[The influence of hypothyroidism on the conversion and binding of thyroid hormones in patients with end-stage renal disease].
Hypothyroidism in patients with renal failure (RF) causes many metabolic and clinical problems, and both these diseases can mutually exacerbate their disturbances.


OBJECTIVE
The aim of this study was to evaluate the effect of hypothyroidism, and end-stage renal disease (ESRD) on conversion of thyroid hormones (TH) in patients with ESRD treated with chronic hemodialysis (HD).


METHODS
The study was performed in 74 patients, including 41 women (K) and 33 men (M) aged 28-83 y.o. in 4 groups: G1 - 12 people with ESRD treated with HD and with newly diagnosed hypothyroidism without substitution (6 K and M 6) aged 66,83±12,90 y.o., G2 - 26 patients with ESRD treated with HD without hypothyroidism (10 F, 16 M) aged 58,85±15,52 y.o., G3 - 11 hypothyroid patients without RF (9 K, 2 M) aged 54,73±21,26 y.o., G4 - 25-persons from control group of healthy subjects (16 M, 9 M) aged 51,24±12,58 y.o. In all subjects the concentration of TSH and TH (T4, T3, fT4, TSH, FT3, rT3) were measured and values of conversion factors (T3/T4, FT3/ fT4, rT3/fT4 and rT3/fT3) and binding TH to protein factors (fT4/T4 and fT3/T3) were calculated.


RESULTS
Lower concentration of T3 (p=0.012), fT3 (p<0.001) i fT4 (p=0.014) was found in patients without hypothyroidism than in healthy subjects. Renal failure with concomitant hypothyroidism intensify the disturbances of T4 to T3 conversion (p=0.034) and hypothyroidism with concomitant renal failure disrupts binding of T3 to proteins (p=0.001). FT3 to fT4 ratio in renal failure with concomitant hypothyroidism group was significantly lower than in each other group. rT3 concentrations were the highest in healthy subjects.


CONCLUSIONS
Concomitance of hypothyroidism and end-stage renal disease reduces the conversion of thyroxine to triiodothyronine, but does not increase the production of rT3. Hypothyroidism significantly increases the disorders of thyroid hormones in end-stage renal disease. There is decreased tendency to bind of thyroid hormone to protein in hypothyroidism in patients with end-stage renal disease.
Department of Internal Medicine, Nephrology and Dialysis, Central Clinical Hospital of the Ministry of Defence, Military Institute of Medicine in Warsaw, Poland.
Iwanna
I
Dubczak
Department of Nephrology, Dialysis and Internal Medicine, Medical University of Warsaw, Poland.
Longin
L
Niemczyk
Department of Internal Medicine and Endocrinology, Medical University of Warsaw, Poland.
Zbigniew
Z
Bartoszewicz
Department of Epidemiology and Biostatistics, Institute of Mother and Child in Warsaw, Poland.
Katarzyna
K
Szamotulska
Department of Internal Medicine, Nephrology and Dialysis, Central Clinical Hospital of the Ministry of Defence, Military Institute of Medicine in Warsaw, Poland.
Marek
M
Saracyn
Department of Internal Medicine, Nephrology and Dialysis, Central Clinical Hospital of the Ministry of Defence, Military Institute of Medicine in Warsaw, Poland.
Stanisław
S
Niemczyk
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000097:blood / Q000150:complications / Q000378:metabolism*; D007676:Kidney Failure, Chronic / Q000097:blood / Q000150:complications / Q000378:metabolism* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D011485:Protein Binding; D006435:Renal Dialysis; D013963:Thyroid Hormones / Q000097:blood / Q000378:metabolism*
D013963:Thyroid Hormones
dialysis; end-stage renal disease; hypothyroidism; rT3; thyroid hormone conversion