title: Thyroid function tests and mortality in aged hospitalized patients: a 7-year prospective observational study.
abstract: BACKGROUND
  Several alterations in thyroid function test (TFT) results have been associated with mortality in elderly patients.
  
  
  OBJECTIVE
  Our aim was to investigate the relationship between TFT results and all-cause and cardiovascular (CV) mortality in aged hospitalized patients.
  
  
  METHODS
  A 7-year prospective observational study was conducted. TFTs were performed at hospital admission, and mortality was registered in the follow-up period.
  
  
  METHODS
  Participants were 404 patients aged >65 years admitted to the Department of Geriatrics, Hospital General, Segovia, Spain, for any reason during 2005.
  
  
  METHODS
  The study evaluated the association between TFT results and mortality from all causes and CV diseases.
  
  
  METHODS
  TSH, free T₄, and free T₃ (FT₃) were measured on the first day of admission. In-hospital and total survival times, number of deaths, and all-cause and CV mortality were registered until the census date on January 1, 2012.
  
  
  RESULTS
  During the study, 323 patients (80%) died. Kaplan-Meier analysis showed that median survival time for all-cause mortality was significantly lower in patients in the first tertile of serum FT₃, in the first tertile of TSH, and in the first tertile of serum free T₄ concentrations. Multivariate adjusted Cox regression analysis showed that the history of cancer (hazard ratio, 1.60; 95% confidence interval, 1.12-2.28; P = .009), age (1.03; 1.01-1.06; P = .003), and FT₃ levels (0.72; 0.63-0.84; P < .001) were significant factors related to all-cause mortality. The cause of death was known in 202 patients. Of this group, 61 patients (30.2%) died of CV disease. Patients in the first tertile of TSH and FT₃ exhibited a significant higher mortality due to CV disease. In the adjusted Cox regression analysis, FT₃ was a significant predictor of CV mortality (0.76; 0.63-0.91; P = .004).
  
  
  CONCLUSIONS
  Alterations in TFT results during hospitalization are associated with long-term mortality in elderly patients. In particular, low FT₃ levels are significantly related to all-cause and CV mortality.
authors.affiliation: Department of Endocrinology, Hospital Ramón y Cajal, Ctra. de colmenar, Km 9,100, 28034 Madrid, Spain. piglo65@gmail.com.
authors.forename: Pedro
authors.initials: P
authors.lastname: Iglesias
authors.forename: Elena
authors.initials: E
authors.lastname: Ridruejo
authors.forename: Angélica
authors.initials: A
authors.lastname: Muñoz
authors.forename: Florentino
authors.initials: F
authors.lastname: Prado
authors.forename: María Cruz
authors.initials: MC
authors.lastname: Macías
authors.forename: María Teresa
authors.initials: MT
authors.lastname: Guerrero
authors.forename: Pilar
authors.initials: P
authors.lastname: Tajada
authors.forename: Carmen
authors.initials: C
authors.lastname: García-Arévalo
authors.forename: Juan José
authors.initials: JJ
authors.lastname: Díez
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D002318:Cardiovascular Diseases / Q000097:blood / Q000150:complications / Q000401:mortality / Q000503:physiopathology*; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006769:Hospitals, General; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood / Q000150:complications / Q000401:mortality / Q000503:physiopathology*; D007037:Hypothyroidism / Q000097:blood / Q000150:complications / Q000401:mortality / Q000503:physiopathology*; D053208:Kaplan-Meier Estimate; D008297:Male; D009026:Mortality; D013030:Spain / Q000453:epidemiology; D013960:Thyroid Function Tests; D013961:Thyroid Gland / Q000378:metabolism / Q000503:physiopathology*; D013972:Thyrotropin / Q000097:blood / Q000378:metabolism; D013974:Thyroxine / Q000097:blood / Q000378:metabolism; D014284:Triiodothyronine / Q000097:blood / Q000378:metabolism
chemical_list: D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine