Prevalence of Thyroid Antibodies in Hyperthyroid patients treated at BMA Medical College and Vajira Hospital

Abstract

Prevalence of Thyroid Antibodies in Hyperthyroid patients treated at BMA Medical College and Vajira Hospital

Suvimol Rimdusid MT*

Swangjit Sura-amornkul MD, MSc**

Prapun Rimdusid MD***

* Radioimmunoassay (RIA) laboratory, Division of Nuclear Medicine, Department of Radiology, BMA Medical College and Vajira Hospital

** Department of Medicine, BMA Medical College and Vajira Hospital

** Medical Department, Trang-ruampat Hospital

Objectives: To study the prevalence of abnormally high thyroid peroxidase (TPO) antibody and thyroglobulin antibody in hyperthyroid patients and to evaluate the association of these antibodies with other clinical characteristics of hyperthyroid patients.

Study design: Descriptive study.

Subjects: 133 hyperthyroid patients with high T3 , total T4 , free T4 and low thyroid stimulating hormone (TSH), who underwent laboratory investigations at RIA laboratory, Division of Nuclear Medicine, Department of Radiology, BMA Medical College and Vajira Hospital during September 2004 and February 2005 were enrolled.

Methods: Demographic data, thyroid hormone level and thyroid antibodies level of the patients were collected from hospital and laboratory records.

Main outcome measures: TPO antibody level and thyroglobulin antibody level.

Results: Mean age of the patients was 39.0 ± 13.8 years old. Female to male ratio was 3.4:1. The etiologies of hyperthyroidism were: Graves' disease (101 cases), toxic multinodular goiter (21 cases), and others (11 cases). Median value of free T4 was high at 4.2 (0.8-6.0) ng/dL while median TSH level was low at 0.012 (0-6.9) IU/mL. Abnormally high level of TPO and thyroglobulin antibody were detected in 80.5% and 67.7% of hyperthyroid patients, respectively. In patients with Graves' disease, high TPO antibody level was found in 85.1%. There was statistically significant association between Graves' disease and TPO antibody, but not with thyroglobulin antibody. No association between thyroid antibodies and age, gender were observed.

Conclusion: The prevalence of abnormally high TPO antibody and thyroglobulin antibody in hyperthyroid patients, especially in Graves' disease, were high. There was statistically significant association between Graves' disease and TPO antibody.

Vajira Med J 2008 ; 52 : 159 - 165