Endocrine Abstracts

Background: Hypothyroidism has profound effects on cardiac function, however, the effect of over- and undertreatment of hypothyroidism on hospitalization outcomes of patients with acute exacerbation of heart failure (HF) has not been evaluated yet.

Methods: We conducted retrospective cohort analyses of outcomes among 231 consecutive patients with treated hypothyroidism who were admitted to the internal medicine departments of Shamir Medical Center with HF from 2011 to 2019. Patients were divided into three groups according to their TSH levels − normal (TSH 0.4-4 mIU/l), over-treated groupTSH<0.4 mIU/l, and undertreated group (TSH>4 mIU/l). The main outcomes were functional deterioration, in-hospital mortality, and recurrent hospitalization within three months.

Results: Among 231 patients, 106 were euthyroid, 14 were overtreated, and 111 were undertreated. Patients’ mean age was 79.8±9.4 years. Heart failure with reduced ejection fraction was found in 41.1%, hypertension in 91.3%, and COPD in 26.8% of patients. The most common triggers to HF decompensation were anemia, infection, and low compliance for treatment. In-hospital mortality occurred in 4.7% in euthyroid patients, 14.3% in the overtreated group, and 10.7% in the undertreated group (P=0.183). Differences in 30- and 90-days mortality were not significantly different as well. Functional deterioration during hospitalization was found in 9.4% in the euthyroid patients, non in the overtreated group, and 6.3% in the undertreated group (P=0.288). There was no significant difference in recurrent hospitalization within 3 months between the three groups (P=0.438). However, when evaluating patients with extreme values of TSH (<0.4 mIU/l or >10 mIU/l), we found higher 90 days mortality (30.4% vs 15.1%, P=0.016), as compared to patients with normal or mildly increased TSH (0.4-10 mIU/l).

Conclsion: Our results show that mild under- or overtreatment of hypothyroidism did not have a significant detrimental effect on mortality, functional deterioration, or rehospitalization of patients with acute decompensated HF. However, significant over- and undertreatment do cause adverse hospitalization outcomes. Larger cohorts are needed to establish the relationship between treatment targets and hospitalization outcomes of patients who are at risk for hospitalization for HF.