Kaiser Study Shows No Elevated Heart Attack Risk for People with HIV

A previously reported increase in the risk of myocardial infarction or heart attack among people living with HIV has been reversed in recent years, according to an analysis of nearly 25,000 Kaiser Permanent members published in the January 18 edition of Clinical Infectious Diseases. In 2010-2011, HIV positive patients were at no greater risk than HIV negative people.

Daniel Klein, Michael Silverberg, and colleagues from Kaiser Permanente conducted a cohort study to evaluate the risk of myocardial infarction and its association with HIV status from 1996 -- the advent of effective combination antiretroviral therapy (ART) -- through 2011.

The analysis included 24,768 HIV positive and 257,600 demographically matched HIV negative members of Kaiser Permanente Northern California and Kaiser Permanente Southern California.

A total of 320 myocardial infarctions occurred among people with HIV (268 per 100,000 person-years) and 2,483 occurred among HIV negative people (165  per 100,000 person-years).

The researchers found that the adjusted myocardial infarction rate ratio -- or the elevation in risk seen among HIV positive compared with HIV negative people -- was 1.4 overall, indicating a 40% higher risk. However, the rate ratio declined steadily over time, from 1.8 during 1996-1999 to 1.0 during 2010-2011, indicating no difference in risk during the most recent period.

The researchers attributed the decrease in heart attack risk to early ART, less toxic antiretroviral drugs, and cardiovascular risk reduction efforts including smoking cessation, frequent monitoring, and management of elevated cholesterol and high blood pressure.

Below is an edited excerpt from a Kaiser Permanente press releasedescribing the study and its findings in more detail.

Dramatic Decline in Risk for Heart Attacks among HIV-Positive Kaiser Permanente Members

Oakland, Calif. -- January 16, 2015 -- Previously reported increased risk of heart attacks among HIV-positive individuals has been largely reversed in recent years for Kaiser Permanente's California patients, according to a study published in the current online issue of Clinical Infectious Diseases.

"Our findings lend support to the concept that increased heart attack risk for HIV patients is largely reversible with continued emphasis on primary prevention in combination with early initiation of antiretroviral therapy to preserve immune function," said lead author Daniel B. Klein, MD, Chief of Infectious Diseases for Kaiser Permanente San Leandro.

The adjusted risk ratio for heart attacks among HIV-positive study participants went from an 80 percent increased risk in 1996 to no increased risk in 2010-2011. The study population included 24,768 HIV-positive and 257,600 demographically matched HIV-negative subjects from Kaiser Permanente Northern California and Kaiser Permanente Southern California.

Noting that the study participants are members of a large integrated health care setting, the investigators say these results may be explained by access to care and broadly disseminated cardiovascular risk reduction efforts. These include the implementation of health prompts that appear during all clinic visits in the electronic medical record with reminders for cholesterol and blood pressure monitoring, diabetes follow-up, and smoking cessation.

One of the first reports documenting an increased risk of cardiovascular disease was conducted among Kaiser Permanente HIV patients and led by Dr. Klein. That early awareness within the Kaiser Permanente health care system may have resulted in enhanced attention to cardiovascular risk reduction and interventions in this population. Over the 16-year study period, HIV-positive subjects had similar increases in the use of lipid-lowering and hypertension therapy compared with HIV-negative subjects.

In addition, in accordance with national treatment guidelines mirrored within Kaiser Permanente, patients are being started on antiretroviral treatments earlier and being prescribed less toxic combination therapies.

"Such early and sustained improvements in care would have been necessary to achieve not only a reduction in risk of heart attack but a virtual leveling of risk between HIV-positive and HIV-negative individuals," said senior author Michael J. Silverberg, PhD, MPH, a senior research scientist with the Kaiser Permanente Division of Research. "The takeaway from this study is that the well-established higher risk of a heart attack in HIV patients may be reversible. With better HIV treatments, and more attention to traditional cardiovascular risk factors, the difference in risk by HIV status has been diminished or even eliminated."

1/29/15

Reference

DB Klein, WA Leyden, L Xu, MJ Silverberg, et al. Declining Relative Risk for Myocardial Infarction Among HIV-Positive Compared with HIV-Negative Individuals with Access to Care. Clinical Infectious Diseases. January 18, 2015 (Epub ahead of print).

Other Source

Kaiser Permanente. Dramatic Decline in Risk for Heart Attacks among HIV-Positive Kaiser Permanente Members. Press release. January 16, 2015.