Changes of the Thyroid Function in Continuous Ambulatory Peritoneal Dialysis Patients / 대한신장학회잡지

ABSTRACT

BACKGROUND: In peritoneal dialysis patients, altered thyroid function was reported but the frequncy and pathophysiology were not well understood. The object of this study is to evaluate the effect of continuous ambulatory peritoneal dialysis (CAPD) on thyroid function by observing the frequency of primary thyroid dysfunction and the sequential change of thyroid function after CAPD. METHODS: In a cross-sectional study, thyroid function test (TFT) was done for 192 CAPD patients between Jan. 2001 and Jan. 2002. For another 38 CAPD patients, we observed the sequential change of thyroid function by performing TFT before and 6, 12, 24 months after CAPD. Thyroid hormones were quantitated after 200 mL sample of 24-hour dialysate effluent was lyophilized. TFTs were interpreted as subclinical hypothyroidism (sbhypo) when TSH is over 5 uIu/mL, mild hypothyroidism (mhypo) when TSH is between 5 and 10 uIu/mL with decreased fT4, and overt hypothyroidism (ohypo) when TSH level is over 10 uIu/mL with decreased fT4. RESULTS: Frequencies of normal thyroid function, sbhypo, mhypo and ohypo were 81.2%, 11%, 5.2%, and 2.6% respectively. Serum levels of TSH before and 6, 12, 24 months after CAPD were 2.6 +/- 0.1, 3.8 +/- 0.3, 4.2 +/- 0.5, 4.1 +/- 0.5 uIu/mL respectively and the frequencies of thyroid dysfunction including subclinical hypothyroidism were 6.4, 23.6, 26.3, 28.8% respectively, which showed the increasing tendency. Peritoneal loss of TSH was 11, 067 +/- 1, 776 uIu/day, and that of TT4 was 11.68 +/- 2.7 microgram/day. These were approximately 7%, and 10% of daily production rate. CONCLUSION: TSH increased after start of CAPD and thyroid dysfunction including subclinical hypothyoidism was observed in significant proportion of CAPD patients. Thyroid hormones were eliminated by peritoneal dialysis. It can be suggested that CAPD affects thyroid function. Clinical significance of the above observation needs further well-controlled study.