[The influence of hypothyroidism on the conversion and binding of thyroid hormones in patients with end-stage renal disease]. / Wplyw niedoczynnosci tarczycy u chorych ze schylkowa niewydolnoscia nerek na wspólczynniki konwersji i wiazania hormonów tarczycy.

Hypothyroidism in patients with renal failure (RF) causes many metabolic and clinical problems, and both these diseases can mutually exacerbate their disturbances. AIM: 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). MATERIALS AND 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.

The influence of hypothyroidism and substitution treatment on thyroid hormone conversion ratios and rT3 concentration in patients with end-stage renal failure.

INTRODUCTION: The increasing number of patients with end-stage renal disease (ESRD) requires seeking new opportunities to improve their quality of life, not only because of kidney disease but also due to other disturbances, such as thyroid hormone disorders. The objective of the study was to evaluate the influence of coexisting hypothyroidism and thyroid hormone therapy in patients with ESRD on thyroid hormone conversion ratios and rT3 concentration. MATERIAL AND METHODS: The study involved 85 patients aged 26 to 87 years, with a mean age of 59.62 ± 15.45 years. Four groups of patients were examined: G1 group - 25 persons without RF and hypothyroidism, G2 - 26 patients with ESRD treated with haemodialysis (HD), G3 - 12 patients with ESRD treated with HD and newly diagnosed hypothyroidism, and G4 - 22 HD patients with hypothyroidism treated with thyroid hormones substitution. The concentrations of TSH, T4, T3, fT4, fT3, and rT3 were measured and the fT3/fT4, T3/T4, and rT3/T4 conversion ratios and rT3/T3 ratio were calculated. Concentrations of protein, hsCRP, Hg, and blood gases were also checked; the anion gap was calculated. RESULTS: Patients from group G1 through G2 to G3 were older (ptrend = 0.002), with lower Hb level (ptrend < 0.001), with lower pH (ptrend < 0.001), with increased anion gap (ptrend < 0.013) and CRP concentrations (ptrend < 0.001), and decreased total protein level (ptrend < 0.001). There were increased TSH values (ptrend < 0.001) and lower T4 (ptrend = 0.024), fT3 (ptrend < 0.001), T3 (ptrend < 0.001), and rT3 (ptrend = 0.008) levels. rT3/T3 ratio did not change, the rT3/T4 ratio tended to decrease (ptrend = 0.065) similarly to T3/T4 ratio (ptrend = 0.063), and the fT3/fT4 ratio also decreased (ptrend = 0.005). It seems that the treatment of thyroid disease in patients with renal failure, treated with haemodialysis, is not associated with change of rT3 and conversion factor levels. CONCLUSIONS: The concentration of rT3 in HD patients in relation to healthy persons tends to decrease, and hypothyroidism increases this tendency in these patients. Hormone substitution treatment does not eliminate the influence of RF on inhibition of rT3 production. In patients with ESRD, hypothyroidism additionally reduces the conversion of thyroid hormones examined by fT3/fT4 and to a lesser extent T3/T4 ratios.