Thyroid dysfunction in a prospectively followed series of patients with progressive systemic sclerosis

Abstract

Thirty-nine patients with progressive systemic sclerosis (PSS) in stable clinical conditions were extensively evaluated for the presence of thyroid disease. Two patients had previously undetected hypothyroidism while 7 additional patients had normal serum thyroid hormone levels but an exaggerated TSH response to thyrotropin-releasing hormone (TRH) administration, consistent with subclinical hypothyroidism. Four of the 9 subjects with abnormal TRH responses had positive antithyroid antibodies and of the remaining 5, 4 had been on chlorambucil or prednisone. Basal TSH and TSH response to TRH were significantly higher in PSS patients as a group when compared to a control group and increased with increasing duration of PSS. Serum antithyroid antibodies (antithyroglobulin and/or antimicrosomal antibodies) were positive in 18% and thyroid scans were abnormal in 18% of the patients. The euthyroid sick syndrome was not seen. Our findings indicate an increased frequency of, sometimes previously unsuspected, clinical and subclinical hypothyroidism in stable PSS patients which appears to be autoimmune in nature and becomes more prevalent with increased PSS duration. Careful and regular monitoring of the thyroid function in PSS patients is advisable.

Clinical and subclinical autoimmune thyroid disorders in systemic sclerosis

“…This indicates that the control was not biased towards a lower hypothyroidsm prevalence in comparison with the general population and that the current results agree closely with those reported by a population-based survey so far in the literature (35), which showed a 8% prevalence for subclinical hypothyroidism in females over the age of 40 years (36). Interestingly, mean TSH value was significantly higher in SSc than in controls, in agreement with other studies (10,12,13). Autoimmune phenomena are an almost constant feature of patients with SSc (1-6).…”

“…Population studies have shown the prevalence of AbTPO to be around 10% in females (range 10-15%), and it increases with age (from 8% in females over 18 years of age to about 30% in women over 70) (35,36). In our female controls, the prevalence of AbTPO positivity was 19%, similar or higher than that reported in some studies in SSc (18-19%) (12,14) and fully in the range of the reported ageadjusted prevalence rates for the Italian population (29,34) and for other population-based surveys (35,36). In female SSc the prevalence of AbTPO positivity was 39%, significantly higher.…”

“…This wide range may be at least partially explained by application of steroids and immune suppressive drugs in SSc, and by the different gender and age composition (23) and iodine intake of SSc patients. In most of the older studies AbTg were more common than antimicrosomal antibodies (11,(16)(17)(18), while in the more recent ones a higher prevalence of AbTPO was found (12)(13)(14)(15). The results of our study demonstrate a significantly higher titer and prevalence of AbTPO, but not of AbTg, both in female and in male SSc than in controls.…”

“…However, most of them do not have an appropriate control group to evaluate the relative risk or odds ratio (OR) of hypothyroidism (8)(9)(10)(11)(12)(13)(14), even if three of them reported a higher mean TSH level in SSc patients than in controls (10,12,13). Furthermore, none take into account iodine intake, which is a major determinant of thyroid disorders, and do not include a complete thyroid work-up (thyroid scan was evaluated only in the study by De Keyser et al (12), while thyroid ultrasonography, which has been progressively becoming one of the most important tools in the diagnosis of thyroid disorders, has never been evaluated in SSc patients). For other thyroid disorders such as Graves' disease (20)(21)(22), central hypothyroidism (23), euthyroid sick syndrome (24), thyroid nodules and thyroid cancer (23,25,26) only anecdotal reports are present in the literature.…”

Prevalence of thyroid autoantibodies in patients with systematic autoimmune rheumatic diseases. Cross-sectional study

“…SSc patients showed a higher odds ratio for the presence of antithyroid antibodies. According to the literature, the percentage of antithyroid antibodies in SSc ranges from 12 to 52% [36][37][38][39][40][41] and the percentage of hypothyroidism from 2.4 to 26%. 38,42 A previous study showed that presence of hypothyroidism in SSc patients was associated with higher prevalence of pulmonary hypertension.…”