High-density lipoprotein cholesterol may not be as effective a biomarker of cardiovascular disease risk as once thought, particularly in Black adults, according to results from a large biracial cohort study that also raised questions about the validity of high HDL cholesterol as a potentially protective factor in White and Black adults alike.
“I think this opens the door to suggest that every biomarker we use might have a race-specific association with disease outcome,” Nathalie Pamir, PhD, an associate professor at Oregon Health & Science University in Portland, said in an interview. “So, something as basic as HDL cholesterol – we’ve known about it since 1970 – has a race signature.”
Dr. Nathalie Pamir
Dr. Pamir and colleagues reported their findings from the REGARDS (Reasons for Geographic and Racial Differences in Stroke) cohort study that recruited 30,239 Black and White individuals aged 45 years and older from the contiguous United States from 2003 to 2007.
The study found that LDL cholesterol “modestly” predicted coronary heart disease (CHD) risk in Black and White adults. However, low HDL cholesterol, while associated with an increased risk in White patients (hazard ratio, 1.22; 95% confidence interval, 1.05-1.43), did not have a similar association in Blacks (HR, 0.94; 95% CI: 0.78-1.14). And high HDL cholesterol wasn’t found to be predictive in either group (HR, 0.96; 95% CI, 0.79-1.16 for White participants: HR, 0.91; 95% CI, 0.74-1.12 for Black participants).
Among 23,901 study participants who were CHD-risk free over a 10-year follow-up, 664 and 951 CHD events occurred in Black and White participants, respectively. The study cohort was 57.8% White and 58.4% women, with a mean age of 65 years.
The study noted that LDL cholesterol and triglycerides conferred similar risks for CHD in both White and Black participants.
Acknowledging that this study focused on Blacks, Dr. Pamir added that “we need to know about Asian Americans; we need to know about Hispanic Americans.”
Change of approach to lipid management called for
Dr. Pamir noted that the current understanding about HDL cholesterol and CHD risk comes from the Framingham heart study in the 1970s, whose population was 100% White.
Care algorithms derived from the Framingham study as well as the Multi-Ethnic Study of Atherosclerosis incorporate that association between HDL cholesterol and CHD risk, she noted, but these findings from REGARDS should change how cardiologists approach lipid management in Black and White patients.
“The conversation would go something like: High HDL cholesterol levels put you in a higher risk [bracket] but HDL cholesterol levels are not something we treat; we have no drugs for that,” Dr. Pamir said.
“The conversation would continue along the lines that: ‘You need to do more exercise, you need to change your diet, incorporate healthy fats, walnuts, and omega 3s.’
“But what might the conversation be for Black patients? ‘We don’t see the association that we see for White patients. Do adopt the good habits to exercise and dietary changes, but don’t get too worried about it.’ ”
The study report raises “caution” about using the Framingham, MESA, and other algorithms for evaluating CHD risk. Dr. Pamir explained what that means. “We might be underestimating risk, because what our study showed was that, when we looked at clinically high HDL cholesterol, about 60 mg/dL, it has no benefit for White and Black patients.”
She added, “So that pat on the back we get for patients that have high HDL-C levels? Maybe that pat on the back shouldn’t be there.”
Dr. Keith C. Ferdinand
In an invited commentary, Keith C. Ferdinand, MD, of Tulane University in New Orleans, wrote that using HDL cholesterol in risk calculations could inaccurately assess atherosclerotic cardiovascular risk in Black adults “and become a barrier to optimal care.”
In an interview, he said the REGARDS findings call for consideration of other biomarkers for evaluating CHD risk and point to the importance of socioeconomic factors in health outcomes.
“Physicians and other clinicians need to recognize the powerful impact of the social determinants of health and to also recognize the limits of HDL itself as either protective if it’s high or a definitive predictor of risk if it’s low, and focus on some more modern approaches, including coronary artery calcium scoring.”
He also said risk evaluation should include lipoprotein(a), which, he noted in the editorial, the European Atherosclerosis Society recommends measuring. “One of the reasons it’s underutilized is that we really don’t have a specific treatment for it,” he said of Lp(a) in the United States.
In his editorial comment, Dr. Ferdinand called for future research aimed at eliminating health disparities. “Regardless of the development of better tools for the assessment of risk, newer drugs to treat CVD, the use of coronary artery calcium, if we don’t apply evidence-based medicine equally across the population based on race, ethnicity, sex, gender, socioeconomic status, or geography, then the disparities are going to persist,” he said.
The National Institute of Neurological Disorders and Stroke and the National Institute on Aging provided funding for the study. Dr. Pamir has no relevant relationships to disclose. Dr. Ferdinand disclosed relationships with Boehringer Ingelheim, Novartis, Janssen, and Lilly.