Wednesday 29 June, 2016 13.00 EDT
26 January 2015
To prevent heart attacks, researchers encourage quitting tobacco
In Canada and other high-income countries, the widespread availability of potent combination anti-HIV therapy (commonly called ART or HAART) has greatly reduced the risk of death from AIDS-related infections. ART is so powerful that doctors increasingly expect that some HIV-positive young adults who are recently infected and who begin treatment shortly after diagnosis and are able to take ART every day as directed and who do not have untreated or undiagnosed pre-existing issues (such as addiction and/or mental health issues) will likely live into their eighth decade.
As a result of the beneficial effects of ART and longer lifespan, doctors caring for HIV-positive people in Canada, Australia, New Zealand, Western Europe and the U.S. are increasingly focused on preventing and treating health issues commonly associated with aging.
One such issue is cardiovascular disease, particularly heart attacks. Over the past 15 years, observational studies have reported that HIV-positive people have an elevated risk for heart attacks. Researchers have proposed the following possibilities for the link between HIV infection and cardiovascular disease:
- HIV infection causes changes to cholesterol and other lipids in the blood.
- HIV triggers inflammation that increases the risk for a heart attack.
Both of these changes brought about by HIV may accelerate the process of underlying cardiovascular disease.
Other potential reasons for the increased risk of cardiovascular disease in HIV-positive people have been proposed, as follows:
- some anti-HIV drugs
- uncontrolled or poorly managed blood pressure and other related conditions
- co-infection with members of the herpes virus family such as CMV (cytomegalovirus)
Taking these and other points into account, infectious disease specialist Line Rasmussen MD, PhD (Odense University Hospital, Denmark), and colleagues have stated “the mechanisms that drive the association between HIV and the risk of [heart attack] seem to rely on complex associations of known and unknown factors.”
Confounding and confusion
Leading HIV researchers John Gill, MD (director of the Southern Alberta HIV Clinic, Calgary, Alberta), and Dominique Costagliola, PhD (Sorbonne Universités, Paris), note that observational studies of cardiovascular risk often have not taken into account the “very high use of tobacco smoking in the HIV population.”
Many studies among HIV-negative people have found that smoking tobacco greatly increases the risk for heart attack. By not collecting sufficient data about the use of this substance among HIV-positive people, observational studies may have inadvertently arrived at flawed conclusions about the cause of cardiovascular risk in this population.
Now two observational studies attempt to cast light on the risk of heart attacks among HIV-positive people today.
Dr. Rasmussen and colleagues compared data collected from about 3,000 HIV-positive people and 13,000 HIV-negative people. Their analysis found that HIV-positive people who never smoked tobacco had no increased risk for a heart attack. However, current smokers had a very large risk—about three-fold greater than HIV-negative people—for a heart attack. The Danish researchers estimated that if HIV-positive people in their study who smoked tobacco quit, 42% of heart attacks could be avoided.
In the U.S.
An American database operated by the health maintenance organization Kaiser Permanente in California first reported a large increased risk for heart attacks among HIV-positive people nearly 15 years ago. In their most recent analysis, the Kaiser researchers compared data from 25,000 HIV-positive people and 258,000 HIV-negative people. They found that particularly since 2010, HIV-positive people in the Kaiser database were no longer at elevated risk for a heart attack, in part because of declining rates of smoking and likely better control of blood pressure and cholesterol levels through medication.
If the life-extending benefits of ART are to be fully realized, more must be done to bolster the health of HIV-positive people in the 21st century. After reviewing the Danish results, researchers Gill and Costagliola encourage the movement to better health by urging doctors, nurses and pharmacists to do the following:
“Seizing every opportunity during HIV care delivery to focus our efforts to reduce the high rate of tobacco smoking offers the greatest potential for reducing [rates of heart attacks].” Furthermore, they added: “Encouragement and support for our patients in their efforts to stop smoking offers immense health benefits.”
Upcoming CATIE News stories will explore the Danish and American studies.
—Sean R. Hosein
- Gill MJ, Costagliola D. Myocardial infarction in HIV-infected persons: Time to focus on the silent elephant in the room? Clinical Infectious Diseases. 2015; in press.
- Klein DB, Leyden WA, Xu L, et al. Declining relative risk for myocardial infarction among HIV-positive compared with HIV-negative individuals with access to care. Clinical Infectious Diseases. 2015; in press.
- Rasmussen LD, Helleberg M, May M, et al. Myocardial infarction among Danish HIV-infected individuals: Population attributable fractions associated with smoking. Clinical Infectious Diseases. 2015; in press.
- Lohse N, Hansen AB, Pedersen G, et al. Survival of persons with and without HIV infection in Denmark, 1995-2005. Annals of Internal Medicine. 2007 Jan 16;146(2):87-95.
- Samji H, Cescon A, Hogg RS, et al. Closing the gap: increases in life expectancy among treated HIV-positive individuals in the United States and Canada. PLoS One. 2013 Dec 18;8(12):e81355.
- May MT, Gompels M, Delpech V, et al. Impact on life expectancy of HIV-1 positive individuals of CD4+ cell count and viral load response to antiretroviral therapy. AIDS. 2014 May 15;28(8):1193-202.
- Lohse N, Gerstoft J, Kronborg G, et al. Comorbidity acquired before HIV diagnosis and mortality in persons infected and uninfected with HIV: a Danish population-based cohort study. Journal of Acquired Immune Deficiency Syndromes. 2011 Aug 1;57(4):334-9.
- Riddler SA, Smit E, Cole SR, et al. Impact of HIV infection and HAART on serum lipids in men. JAMA. 2003 Jun 11;289(22):2978-82.
- Rotger M, Glass TR, Junier T, et al. Contribution of genetic background, traditional risk factors, and HIV-related factors to coronary artery disease events in HIV-positive persons. Clinical Infectious Diseases. 2013 Jul;57(1):112-21.
- Post WS, Budoff M, Kingsley L, et al. Associations between HIV infection and subclinical coronary atherosclerosis. Annals of Internal Medicine. 2014 Apr 1;160(7):458-67.
- Tron L, Lert F, Spire B, et al. Tobacco smoking in HIV-infected versus general population in France: heterogeneity across the various groups of people living with HIV. PLoS One. 2014 Sep 9;9(9):e107451.
- D:A:D Study Group, Sabin CA, Worm SW, Weber R, et al. Use of nucleoside reverse transcriptase inhibitors and risk of myocardial infarction in HIV-infected patients enrolled in the D:A:D study: a multi-cohort collaboration. Lancet. 2008 Apr 26;371(9622):1417-26.
- Obel N, Farkas DK, Kronborg G, et al. Abacavir and risk of myocardial infarction in HIV-infected patients on highly active antiretroviral therapy: a population-based nationwide cohort study. HIV Medicine. 2010 Feb;11(2):130-6.
- Ding X, Andraca-Carrera E, Cooper C, et al. No association of abacavir use with myocardial infarction: findings of an FDA meta-analysis. Journal of Acquired Immune Deficiency Syndromes. 2012 Dec 1;61(4):441-7.
- Costagliola D, Lang S, Mary-Krause M, et al. Abacavir and cardiovascular risk: reviewing the evidence. Current HIV/AIDS Reports. 2010 Aug;7(3):127-33.
- Lang S, Mary-Krause M, Cotte L, et al. Impact of individual antiretroviral drugs on the risk of myocardial infarction in human immunodeficiency virus-infected patients: a case-control study nested within the French Hospital Database on HIV ANRS cohort CO4. Archives of Internal Medicine. 2010 Jul 26;170(14):1228-38.
- Lichtner M, Cicconi P, Vita S, et al. Cytomegalovirus coinfection is associated with an increased risk of severe non-AIDS-defining events in a large cohort of HIV-infected patients. Journal of Infectious Diseases. 2015 Jan 15;211(2):178-86.
- Klein D, Hurley LB, Quesenberry CP, et al. Do protease inhibitors increase the risk for coronary heart disease in patients with HIV-1 infection? Journal of Acquired Immune Deficiency Sydnromes. 2002 Aug 15;30(5):471-7.