred by a physician for an intervention had a significantly lower likelihood of being on a statin, a PCSK9 inhibitor, or an ACE inhibitor.”

Disparities and Future Goals

In the study of fee-for-service Medicare beneficiaries aged 66 or older, Black patients underwent 928 peripheral vascular interventions per 100,000 beneficiaries compared with 530 per 100,000 in white patients (RR 1.75; 95% CI 1.73-1.77). The relative risk of undergoing a peripheral intervention for Black versus white adults was 1.75 (95% CI 1.73-1.77), a finding that was consistent across all regions of the United States. Compared with white patients, those who were Black were more likely to be younger, be female, and have a higher burden of diabetes, chronic kidney disease, heart failure, and stroke.

Compared with white patients, those who were Black also had a higher probability of being dually enrolled in Medicare and Medicaid, and living in distressed and urban communities. Chronic limb-threatening ischemia (CLTI) was more common among Black patients (61% vs 49.9%), while having claudication as the indication for intervention was more common in white patients (37.6% vs 29.6%; P < 0.01 for both).

Despite having higher burdens of comorbid conditions as well as a greater likelihood of prior lower-extremity interventions than white patients, prescription of key CV medications—nearly across the board—was lower in Black patients.

Medical Therapy Among People Who Underwent Peripheral Vascular Interventions

After adjustment for age and sex, Black patients were more likely than white patients to undergo a major amputation or die than white patients following a peripheral intervention after accounting for age and sex in the full cohort (25.0% vs 18.6%), with similar patterns among those with claudication and those with CLTI.

To TCTMD, Krawisz said the study adds more evidence that awareness of PAD and its consequences is lacking in primary care and other specialties, as well as among patients themselves.

It’s important that we add [PAD] to the national healthcare vocabulary as a disease that has a poor prognosis and can reduce quality of life and lead to life-changing and life-shortening complications. Anna Krawisz

“Knowing that atherosclerosis in vascular beds can portend poor outcomes and poor prognosis, knowing to look for it and to screen for it in patients who have risk factors like diabetes and smoking: we're trying to create that natural link in people's minds between risk factors and PAD,” she said. “It’s important that we add [PAD] to the national healthcare vocabulary as a disease that has a poor prognosis and can reduce quality of life and lead to life-changing and life-shortening complications. This isn't something on the forefront of people's minds to be looking for, despite how common it is and it's negative long-term health ramifications, especially among our Black patients.”

In a policy statement last year, the American Heart Association (AHA) proposed recommendations aiming for a 20% reduction in amputations by the year 2030. More recently, the AHA unveiled its National PAD Action Plan, which will incorporate diverse patient groups to provide input on how to deliver the most effective PAD public health messaging to communities and the public at large.

Krawisz and colleagues say given the complex interplay of social determinants of health, structural racism, and excess burden of undertreated risk factors affecting Black patients, the AHA’s goals “will require particular attention to racial disparities in all aspects of PAD care.”