Significance of Anti-TPO as an Early Predictive Marker in Thyroid Disease

Abstract

Even though most thyroid subjects are undiagnosed due to nonspecific symptoms, universal screening for thyroid disease is not recommended for the general population. In this study, our motive is to showcase the early appearance of thyroid autoantibody, anti-TPO, prior to the onset of thyroid hormone disruption; hence the addition of anti-TPO in conjunction with traditional thyroid markers TSH and FT4 would aid to reduce the long-term morbidity and associated health concerns. Here, a total of 4581 subjects were tested multiple times for TSH, FT4, anti-TPO, and anti-Tg and followed up for 2 years. We streamlined our subjects into two groups, A1 (euthyroid at first visit, but converted to subclinical/overt hypothyroidism in follow-up visits) and A2 (euthyroid at first visit, but converted to hyperthyroidism in follow-up visits). According to our results, 73% of hypothyroid subjects (from group A1) and 68.6% of hyperthyroid subjects (from group A2) had anti-TPO 252 (±33) and 277 (±151) days prior to the onset of the thyroid dysfunction, respectively. Both subclinical/overt hypothyroidism and hyperthyroidism showed a significantly higher percentage of subjects who had anti-TPO prior to the onset of thyroid dysfunction compared to the combined control group. However, there was no significant difference in the subjects who had anti-Tg earlier than the control group. Further assessment showed that only anti-TPO could be used as a standalone marker but not anti-Tg. Our results showcase that anti-TPO appear prior to the onset of thyroid hormone dysfunction; hence testing anti-TPO in conjunction with TSH would greatly aid to identify potentially risk individuals and prevent long-term morbidity.

Figure 1

The prevalence of anti-TPO (anti-TPO-Early, blue) and anti-Tg (anti-Tg-Early, orange) prior to the onset of subclinical/overt hypothyroidism compared to the combined control groups. Anti-TPO combined control group (blue) consists of anti-TPO-Parallel, anti-TPO-Following, and anti-TPO-None. Anti-Tg combined control group (orange) consists of anti-Tg-Parallel, anti-Tg-Following, and anti-Tg-None.

Figure 2

The prevalence of anti-TPO (anti-TPO-Early, blue) and anti-Tg (anti-Tg-Early, burgundy) prior to the onset of subclinical/overt hyperthyroidism compared to the combined control groups. Anti-TPO combined control group (blue) consists of anti-TPO-Parallel, anti-TPO-Following, and anti-TPO-None. Anti-Tg combined control group (burgundy) consists of anti-Tg-Parallel, anti-Tg-Following, and anti-Tg-None.

Figure 3

Comparison of the prevalence of anti-TPO (light blue/dark blue), anti-Tg (orange/burgundy) and combined anti-TPO or anti-Tg (grey) in subjects converted to subclinical/overt hypothyroidism (group A1) and hyperthyroidism (group A2).