Age, hypothyroidism type influence all-cause mortality risk in older adults
CHICAGO — All-cause mortality risk is greater for adults aged at least 60 years with overt hypothyroidism compared with adults with euthyroidism, but the same is not true for cardiovascular mortality risk, according to findings presented at the annual meeting of the American Thyroid Association.
“Although hypothyroidism is associated with mortality in the general population, it is less clear whether the same relationship exists in the elderly population,” Kashif M. Munir, MD, an associate professor in the division of endocrinology, diabetes and nutrition at the University of Maryland School of Medicine in Baltimore, told Endocrine Today. “Our study showed that overt hypothyroidism in individuals aged 60 years or more is related to all-cause mortality, but not CV mortality.”
Munir and colleagues searched for and identified studies (n = 27) that included participants aged at least 60 years (n = 1,122,891) and an analysis of hypothyroidism and mortality risks in PubMed, Embase, Cochrane Library, Scopus, and Web of Science.
The researchers found that all-cause mortality risk was greater for individuals with hypothyroidism compared with individuals with euthyroidism (pooled RR = 1.26; 95% CI, 1.15-1.37). The researchers noted that the increase in all-cause mortality risk only persisted for individuals with overt hypothyroidism.
“No treatment is required for the elderly with subclinical hypothyroidism as it would not provide a beneficial effect in symptom relief or survival benefit,” Carol Chiung-Hui Peng, MD, of the University of Maryland Medical Center Midtown Campus in Baltimore, told Endocrine Today. “On the other hand, for older patients with overt hypothyroidism, levothyroxine supplementation would likely decrease all-cause mortality.”
Peng noted that the study design may have been primarily responsible for the observed association between hypothyroidism and all-cause mortality.
“In the prospective studies with minimal heterogeneity, no difference in all-cause and CV mortality was found,” Peng said. “Significant association between hypothyroidism and higher mortality was found only in the retrospective study groups, which endorsed high heterogeneity.”
Peng also said where studies were conducted had an impact.
“Studies from Asia and North America were significantly associated with increased all-cause mortality in patients with hypothyroidism compared to those with euthyroidism,” Peng said. “This phenomenon may be related to higher than required iodine intake.”
Despite finding an association between hypothyroidism and all-cause mortality, the researchers noted that it did not hold for older individuals.
“Interestingly, in the population aged 80 years or older, there was no significant increase for mortality in the hypothyroid group compared with the euthyroid group,” Peng said, with Munir adding that, in this age group, there was a trend toward decreased mortality.
In contrast to the findings for all-cause mortality, individuals with hypothyroidism did not have significantly greater risk for CV mortality compared with individuals with euthyroidism, and Peng noted that the “existence of competing risks — the other causes of mortality instead of CV mortality — may have caused bias.”
“This study provides further evidence to help guide management of hypothyroidism in the elderly,” Munir said. “Namely, in accordance with guidelines, that treating subclinical hypothyroidism in the elderly may not provide benefit. However, overt hypothyroidism in individuals [aged 60-79 years] does lead to an increase in all-cause mortality, and treatment should be considered.” – by Phil Neuffer
Peng C, et al. Poster 56. Presented at: 89th Annual Meeting of the American Thyroid Association; Oct. 30-Nov. 3, 2019; Chicago.
Disclosures: Munir and Peng report no relevant financial disclosures.