Test your medicine knowledge with the MKSAP challenge, in partnership with the American College of Physicians.

A 44-year-old man is evaluated in the office during a routine visit. Medical history is significant for HIV diagnosed at age 25 years, hypertension, and hyperlipidemia. He is a current smoker. Medications are chlorthalidone, tenofovir-emtricitabine, and raltegravir.

On physical examination, the patient is afebrile, and blood pressure is 126/74 mm Hg. Cardiac examination reveals a regular rate and rhythm. S₁and S₂ are normal; there is an S₄.

Laboratory tests are significant for a fasting plasma glucose level of 98 mg/dL (5.43 mmol/L), a total cholesterol level of 210 mg/dL (5.43 mmol/L), and an HDL cholesterol level of 50 mg/dL (1.29 mmol/L).

An electrocardiogram shows normal sinus rhythm and left ventricular hypertrophy with repolarization abnormalities. A chest radiograph is normal.

To determine his need for statin therapy, his estimated 10-year risk for atherosclerotic cardiovascular disease using the Pooled Cohort Equations will be calculated.

Which of the following risk factors will result in underestimation of the risk for atherosclerotic cardiovascular disease in this patient?

A. Age
B. Antihypertensive medication use
C. Blood pressure
D. HDL cholesterol level
E. HIV status

MKSAP Answer and Critique

The correct answer is E. HIV status.

This patient’s HIV status will contribute most to the underestimation of his risk for atherosclerotic cardiovascular disease (ASCVD). This young patient has both traditional risk factors (hypertension and smoking) and a nontraditional risk factor (HIV) for ASCVD, which is defined as coronary death or nonfatal myocardial infarction, or fatal or nonfatal stroke. The Pooled Cohort Equations are a risk assessment instrument developed from multiple community-based cohorts; their use as a primary risk assessment tool was recommended in the 2013 American College of Cardiology/American Heart Association (ACC/AHA) Guideline on Assessment of Cardiovascular Risk. The ACC/AHA ASCVD risk calculator based on the Pooled Cohort Equations includes age, sex, race, total and HDL cholesterol levels, systolic blood pressure, blood pressure–lowering medication use, presence of diabetes mellitus, and smoking status. With use of this method of calculating risk, a 10-year risk for ASCVD below 5% is considered low risk, 5% to below 7.5% is classified as intermediate risk, and 7.5% or higher is designated as high risk. This patient’s calculated 10-year ASCVD risk is 6.2%.

Large observational studies have demonstrated a 1.5- to 2-fold increase in the risk for ASCVD among patients with HIV infection. The increased risk for ASCVD in HIV-infected patients is likely the result of interactions among the viral infection, host factors, traditional risk factors, and therapies for HIV. Traditional risk models, including the ACC/AHA ASCVD risk calculator based on the Pooled Cohort Equations, underestimate the risk for ASCVD in patients with HIV. Alternative risk models, including one based on the D:A:D (Data Collection on Adverse events of Anti-HIV Drugs) study, have been developed, but they lack validation and have not been widely adopted.

This patient’s age, blood pressure, use of antihypertensive medications, and HDL cholesterol level are accounted for in the ACC/AHA ASCVD risk calculator and are not factors responsible for underestimating his ASCVD risk.

Key Point

• In patients with HIV infection, there is a 1.5- to 2-fold increased risk for coronary artery disease.

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