[The prognostic value of free triiodothyronine/free thyroxine ratio in patients hospitalized with heart failure].

ABSTRACT

Objective: To investigate the effect of free triiodothyronine/free thyroxine (FT3/FT4) ratio on the prognosis of patients with heart failure (HF). Methods: A total of 3 527 patients hospitalized in the Heart Failure Center of Fuwai Hospital from March 2009 to June 2018 were analyzed in our study. Patients were divided into two groups according to median of FT3/FT4 ratio low FT3/FT4 group (n=1 764, FT3/FT4<2.15) and high FT3/FT4 group (n=1 763, FT3/FT4≥2.15). The primary endpoint was defined as a composite endpoint of all-cause death or heart transplantation or implantation of a left ventricular assist device. The baseline characteristics of patients with different FT3/FT4 ratio groups were compared, and a multivariate Cox proportional hazard regression model was used to analyze the relationship between FT3/FT4 ratio and the prognosis of hospitalized patients with HF. Results: The age of the total population was (56.8±16.0) years, and 2 544 cases (72.1%) were males. The median follow-up time was 2.79 (1.00, 5.03) years, and a total of 1 542 end-point events were recorded at the final follow-up. The mean ages of patients in the low FT3/FT4 group and high FT3/FT4 group were (58.8±16.5) and (54.8±15.2) years (P<0.001), respectively; and the cumulative survival rates were 38.4% and 61.9%, respectively (P<0.001). FT3 (HR=0.72, 95%CI 0.63-0.84, P<0.001), FT3/FT4 (HR=0.76, 95%CI 0.65-0.87, P<0.001) was associated with all-cause death, heart transplantation, or LVAD implantation in patients with heart failure. HR values (95%CI) of FT3/FT4 ratio predicting the risk of composite endpoint in the subgroup of left ventricular ejection fraction (LVEF)<40%, 40% to 49%, and≥50% were 0.91 (0.77-1.08), 0.83 (0.50-1.39), and 0.65 (0.50-0.85), respectively (P interaction=0.045). Conclusions: Low FT3 and low FT3/FT4 are important correlative factors for poor prognosis in hospitalized HF patients, especially in patients with LVEF≥50%.