Thyroid hormone abnormalities and frailty in elderly patients with chronic kidney disease: a hypothesis

Thyroid hormones play a crucial role in the metabolic activities of adults, affecting almost every organ system. All types of thyroid diseases are encountered in the elderly. As symptoms and signs of thyroid diseases may overlap with what is considered to be "normal aging," the presence of a thyroid disorder may go undiagnosed in the elderly. This potential problem is further compounded in elderly patients with chronic kidney disease (CKD), where the presence of an underlying hormonal problem such as hypothyroidism may be erroneously attributed to multiple comorbidities, the aging process, or the kidney disease. Frailty is being recognized as a contributing factor to the poor outcomes (hospitalization and high mortality) in elderly patients with CKD. Predisposing factors leading to frailty in elderly with CKD such as increased inflammatory markers, anemia, low testosterone, sarcopenia, and depression are associated with thyroid hormonal abnormalities. These associations are remarkable and raise the question of whether routine monitoring and screening for thyroid hormone changes in elderly CKD patients might be helpful in identifying reversible causes of frailty. In this review, we will focus on the associations between thyroid hormone abnormalities and the predisposing factors of frailty in elderly patients with CKD. If a cause-effect relationship of thyroid hormone abnormalities and factors predisposing to frailty in CKD patients is established, identification and treatment of thyroid abnormalities in this population would assume increased importance.