Autoimmune thyroid disease and rheumatoid arthritis: relationship and the role of genetics

Demographic and clinical associations of autoimmune diseases in rheumatoid arthritis patients: Insights from a tertiary care hospital in Saudi Arabia from 2019 to 2023

Background

Rheumatoid arthritis is a severe inflammatory arthritis that causes irreversible damage to joints and bones, resulting in deformities and disabilities. Population-based studies on the co-occurrence in patients with rheumatoid arthritis are lacking despite shared mechanisms with other autoimmune diseases.

Objectives

This study aimed to determine the prevalence and association of autoimmune diseases among patients with rheumatoid arthritis and explore the associations between autoimmune diseases and treatment options for rheumatoid arthritis.

Method

This retrospective study was conducted from 2019 to 2023 at King Fahad Armed Forces Hospitals, Jeddah, Saudi Arabia. Data were cleaned in Excel and analyzed using IBM SPSS version 29. The activity of the disease was assessed through clinical manifestations, laboratory findings, and its associations with other autoimmune diseases.

Results

Our study included 365 patients with rheumatoid arthritis, predominantly female (89%), and observed diverse demographics and comorbidities. Prevalent conditions included diabetes mellitus (28.2%), hypertension (27.3%), and dyslipidemia (14.7%). Other autoimmune diseases were present in 24.9% of patients, with notable associations with age at rheumatoid arthritis diagnosis and endocrine, rheumatology/dermatology, and pulmonary disorders (p < 0.001). Treatment approaches varied, with prednisolone (24.4%) and methotrexate (55.1%) being predominant. No significant associations were observed between autoimmune disorders and specific treatment modalities (p > 0.05).

Conclusion

Our study provides a thorough overview of rheumatoid arthritis in a large cohort, revealing demographic trends, comorbidities, autoimmune disease prevalence, treatment preferences, and associations. Relationships with age at rheumatoid arthritis diagnosis and other autoimmune diseases were noted. Treatment approaches varied, with no significant associations between autoimmune disorders and specific modalities.

Investigating the Bidirectional Association of Rheumatoid Arthritis and Thyroid Function: A Methodologic Assessment of Mendelian Randomization

OBJECTIVE

Rheumatoid arthritis (RA) and thyroid dysfunction are frequently observed in the same patient. However, whether they co-occur or exhibit a causal relationship remains uncertain. We aimed to systematically investigate the causal relationship between RA and thyroid function using a large sample and advanced methods.

METHODS

Bidirectional two-sample Mendelian randomization (MR) analysis was performed based on RA and six thyroid function trait data sets from the European population. The robustness of the results was demonstrated using multiple MR methods and a series of sensitivity analyses. Multivariable MR using Bayesian model averaging (MR-BMA) was performed to adjust for possible competing risk factors. A sensitivity data set, which included data from patients with seropositive RA and controls, was used to repeat the analyses. Furthermore, enrichment analysis was employed to discover the underlying mechanism between RA and thyroid functions.

RESULTS

A significantly positive causal effect was identified for RA on autoimmune thyroid disease (AITD) as well as for AITD on RA (P < 0.001). Further sensitivity analyses showed consistent causal estimates from a variety of MR methods. After removing the outliers, MR-BMA results showed that RA and AITD were independent risk factors in their bidirectional causality, even in the presence of other competing risk factors (adjusted P < 0.05). Enrichment analysis showed immune cell activation and immune response play crucial roles in them.

CONCLUSION

Our results illustrate the significant bidirectional causal effect of RA and AITD, which holds even in multiple competing risk factors. Clinical screening for thyroid dysfunction in patients with RA deserves further attention, and vice versa.

Association Between Hashimoto's Thyroiditis and Rheumatoid Arthritis: A Bidirectional Mendelian Randomization Study

Background: We aim to investigate the possible causal association between Hashimoto's thyroiditis (HT) and rheumatoid arthritis (RA) using Mendelian randomization (MR) methods. Methods: A bidirectional MR analysis was conducted to evaluate the causal association between HT and RA. We obtained summary statistics data from two extensive genome-wide association studies (GWAS) comprising 15,654 cases of HT and 14,361 cases of RA. The primary effect estimate utilized in this study was the inverse-variance weighted (IVW) method. To ensure the reliability and stability of the results, we employed several additional methods for testing, including MR-Egger, weighted median, simple mode, weighted mode, and MR-PRESSO. Results: Our study revealed compelling evidence of bidirectional causality between HT and RA. When HT was considered as an exposure factor and RA was considered as an outcome factor, this study revealed a positive correlation between HT and RA (IVW: odds ratio [OR] = 2.4546, 95% confidence interval [CI], 1.1473-5.2512; p = 0.0207). Conversely, when we examined RA as the exposure factor and HT as the outcome factor, we still found a positive correlation between them (IVW: OR = 1.2113, 95% CI, 1.1248-1.3044; p = 3.9478 × 10-7). Conclusions: According to our research findings, there exists a bidirectional positive causal relationship between HT and RA among European populations. This implies that individuals with HT have an elevated risk of developing RA, and conversely, individuals with RA have an increased risk of developing HT.

Polyautoimmunity in Patients With Anticyclic Citrullinated Peptide Antibody-Positive and -Negative Rheumatoid Arthritis: a Nationwide Cohort Study From Denmark

OBJECTIVE

This study aimed to compare the prevalence and incidence of polyautoimmunity between anticyclic citrullinated peptide antibody (anti-CCP)-positive and anti-CCP-negative patients with rheumatoid arthritis (RA).

METHODS

In a nationwide register-based cohort study, patients with RA (disease duration ≤ 2 yrs) in the DANBIO rheumatology register with an available anti-CCP test in the Register of Laboratory Results for Research were identified. The polyautoimmunity outcome included 21 nonrheumatic autoimmune diseases identified by linkage between the Danish Patient Registry and Prescription Registry. The age- and sex-adjusted prevalence ratio (PR) was calculated by modified Poisson regression to estimate the prevalence at diagnosis in anti-CCP-positive vs anti-CCP-negative patients. The hazard ratio (HR) of polyautoimmunity within 5 years of entry into DANBIO was estimated in cause-specific Cox regression models.

RESULTS

The study included 5839 anti-CCP-positive and 3799 anti-CCP-negative patients with RA. At first visit, the prevalence of prespecified polyautoimmune diseases in the Danish registers was 11.1% and 11.9% in anti-CCP-positive and anti-CCP-negative patients, respectively (PR 0.93, 95% CI 0.84-1.05). The most frequent autoimmune diseases were autoimmune thyroid disease, inflammatory bowel disease, and type 1 diabetes mellitus. During a mean follow-up of 3.5 years, only a few (n = 210) patients developed polyautoimmunity (HR 0.6, 95% CI 0.46-0.79).

CONCLUSION

Polyautoimmunity as captured through the Danish National Patient Registry occurred in approximately 1 in 10 patients with RA at time of diagnosis regardless of anti-CCP status. In the years subsequent to the RA diagnosis, only a few and mainly anti-CCP-negative patients developed autoimmune disease.

Shared genetic architecture between hypothyroidism and rheumatoid arthritis: A large-scale cross-trait analysis

BACKGROUND

In recent years, mounting evidence has indicated a co-morbid relationship between hypothyroidism and rheumatoid arthritis (RA), however, the shared genetic factors underlying this association remain unclear. This study aims to investigate the common genetic architecture between hypothyroidism and RA.

METHODS

Genome-wide association study (GWAS) summary statistics from recently published studies were utilized to examine the genetic correlation, shared genetic loci, and potential causal relationship between hypothyroidism and RA. Statistical methods included linkage disequilibrium score regression (LDSC), high-definition likelihood (HDL), cross-trait meta-analyses, colocalization analysis, multi-marker analysis of genomic annotation (MAGMA), tissue-specific enrichment analysis (TSEA), functional enrichment analysis, and latent causal variable method (LCV).

RESULTS

Our study demonstrated a significant genetic correlation between hypothyroidism and RA(LDSC:rg=0.3803,p=7.23e-11;HDL:rg=0.3849,p=1.02e-21). Through cross-trait meta-analysis, we identified 1035 loci, including 43 novel genetic loci. By integrating colocalization analysis and the MAGMA algorithm, we found a substantial number of genes, such as PTPN22, TYK2, and CTLA-4, shared between the two diseases, which showed significant enrichment across 14 tissues. These genes were primarily associated with the regulation of alpha-beta T cell proliferation, positive regulation of T cell activation, positive regulation of leukocyte cell-cell adhesion, T cell receptor signaling pathway, and JAK-STAT signaling pathway. However, our study did not reveal a significant causal association between the two diseases using the LCV approach.

CONCLUSION

Based on these findings, there is a significant genetic correlation between hypothyroidism and RA, suggesting a shared genetic basis for these conditions.

Disease-modifying antirheumatic drugs and risk of thyroxine-treated autoimmune thyroid disease in patients with rheumatoid arthritis

BACKGROUND

Autoimmune thyroid disease (AITD) and rheumatoid arthritis (RA) share a genetic background, and the prevalence of AITD in RA patients is increased. Whereas immunomodulatory treatments are used in RA, they are rarely used in AITD.

OBJECTIVES

We hypothesized that disease-modifying antirheumatic drugs (DMARDs) as used in RA might lower the risk of incident AITD.

METHODS

A nationwide cohort study including 13,731 patients with new-onset RA from the Swedish Rheumatology Quality Register 2006-2018 and 63,201 matched general population comparators linked to national registers to identify AITD. We estimated relative risks (hazard ratios) of AITD after RA diagnosis in RA patients compared to the general population, and in relation to DMARD treatment, using Cox regression.

RESULTS

Following RA diagnosis, 321 (2.3%) of the RA patients and 1838 (2.9%) of the population comparators developed AITD, corresponding to an incidence of 3.7 versus 4.6 per 1000 person-years, hazard ratio, 0.81; 95% CI, 0.72-0.91. The decreased risk of incident AITD among RA patients compared to the general population was most pronounced among biologic DMARD (bDMARD) treated patients, with a hazard ratio of 0.54; 95% CI, 0.39-0.76. Among RA patients, subgrouped by bDMARD use, TNF-inhibitors were associated with the most pronounced decrease, hazard ratio, 0.67; 95% CI, 0.47-0.96.

CONCLUSIONS

In contrast to the increased prevalence of AITD in RA patients at diagnosis, our results indicate that the risk of AITD decreases following RA diagnosis. This decrease is especially pronounced in RA patients treated with bDMARDs. These findings support the hypothesis that DMARDs might have a preventive effect on AITD.

Thyroid Disease and Systemic Lupus Erythematosus

Background and Objectives: Thyroid disease has been associated with autoimmune disorders. As systemic lupus erythematosus (SLE) is a systemic autoimmune disease with diverse manifestations spanning across all organ systems, the relationship of SLE with thyroid disorders needs investigation. In particular, the relationship of SLE with autoimmune thyroid disease has attracted the interest of the research community. The aim was to evaluate the relationship of SLE with autoimmune thyroid disease. Materials and Methods: A cohort of 45 consecutive patients with a mean age of 47.97 years (range 21-79 years) and 45 age- and sex-matched controls were prospectively studied over a period of 12 months for the presence of thyroid disease and the prevalence of antithyroid antibodies. Results: Four patients (8.9%) were found to suffer from primary hypothyroidism, five (11.11%) from subclinical hypothyroidism and one (2.22%) from hyperthyroidism, whereas one (2.22%) of the controls had primary hypothyroidism and one (2.22%) had hyperthyroidism. Five patients (11.11%) had a thyroid hormone profile that was compatible with the presence of euthyroid sick syndrome. Thyroid peroxidase (TPOab) and thyroglobulin (Tgab) antibodies were detected in 20/45 and 15/45 of the SLE population and in 7/45 and 5/45 of the controls, respectively (p < 0.05, chi-square test). Conclusions: In conclusion, the incidence of clinical thyroid disease is greater amongst SLE patients than in a control population, and in a significant number of these patients, antithyroid antibodies are detectable. Thus, a subset of lupus patients appears to be predisposed to the development of thyroid disease, and this should be considered when evaluating patients with SLE.

The association between thyroid dysfunction, autoimmune thyroid disease, and rheumatoid arthritis disease severity

BACKGROUND

Rheumatoid Arthritis (RA) and autoimmune thyroid disease (AITD) are the two most prevalent coexisting autoimmune diseases due to their similar pathogenesis. Considering the potential effect of AITD on the severity of RA disease, this study aimed to determine the association between thyroid dysfunction, anti-thyroid peroxidase (anti-TPO) positivity, AITD, and RA disease severity in the Iranian population.

METHODS

Three hundred and fifty RA patients who presented to Shahid Beheshti tertiary care center, Qom, Iran, were included in this cross-sectional study. The data were collected through the patient's medical records, interviews, physical examinations, and laboratory tests. The RA disease activity score in 28 joints for RA with erythrocyte sedimentation rate (DAS-28-ESR) was used to divide patients into three subgroups, remission (DAS-28-ESR ⩽ 2.6), mild-to-moderate (2.6 < DAS-28-ESR ⩽ 5.1), and severe disease activity (DAS-28-ESR > 5.1).

RESULTS

Using the aforementioned method, 111, 96, and 138 patients were put into remission, mild-to-moderate, and severe disease activity groups, respectively. Anti-TPO antibody positivity rate was 2.93 times more prevalent among patients with severe disease compared to the remission subgroup (OR: 2.93; P-value < 0.001). Patients suffering from a more severe disease were almost 2.7 times more probable to have AITD (OR = 2.71; P-value < 0.001) and they were 82% more likely to have thyroid dysfunction compared to patients in remission (OR = 1.82; P-value = 0.006).

CONCLUSIONS

It was demonstrated that thyroid dysfunction, anti-TPO antibody positivity, and AITD were significantly more common among RA patients with more severe disease activity.

Autoimmune polyendocrine syndromes associated with autoimmune rheumatic diseases

Autoimmune polyendocrine syndromes (APSs), also called autoimmune polyglandular syndromes, are a group of autoimmune diseases characterized by the co-occurrence of dysfunctions of several (at least two) endocrine glands. They develop under the influence of environmental factors in genetically predisposed people. Autoimmune polyendocrine syndromes may accompany autoimmune rheumatic diseases and worsen their course - APS-2 and APS-3 are the most common. The APS-2 includes the coexistence of, e.g. Hashimoto's disease, celiac disease and rheumatoid arthritis (RA). In APS-3, rheumatic diseases such as RA, systemic lupus erythematosus, and Sjögren's syndrome may coexist with Hashimoto's disease, type 1 diabetes and hypogonadism or other endocrinopathies. Undiagnosed endocrine diseases may be the reason for the intensification of metabolic disorders observed in the course of rheumatic diseases, cause the ineffectiveness of rheumatological treatment and also increase the frequency of bone fractures due to osteoporosis, cardiovascular complications and even miscarriages when coexistent, e.g. Hashimoto's disease with hypothyroiditis, which increases the risk of pregnancy loss. It is important to be able to conduct an extensive interview, paying attention to the symptoms of possible endocrinopathy as well as the features of other autoimmune disorders in the physical examination (e.g. vitiligo or darkening of the skin in Addison's disease). Depending on the history and physical examination, screening for various APSs is advised.

A novel hybrid model to predict concomitant diseases for Hashimoto's thyroiditis

Hashimoto's thyroiditis is an autoimmune disorder characterized by the destruction of thyroid cells through immune-mediated mechanisms involving cells and antibodies. The condition can trigger disturbances in metabolism, leading to the development of other autoimmune diseases, known as concomitant diseases. Multiple concomitant diseases may coexist in a single individual, making it challenging to diagnose and manage them effectively. This study aims to propose a novel hybrid algorithm that classifies concomitant diseases associated with Hashimoto's thyroiditis based on sequences. The approach involves building distinct prediction models for each class and using the output of one model as input for the subsequent one, resulting in a dynamic decision-making process. Genes associated with concomitant diseases were collected alongside those related to Hashimoto's thyroiditis, and their sequences were obtained from the NCBI site in fasta format. The hybrid algorithm was evaluated against common machine learning algorithms and their various combinations. The experimental results demonstrate that the proposed hybrid model outperforms existing classification methods in terms of performance metrics. The significance of this study lies in its two distinctive aspects. Firstly, it presents a new benchmarking dataset that has not been previously developed in this field, using diverse methods. Secondly, it proposes a more effective and efficient solution that accounts for the dynamic nature of the dataset. The hybrid approach holds promise in investigating the genetic heterogeneity of complex diseases such as Hashimoto's thyroiditis and identifying new autoimmune disease genes. Additionally, the results of this study may aid in the development of genetic screening tools and laboratory experiments targeting Hashimoto's thyroiditis genetic risk factors. New software, models, and techniques for computing, including systems biology, machine learning, and artificial intelligence, are used in our study.

Thyroid Autoimmunity Is Not Associated with Embryo Quality or Pregnancy Outcomes in Euthyroid Women Undergoing Assisted Reproductive Technology in China

Background: Studies have shown that thyroid autoimmunity (TAI) is associated with increased risks of adverse pregnancy outcomes. The aim of this study was to investigate the associations between TAI and embryo quality in euthyroid women undergoing in vitro fertilization or intracytoplasmic sperm injection (IVF/ICSI). Methods: This retrospective cohort study included euthyroid infertile women with and without TAI (defined as a serum thyroperoxidase concentration ≥34 IU/mL or a thyroglobulin concentration ≥115.0 IU/mL) who underwent their first complete IVF/ICSI treatment cycles at a tertiary referral center between April 2016 and February 2022. Embryo quality measurements and clinical outcomes were compared between women with (TAI positive) and without TAI (TAI negative). The high-quality cleavage embryo rate and cumulative live birth rate (cLBR) were the primary outcomes. Results: A total of 499 TAI-positive and 2945 TAI-negative women were included in this study, and their mean (standard deviation) ages were 31.6 (4.5) and 30.9 (4.4) years, respectively (p = 0.001). The overall analysis showed no significant differences between TAI-negative and TAI-positive women in the high-quality cleavage embryo rate (n/N: 11,139/22,553 vs. 1971/3820; adjusted rate: 52.8% vs. 53.4%, p = 0.66) and cLBR (1917/2945 vs. 327/499; 53.4% vs. 56.2%, p = 0.31). Moreover, no significant differences were observed between TAI-negative and TAI-positive women in the rates of oocyte retrieval (35,078/51,978 vs. 5853/8628; 69.1% vs. 69.4%; p = 0.65), fertilization (23,067/34,197 vs. 3902/5728; 61.1% vs. 62.2%, p = 0.34), embryo utilization (18,233/22,553 vs. 3156/3820; 80.2% vs. 80.8%, p = 0.61), blastocyst formation (7051/13,721 vs. 1192/2330; 48.5% vs. 48.4%, p = 0.97), and high-quality blastocysts (4819/13,721 vs. 799/2330; 29.9% vs. 29.4%, p = 0.73). Furthermore, no significant differences were observed between TAI-negative and TAI-positive women in the clinical pregnancy rate (1524/2808 vs. 248/482; 46.7% vs. 44.6%, p = 0.40), early pregnancy loss rate (156/1524 vs. 23/248; 13.5% vs. 11.5%, p = 0.44), and LBR (1338/2808 vs. 218/482; 37.4% vs. 36.0%, p = 0.55) of the first transfer cycle. Conclusions: This study demonstrated that TAI in women was not associated with embryo quality or the cLBR following IVF/ICSI. Future large studies are warranted to confirm these findings.

Comorbidities at diagnosis of rheumatoid arthritis: a population-based case-control study

OBJECTIVES

Comorbidities contribute to the morbidity and mortality in RA, and are thus important to capture and treat early. In contrast to the well-studied comorbidity risks in established RA, less is known about the comorbidity pattern up until diagnosis of RA. We therefore compared whether the occurrence of defined conditions, and the overall comorbidity burden at RA diagnosis, is different from that in the general population, and if it differs between seropositive and seronegative RA.

METHODS

Using Swedish national clinical and demographic registers, we identified new-onset RA patients (n = 11 086), and matched (1:5) to general population controls (n = 54 813). Comorbidities prior to RA diagnosis were identified in the Patient and Prescribed Drug Registers, and compared using logistic regression.

RESULTS

At diagnosis of RA, respiratory (odds ratio (OR) = 1.58, 95% CI: 1.44, 1.74), endocrine (OR = 1.39, 95% CI: 1.31, 1.47) and certain neurological diseases (OR = 1.73, 95% CI: 1.59, 1.89) were more common in RA vs controls, with a similar pattern in seropositive and seronegative RA. In contrast, psychiatric disorders (OR = 0.87, 95% CI: 0.82, 0.92) and malignancies (OR = 0.88, 95% CI: 0.79, 0.97) were less commonly diagnosed in RA vs controls. The comorbidity burden was slightly higher in RA patients compared with controls (P <0.0001).

CONCLUSION

We found several differences in comorbidity prevalence between patients with new-onset seropositive and seronegative RA compared with matched controls from the general population. These findings are important both for our understanding of the evolvement of comorbidities in established RA and for early detection of these conditions.

The prevalence of thyroid autoantibodies in autoimmune connective tissue diseases: a systematic review and meta-analysis

AIM

Patients with autoimmune connective tissue disease (ACTD) may have anti-thyroid peroxidase antibody (TPOAb) and anti-thyroglobulin antibody (TgAb). This study aimed to compare the prevalence of thyroid autoantibodies in ACTD patients and controls.

METHODS

All case-control studies published between 1980 and 2019 in English were searched from Medline, Embase, Web of Science, PubMed databases for meta-analysis and subgroup analyses.

RESULTS

Total 10,321 ACTD cases and 12,949 healthy controls were included, and the prevalence of thyroid autoantibody positivity was higher in ACTD patients than in controls. Subgroup analysis revealed positive association between TgAb and ACTD in populations from all continents including European, Asian, African, and American. In addition, we found positive association between TgAb positivity and most ACTD cases including RA, SLE, pSS, and UCTD, positive association between TPOAb positivity and all ACTD cases including RA, SLE, pSS, SSc, and UCTD, and positive association between TPOAb positivity and ACTD in European, Asian, and African but not in American populations.

CONCLUSION

Thyroid autoantibodies are more prevalent in ACTD patients than in healthy controls. It is important to screen patients with ACTD for the presence of thyroid autoimmunity, and perform thyroid function tests in clinical evaluation of ACTD patients.

Does autoimmune thyroid disease affect rheumatoid arthritis disease activity or response to methotrexate?

OBJECTIVE

To investigate if autoimmune thyroid disease (AITD) impacts rheumatoid arthritis (RA) disease activity or response to methotrexate.

METHODS

A nationwide register-based cohort study of 9 004 patients with new-onset RA from the Swedish Rheumatology Quality Register year 2006-2016, with linkage to other nationwide registers to identify comorbidity with AITD defined as thyroxine prescription before RA diagnosis, excluding non-autoimmune causes. We compared RA disease activity using 28-joint Disease Activity Score (DAS28) and its components, and EULAR response, between patients with and without AITD, using logistic regression.

RESULTS

At diagnosis, patient reported outcome measures (PROMs; patient global, Health Assessment Questionnaire Disability Index and pain) but not objective disease activity measures (erythrocyte sedimentation rate and swollen joint count) were significantly higher (p<0.05 for all PROMs) among RA patients with AITD compared with those without. The level of DAS28 was 5.2 vs 5.1. By contrast, AITD had little influence on EULAR response to methotrexate at 3 months (OR of non/moderate response=0.95, 95% CI 0.8 to 1.1), nor at 6 months. When stratified by age, however, AITD was more common among EULAR non/moderate responders at 3 and 6 months in patients below 45 years resulting in ORs of non/moderate response of 1.44 (0.76-2.76) and 2.75 (1.04-7.28).

CONCLUSION

At diagnosis, RA patients with concomitant AITD score worse on patient reported but not on objective RA disease activity measures, while DAS28 was only marginally elevated. The overall chance of achieving a EULAR good response at 3 or 6 months remains unaffected, although among a limited subgroup of younger patients, AITD may be a predictor for an inferior primary response.

Aspartic acid70 in the HLA-DRB1 chain and shared epitope alleles partially explain the high prevalence of autoimmunity in Mexicans

INTRODUCTION

Autoimmune thyroid disease (AITD) is the most common autoimmune disorder worldwide. Remarkably, it is commonly accompanied by other autoimmune diseases, such as rheumatoid arthritis (RA). The immunopathogenic mechanisms behind the coexistence of these disorders are still not completely understood. Immunogenetics influences the physiopathology of these diseases since ethnicity plays an essential role in the inheritance of susceptibility markers.

METHODS

High-resolution HLA class II typing was performed using a sequence-based method.

RESULTS

The allele frequency of HLA-DRB1∗04:04 and -DRB1∗03:01 were significantly increased in patients with AITD and RA compared to healthy individuals, pC ​= ​0.021, OR ​= ​2.4, 95%CI ​= ​1.19-4.75 and pC ​= ​0.009, OR ​= ​3.4, 95%CI ​= ​1.42-7.93, respectively. Remarkably, these patients have a combined risk given by susceptibility HLA-DRB1 alleles that contain the shared epitope, pC ​= ​0.03, OR ​= ​1.7, IC95% ​= ​1.07-2.76, and a lack of protective alleles carrying aspartic acid70, pC ​= ​0.009, OR ​= ​0.5, IC95% ​= ​0.32-0.84.

DISCUSSION

The results suggest that patients with AITD and RA have an immunogenetic mechanism that combines the susceptibility alleles associated with both diseases. Importantly, it seems to be linked mainly to the lack of protective alleles with aspartic acid in the position 70, along with the presence of susceptibility alleles that have the sequences QRRAA, QKRAA, and RRRAA at positions 70-74.

CONCLUSION

Patients with AITD and RA have a characteristic immunogenetic signature, which could be useful for determining multiple autoimmunities and assessing their relatives' risk of developing it.

Autoimmune thyroid disorders and rheumatoid arthritis: A bidirectional interplay

Rheumatoid arthritis (RA) and autoimmune thyroid disease (AITD) can occur in the same patient in the autoimmune polyglandular syndrome 2. The association of the two conditions has been recognized long-time ago and the prevalence of AITD in patients with RA and vice versa is well assessed. Geographical variation of AITD and related autoantibodies in RA patients is partly due to ethnic and environmental differences of the studied populations. The impacts of thyroid disorders on RA outcome and vice versa are still controversy. In both AITD and RA genetic susceptibility and environmental factors play a synergic role in the development of the diseases. In this review we aimed at investigating the association of AITD and thyroid autoantibodies with RA, the common pathogenic pathways, the correlation with RA disease activity, and influence of the treatment.

Anti-N-methyl-D-aspartate receptor encephalitis with accompanying ovarian teratoma in female patients from East China: Clinical features, treatment, and prognostic outcomes

PURPOSE

The association between anti-N-methyl-D-aspartate receptor encephalitis (anti-NMDAR encephalitis) and teratoma is formally recognized. This study compared the clinical features, treatments and outcomes between female patients with or without accompanying teratomas and determined the potential influences of coexisting teratomas.

METHOD

Fifty-six female patients diagnosed with anti-NMDAR encephalitis were enrolled in two major tertiary hospitals in East China from January 2013 through March 2018 and were grouped as patients with or without teratoma. The clinical features were reviewed, and follow-up studies were performed. Comparisons were made between the two groups.

RESULTS

Patients with teratoma reported fewer viral prodromes (p = 0.0085) and stronger positive intensity of anti-NMDAR antibodies in cerebrospinal fluid (CSF) (p = 0.0368), while nontumor patients tended to demonstrate lymphocytic pleocytosis in CSF (p = 0.0306). Seizure types varied between individuals, with complex partial seizures more common in teratoma patients (p = 0.0105). Nontumor patients frequently required combinations of first-line and second-line immunotherapy (p = 0.0014), which may be attributed to higher mRS scores at admission (p = 0.0300). Also, they had higher mean mRS scores since the 12-month follow-up and greater probability of relapse than did patients with teratomas (p = 0.0286).

CONCLUSIONS

Symptomatology and auxiliary findings indicate that ovarian teratoma may be the immunologic trigger for anti-NMDAR encephalitis patients, while viral infection is likely to play a major part in pathogenesis for those without any detectable tumor. Overall, anti-NMDAR encephalitis patients with teratomas present with milder neurological symptoms and have better long-term outcomes after tumor removal.

Children Born by Women With Rheumatoid Arthritis and Increased Susceptibility for Chronic Diseases: A Nationwide Cohort Study

OBJECTIVE

Fetal exposure to maternal rheumatoid arthritis (RA) might impact the long-term risk of disease in the offspring. We examined a possible association between maternal RA and 15 selected groups of chronic diseases in the offspring.

METHODS

This nationwide cohort study was based on the Danish health registries and included data on all children born alive in Denmark between January 1, 1989 and December 31, 2013. The cohort comprised 2,106 children born by women with RA (exposed), and 1,378,539 children born by women without RA (unexposed). Cox proportional hazards regression models were used, taking a large range of confounders into consideration, and the hazard ratios (HRs) of child and adolescent diseases were calculated.

RESULTS

In children exposed to maternal RA in utero, the HR of thyroid diseases was 2.19 (95% confidence interval [95% CI] 1.14-4.21), epilepsy 1.61 (95% CI 1.16-2.25), and RA 2.89 (95% CI 2.06-4.05). The HRs for anxiety and personality disorders and chronic lung disease including asthma were in the range of 1.15-1.16, but these were not statistically significant associations.

CONCLUSION

Our results suggest that in utero exposure to maternal RA is associated with an increased risk of thyroid disease and epilepsy in childhood and adolescence, and in particular an increased risk of RA, compared to children born to mothers without RA. These important findings should encourage pediatricians and general practitioners to have an increased awareness of certain chronic diseases in children exposed to RA in utero.

Risk of Thyroxine-Treated Autoimmune Thyroid Disease Associated With Disease Onset in Patients With Rheumatoid Arthritis

IMPORTANCE

Autoimmune thyroid disease ([AITD] including hypothyroidism and hyperthyroidism) is the most common organ-specific autoimmune disorder and is more prevalent among patients with rheumatoid arthritis (RA). Real-world studies on when and how this increased risk of AITD develops, in association with the time before or after the onset of RA, are lacking.

OBJECTIVE

To estimate the risk of thyroxine-treated AITD among patients with RA at different time points before and after the diagnosis of RA.

DESIGN, SETTING, AND PARTICIPANTS

A nationwide register-based case-control and cohort study was conducted between January 1, 2006, and June 30, 2013, with a maximum follow-up time of 7 years before and 8 years after diagnosis of RA. The study used the Swedish Rheumatology Quality Register and linkage to other nationwide registers to identify 8090 adults with new-onset RA and a random population-based sample of 80 782 referents matched by age, sex, and residential area. Statistical analysis was performed from July 1, 2015, to June 30, 2017.

EXPOSURES

Presence of AITD in the participants in the case-control design and RA in the participants in the cohort design.

MAIN OUTCOMES AND MEASURES

Prevalence and relative risk of incident AITD before (odds ratios) and after (hazard ratios) diagnosis of RA compared with the population as reference.

RESULTS

There were 8090 patients with RA (5529 women and 2561 men; mean [SD] age, 58.3 [15.2] years) and 80 782 population-based participants as reference who were identified. By the time of diagnosis of RA, the prevalence of AITD was 10.3% among the patients with RA (n = 832) vs 7.1% among the controls (5725 of 80 350) (odds ratio, 1.5; 95% CI, 1.4-1.7). This increased risk of AITD developed during the 5 years (range, 2-5 years) before diagnosis of RA (odds ratio, 1.5; 95% CI, 1.2-1.8) and peaked by the time of diagnosis of RA (range, 0-3 months before diagnosis of RA) (odds ratio, 5.3; 95% CI, 3.7-7.6). From diagnosis of RA and onward, the risk of developing AITD decreased (range, 2-5 years after diagnosis of RA) (hazard ratio, 0.7; 95% CI, 0.5-1.0).

CONCLUSIONS AND RELEVANCE

Compared with the general population, Swedish patients with RA appear to have a higher prevalence of thyroxine-treated AITD at diagnosis of RA and an increased incidence of AITD during the 5-year period before diagnosis of RA. After diagnosis of RA, the risk of developing AITD is suggested to decrease below the expected rate. Besides temporal changes in diagnostic intensity, this pattern of risk raises the question whether AITD may influence the pathogenesis of RA (or vice versa) and, conversely, the question whether antirheumatic therapies may prevent AITD.

The influence of thyroid diseases, diabetes mellitus, primary hyperparathyroidism, vitamin B12 deficiency and other comorbid autoimmune diseases on treatment outcome in patients with rheumatoid arthritis: An exploratory cohort study

To investigate the impact of comorbid diseases on rheumatoid arthritis (RA) outcome.All patients diagnosed with RA since 2006, who were registered in our local Danbio registry, were included in this cohort study. Patients' demographics, serology results, and Disease Activity Score in 28 joints-C-reactive protein (DAS28-CRP) at the time of diagnosis and after 4 months of treatment initiation were collected. Patients' electronic hospital records were evaluated for a positive history of thyroid diseases, diabetes mellitus, primary hyperparathyroidism, vitamin B12 deficiency, and the presence of other diagnosed autoimmune diseases.1035 RA patients were included. The observed prevalence of thyroid diseases was 11.8%, DM 10.4%, primary hyperparathyroidism 2.8%, vitamin B12 deficiency 5.8%, and other diagnosed autoimmune diseases 1.6%. There were significant associations between presence of thyroid diseases and female gender (P < .001); DM and greater age (P < .001); primary hyperparathyroidism and longer disease duration (P = .002); other diagnosed autoimmune diseases and antinuclear antibody positivity (P < .001). RA patients with thyroid diseases (P = .001) and other comorbid autoimmune diseases (P < .001) had significantly poorer initial response to the RA treatment compared to patients with isolated RA.Univariate analyses revealed that age, the presence of thyroid diseases, the presence of other diagnosed autoimmune diseases and DAS28-CRP at the time of diagnosis were significantly associated with ΔDAS28-CRP. Additionally, multivariate analysis demonstrated that ΔDAS28-CRP deterioration was significantly correlated to the presence of thyroid diseases (unstandardized regression coefficient (standard error); -0.188 (0.088), P = .030) and the presence of other diagnosed autoimmune diseases (-0.537 (0.208), P = .010).RA patients are at increased risk of specific comorbidities with possible impact on the treatment outcome. To improve this situation, periodic assessment of comorbidities should be considered.

Thyroid disorders in patients with newly diagnosed rheumatoid arthritis is associated with poor initial treatment response evaluated by disease activity score in 28 joints-C-reactive protein (DAS28-CRP): An observational cohort study

To determine the prevalence of thyroid disorders among newly diagnosed rheumatoid arthritis (RA) patients and evaluate the association between clinical characteristics of RA and thyroid disorders, and also initial treatment response in the RA patients with thyroid disorders.Newly diagnosed, adult RA patients who were diagnosed according to the new 2010 American College of Rheumatology/European League Against Rheumatism criteria since January 1, 2010, were included. Patients' demographic data, serology results including immunoglobulin M rheumatoid factor (IgM RF), anticyclic citrullinated peptide antibody (anti-CCP), and antinuclear antibody (ANA), and also disease activity score in 28 joints-C-reactive protein at the time of diagnosis and after 4 months (±1-2 months) of treatment initiation were extracted from Danish Danbio Registry. Patients' electronic hospital records for the past 10 years were reviewed to reveal if they had been diagnosed with thyroid disorders or they had abnormal thyroid test.In all, 439 patients were included, female 60.1%, mean age 64.6 ± 15.0 years and disease duration 2.6 ± 1.7 years. Prevalence of thyroid disorders was 69/439 (15.7%) and hypothyroidism was the most frequent disorder (30.4%). The presence of thyroid disorders among RA patients was significantly associated with female sex (P < .001), ANA positivity (P = .04), and anti-CCP ≥100 EU/mL (P = .05). Furthermore, RA patients with thyroid disorders had significantly poorer initial response to RA treatment compared with patients with isolated RA after 4 months of treatment (P = .02). There were no associations between thyroid disorders and age, disease duration, and also IgM RF positivity.Presence of thyroid disorders in RA patients is suggestive of a more aggressive disease and poor outcome, with direct effect on initial treatment response. To diagnose concurrent thyroid disorders at an earlier stage, routine measurement of serum thyroid-stimulating hormone is recommended in all RA patients at the time of diagnosis and with yearly interval thereafter.

Association between giant cell arteritis and thyroid dysfunction in a "real life" population

PURPOSE

Giant cell arteritis is a systemic autoimmune disorder which involves inflammation of medium to large vessels. The association between giant cell arteritis and autoimmune thyroid disorders has been investigated numerous times in the literature with inconsistent results. Our objective was to evaluate whether a genuine association exists between giant cell arteritis and thyroid dysfunction, which is often due to immune-mediated thyroid disease.

METHODS

Utilizing the medical database of Clalit Health Services, we compared the proportion of hypo and hyperthyroidisim between patients with giant cell arteritis and age-matched and gender-matched controls in a cross-sectional study. Univariate analysis was performed using Chi-square and student t-test and a multivariate analysis was performed using a logistic regression model.

RESULTS

Five thousand six hundred and sixty three giant cell arteritis patients and 23,308 age-matched and gender-matched controls were included in the study. The proportion of hypothyroidism amongst giant cell arteritis patients was increased in comparison with controls (18.2 vs. 6.91%, respectively, p-value < 0.001), as was hyperthyroidism (2.56 and 1.19% respectively, p-value < 0.001). Giant cell arteritis demonstrated an independent association with hypothyroidism on multivariate analysis (Odd Ratios 1.297, 95% Confidence Intervals 1.19-1.42), yet not with hyperthyroidism.

CONCLUSIONS

Giant cell arteritis patients have a higher proportion of hypothyroidism in comparison with matched controls. Physicians treating giant cell arteritis patients should consider screening for thyroid dysfunction on a regular basis.

Connective tissue diseases and autoimmune thyroid disorders in the first trimester of pregnancy

OBJECTIVE

To investigate the rates and coexistence of autoimmune thyroid and connective tissue diseases (CTD) during the first trimester of pregnancy and their influence on pregnancy outcome.

STUDY DESIGN

A cohort study of 150 women with CTD diagnosed during first trimester of pregnancy and 150 negative controls.

MAIN OUTCOME MEASURES

Screening of CTD by a self-reported questionnaire, rheumatic and thyroid autoantibody detection, clinical rheumatological evaluation and obstetric outcomes.

RESULTS

Out of 3852 women screened, 61 (1.6%) were diagnosed with undefined connective tissue disease (UCTD), 28 (0.7%) with major CTD (six rheumatoid arthritis, five systemic lupus erythematosus, eight Sjogren syndrome, five anti-phospholipid syndrome, two systemic sclerosis, one mixed CTD and one monoarticular arthritis) and 61 (1.6%) had insufficient criteria for a diagnosis of a rheumatic disease. The overall prevalence of either thyroid peroxidase (TPO-a) or thyroglobulin (TG-a) autoantibodies detection was 8% (12/150) among controls, 62.3% (38/61) among UCTD and 60.7% (17/28) in women with a major CTD (p<.001 compared to controls for both comparisons). After adjustment for confounders, overall CTDs (major or undefined) (OR=3.54, 95% CI; 1.61-7.78) and TPO-a plus TG-a positivity (OR=2.78, 95% CI;1.29-5.98) were independently associated with increased risks of moderate-severe complications of pregnancy (miscarriage, fetal growth restriction, preeclampsia, delivery before 34 weeks).

CONCLUSIONS

Rheumatic and thyroid autoantibodies during pregnancy are closely associated. Thyroid antibodies could add to the risk of adverse pregnancy outcome associated with connective tissue diseases.

MOLECULAR GENETIC STUDIES OF COMORBIDITY

This review focuses at the problem of the genetic basis of comorbidity. We discuss the concepts and terms relating to combinations of diseases. The guidelines of the study of comorbidity using modern high throughput methods and approaches of genetics, molecular biology and bioinformatics are designated. In this review we present results of studies showing genetic specificity for the combined phenotypes dif-ferent from the isolated disease, we considergene-gene and gene-environment interactions in comorbidity. We also discuss the role of single nucleotide polymorphisms and structural genome variations in the development of comorbidity. Own results of researching shared genes of inversely comorbid diseases like as bronchial asthma and tuberculosis are presented.

Association of antithyroid peroxidase antibody with fibromyalgia in rheumatoid arthritis

To investigate how autoimmune thyroiditis (ATD) affects the clinical presentation of established rheumatoid arthritis (RA) with particular reference to fibromyalgia and chronic widespread pain (CWP). A cohort of 204 patients with RA for whom the presence or absence of autoimmune thyroid antibodies was documented was examined for the relationships between thyroid autoantibodies and fibromyalgia or CWP. We identified 29 % who tested positive for antithyroid peroxidase antibodies (TPOAb). The anti-thyroglobulin antibody (TgAb) was found in 24 %. Among the thyroid autoantibody-positive patients, 40 % had a diagnosis of fibromyalgia or CWP versus 17 % for antibody negative patients. Logistic regression analyses (adjusted by age, sex, diabetes and BMI) indicated that TPOAb-positive patients were more likely to have fibromyalgia or CWP, with an odds ratio (OR) of 4.641, 95 % confidence interval (CI) (2.110-10.207) P < .001. Adjusting for spinal degenerative disc disease did not change the association with fibromyalgia, OR 4.458, 95 % CI (1.950-10.191), P < .001. The OR between TgAb and fibromyalgia was not significant (P > .05). Additional logistic regression analyses (adjusted by age, sex and BMI) indicated a significant relationship between TPOAb and fibromyalgia or CWP in patients without diabetes and those without hypothyroidism (OR of 4.873, 95 % CI (1.877-12.653), P = .001 and OR of 4.615 95 % CI (1.810-11.770), P = .001, respectively). There may be a positive association between the ATD antibody TPOAb, and fibromyalgia syndrome and CWP in patients with established RA.