In the Journals

Hypothyroidism a risk factor for new-onset diabetes

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June 25, 2015

Hypothyroidism is a risk factor for diabetes regardless of statin use, and subclinical hypothyroidism is a risk factor for statin-associated diabetes, according to research in Diabetes Care.

Naomi Gronich , MD, of Carmel Medical Center and the Israel Institute of Technology, and colleagues at other institutions conducted a two-phase investigation combining high-throughput, in silico biomedical data analysis and an observational cohort study. The researchers analyzed electronic medical data from 20,334 patients without diabetes who began statin treatment from 2004 to 2005 (mean age, 63 years; 42% men) who were randomly matched by propensity score to 39,263 non-statin users (mean age, 64 years; 36% men).

Researchers identified participants through electronic medical records from Clalit Health Services in Israel, and followed patients until December 2010. Researchers evaluated the cohorts for thyroid disease as a risk factor for diabetes, assigning each patient a thyroid status: subclinical hypothyroidism, untreated hypothyroidism, hypothyroidism treated with hormone replacement, hyperthyroidism or normal thyroid function (euthyroidism).

Researchers found that highly compliant statin users (those taking at least 80% of their prescribed statin doses in a follow-up of 5 to 7 years) had a risk ratio of 2.57 to develop diabetes (95% CI, 2.45-2.70). According to a multivariable model, hypothyroidism and subclinical hypothyroidism carried an increased risk for diabetes, with rate ratios of 1.53 (95% CI, 1.31-1.79) and 1.75 (95% CI, 1.40-2.18), respectively. Hypothyroidism increased the risk for developing diabetes regardless of statin use, with an increased rate ratio of 2.06 (95% CI, 1.42-2.99) in statin users and 1.66 (95% CI, 1.05-2.64) in non-users. Subclinical hypothyroidism increased the risk for developing diabetes only among statin users, who had a rate ratio of 1.94 (95% CI, 1.13-3.34).

“While subclinical hypothyroidism does not carry increased risk compared with euthyroidism, subclinical hypothyroid patients treated with statins are at increased risk for diabetes mellitus, due to the additive effects of statins and the subclinical hypothyroid state on diabetes mellitus risk,” Gronich told Endocrine Today.

Researchers also found that patients who were treated with thyroid HT therapy for their hypothyroidism were not at an increased risk for developing diabetes.

More prospective cohort studies with long term follow-up on hypothyroid patients are needed to confirm the findings, Gronich said.

“Hypothyroidism and subclinical hypothyroidism are pathological conditions that are easy to monitor and treat,” the researchers wrote. “Detecting and correcting hypothyroidism and considering treating subclinical hypothyroidism before initiating a statin are strategies that can potentially decrease [diabetes] incidence.” by Regina Schaffer

Disclosure: Gronich reports no relevant financial disclosures. Two of the study authors are employees of Biovista Inc., a company specializing in drug repurposing and adverse drug prediction.