title: Subclinical thyroid dysfunction and the risk of heart failure in older persons at high cardiovascular risk.
abstract: BACKGROUND
  Subclinical thyroid dysfunction is common in older people. However, its clinical importance is uncertain.
  
  
  OBJECTIVE
  Our objective was to determine the extent to which subclinical hyperthyroidism and hypothyroidism influence the risk of heart failure and cardiovascular diseases in older people.
  
  
  METHODS
  The Prospective Study of Pravastatin in the Elderly at Risk (PROSPER) is an prospective cohort study.
  
  
  METHODS
  Patients included men and women aged 70-82 yr (n=5316) with known cardiovascular risk factors or previous cardiovascular disease.
  
  
  METHODS
  Incidence rate of heart failure hospitalization, atrial fibrillation, and cardiovascular events and mortality according to baseline thyroid status were evaluated. Euthyroid participants (TSH=0.45-4.5 mIU/liter) were compared with those with subclinical hyperthyroidism (TSH<0.45 mIU/liter) and those with subclinical hypothyroidism (TSH≥4.5 mIU/liter, both with normal free T4).
  
  
  RESULTS
  Subclinical hyperthyroidism was present in 71 participants and subclinical hypothyroidism in 199 participants. Over 3.2 yr follow-up, the rate of heart failure was higher for subclinical hyperthyroidism compared with euthyroidism [age- and sex-adjusted hazard ratio (HR)=2.93, 95% confidence interval (CI)=1.37-6.24, P=0.005; multivariate-adjusted HR=3.27, 95% CI=1.52-7.02, P=0.002). Subclinical hypothyroidism (only at threshold>10 mIU/liter) was associated with heart failure (age- and sex-adjusted HR=3.01, 95% CI=1.12-8.11, P=0.029; multivariate HR=2.28, 95% CI=0.84-6.23). There were no strong evidence of an association between subclinical thyroid dysfunction and cardiovascular events or mortality, except in those with TSH below 0.1 or over 10 mIU/liter and not taking pravastatin.
  
  
  CONCLUSIONS
  Older people at high cardiovascular risk with low or very high TSH along with normal free T4 appear at increased risk of incident heart failure.
authors.affiliation: Leiden University Medical Center, Department of Gerontology and Geriatrics, Netherlands Consortium for Health Aging, Leiden, The Netherlands. david.nanchen@chuv.ch
authors.forename: David
authors.initials: D
authors.lastname: Nanchen
authors.forename: Jacobijn
authors.initials: J
authors.lastname: Gussekloo
authors.forename: Rudi G J
authors.initials: RG
authors.lastname: Westendorp
authors.forename: David J
authors.initials: DJ
authors.lastname: Stott
authors.forename: J Wouter
authors.initials: JW
authors.lastname: Jukema
authors.forename: Stella
authors.initials: S
authors.lastname: Trompet
authors.forename: Ian
authors.initials: I
authors.lastname: Ford
authors.forename: Paul
authors.initials: P
authors.lastname: Welsh
authors.forename: Naveed
authors.initials: N
authors.lastname: Sattar
authors.forename: Peter W
authors.initials: PW
authors.lastname: Macfarlane
authors.forename: Simon P
authors.initials: SP
authors.lastname: Mooijaart
authors.forename: Nicolas
authors.initials: N
authors.lastname: Rodondi
authors.forename: Anton J M
authors.initials: AJ
authors.lastname: de Craen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000209:etiology / Q000401:mortality; D002318:Cardiovascular Diseases / Q000209:etiology / Q000401:mortality; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000209:etiology / Q000401:mortality*; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012306:Risk; D012307:Risk Factors; D015996:Survival Rate; D013959:Thyroid Diseases / Q000150:complications* / Q000503:physiopathology