Increased prevalence of subclinical hypothyroidism in common bile duct stone patients

CONTEXT: 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. OBJECTIVE: In this study, the prevalence of previously undiagnosed subclinical hypothyroidism in CBD stone patients was compared with nongallstone controls. PATIENTS: 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). MAIN OUTCOME MEASURES: 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. RESULTS: 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). CONCLUSION: 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.