Spotlight on nonalcoholic fatty liver disease and cardiac risk

Two studies published in August looked at associations between nonalcoholic fatty liver disease (NAFLD) and cardiovascular disease (CVD).

The first study, published in the August issue of Obesity, focused on a retrospective cohort of 65 patients with no known heart disease and recent transthoracic echocardiography who were undergoing elective bariatric surgery with perioperative liver biopsy. Fourteen of the patients (22%) were found to have nonalcoholic steatohepatitis (NASH). Those with NASH had significantly increased left atrial volume and left ventricular mass and worse results on markers of diastolic function.

The associations remained after adjustment, leading the study authors to conclude that NASH was associated with changes in myocardial structure and load-dependent indices of left ventricular diastolic function, suggestive of subclinical heart failure (HF). “Additionally, our results highlight the potential clinical utility of echocardiography for assessing NAFLD-related HF risk. If validated, early cardiac abnormalities could serve as predictive biomarkers of HF risk, allowing providers to accurately identify NAFLD patients most likely to benefit from personalized interventions,” they wrote.

The study was limited by its very small, selected patient sample and retrospective design, the authors noted. These limitations should “temper enthusiasm for the study findings,” according to an accompanying commentary, which cautioned that “neither temporal nor causal relationships can be inferred.” The study was also limited by not having measurements of cardiac hemodynamics, which future prospective studies of the topic should include, the commentary said.

The other study, published online by Gastroenterology on Aug. 9, looked at associations between CVD and alcohol use in patients with NAFLD. Researchers used data from the Coronary Artery Risk Development in Young Adults longitudinal cohort study. Of the 570 patients with NAFLD, 58% were drinkers (defined as men who reported drinking 1 to 21 drinks per week or women who reported drinking 1 to 14 drinks per week). Compared to patients who reported no alcohol use, higher proportions of the drinkers had obesity, diabetes, and metabolic syndrome. However, there was no difference in liver attenuation between the groups, and after multivariable adjustment, there was no association between alcohol use and CVD risk factors (diabetes, hypertension, hyperlipidemia) or subclinical CVD measures (coronary artery calcification, E/A ratio, global longitudinal strain).

The results show that, in contrast to findings in the general population, alcohol use may not reduce the risk of CVD in patients with NAFLD, the study authors concluded. They noted that associations between moderate alcohol use and demographic and lifestyle factors like socioeconomic status and physical activity were similar in patients with and without NAFLD, and adjustment for these factors canceled out any evidence of reduced CVD risk with alcohol use, “suggesting that better overall health may account for the observed ‘protective’ effect of alcohol intake in the NAFLD population.” Based on these results, “a recommendation of CVD risk benefit of alcohol use in persons with NAFLD cannot be made.”