Subclinical hypothyroidism and the risk of heart failure, other cardiovascular events, and death

Arch Intern Med. 2005 Nov 28;165(21):2460-6. doi: 10.1001/archinte.165.21.2460.


Background: Subclinical hypothyroidism has been associated with systolic and diastolic cardiac dysfunction and an elevated cholesterol level, but data on cardiovascular outcomes and death are limited.

Methods: We studied 2730 men and women, aged 70 to 79 years, with baseline thyrotropin (TSH) measurements and 4-year follow-up data to determine whether subclinical hypothyroidism was associated with congestive heart failure (CHF), coronary heart disease, stroke, peripheral arterial disease, and cardiovascular-related and total mortality. After the exclusion of participants with abnormal thyroxine levels, subclinical hypothyroidism was defined as a TSH level of 4.5 mIU/L or greater, and was further classified according to TSH levels (4.5-6.9, 7.0-9.9, and > or = 10.0 mIU/L).

Results: Subclinical hypothyroidism was present in 338 (12.4%) of the participants. Compared with euthyroid participants, CHF events occurred more frequently among those with a TSH level of 7.0 mIU/L or greater (35.0 vs 16.5 per 1000 person-years; P = .006), but not among those with TSH levels between 4.5 and 6.9 mIU/L. In multivariate analyses, the risk of CHF was higher among those with high TSH levels (TSH of 7.0-9.9 mIU/L: hazard ratio, 2.58 [95% confidence interval, 1.19-5.60]; and TSH of > or = 10.0 mIU/L: hazard ratio, 3.26 [95% confidence interval, 1.37-7.77]). Among the 2555 participants without CHF at baseline, the hazard ratio for incident CHF events was 2.33 (95% confidence interval, 1.10-4.96; P = .03) in those with a TSH of 7.0 mIU/L or greater. Subclinical hypothyroidism was not associated with increased risk for coronary heart disease, stroke, peripheral arterial disease, or cardiovascular-related or total mortality.

Conclusions: Subclinical hypothyroidism is associated with an increased risk of CHF among older adults with a TSH level of 7.0 mIU/L or greater, but not with other cardiovascular events and mortality. Further investigation is warranted to assess whether subclinical hypothyroidism causes or worsens preexisting heart failure.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Arterial Occlusive Diseases / blood
  • Arterial Occlusive Diseases / etiology*
  • Arterial Occlusive Diseases / mortality
  • Biomarkers / blood
  • Coronary Disease / blood
  • Coronary Disease / etiology*
  • Coronary Disease / mortality
  • Female
  • Follow-Up Studies
  • Heart Failure / blood
  • Heart Failure / etiology*
  • Heart Failure / mortality
  • Humans
  • Hypothyroidism / blood
  • Hypothyroidism / complications*
  • Immunoassay
  • Male
  • Prospective Studies
  • Risk Factors
  • Stroke / blood
  • Stroke / etiology*
  • Stroke / mortality
  • Survival Rate / trends
  • Thyrotropin / blood


  • Biomarkers
  • Thyrotropin