Hypothyroidism increases death risk in elderly population

Taiwan: While previous studies have established a link between hypothyroidism and cardiovascular mortality, a new study has found hypothyroidism to be associated with an increased risk of all-cause mortality instead of cardiovascular mortality in the elderly. The study is published in The Journal of Clinical Endocrinology and Metabolism.

The evidence of whether hypothyroidism increases mortality in the elderly population is currently inconsistent and conflicting. Huei-Kai Huang, School of Medicine, Tzu Chi University, Hualien, Taiwan, and colleagues determined the impact of hypothyroidism on mortality in the elderly population.

For the purpose, the researchers searched the online databases for studies evaluating the association between hypothyroidism and all-cause and/or cardiovascular mortality in the elderly population (aged ≥ 60 years). Two reviewers independently extracted data and assessed the quality of studies. The relative risk (RR) was retrieved for synthesis. The random-effects model for meta-analyses was used.

The primary outcome of the current analyses was all-cause mortality. Secondary outcomes included cardiovascular mortality, which includes deaths from ischemic heart disease, progressive heart failure, arrhythmia, cardiac arrest, and other diseases of the circulatory system.

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Key findings of the study include:

• A total of 27 cohort studies with 1,114,638 participants met the inclusion criteria.


• Patients with hypothyroidism experienced a higher risk of all-cause mortality than those with euthyroidism (pooled RR=1.26); meanwhile, no significant difference in cardiovascular mortality was found between patients with hypothyroidism and those with euthyroidism (pooled RR=1.10).


• Subgroup analyses revealed that overt hypothyroidism (pooled RR=1.10) rather than subclinical hypothyroidism (pooled RR=1.14) was associated with increased all-cause mortality.


• The heterogeneity primarily originated from different study designs (prospective and retrospective) and geographic locations (Europe, North America, Asia, and Oceania).

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“In accordance with guidelines, our findings imply that individuals with subclinical hypothyroidism--those who have milder thyroid dysfunction--may not benefit from being treated with synthetic thyroid hormone," said Kashif Munir, associate professor in the division of endocrinology, diabetes, and nutrition at the University of Maryland School of Medicine in Baltimore.

"Our analysis found individuals with hypothyroidism aged 60 years or older were 26 percent more likely to die from all causes than individuals in the same age range who did not have the thyroid condition," wrote the authors.

"We observed considerable heterogeneity, so caution is needed when interpreting the results. Further prospective large-scale high-quality studies are warranted to confirm these findings," they concluded.

The study, "Association of hypothyroidism and mortality in the elderly population: A systematic review and meta-analysis," is published in The Journal of Clinical Endocrinology and Metabolism.

DOI: https://doi.org/10.1210/clinem/dgz186