Assessment of Thyroid Function in Patients with Parkinson’s Disease

INTRODUCTION: The study aims to observe thyroid dysfunction, its prevalence, and the relationship between the Unified Parkinson’s Disease Rating Scale (UPDRS) and thyroid function in Parkinson’s patients.
METHODS: Seventy patients with Parkinson’s disease (PD) and 60 age-and sex-matched controls were enrolled in the study. PD patients were divided into tremor dominant-type (TDT) and akinetic-rigid-type (ART) subgroups. Serum fT4, TSH, and Anti TPO levels of patients were retrospectively reviewed. The results of the patients were compared with the controls, and the relationship between the UPDRS score and thyroid hormone levels was observed.
RESULTS: The mean levels of TSH and fT4 were higher in PD patients, but the difference was not statistically significant. TDT and ART subgroups did not show differences in age, UPDRS motor score, and TSH level. Only 1 (1.42%) female patient had hypothyroidism in the TDT subgroup. Three females and 2 males had subclinical hyperthyroidism in the PD group (2 females and 2 males in TDT and 1 female in the ART subgroup). The fT4 level and subclinical hyperthyroidism were significantly higher in the TDT subgroup than in ART. None of the patients in the PD group had hyperthyroidism or subclinical hypothyroidism. The prevalence of subclinical hyperthyroidism was higher in the PD group and the prevalence of hypothyroidism did not differ between the two groups. There was no significant relationship between the UPDRS score and thyroid hormone levels or anti-TPO.
DISCUSSION AND CONCLUSION: Thyroid dysfunction in Parkinson’s patients may cause difficulties in the treatment and follow-up process, as thyroid hormone levels may aggravate or camouflage Parkinson’s symptoms. In the study, the frequency of subclinical hyperthyroidism was higher in PD patients. The mean fT4 level and subclinical hyperthyroidism in TDT were significantly higher than those with ART. In addition, there was no correlation between the severity of the disease and the thyroid results. Thyroid tests should be carefully evaluated to facilitate treatment regulation in Parkinson’s disease.