Smoking Lowers Risk of Cardiovascular Disease in People with HIV
Cigarette smoking was associated with a significantly higher
rate of cardiovascular disease among people
with HIV, but the risk began to decline after quitting
and continued to fall over time, researchers reported at the
17th Conference on Retroviruses & Opportunistic Infections
(CROI 2010) last week in San Francisco.
A similar pattern was not seen for overall mortality, however.
people with HIV live longer thanks to effective antiretroviral
therapy (ART), they are at increased risk for a host of chronic
non-AIDS conditions including cardiovascular disease and cancer.
While ongoing HIV replication, immune activation, and ART all contribute
in ways that are not fully understood, modifiable lifestyle factors
such as smoking also play a large role. Numerous studies have found
that HIV positive people are more
likely to smoke than their HIV negative counterparts.
(Photo by Liz Highleyman)
has shown that the risk of coronary artery disease falls within 1-2
years after smoking cessation in HIV negative people. Kathy Petoumenos
and fellow investigators with the D:A:D cohort designed a study to see
if rates of cardiovascular disease and death would also decrease for
HIV positive people who quit.
(Data Collection on Adverse events of Anti-HIV Drugs) is a large, ongoing
observational study with 33,308 HIV positive participants in the U.S.,
Europe, and Australia. The researchers divided the participants into
groups according to smoking status: 36% were current smokers, 27% had
never smoked, and 19% were former smokers. In addition, one-quarter
(8197 individuals) said they quit after entering the study. (There was
not enough data to evaluate smokers based on packs per day or number
of years smoking.)
(about 75%) were men, about half were white, and the average age was
about 40 years. There were more injection drug users in the current
and ex-smoker groups (32% and 18%, respectively) compared with the never-smokers
(5%). Most were on combination ART, with an average duration of about
1.5 years; more than 60% had HIV viral load < 50 copies/mL and the
median CD4 cell count was approximately 450 cells/mm3.
in the different smoking status groups were similar with regard to other
traditional cardiovascular risk factors including body weight (generally
normal, with an average BMI of about 23), blood pressure (again normal),
and blood lipid levels.
The researchers looked at clinical outcomes including myocardial infarction
(MI, or heart attack), coronary heart disease (MIs plus invasive coronary
artery procedures or death from other coronary heart disease), cardiovascular
disease (a broader category including coronary heart disease plus carotid
artery endarterectomy or stroke), and deaths due to all causes. They
determined event rates for the different smoking status groups and compared
them to derive incidence rate ratios (IRRs).
smokers had more than 3 times the risk for MIs (IRR 3.4) and ex-smokers
approached 2 times the risk (IRR 1.73) compared with people who
participants who quit smoking during follow-up, excess MI risk decreased
from 3.73-fold higher during the first non-smoking year, to 3.00-fold
after 1-2 years, to 2.62-fold after 2-3 years, and finally to 2.07-fold
after more than 3 years without smoking.
coronary heart disease, current smokers had about a 2.5-fold risk
(IRR 2.48) and ex-smokers a 1.6-fold risk (IRR 1.60) compared with
people who never smoked.
participants who quit, excess coronary heart disease risk decreased
from 2.93-fold higher during the first non-smoking year, to 2.48-fold
after 1-2 years, 1.90-fold after 2-3 years, and 1.83-fold after
more than 3 years.
at cardiovascular disease overall, current smokers had 2.19-fold
higher risk relative to non-smokers, and ex-smokers had a 1.38-fold
excess risk declined steadily among people who quit during the study,
from 2.32-fold higher during the first year, to 1.84-fold after
1-2 years, 1.60-fold after 2-3 years, and 1.49-fold after more than
all-cause mortality, however, the pattern was somewhat different.
The risk of death was 1.28 higher among current smokers, but former
smokers had essentially the same risk as people who never smoked
people who quit smoking during the study, the excess risk of death
did not decline consistently over time (from 1.67-fold higher during
the first year to 1.02-fold after 1-2 years, 1.34-fold after 2-3
years, and 1.30-fold after more than 3 years).
similar inconsistent pattern was also see when the analysis was
restricted to deaths of people older than 50 years.
who never smoked were more likely to die form HIV/AIDS-related causes,
while current and previous smokers were more likely to have other
causes of death including cardiovascular disease and non-AIDS malignancies.
on these findings, the researchers concluded, "The risk of cardiovascular
disease events in HIV-positive patients decreased with increasing time
since stopping smoking." However, they added, "we did not
see this in terms of mortality."
Another study presented at CROI found
that people with HIV had a higher rate of lung cancer, and smoking was
by far the strongest risk factor. After 8 years of follow-up -- more
than twice as long as this D:A:D analysis -- ex-smokers still had a
5-fold greater lung cancer risk.
"Smoking cessation efforts should be a priority in the management
of HIV-positive patients," the D:A:D investigators recommended.
"Further research is needed regarding smoking cessation in this
National Center in HIV Epidemiology and Clinical Research, University
of New South Wales, Sydney, Australia; Copenhagen HIV Program, Hvidovre
University Hospital, Copenhagen, Denmark; HIV Monitoring Foundation,
Academic Medical Center, Amsterdam, Netherlands; Ctr Hosp Univ Saint-Pierre,
Brussels, Belgium; ICONA, Azienda Ospedaliera-Polo Univ San Paolo, Milan,
Italy; Univ Hosp Zurich, Switzerland; INSERM E0338 and U593, Univ Victor
Segalen Bordeaux, France; Ctr Hosp Univ Nice, Hosp de l'Archet, France.
Petoumenos, S Worm, P Reiss, and others (D:A:D Study Group. Rates of
Cardiovascular Disease Following Smoking Cessation in Patients with
HIV Infection: Results from the D:A:D Study. 17th Conference on Retroviruses
& Opportunistic Infections (CROI 2010). San Francisco. February
16-19, 2010. Abstract 124.