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HIV Infection Associated with Increased Risk of Sudden Cardiac Death

People with HIV at a public clinic in San Francisco had a sudden cardiac death rate more than 4 times higher than that of the general population, and most who died had identifiable cardiovascular risk factors, according to a study described in the May 22, 2012, Journal of the American College of Cardiology.

Several observational studies have found that HIV positive people have higher rates of cardiovascular disease and related events such as heart attacks and strokes, but it is not yet clear whether this is due to HIV infection itself, resulting immune activation and inflammation, side effects of antiretroviral drugs, traditional risk factors, or some combination of causes.

Zian Tseng from the University of California at San Francisco and colleagues conducted a study to determine the incidence and clinical characteristics of sudden cardiac death among patients seen at a public HIV clinic in San Francisco.

This retrospective analysis looked at medical records of 2860 consecutive adult HIV clinic patients seen between April 2000 and August 2009. The researchers analyzed the number of deaths, causes of death, and patients' clinical characteristics.

The patient profile was characteristic of the city's HIV/AIDS epidemic. Most (87%) were men, about half were white, and the median age was 39 years. Among those with known HIV risk factors, 72% were men who have sex with men, 21% were at risk through heterosexual sex, and 7% were injection drug users. At entry to care the median CD4 T-cell count was 353 cells/mm³, the median HIV viral load was 4.1 copies/mL, and 21% had undetectable HIV RNA indicating successful antiretroviral therapy.

Results

·       A total of 230 deaths occurred over a median follow-up period of 3.7 years:

o      30 (13%) due to sudden cardiac death;

o      131 (57%) due to AIDS;

o      25 (11%) due to other diseases or natural causes;

o      44 (19%) due to drug overdose, suicide, or unknown causes.

·       Sudden cardiac death accounted for 86% of all cardiac deaths.

·       The mean sudden cardiac death rate was 2.6 per 1000 person-years, 4.5-fold higher than the expected rate in the general population (standardized mortality ratio 4.46).

·       Patients with sudden cardiac death were, on average, significantly older than those who died of AIDS (mean 49.0 vs 44.9 years, respectively) and had a higher median CD4 count (312 vs 87 cells/mm³) and lower median viral load (3.8 vs. 4.8 copies/mL).

·       Most patients with sudden cardiac death -- 80% -- had known cardiovascular risk factors:

o      More than half reported current or past tobacco, excessive alcohol, or illicit drug use;

o      17% had a family history of cardiovascular disease;

o      33% reported chest pain, palpitations, syncope (fainting), or dyspnea (shortness of breath) at their final clinic visit;

o      83% were prescribed cardiac medications.

·       People with sudden cardiac death had a much higher likelihood of prior cardiac events than those who died of AIDS or other natural causes:

o      Myocardial infarction (heart attack): 17% vs 1%, respectively;

o      Cardiomyopathy (heart muscle damage): 23% vs 3%;

o      Heart failure: 30% vs. 9%:

o      Cardiac arrhythmias (abnormal heart rhythm): 20% vs. 3%.

o      Hypertension (high blood pressure): 67% vs 27%;

o      Abnormal blood lipids: 20% vs 6%.

"Sudden cardiac deaths account for most cardiac and many non-AIDS natural deaths in HIV-infected patients," the study authors concluded. "Further investigation is needed to ascertain underlying mechanisms, which may include inflammation, antiretroviral therapy interruption, and concomitant medications." 

"We found that sudden cardiac deaths constituted an unexpectedly high proportion of overall deaths in this urban HIV cohort, with most cardiac deaths presenting suddenly," they elaborated in their discussion. "Sudden cardiac death occurred at a rate more than 4 times expected in the general population, with similar risk factors."

Given that prior cardiovascular symptoms were common among people who experienced sudden cardiac death, they recommended that, "aggressive primary prevention of cardiovascular disease should be considered in HIV-infected patients, especially those with traditional risk factors."

5/15/12

Reference

ZH Tseng, EA Secemsky, D Dowdy, P Hsue, et al. Sudden Cardiac Death in Patients With Human Immunodeficiency Virus Infection. Journal of the American College of Cardiology 59(21):1891-1896. May 22, 2012.