MP764RELATION OF SERUM INORGANIC IODINE LEVEL TO THYROID DISEASES IN PREVALENT HEMODIALYSIS PATIENTS

Abstract

INTRODUCTION AND AIMS: Thyroid disorders are not uncommon in prevalent hemodialysis (HD) patients. Inorganic iodine is mainly excreted by the kidneys and hence it is expected to increase in CKD and HD patients. The aim of this study is to assess inorganic iodine level in prevalent HD patients and its possible relation to thyroid diseases . METHODS: Forty stable prevalent HD patients were randomly selected from our HD unit and were studied by full history and detailed clinical examination , CBC & routine chemistry as well as free T3 free T4 , TSH, serum inorganic iodine level (by spectrophotometry) as well as thyroid ultra sound . Exclusion criteria included those with known thyroid disorders or receiving drugs affecting thyroid or iodine levels or suffering from associated systemic diseases that may affect thyroid functions e.g. diabetics . A control group of thirty apparently healthy subjects of similar age and sex were similarly studied. RESULTS: We detected increased pre-dialysis increased serum inorganic iodine levels in 34 (85%) of HD patients(group A) . Compared to group of patients with normal iodine level (group B) there was no significant differences regarding age, sex, duration oh HD, free T3 ,TSH ,but we detected significantly lower levels of free T4 and higher frequency of thyroid nodules (detected by ultra-sound) in patients with increased iodine levels(group A). The increased iodine level in group A signific-antly correlated negatively with TSH levels using both univariate correlations and linear regression analysis. Though inorganic iodine level increased markedly in outlet dialysate samples ( median level 19.5 ng/dl ) compared to dialysate sample ( median level 4.1 ng/dl ) yet we detected increased post-dialysis serum inorganic iodine level by 35% compared to pre-dialysis serum level possibly due to hemoconcent-ration . CONCLUSIONS: It may be concluded that increased inorganic iodine levels in most HD patients may be associated with abnormal thyroid function tests and increased frequency of thyroid nodules. We may also recommend monitoring of iodine levels in HD patients and dialysate regularly particularly in the presence of thyroid gland clinical or chemical abnormalities to avoid possible long term complications.