Objectives and methods: Low free plasma triiodothyronine (fT3) is associated with inflammation and cardiovascular damage in patients with end-stage renal disease (ESRD). We investigated the relationship between fT3, left ventricular systolic function and left ventricular mass in a group of 234 dialysis patients, and modelled the association between fT3 and cardiomyopathy in statistical analyses including both direct (interleukin-6 and C-reactive protein) and inverse (serum albumin) acute phase inflammation markers.
Results: Plasma fT3 concentration in dialysis patients was significantly (P < 0.001) reduced in comparison with healthy participants and clinically euthyroid patients with normal renal function. Left ventricular systolic function was depressed (P <or= 0.003) and left ventricular mass increased (P < 0.001) in patients in the first fT3 quartile as compared with patients in other quartiles. In multiple regression analyses these associations remained significant also after adjustment for Framingham risk factors and antihypertensive therapy (P </= 0.01), and for risk factors peculiar to ESRD (P = 0.03). Adjustments for interleukin-6 or for albumin, however, abrogated these relationships.
Conclusions: Low triiodothyronine is associated with left ventricular dysfunction and left ventricular hypertrophy in ESRD patients. These associations appear largely mediated by inflammation. Low fT3 may be an intermediate mechanism implicated in the adverse cardiac effects of inflammation in patients with ESRD.