Association of Subclinical hypothyroidism with clinical symptomatology

Introduction: Subclinical hypothyroidism (SCH) often remains undetected because of the absence of clinical symptoms or unspecific symptomatology. The aim of the study was to discover whether SCH is associated with relevant clinical symptomatology.
Material and methods: The study included 69 consecutive patients, in whom SCH was detected for the first time (level of serum thyrotropin (TSH) between 4.2-20 mU/l with the reference values of free thyroxine (fT4) 10.3-24.45 pmol/l) and a control group of 30 healthy subjects without goiter and with reference values of fT4 and TSH (0.2-4.2 U/l). All participants completed a previously prepared anamnestic questionnaire and blood was taken for evaluation of TSH and fT4.
Results: Patients with SCH unlike the control group presented significantly more often with: fatigue, dry skin, insomnia and menorrhagia (in all cases p<0.05). There was a positive correlation between serum concentrations of TSH and percentage of symptoms of hypothyroidism (r= 0.25, p=0.04). Value of TSH over 7.1mU/l was associated with a significantly larger number of symptoms.
Conclusion: SCH is associated with fatigue, dry skin, insomnia and menorrhagia, that justifies initiating thyroid replacement therapy at low values of TSH. Instead of the current recommendations for beginning thyroid replacement therapy when TSH >10mU/l, the cut-off value should be moved to TSH >7,1mU/l.