Assessment and Treatment of Thyroid Function in Heart Failure Clinics - Incidence of Abnormal Thyroid Function and Impact on Heart Failure Decompensation.

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Daniel Shafran
Debra L Isaac

Keywords

thyroid, heart failure, decompensation, cardiac function

Abstract

BACKGROUND Abnormal thyroid function (TF) is associated with cardiac dysfunction and may result in decompensation in patients with pre-existing heart failure (HF). International HF guidelines recommend routine assessment and treatment of TF. It is unclear to what extent TF is monitored in Canadian clinics, what the incidence of abnormal TF is in HF patients, and how TF abnormalities impact outcomes. METHODS Retrospective review was performed for all patients managed at 3 hospital-based HF clinics in Calgary from November 2010 to January 2011. RESULTS Charts of 773 patients were reviewed. Of these, 719 (93.0%) patients had some documentation of TFTs; 592 (76.6%) had TFTs in the previous 12 months, and 54 (7.0%) had no record of TFTs. 21.3% (165) of patients had documented abnormal TF. Of 658 patients with normal TFTs (treated or not), 30.2% (199) decompensated compared with 41.0% (25) with abnormal TFTs (P=0.1109). Decompensation rates in patients with normal TFTs versus patients whose TFTs were abnormal or never measured were 30.2% (199) and 47.8% (55) respectively (P=0.0003). CONCLUSIONS TF abnormalities are common in Calgary HF Clinic patients. The rate of HF decompensation is significantly lower in patients with normal TFTs than in those with unmeasured or abnormal TFTs. Further investigation is required to further evaluate the role of assessment and treatment of TF in reducing HF decompensation.