Effects of Levothyroxine Treatment on Hemodynamic and Renal Functions in Subclinical Hypothyroidism
Effects of Levothyroxine Treatment on Hemodynamic and Renal Functions in Subclinical Hypothyroidism
Renal and cardiovascular effects of subclinical hypothyroidism, defined by a high TSH and
 normal T4 are less known and the indications for treatment of subclinical hypothyroidism are
 subject to controversies.

 The investigators propose to assess whether the hormone replacement for subclinical
 hypothyroidism in patients with chronic kidney disease is beneficial for hemodynamic and
 renal functions and which mechanisms are involved.

 Isotopic measurements of glomerular filtration and renal blood flow and an hemodynamic
 evaluation by transthoracic echocardiography and flow-mediated vasodilation will be carried
 out before and 6 months after substitution.
Animal experimental hypothyroidism is associated with renal and hemodynamic abnormalities. In
 human, exact measurements of GFR showed a decline in GFR after thyroidectomy and an increase
 in GFR and renal blood flow after hormone replacement. Renal and cardiovascular effects of
 subclinical hypothyroidism, defined by a high TSH and normal T4 are less known and the
 indications for treatment of subclinical hypothyroidism are subject to controversies. A
 retrospective study suggests that treatment of subclinical hypothyroidism may slow the
 degradation rate of renal function estimated by MDRD. However, the potential hemodynamic
 benefit of treatment has not yet been studied.

 The investigators propose to assess whether the hormone replacement for subclinical
 hypothyroidism in patients with chronic kidney disease is beneficial for hemodynamic and
 renal functions and which mechanisms are involved.

 Isotopic measurements of glomerular filtration and renal blood flow and an hemodynamic
 evaluation by transthoracic echocardiography and flow-mediated vasodilation will be carried
 out before and 6 months after substitution. This open prospective study will include 16
 patients in order to detect an increase of 1.2 standard deviation for the measured glomerular
 filtration.
Inclusion Criteria:

 -  over 18 years

 -  chronic kidney disease

 -  subclinical hypothyroidism

 non-inclusion Criteria:

 -  insulin-dependent diabetes

 -  dialysis