Abstract
Hypothyroidism is relatively common in patients with CKD. The risk is higher in women and positively associated with age and negatively with glomerular filtration rate; hyponatraemia may be a warning sign.
Hypothyroidism is confirmed by higher serum thyrotropin (TSH) level and treated by usual levothyroxine replacement, aimed at TSH level normalization. An even more common finding in CKD patients is a decrease in serum levels of thyroxine (T4) and namely of triiodothyronine (T3).
If TSH is not elevated then low T4 and/or low T3 are probably not due to hypothyroidism but rather due to non-thyroidal illness syndrome. This syndrome is associated with an increased risk of complications, including higher mortality; however, T4 and/or T3 replacement is not indicated.