Fatty liver disease associated with cardiovascular risk in patients with HIV

Hardening of the arteries is common in HIV-positive patients, and is associated with fatty liver disease, US investigators report in the online edition of HIV Medicine.

“HIV-infected persons with fatty liver disease may warrant early cardiovascular assessment and institution of risk reduction methods,” comment the researchers.

Cardiovascular disease is an increasingly important cause of illness and death in patients with HIV. Studies conducted in HIV-negative individuals have shown that the presence of a fatty liver is associated with hardening of the coronary artery (atherosclerosis), an important risk factor for heart disease.

A team of investigators lead by Dr Nancy Crum-Cianflone wished to see if this was also the case for HIV-infected individuals.

They write: “Given that liver test abnormalities and fatty liver disease are common in among HIV infected persons, determining their relationship with coronary artery atherosclerosis may be helpful in the development of screening guidelines and risk stratification for underlying cardiovascular risk in this population.”

Between 2008 and 2010 they undertook a cross sectional study involving 223 HIV-positive adults. All the patients had a CT scan which checked for hardening, or calcification, of the coronary artery and fatty liver disease.

Atherosclerosis in the coronary artery was diagnosed if any calcification was detected (a score above 0), and a score above 100 was considered clinically significant. Fatty liver was defined as a liver-to-spleen ratio < 0.1.

Information was also gathered on the patients’ demographics, CD4 cell count and viral load, use of antiretroviral drugs, lipid levels, and medical histories. A series of statistical analyses were then performed to see which factors were associated with hardening of the coronary artery.

With a median age of 43 years (range 36-50), the patients were relatively young. Risk factors for cardiovascular disease were common, and 39% had hypertension and 6% diabetes. Fatty liver can be a complication of viral hepatitis, but only 3% of the study population were co-infected with hepatitis C.

Most patients (83%) were taking antiretroviral therapy, 70% had an undetectable viral load and median CD4 cell count was 586 cells/mm³.

CT scanning showed that 34% of individuals had some hardening of the coronary artery, and that this was clinically significant for 8% of patients. Fatty liver was diagnosed in 13% of individuals.

Prevalence of fatty liver for patients with no evidence of hardening of the coronary artery was 8%. But this increased to 18% for individuals with a calcification score between 1-100, and was 41% for patients with clinically significant arterial hardening.

Overall, 59% of patients with fatty liver also had coronary atherosclerosis, and the correlation between the two conditions was significant (p = 0.02).

Statistical analysis that controlled for potentially confounding factors showed that three factors were significantly associated with calcification of the coronary artery: older age (each ten year increase, p < 0.01); fatty liver disease (p < 0.01), and hypertension (p < 0.01).

The relationship between hardening of the coronary artery and fatty liver disease was extremely robust, and was unaltered when the investigators excluded the small number of patients with hepatitis C, or those with metabolic syndrome. It was also present when patients with alcohol use were excluded from analysis.

“In our study, HIV-infected persons, despite their relatively young age, had a high prevalence of subclinical heart disease,” write the authors. They believe their results “emphasize the importance of cardiovascular disease among HIV-infected patients and suggest that addressing underlying heart disease may be an important component of further normalizing the life expectancy of this group.”

Inflammation could, the authors believe, be causing both the hardening of the arteries and the fatty liver disease observed in their patients.

Dr Crum-Cianflone and her colleagues conclude: “Fatty liver disease is associated with underlying cardiovascular disease and should be considered as a novel marker for risk stratification among HIV-infected persons.”