Search Results
Search for other papers by L E Zijlstra in
Google Scholar
PubMed
Search for other papers by D M van Velzen in
Google Scholar
PubMed
Search for other papers by S Simsek in
Google Scholar
PubMed
Search for other papers by S P Mooijaart in
Google Scholar
PubMed
Department of Internal Medicine, HagaHospital, The Hague, The Netherlands
Search for other papers by M van Buren in
Google Scholar
PubMed
Search for other papers by D J Stott in
Google Scholar
PubMed
Search for other papers by I Ford in
Google Scholar
PubMed
Search for other papers by J W Jukema in
Google Scholar
PubMed
Department of Internal Medicine, Section of Gerontology and Geriatrics, Leiden University Medical Center, Leiden, The Netherlands
Search for other papers by S Trompet in
Google Scholar
PubMed
Objective
Thyroid hormones have been implicated to play a role in cardiovascular disease, along with studies linking thyroid hormone to kidney function. The aim of this study is to investigate whether kidney function modifies the association of subclinical thyroid dysfunction and the risk of cardiovascular outcomes.
Methods
In total, 5804 patients were included in the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER). For the current analysis, 426 were excluded because of overt thyroid disease at baseline or 6 months, 266 because of inconsistent thyroid function at baseline and 6 months, 294 because of medication use that could influence thyroid function, and 16 because of missing kidney or thyroid values. Participants with normal fT4 were classified, based on TSH both at inclusion and 6 months, into three groups: subclinical hypothyroidism (TSH >4.5 mIU/L); euthyroidism (TSH = 0.45–4.5 mIU/L); and subclinical hyperthyroidism (TSH <0.45 mIU/L). Strata of kidney function were made based on estimated glomerular filtration rate into three clinically relevant groups: <45, 45–60, and >60 mL/min/1.73 m2. The primary endpoint consists of death from coronary heart disease, non-fatal myocardial infarction and (non)fatal stroke.
Results
Mean age was 75.3 years, and 49.0% patients were male. Mean follow-up was 3.2 years. Of all participants, 109 subjects (2.2%) had subclinical hypothyroidism, 4573 (94.0%) had euthyroidism, and 182 (3.7%) subclinical hyperthyroidism. For patients with subclinical hypothyroidism, euthyroidism, and subclinical hyperthyroidism, primary outcome occurred in 9 (8.3%), 712 (15.6%), and 23 (12.6%) patients, respectively. No statistically significant relationship was found between subclinical thyroid dysfunction and primary endpoint with adjusted hazard ratios of 0.51 (0.24–1.07) comparing subclinical hyperthyroidism and 0.90 (0.58–1.39) comparing subclinical hypothyroidism with euthyroidism. Neither was this relationship present in any of the strata of kidney function, nor did kidney function interact with subclinical thyroid dysfunction in the association with primary endpoint (P interaction = 0.602 for subclinical hyperthyroidism and 0.388 for subclinical hypothyroidism).
Conclusions
In this secondary analysis from PROSPER, we found no evidence that the potential association between thyroid hormones and cardiovascular disease is modified by kidney function in older patients with subclinical thyroid dysfunction.
