Thyroid status, quality of life, and mental health in patients on hemodialysis

Background and objectives In the general population, there is increasing recognition of the effect of thyroid function on patient-centered outcomes, including health-related quality of life and depression. Although hypothyroidism is highly prevalent in hemodialysis patients, it is unknown whether thyroid status is a risk factor for impaired health-related quality of life or mental health in this population. Design, setting, participants, & measurements We examined the association of thyroid status, defined by serum thyrotropin, with health-related quality of life and depressive symptoms over time in a prospective cohort of 450 patients on hemodialysis from 17 outpatient dialysis facilities from May of 2013 to May of 2015 who underwent protocolized thyrotropin testing, Short-Form 36 surveys, and Beck Depression Inventory-II questionnaires every 6 months. We examined the association of baseline and time-dependent thyrotropin categorized as tertiles and continuous variables with eight Short-Form 36 domains and Beck Depression Inventory-II scores using expanded case mix plus laboratory adjusted linear mixed effects models. Results In categorical analyses, the highest baseline thyrotropin tertile was associated with a five-point lower Short-Form 36 domain score for energy/fatigue (P=0.04); the highest time-dependent tertile was associated with a five-point lower physical function score (P=0.03; reference: lowest tertile). In continuous analyses, higher baseline serum thyrotropin levels (+∆1 mIU/L) were associated with lower role limitations due to physical health (β=-1.3; P=0.04), energy/fatigue (β=-0.8; P=0.03), and pain scores (β=-1.4; P=0.002), equivalent to five-, three-, and five-point lower scores, respectively, for every 1-SD higher thyrotropin. Higher time-dependent thyrotropin levels were associated with lower role limitations due to physical health scores (β=-1.0; P=0.03), equivalent to a three-point decline for every 1-SD higher thyrotropin. Baseline and time-dependent thyrotropin were not associated with Beck Depression Inventory-II scores. Conclusions In patients on hemodialysis, higher serum thyrotropin levels are associated with impaired health-related quality of life across energy/fatigue, physical function, and pain domains. Studies are needed to determine if thyroid-modulating therapy improves the health-related quality of life of hemodialysis patients with thyroid dysfunction.