CHICAGO – Levothyroxine treatment is associated with increased mortality in patients 65 years and older with subclinical hypothyroidism, according to a study presented at the annual meeting of the Endocrine Society.

With increased mortality and similar prevalence of atrial fibrillation and femoral fractures between study and control groups, physicians may want to reevaluate giving their elderly patients levothyroxine until more information is available, according to presenter Joseph Meyerovitch, MD, of Schneider Children’s Medical Center, Ramat Hasharon, Israel.

The case-control study included 416 patients 65 years or older with TSH levels of 4.2-10 mIU/L who died between 2012 and 2016, and 1,461 patients with comparable TSH levels who did not die during that time.

Most of the patients in both the control and study group were women. The average age of the patients was 84 years, and most had some form of dementia or senility (86.4%).

Mortality was 19% more likely in the group taking levothyroxine, according to an analysis by Dr. Meyerovitch and his fellow investigators.

When broken down further, presence of certain comorbidities increased mortality dramatically, including dementia (odds ratio, 1.61), heart failure (OR, 2.67), chronic renal failure (OR, 1.89), and cerebrovascular disease (OR, 1.94).

There was no significant difference in prevalence of atrial fibrillation between the test and control groups with thyroid stimulating hormone (TSH) testing, nor any difference in femur fracture prevalence.

Patients were given a TSH test three times during follow-up and showed significantly lower TSH levels compared with controls, according to Dr. Meyerovitch.

Dr. Meyerovitch acknowledged that the data he and his team used did not include the reason for a TSH evaluation, nor why patients began levothyroxine treatment. This leaves unanswered questions about the initial baseline mortality risk in patients included in the study.

“This may have resulted in treatment of patients with a higher risk, since we don’t know the reason for the treatment,” he said. “There may have been other reasons that were not included in the database that caused the physician to treat with levothyroxine.”

Details on the cause of death were not included.

Despite these limitations, Dr. Meyerovitch and his team stressed the need for more research before continuing to recommend this treatment to their elderly patients.

Dr. Meyerovitch reported no relevant financial disclosures.

ezimmerman@mdedge.com

Source: Meyerovitch J et al. ENDO 2018 Abstract OR34-2.

Levothyroxine may increase mortality in older patients