CV Risk Calculator 'Adequate' For HIV Patients

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The standard atherosclerotic disease risk predictor worked as well as other models for HIV-positive individuals on antiretroviral therapy, researchers reported in a study.

The American College of Cardiology and American Heart Association's 2013 Pooled Cohort Equations -- intended for use in the general population -- were an adequate predictor of combined MI and stroke risk over 10 years among HIV-positive patients (Harrell C-statistic 0.75, 95% CI 0.71-0.78), according to the study published online in JAMA Cardiology.

Donald M. Lloyd-Jones, MD, ScM, of Northwestern University Feinberg School of Medicine in Chicago, and colleagues tried to incorporate HIV-specific factors to create two better models. But both failed to beat the Pooled Cohort Equations, with Harrell C-statistics of 0.72 and 0.73, respectively.

"The Pooled Cohort Equations discriminated MI risk and were moderately calibrated in this multicenter HIV cohort," the authors wrote.

"Participants for whom the Pooled Cohort Equations predicted less than 10% 10-year atherosclerotic cardiovascular disease risk had consistently higher-than-predicted MI rates, while participants with greater than or equal to 10% predicted risk generally had lower-than-predicted MI rates."

"As HIV-infected cohorts capture and assess MI and stroke outcomes, researchers should revisit the performance of risk estimation tools," Lloyd-Jones and colleagues recommended.

That may itself require the collection of better data -- derived, perhaps, from the use of new techniques in coronary CT angiography and fluorodeoxyglucose positron emission tomography, suggested Anthony S. Fauci, MD, director of the National Institute of Allergy and Infectious Diseases in Bethesda, Md., and two co-authors.

"Inflammatory biomarkers and advances in cardiac imaging can be used as research tools to delineate the role of immune activation in the development of atherosclerosis in HIV-infected individuals and may improve our ability to predict myocardial events related to atherosclerosis in this unique population, " they wrote in an accompanying editorial.

For now, Fauci's group noted that the ongoing REPRIEVE trial is gathering information on the effects of pitavastatin (Livalo) use on cardiovascular outcomes among HIV-positive patients on antiretrovirals.

The two novel models from Lloyd-Jones' group incorporated trends they found poring over data from five participating sites of the Centers for AIDS Research of Integrated Clinical Systems, which included 19,829 HIV-positive adults who received care since 1995. The present analysis was performed on patients with complete baseline data (n=11,288), of whom 61.2% were white and and 81.9% were men.

Investigators found that race was a factor in cardiovascular risk: MI risk was higher during follow-up for black men and women (6.9 and 7.2 per 1,000 person-years, respectively), compared with white men and women (4.4 and 3.3 per 1,000 person-years, respectively).

Patients age 4o or older at the time of study entry also had a higher MI rate (7.5 versus 2.2 per 1,000 person-years among their younger counterparts), as did participants with a detectable viral load (6.3 versus 4.7 per 1,000 person-years for patients who were virally suppressed).