Background: Thyroid diseases are commonly encountered in the population though it is unanswered for whom screening tests are useful. We aimed to see the value of TSH screening and to find out comorbidities of any thyroid diseases among these patients who were diagnosed by screening.
Method: All consecutive patients (n: 796) who admitted to outpatient Clinics of Internal Medicine, between 1 and 31 January 2007 were recruited in the study. Age, gender, final diagnosis were recorded. TSH levels were measured by chemiluminesance method (Roche Diagnostics GmbH, Mannheim, Germany). When they were found out of reference values, after two weeks, TSH levels were repeated and FT3 and FT4 levels were also measured by the same method.
Results: Data were collected from 796 patients (393 male, 403 female). Thirty-seven patients had been followed up with known thyroid disease. Among these 10 were hyperthyroid, 10 were hypothyroid despite treatment and 17 were euthyroid. 55 (7.2%) subclinical hyperthyroidism (TSH: 0.12±0.08 μIU/ml), 48 (6.3%) subclinical hypothyroidism (TSH: 6.24±2.76 μIU/ml) and 4 (0.5%) overt thyroid disease (3 hypothroidism and 1 hyperthyroidism) were diagnosed. Subclinical hyperthyroidism and hypothyroidism rates were found similar with overt thyroid disfunction. Subclinical hypothyroidism was more common among women than men (68 vs 32%, P=0.001) although there was not such a relation for subclinical hyperthyroidism (P=0.919). With regard to comorbidities we could not find a significant relation between cardiovascular disease or hypertension in both subclinical thyroid diseases (P>0.05). There was a slight increase of diabetes mellitus in subclinical hyperthyroid group (P=0.08), compared to subclinical hypothyroid group (P=0.367).
Conclusion: Although it is not clearly supported by our study, considering the burden of comorbidity of thyroid dysfunction, we recommend TSH screening for patients with diabetes and cardiovascular disease, especially for women.