Hypothyroidism ups risk of all-cause mortality in older patients

Elderly patients with hypothyroidism are at increased risk of all-cause mortality, but not cardiovascular mortality, results of a systematic review and meta-analysis have shown.

The investigators searched the databases of PubMed, Embase, Cochrane Library, Scopus and Web of Science from inception until 10 May 2019 for studies assessing the association between hypothyroidism and all-cause or cardiovascular mortality in the elderly population (ages ≥60 years).

Data were extracted and the quality of studies was assessed independently by two reviewers. Relative risk (RR) was retrieved for synthesis, while a random-effects model was used for meta-analysis.

Twenty-seven cohort studies involving a total of 1,114,638 participants were included in the meta-analysis. Hypothyroidism was significantly associated with a higher risk of all-cause mortality compared with euthyroidism (pooled RR, 1.26, 95 percent confidence interval [CI], 1.15–1.37). On the other hand, cardiovascular mortality did not significantly differ between patients with hypothyroidism and those with euthyroidism (pooled RR, 1.10, 95 percent CI, 0.84–1.43).

In subgroup analysis, an association was found between increased all-cause mortality and overt hypothyroidism (pooled RR, 1.10, 95 percent CI, 1.01–1.20) rather than subclinical hypothyroidism (pooled RR, 1.14, 95 percent CI, 0.92–1.41).

Heterogeneity stemmed from various study designs (ie, prospective and retrospective) and geographic locations (ie, Europe, Asia, Oceania and North America).

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