title: Hypothyroidism and mortality among dialysis patients.
abstract: OBJECTIVE
  Hypothyroidism is highly prevalent among ESRD patients, but its clinical significance and the benefits of thyroid hormone replacement in this context remain unclear.
  
  
  METHODS
  This study examined the association between hypothyroidism and all-cause mortality among 2715 adult dialysis patients with baseline thyrotropin levels measured between April of 2005 and April of 2011. Mortality was ascertained from Social Security Death Master Index and local registration systems. The association between hypothyroidism (thyrotropin greater than assay upper limit normal) and mortality was estimated using Cox proportional hazards models. To reduce the risk of observing reverse-causal associations, models included a 30-day lag between thyrotropin measurement and at-risk time.
  
  
  RESULTS
  Among 350 (12.9%) hypothyroid and 2365 (87.1%) euthyroid (assay within referent range) patients, 917 deaths were observed during 5352 patient-years of at-risk time. Hypothyroidism was associated with higher mortality. Compared with thyrotropin in the low-normal range (0.4-2.9 mIU/L), subclinical hypothyroidism (thyrotropin >upper limit normal and ≤10.0 mIU/L) was associated with higher mortality; high-normal thyrotropin (≥3.0 mIU/L and ≤upper limit normal) and overt hypothyroidism (thyrotropin >10.0 mIU/L) were associated with numerically greater risk, but estimates were not statistically significant. Compared with spontaneously euthyroid controls, patients who were euthyroid while on exogenous thyroid replacement were not at higher mortality risk, whereas patients who were hypothyroid were at higher mortality risk. Sensitivity analyses indicated that effects on cardiovascular risk factors may mediate the observed association between hypothyroidism and death.
  
  
  CONCLUSIONS
  These data suggest that hypothyroidism is associated with higher mortality in dialysis patients, which may be ameliorated by thyroid hormone replacement therapy.
authors.affiliation: Renal Division, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA.
authors.forename: Connie M
authors.initials: CM
authors.lastname: Rhee
authors.forename: Erik K
authors.initials: EK
authors.lastname: Alexander
authors.forename: Ishir
authors.initials: I
authors.lastname: Bhan
authors.forename: Steven M
authors.initials: SM
authors.lastname: Brunelli
mesh_terms: D000368:Aged; D005260:Female; D020249:Hormone Replacement Therapy; D006801:Humans; D007037:Hypothyroidism / Q000097:blood / Q000188:drug therapy / Q000401:mortality*; D007676:Kidney Failure, Chronic / Q000401:mortality* / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D016016:Proportional Hazards Models; D012042:Registries / Q000706:statistics & numerical data; D006435:Renal Dialysis / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D012307:Risk Factors; D012943:Social Security / Q000706:statistics & numerical data; D013972:Thyrotropin / Q000097:blood
chemical_list: D013972:Thyrotropin