The Association Between Non-Clinically Apparent Liver Fibrosis and Pulmonary Arterial Hypertension in Hispanic Patients

Abstract

Background: Pulmonary arterial hypertension (PAH) is a deadly cardiopulmonary disease with multi-organ involvement including impaired liver function. Liver dysfunction in PAH is poorly understood but significantly associated with morbidity and mortality. Hispanics have a significantly higher prevalence of non-alcoholic fatty liver disease (NAFLD) and evidence of more advanced disease in comparison to other ethnic groups. The clinical impact of NAFLD in Hispanic PAH patients is unknown. We aimed to investigate the impact of a validated scoring system, non-alcoholic fatty liver disease fibrosis score (NFS), to predict the degree of liver fibrosis in a Hispanic PAH population and its relationship to hemodynamics, functional class, and outcomes.

Methods: A retrospective review of all treatment-naive Hispanic patients with group I World Health Organization (WHO) pulmonary hypertension (PH) at a single academic center between February 2016 and March 2021 was performed. Patients with history of substance or alcohol abuse, non-group I WHO PH, pre-existent liver disease, chronic kidney disease, atrial fibrillation, thyroid disease, and warfarin use were excluded from the study. The diagnosis of group I WHO PH was determined by cardiac catheterization after the exclusion of other etiologies. NFS was calculated for each patient and correlated with functional capacity, hemodynamics, N-terminal-pro-B-type natriuretic peptide (NT-proBNP), and survival.

Results: A total of 96 Hispanic patients were included in our study. The median age of patients in our cohort was 49 years (interquartile range: 15) and 69% of our cohort were females. Higher NFSs indicating advanced hepatic fibrosis (F3-F4) were found to correlate with elevated right-sided cardiac filling pressures (r = 0.27, P = 0.03), elevated levels of NT-proBNP (r = 0.32, P = 0.01), lower 6-minute walk distance (6MWD) (r = -0.49, P = 0.001), lower functional capacity (World Health Organization functional class, WHO-FC, r = -0.35, P = 0.051), a higher prevalence of diabetes (21.1% versus 51.9%, P = 0.001), a higher prevalence of risk factors for metabolic syndrome (81.5% versus 65.0%, P = 0.035), and worse 5-year survival rates.

Conclusion: In Hispanic patients with PAH, NFSs correlate with the degree of right-sided pressure overload. In addition, advanced NFSs were independently associated with lower 5-year survival rates and added prognostic information to other established risk parameters in PAH. This study suggests that screening for liver disease in this vulnerable patient population can aid in earlier detection leading to discussion of lifestyle modifications and possible escalation of PAH-targeted therapies, thus leading to potential improvement in survival rates.

Keywords: Liver fibrosis; Non-alcoholic fatty liver disease fibrosis score; Non-invasive assessment; Pulmonary arterial hypertension.

Figure 1

Flow diagram of patient selection.

Figure 2

Kaplan-Meier analysis according to low and advanced fibrosis scores.