A study published in Archives of Internal Medicine reveals that younger patients with subclinical hypothyroidism (SCH) who receive the medication levothyroxine are less likely to experience ischemic heart disease events. However, according to the researchers, this finding was not seen in older patients.

SCH is a relatively common condition in which the thyroid gland does not produce enough thyroid hormone. Although the condition is often asymptomatic, recent studies have indicated that SCH is linked with increased cardiovascular events and mortality, especially in young and middle-aged patients. However, the researchers highlight that those epidemiologic associations do not verify that treatment of SCH would be effective.

The researchers explain:

“Thus, only adequately powered randomized controlled intervention trials will be able to demonstrate whether treatment of SCH is worthwhile in terms of improvement in both cardiovascular disease risk and symptoms. However, such a trial has not been performed to date and no such trials are ongoing.”

Using the United Kingdom General Practitioner Research Database, Salman Razvi, M.D., F.R.C.P., of Gateshead Health National Health Service Foundation Trust and Newcastle University, England, and colleagues, identified 3,093 younger patients (40-70 years old) with SCH and 1,642 patients aged 70+.

Levothyroxine was used to treat 49.9% of older patients and 52.8% of younger patients.

In the older group, the researchers found 104 incident IHD events among 819 patients treated with levothyroxine (12.7%) vs. 88 events among 823 untreated patients (10.7%). In the younger group, there were 68 events among treated patients (4.2%) vs. 97 events among 1,459 untreated patients (6.6%).

The researchers conclude:

“In conclusion, treatment with levothyroxine was associated with fewer IHD events and reduced all-cause mortality during an eight-year period of observation in 40 to 70-year-old individuals with SCH but not in those who were older. A prospective randomized controlled trial is required to confirm these findings.”

Written By Grace Rattue