Traditional Cardiovascular Risk Factors Strongly Predict Likelihood of Myocardial Infarction in People with HIV

		SUMMARY: Traditional risk factors are major contributors to the elevated risk of myocardial infarction, or heart attack, observed in many studies of people with HIV. In an analysis of the French ANRS CO4 cohort presented last month at the 12th European AIDS Conference (EACS 2009), investigators found that smoking, high blood pressure, and elevated blood cholesterol and glucose were all independent MI predictors. But cocaine and injection drug use also raised the risk, as did HIV viral load over 50 copies/mL and low CD4/CD8 ratio.

By Liz Highleyman

Dominique Costagliola and colleagues described results from a nested case-control analysis from ANRS C04, one of the studies that have contributed to the pool of data suggesting that recent use of abacavir (Ziagen, also in the Epzicom and Trizivir coformulations) may be associated with an increased risk of heart attacks. However, further analysis suggested that confounding factors might explain the apparent link.

In the present study, the researchers devised mathematical models to show how various HIV-related factors and traditional cardiovascular risk factors -- such as male sex, older age, family history, smoking, hypertension (high blood pressure), blood lipid abnormalities, and elevated blood glucose or diabetes -- influence risk of myocardial infarction (MI).

Myocardial infarction, commonly known as a heart attack, occurs when the blood supply to part of the heart is interrupted causing some heart cells to die.

They hypothesized that the impact of traditional risk factors may be different in HIV positive people compared with the general population, and that ongoing viral replication also seems to play a role due, perhaps related to its association with inflammation or metabolic abnormalities.

The analysis included 289 case patients who experienced a first myocardial infarction between January 2000 and December 2006, and 884 sex- and age-matched control patients who did not have heart attacks, all selected from among 74,958 HIV positive individuals in the French Hospital Database on HIV. Most participants (about 90%) were men, the average age was about 47 years, nearly three-quarters were tobacco smokers, and 13% used cocaine or injection drugs.

Case and control patients were classified into groups according to whether they had available data about CD4/CD8 T-cell ratios, HIV viral load, high-density lipoprotein (HDL) levels, cocaine and injection drug use, and traditional cardiovascular risk factors. HDL -- known as "good" cholesterol -- is a protective factor against cardiovascular disease. Complete data, except for family history, were available for 252 case patients and 744 control patients.

Results

	" In the first multifactorial model, the following factors were found to be significant independent predictors of MI:
	Each traditional risk factor: odds ratio (OR) 2.3 -- or just over twice the risk -- for the overall population and 1.6 for the group with complete data (both P < 0.001); Cocaine or injection drug use: OR 1.6 (P = 0.088) and 1.5 (P = 0.040), respectively; Viral load > 50 copies/mL: OR 1.3 (P = 0.092) and 1.4 (P = 0.015), respectively. CD4/CD8 ratio: OR 0.5 -- or half the risk -- per unit (P = 0.005) and 0.6 per unit (P = 0.014), respectively;
	Current and nadir (lowest-ever) CD4 count, however, were not significant risk factors, nor was a diagnosis of AIDS.
	In the second model, which looked at each individual risk factor separately, the following were determined to be significant MI predictors:
	Smoking: OR 4.1 -- or 4 times the risk -- for the overall population and 4.8 for the complete data population (both P < 0.001); Elevated cholesterol: OR 2.5 for both populations (both P < 0.001); Cocaine or injection drug use: OR 1.8 (P = 0.043) and 1.7 (P = 0.100), respectively; Hypertension: OR 1.7 for both populations (P = 0.024 and 0.042, respectively); Elevated glucose (>5.45 mmol/L): OR 1.6 for both populations (P = 0.042 and 0.058, respectively); HIV RNA > 50 copies/mL: OR 1.4 (P = 0.068) and 1.6 (P = 0.025), respectively. CD4/CD8: OR 0.5 per unit (P = 0.012) and 0.6 per unit (P = 0.060), respectively; in the complete population Missing family history data: OR 0.3 for both populations (both P < 0.001).

Based on these findings, the investigators concluded, "The traditional cardiovascular risk factors are very strong risk factors of MI in HIV-infected patients."

"Cocaine and IV drug use is a risk factor of MI in HIV-infected patients," they continued. "The role of HIV parameters must also be accounted for," including viral load and CD4/CD8 ratio, which may reflect inflammation better than CD4 count.

Finally, they recommended, "Family history of premature coronary artery disease should be better collected in routine practice."

12/1/09

Reference
S Lang, M Mary-Krause, L Cotte, D Costagliola, and others. Impact of traditional cardiovascular risk factors and HIV parameters on the risk of myocardial infarction: a case-control study nested within NHDH ANRS CO4. 12th European AIDS Conference (EACS 2009). Cologne, Germany. November 11-13, 2009. Abstract PS11/2.