Hypothyroidism and its Association with Systemic Lupus Erythematosus: A Cross Sectional Study in Chinese Patients

BACKGROUND

Specific factors correlated with hypothyroidism in systemic lupus erythematosus (SLE) patients remain unclear. Therefore, we aim to evaluate the prevalence of thyroid dysfunction in Chinese patients with SLE and the relationship between clinical hypothyroidism and SLE.

METHODS

We conducted a cross sectional study of the prevalence of thyroid dysfunction in 672 patients with SLE and 605 age- and sex-matched healthy controls. Demographic, clinical, and biochemical data were compared between 58 patients with SLE with hypothyroidism and 197 patients with SLE with euthyroidism. Multivariate analysis was performed using binomial logistic regression analysis. Spearman's rank correlation was used to identify an association between thyroid function and disease activity.

RESULTS

The prevalence of thyroid dysfunction was significantly higher in patients with SLE than in controls (70.7% vs 19.7%). SLE was associated with higher rates of hypothyroidism (9.6%, P ≤ 0.001) and euthyroid sick syndrome (49.6%, P ≤ 0.001) compared with control subjects. Further analyses showed that hypothyroidism in patients with SLE was associated with high blood pressure, renal disorder, high serum creatinine, high uric acid, hyperlipidaemia, low C3 and C4, positive anti-dsDNA antibodies, and high SLE disease activity index (SLEDAI) score. In multiple logistic regression models, albumin, platelet count, serum creatinine, and anti-dsDNA antibodies were associated with hypothyroidism. Finally, free tri-iodothyronine was significantly negatively correlated with SLEDAI score.

CONCLUSIONS

Hypothyroidism was more prevalent in patients with SLE. There was a relationship between hypothyroidism with renal disorder and lupus activity. Albumin, platelet count, serum creatinine, and anti-dsDNA antibodies were correlated with hypothyroidism.

Application of principal component analysis and logistic regression model in lupus nephritis patients with clinical hypothyroidism

Background

Previous studies indicate that the prevalence of hypothyroidism is much higher in patients with lupus nephritis (LN) than in the general population, and is associated with LN’s activity. Principal component analysis (PCA) and logistic regression can help determine relevant risk factors and identify LN patients at high risk of hypothyroidism; as such, these tools may prove useful in managing this disease.

Methods

We carried out a cross-sectional study of 143 LN patients diagnosed by renal biopsy, all of whom had been admitted to Xiangya Hospital of Central South University in Changsha, China, between June 2012 and December 2016. The PCA–logistic regression model was used to determine the influential principal components for LN patients who have hypothyroidism.

Results

Our PCA–logistic regression analysis results demonstrated that serum creatinine, blood urea nitrogen, blood uric acid, total protein, albumin, and anti-ribonucleoprotein antibody were important clinical variables for LN patients with hypothyroidism. The area under the curve of this model was 0.855.

Conclusion

The PCA–logistic regression model performed well in identifying important risk factors for certain clinical outcomes, and promoting clinical research on other diseases will be beneficial. Using this model, clinicians can identify at-risk subjects and either implement preventative strategies or manage current treatments.

One-decade study of distinct features, morbidity and mortality of systemic lupus erythematosus (an update on systemic lupus erythematosus in the Fars Province of Iran)

OBJECTIVE

The objective of this article is to investigate the distinct features, morbidity and mortality of systemic lupus erythematosus (SLE) patients registered in rheumatology tertiary centers of Shiraz University of Medical Sciences from 2008 to 2018.

METHOD

A cross-sectional study was conducted on registered patients by reviewing their medical records. The clinical presentations were classified based on each organ's distinct involvement.

RESULT

Data of 1322 patients with a mean age of 40 at the time of the study were reviewed. The most common primary manifestation of the disease was arthralgia (37.5%), and the most common clinical presentation in course of the disease was skin involvement (61.8%). The most common cause of hospital admission was disease flare (27.8% (108/388)), and mortality was mainly due to pulmonary complications (27.5% (8/29)). Patients who had hypothyroidism had statistically significantly lower rates of constitutional symptoms (p = 0.006), gastrointestinal involvement (p = 0.024), hypertension (p = 0.002), headache (p = 0.019), depression (p = 0.049) and anemia (p = 0.014). Patients who presented with malar rash and photosensitivity in their course of disease were detected to have statistically significantly lower ages of disease onset (p = 0.013 and 0.003, respectively).

CONCLUSION

This study is an update to an epidemiologic study conducted in 2008 in the south of Iran. By comparing results between the two studies, we have tried to investigate the change in morbidity and mortality of SLE during these years.

Autoimmune thyroid disease in a cohort of Malaysian SLE patients: frequency, clinical and immunological associations

Autoimmune thyroid disease (ATD) has been associated with other systemic autoimmune diseases. To date, there is limited data on thyroid disorders and autoimmune thyroid disease in Malaysia. The frequency of ATD among 189 systemic lupus erythematosus (SLE) patients was 6.3%, with 2.6% in the hyperthyroid group and 3.7% in the hypothyroid group. Hypothyroidism developed at a much younger mean age (24.3 years), suggesting that SLE might be a predisposing factor for the development of Hashimoto's thyroiditis. There was a higher rate of thyroid peroxidase antibody (TPO) positivity compared with anti-thyroglobulin antibody (Tg) in the hyperthyroid subgroup. This study also demonstrated a greater proportion of ATD patients who demonstrated high titres (≥ 1:6400) of TPO compared with high titres of Tg. Although there was an association between ATD and the presence of anti-Ro/SSA and/or anti-La/SSB antibodies, the absence of sicca symptoms and negative Schirmer's tests suggest a lack of association with secondary Sjogren's syndrome. A novel association between ATD and antiphospholipid syndrome (APS) was detected in our cohort. Hence we propose that patients affected by APS be routinely screened for ATD.

Subclinical hypothyroidism and its association with lupus nephritis: a case control study in a large cohort of Chinese systemic lupus erythematosus patients

The aim of this study was to evaluate the prevalence of thyroid diseases in Chinese systemic lupus erythematosus (SLE) patients and the relevance of subclinical hypothyroidism (SCH) with lupus nephritis (LN). A large cohort of 1006 SLE patients was retrospectively analyzed. The prevalence of autoimmune thyroid disease was 2.78%, clinical hypothyroidism 1.69%, subclinical hypothyroidism 10.04%, central hypothyroidism 1.29%, hyperthyroidism 1.19%, euthyroid sick syndrome (ESS) 9.54%, and nodules 1.09%, respectively. Compared with the prevalence of thyroid abnormalities in the general Chinese population (0.91–6.05%), SCH was much higher (10.04%) in this study. In addition, SCH was more frequent in patients with LN (13.4%) than those without LN (7.3%, p = 0.001). Case control study was performed to explore the relative risk factors of SCH. In multiple logistic regression models, 24 h urine protein and estimated glomerular filtration rate (eGFR) were retained as independent correlates of SCH after adjusting for demographic variables, risk factors, and other potential confounders. The results of the present study suggest that SCH is a common complication in SLE patients, and closely related with LN.