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ACC/AHA guidelines for atherosclerotic CVD beneficial for black patients
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WASHINGTON — Physicians diagnosed more black participants with atherosclerotic CVD and recommended statin therapy using the American College of Cardiology/American Heart Association guidelines than the U.S. Preventive Services Task Force guidelines, according to new findings.
Black individuals are at “disproportionately high risk for atherosclerotic CVD” and typically have a poor response to CV risk and subclinical atherosclerotic CVD compared with people of other races, according to the researchers, who presented the findings at the ACC Scientific Session and published them in JAMA Cardiology.
“Statin eligibility by contemporary ACC/AHA guidelines is more effective at identifying subclinical high-risk vascular phenotypes relative to (Adult Treatment Panel III),” Aferdita Spahillari, MD, cardiovascular disease clinical and research fellow at Beth Israel Deaconess Medical Center, Boston, and colleagues wrote in an abstract for the poster presented at ACC Scientific Session. “Statin-ineligible African Americans are at low risk regardless of [coronary artery calcium] status.”
Study methods
Researchers compared data from 2,812 participants (mean age: 55 years; 65.3% women; mean BMI: 31.6 kg/m2). All participants were black, aged 40 to 75 years, not receiving statin therapy and without prevalent atherosclerotic CVD. Of these participants, 96.6% (n = 2,716) had comprehensive data on incident atherosclerotic CVD and 62% (n = 1,743) had CT imaging available for review. Risk factors such as diabetes, cigarette smoking, BP, hypertension and lipid profile were measured and analyzed.
Based on the ACC/AHA guidelines, participants were eligible for statin therapy if they met one of the following criteria: LDL 190 mg/dL; aged 40 to 75 years with diabetes and LDL 70 to 189 mg/dL; aged 40 to 75 years without diabetes, LDL 70 to 89 mg/dL and an estimated 10-year atherosclerotic CVD risk score 7.5%.
USPSTF guidelines identified participants as statin-eligible if they were between ages 40 and 75 years, had a calculated 10-year atherosclerotic CVD risk of 10% or greater, and had one or more atherosclerotic CVD risk factor. These risk factors included diabetes, dyslipidemia, smoking or hypertension.
USPSTF guidelines determined that 38.1% of participants (n = 1,072 participants) qualified for statin therapy vs. 49.9% (n = 1,404) of participants using the ACC/AHA guidelines (risk difference, 11.8%; 95% CI, 10.5–13.1).
Among the group of participants, the median 10-year atherosclerotic CVD risk was 6.9% (interquartile range, 3.1%–13.1%). Of the participants with available CT imaging and eligible for statins, 42% (n = 732) had coronary calcification and 63.7% (n = 1,110) had abdominal aortic calcification.
Participants who fit the requirements for statin therapy with both guidelines exhibited a higher event rate (9.6 events per 1,000 patient-years; 95% CI, 7.8–11.8) compared with those who met the requirements under the ACC/AHA guidelines (4.1 events per 1,000 patient-years; 95% CI, 2.4–6.9).
Participants who had CT scans available had a lower atherosclerotic CVD risk. Coronary calcification was noted in 507 of 732 participants (69.3%) according to ACC/AHA guidelines vs. 55.2% with the USPSTF guidelines (risk difference, 14.1%; 95% CI, 11.2–17; P < .001). Aortic calcification was seen in 61.4% of participants with the ACC/AHA guidelines vs. 46.1% with the USPSTF guidelines (risk difference: 15.2%; 95% CI, 12.9–17.5; P < .001).
For coronary artery calcium, the researchers wrote the USPSTF guidelines were “significantly less sensitive” (net reclassification index for CAC: -14%; P < .001) and “more specific” (net reclassification index for no CAC: 11%; P < .001). For aortic calcification, ACC/AHA guidelines conferred improved net reclassification and risk discrimination. “Individuals with [aortic artery calcium] were more often incorrectly reclassified by USPSTF statin eligibility guidelines,” Ravi V. Shah, MD, instructor in medicine at Harvard Medical School and an associate physician in the Heart Failure and Transplant section at Massachusetts General Hospital, and colleagues wrote.
Participants with CAC who were statin-eligible according to USPSTF guidelines had a higher 10-year atherosclerotic CVD event rate (8.4 per 1,000 person-years; 95% CI, 5.9–11.9) vs. those without coronary artery calcium (4.4 per 1,000 person-years; 95% CI, 2.2–8.8). The same was noted for participants using the same guidelines who were not statin-eligible.
Based on ACC/AHA guidelines, those who were statin-eligible with CAC had a higher 10-year atherosclerotic CVD event rate (8.1 per 1,000 person-years; 95% CI, 5.9–11.1) vs. those without CAC (3.1 per 1,000 person-years; 95% CI, 1.6–5.9; P for interaction = .02). There was no difference in those who were not statin-eligible using the ACC/AHA guidelines with and without coronary artery calcium.
However, according to the researchers, participants not statin-eligible by the USPSTF guidelines were more likely to have an atherosclerotic CVD event if they had CAC (2.8 per 1,000 person-years; 95% CI, 1.5-5.4) than if they did not (0.8 per 1,000 person-years; 95% CI, 0.3-1.7; P for interaction = .03).
“Approximately 1 in 4 African American individuals recommended for statin therapy under ACC/AHA guidelines are no longer recommended for statin therapy under USPSTF guidelines,” Shah and colleagues wrote. “Individuals only eligible for statins under ACC/AHA guidelines experienced a low to intermediate event rate (equivalent to 4.1% per 10 years of patient follow-up), suggesting decreased sensitivity of the USPSTF recommendations in identifying participants at risk of [atherosclerotic CVD].
“Despite debate over the potential cost, risk calibration and metabolic health implications of increasing statin use, these results support a guideline-based approach to statin recommendation, leveraging targeted imaging (or other surrogate atherosclerotic measures) in African American individuals to further personalize statin-based prevention programs,” Shah and colleagues wrote. – by Darlene Dobkowski
Reference:
Spahillari A, et al. Abstract 1236-059. Presented at: American College of Cardiology Scientific Session; March 17-19, 2017; Washington, D.C.
Shah R, et al. JAMA Cardiol. 2017;doi:10.1001/jamacardio.2017.0944.
Disclosure: Shah and Spahillari report no relevant financial disclosures. One researcher reports holding minor equity in General Electric.
Perspective
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Keith C. Ferdinand, MD, FACC, FAHA, FASH, FNLA
These findings confirm that African Americans are a patient population who would clearly benefit from wider use of statin therapy, and that the ACC/AHA guidelines, although criticized in many circles, may actually be a better way of identifying patients who would decrease [CV] risk with the application of statins.
In clinical practice, many providers routinely utilize the ACC/AHA Atherosclerotic CVD Risk Calculator. It can be downloaded onto a mobile phone or laptop, and can be easily used in the clinical setting to demonstrate their risk status to many patients who are without symptoms or prior knowledge of [CVD] that makes them candidates for statin therapy. The USPSTF guidelines take a more cautious approach to statin eligibility. Based on these recent data from the Jackson Heart Study (JHS), while appropriately identifying most high-risk patients, the USPSTF approach may underestimate patients who are at risk for CVD based on the presence of CAC, and would not have the benefits of statin therapy if adhering strictly to the USPSTF clinical guidelines.
The concerns with the overuse of statins should take a back seat to the findings that, in general, African Americans are at a higher risk for [CV] morbidity and mortality than the overall population and that lipid management is, in general, less aggressive in black individuals than white individuals. Statins are well-tolerated in most patients. The small increases in glucose are not as important as the CV protection offered to patients who even have antecedent diabetes or metabolic syndrome. Furthermore, the cognitive dysfunction noted in some post-marketing surveillance studies has not been shown in rigorous trials, and with the additional data on PCSK9 inhibitors, it is now clear, supported by epidemiologic evidence, that lower LDL is protective against CV events in higher-risk patients.
Despite the robust data on statins, we should clarify whether or not there is any specific difference in how patients respond to medications across the multicultural population we have in the United States. Most of the large, randomized, clinical outcomes trials with statins were done in European or white American populations, including the Scandinavian Simvastatin Survival Study, the Long-Term West of Scotland Cardiovascular Outcomes Study, the LIPID trial, the Heart Protection Study. Even in CARE and AFCAPS/TexCaps, in the United States, black patients were underrepresented. Nevertheless, there are data to suggest that calcium scoring may help identify patients with increased risk, especially when there is uncertainty in the wider use of statins. While understanding the need to avoid the overuse of any medication, most public health officials recognize the high risk in the African American population and would suggest that wider, not limited, statin use would be a wise public health intervention in this high-risk subpopulation.
The study from the Jackson Heart group is mainly applicable to self-identified African Americans. Although calcium scoring appears to be predictive in all populations, including in African Americans, it is important to identify those patients who need more rigorous intervention, not only for LDL lowering, but also for the control of BP. In fact, there is some data to suggest that CAC scores may be less, not higher, in African Americans, Hispanics and Asians compared to whites. On the other hand, in African Americans, among all of the racial/ethnic groups, there is lower survival despite not having higher levels of calcium scores. Therefore, a high-risk population such as African Americans, would benefit from more, not less, intervention.
The JHS provides peer-reviewed evidence that, based on coronary calcium scoring, the stricter guidelines from USPSTF may actually underestimate the value of statins in high-risk African American individuals, leading to further undertreatment.
It is unclear exactly why a clinician would rather use the USPSTF recommendations vs. the ACC/AHA guidelines. Although the USPSTF recommendations are based on clear science, the public health implications are that getting appropriate statin use in high-risk patients is essential. Based on the JHS, the potential harms of undertreatment may outweigh the harm of overtreatment.
In general, both guidelines suggest that the interpretation of clinical guidelines are not laws, but only assist providers in making the best choices for the individual patient. In the setting of using either the USPSTF or the ACC/AHA guidelines, it is important that the provider/patient relationship involves a shared decision as the final pathway for the use of any intervention, including statins. The risk, however, of undertreatment is the increase in MIs, strokes and perhaps even CV deaths in high-risk populations. While the ACC/AHA guidelines can be criticized for leading to overtreatment, based on the JHS, it appears that comparing the ACC/AHA guidelines to the USPSTF guidelines will actually locate many African Americans with vascular calcification who may not have been identified for the benefits of statin therapy if the more rigorous USPSTF guidelines had been applied.
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