Canadian study shows increased interventional cardiovascular procedures associated with HAART
Sean R Hosein, CATIE
In high-income countries, the availability of highly active antiretroviral therapy (HAART) has greatly decreased the risk of illness from AIDS-related complications. Although HAART can prolong life, it is not a cure. HAART also can have side effects; in some cases, users develop increased levels of fatty substances or lipids (cholesterol and triglycerides) and sugar in the blood. In theory, these changes increase the risk of developing cardiovascular disease (CVD)—heart attacks, strokes and other complications.
Certainly if similar changes occurred in HIV negative people, they would have the same effect. But what exactly is the risk of severe CVD in HAART-users? To try to answer this question researcher Paula Braitstein and colleagues in Vancouver, British Columbia, conducted a study. According to their results, about 1% of users of anti-HIV therapy in that province needed surgery for CVD between the years 1995 and 2000.
Types of surgery
Researchers in Vancouver (including the British Columbia Centre for Excellence in HIV/AIDS) reviewed information in large databases on people with HIV/AIDS (PHAs) who had required surgery for CVD. The analysis of information focused between the years 1995 and 2000. During this time, the database of PHAs on therapy contained information on 5,082 people. Of these 5,082 PHAs, only 1% (63) was also registered in provincial cardiac registries during the same years. These 63 PHAs required the following procedures:
- 30 – open heart surgery
- 31 – coronary angioplasty (unclogging of the arteries)
- 36 – diagnostic coronary catheterisations (this involves sticking a thin tube into a vein to the heart and injecting dyes that appear on X-ray pictures that help doctors see clogged blood vessels and how well the heart works)
Among PHAs using HAART, at least half of these procedures occurred since 1999.
Over time and taking age into account, there was a trend for a steep increase in cardiac surgery after 1997 among PHAs. In contrast, among HIV negative people in British Columbia, the trend for cardiac surgery was generally stable, although there was an increase in the year 2000.
In PHAs, factors that were linked to having cardiac surgery included the following:
- Being older at the beginning of the study: for instance, PHAs who were 45 years old were at significantly greater risk of having CVD surgery than PHAs who were 37.
- Longer time on therapy: PHAs who were on therapy for an average of 4.5 years were significantly more likely to have CVD surgery than PHAs who had been on therapy for three years.
Other factors, such as gender, CD4+ cell count, viral load, number of drugs in an initial regimen, HIV risk group and adherence had no relation to the risk of CVD surgery.
The results of this study support the idea that use of HAART may increase the risk of CVD in some PHAs. Bear in mind that the risk of cardiac surgery (and severe CVD) was low in this study — about 1%. These results also support the fact that the benefits of HAART outweigh the risks.
The Vancouver study would have been strengthened if the researchers had been able to collect information on whether or not recipients of surgery were tobacco smokers or had family members who also had CVD, both of which increase the risk of CVD.
Although the study found a sharply increasing trend for cardiac surgery among PHAs since 1997, this trend may not continue indefinitely. As PHAs and their doctors become more aware of the risks of CVD, they may make use of strategies to help reduce their CVD risk, including dietary changes, regular exercise, programmes for quitting smoking and use of lipid-lowering drugs.
Braitstein P, Yip B, Heath KV, et al. Interventional cardiovascular procedures among HIV-infected individuals on antiretroviral therapy 1995 – 2000. AIDS 2003;17;2071-2075.
Copyright 2003 – CATIE Treatment Update. Reproduced with permission. Reproduction of this article (other than one copy for personal reference) must be cleared through the Editor, The Community AIDS Treatment Information Exchange, Suite 420 – 517 College Street, Toronto, On M6G 4A2 Canada http://www.catie.ca