Increased prevalence of subclinical hypothyroidism in common bile duct stone patients

Earlier, we have shown an increased prevalence of previously diagnosed hypothyroidism in common bile duct (CBD) stone patients and a delayed emptying of the biliary tract in hypothyroidism, explained partly by the missing prorelaxing effect of T(4) on the sphincter of Oddi contractility.

In this study, the prevalence of previously undiagnosed subclinical hypothyroidism in CBD stone patients was compared with nongallstone controls.

All patients were clinically euthyreotic and without a history of thyroid function abnormalities. CBD stones were diagnosed at endoscopic retrograde cholangiopancreatography (group 1; n = 303) or ruled out by previous medical history, liver function tests, and ultrasonography (control group II; n = 142).

Serum free FT(4) and TSH (S-TSH) were analyzed; S-TSH above the normal range (>6.0 mU/liter) was considered as subclinical and S-TSH 5.0-6.0 mU/liter as borderline-subclinical hypothyroidism.

A total of 5.3 and 5.0% (total 10.2%; 31 of 303) of the CBD stone patients were diagnosed to have subclinical and borderline-subclinical hypothyroidism, compared with 1.4% (P = 0.05) and 1.4% (total 2.8%, four of 142; P = 0.026) in the control group, respectively. In women older than 60 yr, the prevalence of subclinical hypothyroidism was 11.4% in CBD stone and 1.8% in control patients (P = 0.032) and subclinical plus borderline-subclinical hypothyroidism 23.8% in CBD stone and 1.8% in control patients (P = 0.012).

Subclinical hypothyroidism is more common in the CBD stone patients, compared with nongallstone controls, supporting our hypothesis that hypothyroidism might play a role in the forming of CBD stones. At minimum, women older than 60 yr with CBD stones should be screened for borderline or overt subclinical hypothyroidism.