The immediate effect of hemodialysis on thyroid function

The prevalence of chronic kidney disease (CKD) is rapidly increasing globally. There has been an established association between CKD and thyroid dysfunction. Hemodialysis appears to alter thyroid hormone levels. The purpose of this research was to determine the immediate impact of hemodialysis sessions on thyroid hormone levels. This prospective research was conducted in the Hemodialysis Unit at King Abdul-Aziz University Hospital (KAUH), Jeddah, Saudi Arabia. We reviewed 40 consecutive patients undergoing hemodialysis from November 2018 to January 2019, excluding those aged <= 18 years, cancer patients, and pregnant women. We analyzed thyroid-stimulating hormone (TSH), free triiodothyronine (T3), and free thyroxine (T4) levels before and after a single hemodialysis session, considering the presence of any previous thyroid dysfunction. The study population was divided according to their thyroid function markers into low, normal, and high levels. Of the study patients, 27.5% and 30% had low free T3 levels pre-dialysis and post-dialysis, respectively. Low free T4 levels were observed in 27.5% of pre-dialysis patients compared to 25% of post-dialysis patients. High TSH levels were found in 15% of pre-dialysis patients and 17.5% of post-dialysis patients. The mean free T3 and free T4 levels were significantly higher post-dialysis (p <= 0.01). Longer dialysis duration was significantly associated with higher TSH levels post-dialysis. In conclusion, thyroid function markers were disturbed after a single dialysis session. Longer dialysis duration was associated with changes in TSH levels, supporting the development of hypothyroidism.