title: Subclinical thyroid dysfunction and the risk of heart failure events: an individual participant data analysis from 6 prospective cohorts.
abstract: BACKGROUND
  American College of Cardiology/American Heart Association guidelines for the diagnosis and management of heart failure recommend investigating exacerbating conditions such as thyroid dysfunction, but without specifying the impact of different thyroid-stimulation hormone (TSH) levels. Limited prospective data exist on the association between subclinical thyroid dysfunction and heart failure events.
  
  
  RESULTS
  We performed a pooled analysis of individual participant data using all available prospective cohorts with thyroid function tests and subsequent follow-up of heart failure events. Individual data on 25 390 participants with 216 248 person-years of follow-up were supplied from 6 prospective cohorts in the United States and Europe. Euthyroidism was defined as TSH of 0.45 to 4.49 mIU/L, subclinical hypothyroidism as TSH of 4.5 to 19.9 mIU/L, and subclinical hyperthyroidism as TSH <0.45 mIU/L, the last two with normal free thyroxine levels. Among 25 390 participants, 2068 (8.1%) had subclinical hypothyroidism and 648 (2.6%) had subclinical hyperthyroidism. In age- and sex-adjusted analyses, risks of heart failure events were increased with both higher and lower TSH levels (P for quadratic pattern <0.01); the hazard ratio was 1.01 (95% confidence interval, 0.81-1.26) for TSH of 4.5 to 6.9 mIU/L, 1.65 (95% confidence interval, 0.84-3.23) for TSH of 7.0 to 9.9 mIU/L, 1.86 (95% confidence interval, 1.27-2.72) for TSH of 10.0 to 19.9 mIU/L (P for trend <0.01) and 1.31 (95% confidence interval, 0.88-1.95) for TSH of 0.10 to 0.44 mIU/L and 1.94 (95% confidence interval, 1.01-3.72) for TSH <0.10 mIU/L (P for trend=0.047). Risks remained similar after adjustment for cardiovascular risk factors.
  
  
  CONCLUSIONS
  Risks of heart failure events were increased with both higher and lower TSH levels, particularly for TSH ≥10 and <0.10 mIU/L.
authors: Department of Ambulatory Care and Community Medicine, University of Lausanne, Lausanne, Switzerland.
authors: Baris
authors: B
authors: Gencer
authors: Tinh-Hai
authors: TH
authors: Collet
authors: Vanessa
authors: V
authors: Virgini
authors: Douglas C
authors: DC
authors: Bauer
authors: Jacobijn
authors: J
authors: Gussekloo
authors: Anne R
authors: AR
authors: Cappola
authors: David
authors: D
authors: Nanchen
authors: Wendy P J
authors: WP
authors: den Elzen
authors: Philippe
authors: P
authors: Balmer
authors: Robert N
authors: RN
authors: Luben
authors: Massimo
authors: M
authors: Iacoviello
authors: Vincenzo
authors: V
authors: Triggiani
authors: Jacques
authors: J
authors: Cornuz
authors: Anne B
authors: AB
authors: Newman
authors: Kay-Tee
authors: KT
authors: Khaw
authors: J Wouter
authors: JW
authors: Jukema
authors: Rudi G J
authors: RG
authors: Westendorp
authors: Eric
authors: E
authors: Vittinghoff
authors: Drahomir
authors: D
authors: Aujesky
authors: Nicolas
authors: N
authors: Rodondi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015897:Comorbidity; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000453:epidemiology*; D006801:Humans; D007037:Hypothyroidism / Q000097:blood / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012306:Risk; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood
chemical_list: D013972:Thyrotropin; D013974:Thyroxine