Smoking is the single biggest risk factor
for acute coronary syndrome in HIV-positive adults, Spanish researchers report
in the online edition of HIV Medicine. Smoking was a much more important factor
than diabetes and hypertension combined.
“Future efforts to decrease the burden of
cardiovascular disease should focus on developing widespread and effective
smoking cessation strategies in HIV-positive adults,” comment the authors.
Improvements in HIV treatment and care mean
that many HIV-positive people can expect to live long and healthy lives.
Nevertheless, the life expectancy of people with HIV is often still shorter than
that of HIV-negative individuals. One reason for this is higher rates of
cardiovascular disease seen in those with HIV.
The exact reasons for this increased risk
of cardiovascular risk are controversial.
However, it is likely to be because of a
high prevalence of traditional risk factors, such as smoking, diabetes and
hypertension; the immune damage and inflammation caused by HIV; and the side-effects
of some antiretroviral drugs.
Prevention and detection of cardiovascular disease are now
a priority in routine HIV care. It is therefore important to understand the
contribution of individual factors to the overall risk of cardiovascular
Investigators in Spain designed a
case-controlled study. The study involved people who received
care between 1997 and 2009 in Barcelona.
A total of 57 HIV-positive people with
acute coronary syndrome (an umbrella term for situations when blood supply to
the heart is obstructed due to blocked arteries) were matched with HIV-positive
people without this form of cardiovascular risk. They were also matched with
HIV-negative patients who had similarly been diagnosed with acute coronary
syndrome, and these HIV-negative patients were in turn matched with
HIV-negative people who were not diagnosed with this disorder.
The study enabled the investigators to
identify the risk factors for acute coronary syndrome in HIV-positive and
HIV-negative people and to calculate the risks attributable to specific
factors such as smoking, diabetes, hypertension, family history and elevated
Most (57%) of the participants were men and
their mean age was 53 years.
Traditional risk factors were highly
prevalent in both the HIV-positive and HIV-negative participants who were diagnosed
with acute coronary syndrome.
However, the prevalence of smoking in those
with HIV was almost twice that observed in the HIV-negative participants (72 vs
40%). These HIV-negative individuals were approximately twice as likely as
HIV-positive people to have hypertension (46 vs 25%).
Restricting analysis to the participants with
HIV showed that those with acute coronary syndrome were significantly more
likely to smoke (72 vs 42%, p < 0.001), have a family history of
cardiovascular disease (12 vs 3%, p < 0.02) and to have elevated
cholesterol (39 vs 25%, p 0.04) than those without this form of
cardiovascular disease. HIV-related parameters such as CD4 cell count, viral
load and use of antiretroviral therapy were similar between HIV-infected
participants diagnosed with acute coronary syndrome and HIV-positive people without this diagnosis.
The investigators calculated that smoking
(OR = 4.1; 95% CI, 2.0-8.4, p < 0.001) and family history (OR = 7.6; 95% CI,
1.9-32.1, p = 0.003) were significant risk factors for acute coronary syndrome
in the HIV-positive participants. Diabetes, hypertension and elevated cholesterol
Risk factors for the HIV-negative participants also
included smoking (OR = 4.3; 95% CI, 2.4-7.8, p < 0.001), but unlike
HIV-positive people, diabetes (p = 0.002) and hypertension (p < 0.001)
were also significant whereas family history was not.
Smoking accounted for 54% of the risk of
acute coronary syndrome in the HIV-positive people, almost double the risk
(31%) attributed to this risk factor among HIV-negative participants.
“Of all interventions targeting modifiable
cardiovascular risk factors…stopping smoking is probably the intervention with
the greatest impact,” write the authors. “The Data Collection on Adverse events
of Anti-HIV Drugs (D:A:D) study found that the risk of myocardial infarction and
cardiovascular disease decreased with each passing year of having stopped smoking, and
the risk almost halved after 3 years.”
The investigators also stress the
importance of intervening to address other factors, such as diabetes,
cholesterol and diabetes, even though these made a relatively minor
contribution to the overall risk of acute coronary syndrome in HIV-positive
people. “HIV physicians should…pursue optimal management strategies of these
conditions and targeted prevention and treatment strategies with hard