Background: Hypothyroidism and low T3 syndrome frequently occur in HF patients.
Aim of the study: To evaluate in a large sample of CHF patients the association between thyroid hormone deficiencies and poor outcome.
Methods and results: From 2006 to 2015, we screened 712 consecutive CHF outpatients (551 males, 64±14 years, left ventricular ejection fraction (LVEF) 33±10%, NYHA class 2.3±0.6, NTproBNP 2153±4696 pg/ml, GFR-EPI 71±25 ml/min*1.73 m2) in stable clinical conditions (>1 month) and in conventional therapy. All patients underwent assessment of thyroid function. A total of 34 patients were excluded for hyperthyroidism; among the remaining 678, 58 (9%) showed a TSH level above the upper normal limit, but below 10 microU/ml, 23 (3%) a TSH value above 10 microU/mL, and 20 patients (3%) low fT3 (LT3) levels without changes in TSH levels. During a mean follow-up of 38 months, 122 patients died (101 for cardiovascular causes) and 202 experienced at least one admission for acute decompensated heart failure. TSH >10 microU/mL (HR:2.96; 95%CI: 1.545.68; P: 0.001) and LT3 (HR: 3.79; 95%CI: 1.917.54; P<0.001), but not high TSH<10 microU/mL (HR: 1.59; 95%CI: 0.8712.91; P: 0.13), were associated with an increased risk of death at univariate analysis. At multivariate Cox regression analysis, after correction for the presence of NYHA class 3, LVEF<35%, NTproBNP >1000, systolic arterial pressure <100 mm Hg and GFR-EPI <60 ml/min, only LT3 remained significantly associated with events (HR: 2.75; 95%CI:1.385.49; P: 0.004). When the occurrence of heart failure hospitalization was considered, high TSH levels with a value <10 microU/ml (HR 1.82; 95% CI: 1.182.83; P<0.01), TSH>10 microU/ml (HR 2.84; 95%CI:1.615.01; P<0.001) and LT3 (HR: 3.33; 95%CI: 1.895.88; P<0.0001) were all associated with events at univariate regression analysis. At multivariate regression analysis TSH>10 microU/ml (HR: 1.91; 95%CI:1.063.46; P:0.03) and LT3 (HR: 2.39; 95%CI: 1.364.24; P:0.002), but not high TSH with value <10 microU/ml, remained associated with HF hospitalization.
Conclusions: In this observational study on a large cohort of CHF outpatients, we found that impaired thyroid function, particularly when high levels of TSH (>10 microUI/ml) and low T3 levels are considered, has an independent adverse impact on CHF events.
20 May 2017 - 23 May 2017