Reposted at
http://www.keystotheclosetblogspot.com
Anyone else read the recent publication "Mortality
attributable to smoking among HIV-1-infected individuals" in Clinical
Infectious Disease?
A summary from AIDSmap.com is included at the bottom for
those without academic journal access.
The main figure: Number of Life-Years Lost:
HIV among never smokers: 5.1
(never smoking HIV patients vs never smoking controls)
Smoking among controls: 3.6
(comparing smoking HIV-neg to never smoking HIV-neg)
Smoking among HIV patients: 12.3
(comparing smoking HIV+ to non-smoking HIV+)
Though
this number is pretty shocking, I find some of the methodology suspect (though
I'm no biostatistician - correct me if I'm wrong).
I don't exactly know how the number of life years
lost due to smoking could be so different for HIV+ and HIV- groups (12.3 YLLs
vs 3.6 YLLs) without an interaction between smoking and HIV (or, alternatively,
a very important confounding variable). But they write: "One might
speculate that smoking could have a synergistic rather than additive
effect on inflammation in HIV-infected individuals, but we found no
interaction between HIV and smoking in the associated risk of death."
Also, look at table 2 - there's such drastic
differences in AIDS related mortality for smokers and nonsmokers (considerably
more than the disparities in cardiovascular disease), and previous smokers are
similar to current smokers rather than non-smokers. To me, this suggests that
there are SES or demographic differences between smokers (past or present) and
non-smokers that this study is not controlling for that impact access to and
retention in care, health behaviors more broadly, etc.
Just wanted to through my 2 cents out there. Interesting
work, and I'm glad its being read and forwarded.
- Sam Bakkila
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Michael Carter
Published: 31 December 2012
Much of the increased mortality seen in patients with HIV can be attributed to
smoking, Danish investigators report in the online edition of Clinical
Infectious Diseases. “The loss of life-years associated with smoking was larger
than that associated with HIV,” write the investigators. The authors believe their
findings have important implications for HIV care, showing the importance of
smoking cessation counselling and support.
Thanks to antiretroviral therapy, the prognosis of many HIV-positive patients
is now excellent. Rates of HIV-related illnesses and deaths have fallen
dramatically since the mid 1990s, meaning that lifestyle-related factors are
now a major cause of morbidity and mortality in HIV-infected individuals.
A number of studies have shown that HIV-positive individuals are more likely to
smoke than their HIV-negative peers. Illnesses that are potentially related to
smoking, such as cardiovascular disease and cancers, are being seen with
increased frequency in HIV-positive patients. The role of smoking and other
potentially modifiable risk factors is currently unclear.
Investigators from Denmark therefore designed a study to evaluate the effect of
smoking on mortality among patients with HIV. They also compared the risk of
death and loss of life-years associated with smoking with the risk associated
with HIV-related factors.
The study population involved 2921 adults who received HIV care between 1995
and 2010. Injecting drug users were excluded from participation. The
HIV-infected patients were matched with 10,642 controls.
Both the patients and the controls were followed for a median of four years.
Among HIV-positive patients, 47% were current smokers, 18% were former smokers
and 35% had never smoked. The corresponding rates for the controls were 21%,
33% and 47%.
The excess mortality rate for HIV-positive current smokers (compared to
HIV-positive patients who had never smoked) was 18 per 1000 patient years. The
corresponding rate for the HIV-negative controls was 5 per 1000 patient years.
The risk of non-HIV-related death was five-fold higher for current smokers
compared to HIV-infected patients who had never smoked. HIV-positive patients
who were current smokers also had a four-fold increase in their risk of
all-cause mortality.
The risk of death due to cardiovascular disease was approximately two times
higher for HIV-positive current smokers compared to HIV-positive non-smokers.
Current smokers were also three times more likely to die of cancer.
Smoking had a significant impact on the life expectancy of HIV-positive
patients.
The authors calculated that 35-year-old non-smokers had a life expectancy of 78
years. This compared to a life expectancy of 69 years for former smokers, and a
life expectancy of just 63 years for current smokers.
“Our finding of lower mortality among previous compared to current smokers
emphasizes the importance of counseling HIV patients onsmoking cessation,”
comment the researchers.
They calculated that the HIV-positive patients lost five years of life
expectancy due to their HIV infection and that twelve life years were lost
because of smoking.
“The loss of life-years associated with smoking was larger than that associated
with HIV,” write the investigators. “HIV-infected smokerswith long-term
engagement in care lose more life-years to smoking than HIV.”
Reference
Helleberg M et al. Mortality attributable to smoking among HIV-1-infected
individuals: a nationwide population-based cohort study. Clin Infect Dis,
online edition. DOI: 10.1093/cid/cis933, 2012.
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Original Page: http://www.aidsmap.com/Smoking-has-a-bigger-impact-on-the-prognosis-of-HIV-positive-patients-than-HIV-related-factors/page/2561382/
