Chapter 27 - Thyroid Status in Chronic Renal Failure Patients

Abstract

Epidemiologic data show that predialysis and dialysis-dependent chronic kidney disease (CKD) patients have a substantially higher prevalence of hypothyroidism compared to their non-CKD counterparts. Various thyroid functional test alterations are also commonly observed in CKD due to the impaired metabolism, degradation, and excretion of thyroid hormone and its metabolites. While the mechanistic link and directionality of associations between thyroid and kidney disease have not been fully elucidated, existing data suggest that the relationship may be bidirectional. At this time, a growing body of evidence shows that thyroid functional derangements such as hypothyroidism and low circulating triiodothyronine levels are associated with higher risk of cardiovascular disease and death in dialysis patients. While levothyroxine is among the most commonly prescribed medications in predialysis and dialysis-dependent CKD patients based on United States Renal Data System data, there has been limited study of the impact of thyroid hormone replacement therapy on outcomes in this context. In this chapter, we will review the epidemiology of hypothyroidism and various thyroid functional test alterations commonly observed in CKD; potential mechanisms linking thyroid and kidney disease; and the prognostic implications of hypothyroidism, thyroid hormone alterations, and exogenous thyroid hormone replacement in the CKD population.