High Levels of Serum Bile Acids in COVID-19 Patients on Hospital Admission.

Introduction: Bile acids are signaling molecules with immune, metabolic and intestinal microbiota control actions. In high serum concentrations they increase inflammatory response from the liver-gut axis, until causing multiorgan failure and death; therefore, they may be associated with COVID-19's clinical progression, as a consequence of tissue and metabolic damage caused by SARS-CoV-2. While this topic is of considerable clinical interest, to our knowledge, it has not been studied in Cuba.

Objective: Study and preliminarily characterize patients admitted with a diagnosis of COVID-19 and high levels of serum bile acids.

Methods: A preliminary exploratory study was carried out with descriptive statistical techniques in 28 COVID-19 patients (17 women, 11 men; aged 19-92 years) who exhibited high levels of serum bile acids (≥10.1 µmol/L) on admission to the Dr. Luis Díaz Soto Central Military Hospital in Havana, Cuba, from September through November 2021.

Results: On admission patients presented hypocholesterolemia (13/28; 46.4%), hyperglycemia (12/28; 43.0%) and hyper gamma-glutamyl transpeptidase (23/28; 84.2%). Median blood glucose (5.8 mmol/L) and cholesterol (4.1 mmol/L) were within normal ranges (3.2‒6.2 mmol/L and 3.9‒5.2 mmol/L, respectively). Severe or critical stage was the most frequent (13/28) and median serum bile acids (31.6 µmol/L) and gamma-glutamyl transferase (108.6 U/L) averaged well above their respective normal ranges (serum bile acids: 0‒10 µmol/L; GGT: 9‒36 U/L). Arterial hypertension was the most frequent comorbidity (19/28; 67.9%).

Conclusions: Severe or critical stage predominated, with serum bile acids and gamma-glutamyl transferase blood levels above normal ranges. The study suggests that serum bile acid is toxic at levels ≥10.1 µmol/L, and at such levels is involved in the inflammatory process and in progression to severe and critical clinical stages of the disease. In turn, this indicates the importance of monitoring bile acid homeostasis in hospitalized COVID-19 patients and including control of its toxicity in treatment protocols.