TY - JOUR
T1 - Effects of atrial fibrillation screening according to thyroid function
T2 - Post-hoc analysis of the randomized LOOP study
AU - Spona, Daniel Camillo
AU - Frodi, Diana My
AU - Xing, Lucas Yixi
AU - Kongebro, Emilie Katrine
AU - Haugan, Ketil Jørgen
AU - Graff, Claus
AU - Højberg, Søren
AU - Krieger, Derk
AU - Brandes, Axel
AU - Køber, Lars
AU - Olesen, Morten S
AU - Andersen, Andreas
AU - Hædersdal, Sofie
AU - Frikke-Schmidt, Ruth
AU - Svendsen, Jesper Hastrup
AU - Diederichsen, Søren Zöga
N1 - © The Author(s) 2024. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For commercial re-use, please contact [email protected] for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact [email protected]. See the journal About page for additional terms.
PY - 2024/9/4
Y1 - 2024/9/4
N2 - PURPOSE: Subclinical thyroid dysfunction is a marker for atrial fibrillation (AF) and stroke risk. This study explored the effects of AF screening according to thyroid-stimulating hormone (TSH) levels.METHODS: An AF screening trial (the LOOP study) was analyzed post-hoc according to baseline TSH. The primary outcome was stroke or systemic embolism (SE). Secondary outcomes included major bleeding, all-cause death, and the combination of stroke, SE, and cardiovascular death.RESULTS: TSH measurement was available in 6003 of 6004 trial participants, 1500 randomized to implantable loop recorder (ILR) screening for AF and anticoagulation upon detection vs. 4503 to usual care; mean age was 74.7±4.1 years and 2836 (47%) were women. AF detection was approximately triple for ILR vs usual care across TSH tertiles (adjusted p-interaction=0.44). In the first tertile, screening was associated with decreased risk of the primary outcome (hazard ratio 0.52 [0.30-0.90]; p=0.02) and stroke, SE, or cardiovascular death (hazard ratio 0.54 [0.34-0.84]; p=0.006) compared to usual care, while no effect was observed among participants with higher TSH (adjusted p-interaction 0.03 and 0.01, respectively). There was no effect on other outcomes. Analyses of continuous TSH or excluding those with abnormal TSH or thyroid medication showed similar results.CONCLUSION: AF screening and subsequent treatment was associated with decreased stroke risk among participants with low TSH, though the yield of screening was similar across TSH levels. TSH may be useful as a marker to indicate benefit from AF screening vs. overdiagnosis and overtreatment. These findings should be considered exploratory and warrant further study.TRIAL REGISTRATION: ClinicalTrials.gov, identifier: NCT0203645.
AB - PURPOSE: Subclinical thyroid dysfunction is a marker for atrial fibrillation (AF) and stroke risk. This study explored the effects of AF screening according to thyroid-stimulating hormone (TSH) levels.METHODS: An AF screening trial (the LOOP study) was analyzed post-hoc according to baseline TSH. The primary outcome was stroke or systemic embolism (SE). Secondary outcomes included major bleeding, all-cause death, and the combination of stroke, SE, and cardiovascular death.RESULTS: TSH measurement was available in 6003 of 6004 trial participants, 1500 randomized to implantable loop recorder (ILR) screening for AF and anticoagulation upon detection vs. 4503 to usual care; mean age was 74.7±4.1 years and 2836 (47%) were women. AF detection was approximately triple for ILR vs usual care across TSH tertiles (adjusted p-interaction=0.44). In the first tertile, screening was associated with decreased risk of the primary outcome (hazard ratio 0.52 [0.30-0.90]; p=0.02) and stroke, SE, or cardiovascular death (hazard ratio 0.54 [0.34-0.84]; p=0.006) compared to usual care, while no effect was observed among participants with higher TSH (adjusted p-interaction 0.03 and 0.01, respectively). There was no effect on other outcomes. Analyses of continuous TSH or excluding those with abnormal TSH or thyroid medication showed similar results.CONCLUSION: AF screening and subsequent treatment was associated with decreased stroke risk among participants with low TSH, though the yield of screening was similar across TSH levels. TSH may be useful as a marker to indicate benefit from AF screening vs. overdiagnosis and overtreatment. These findings should be considered exploratory and warrant further study.TRIAL REGISTRATION: ClinicalTrials.gov, identifier: NCT0203645.
U2 - 10.1210/clinem/dgae610
DO - 10.1210/clinem/dgae610
M3 - Journal article
C2 - 39231015
SN - 0021-972X
JO - The Journal of clinical endocrinology and metabolism
JF - The Journal of clinical endocrinology and metabolism
ER -