Low alanine aminotransferase levels are independently associated with mortality risk in patients with atrial fibrillation

Extremely low alanine aminotransferase (ALT) may reflect aging, frailty, sarcopenia, and malnutrition in several cardiovascular diseases, but the association between low ALT and patient characteristics, cardiovascular and all-cause mortality is not well investigated in the population with atrial fibrillation. We conducted a post hoc analysis of a prospective, observational multicenter study. Patients with nonvalvular AF in the SAKURA AF Registry (n = 3156) were classified into 3 tertiles according to baseline ALT: first (ALT ≤ 15 U/L, n = 1098), second (15 < ALT < 23 U/L, n = 1055), and third (ALT ≥ 23 U/L, n = 1003). The first tertile had an older age; lower body mass index (BMI); higher prevalence of heart failure; and lower hemoglobin, total cholesterol, and triglycerides (all P < 0.05). During median 39.2 months follow-up, the first tertile had significantly higher incidences of cardiovascular and all-cause mortality (log-rank P < 0.001). Lower ALT was significantly associated with the incidence of cardiovascular and all-cause mortality, even after adjusting for clinically relevant factors (P < 0.05). Low ALT may reflect aging, sarcopenia, and malnutrition and be independently associated with a high risk of all-cause mortality in patients with AF.