Association between systemic lupus erythematosus and myasthenia gravis: A population-based National Study

BACKGROUND

Systemic lupus erythematosus (SLE) and myasthenia gravis (MG) are autoimmune diseases. Previous case reports and case series suggest an association may exist between these diseases, as well as an increased risk of SLE after thymectomy for MG. We undertook this study to determine whether SLE and MG were associated in large cohorts.

METHODS

We searched the IBM Watson Health Explorys platform and the Department of Veterans Affairs Million Veteran Program (MVP) database for diagnoses of SLE and MG. In addition, we examined subjects enrolled in the Lupus Family Registry and Repository (LFRR) as well as controls for a diagnosis of MG.

RESULTS

Among 59,780,210 individuals captured in Explorys, there were 25,750 with MG and 65,370 with SLE. 370 subjects had both. Those with MG were >10 times more likely to have SLE than those without MG. Those with both diseases were more likely to be women, African American, and at a younger age than MG subjects without SLE. In addition, the MG patients who underwent thymectomy had an increased risk of SLE compared to MG patients who had not undergone thymectomy (OR 3.11, 95% CI: 2.12 to 4.55). Autoimmune diseases such as pernicious anemia and miscellaneous comorbidities such as chronic kidney disease were significantly more common in MG patients who developed SLE. In the MVP, SLE and MG were also significantly associated. Association of SLE and MG in a large SLE cohort with rigorous SLE classification confirmed the association of SLE with MG at a similar level.

CONCLUSION

While the number of patients with both MG and SLE is small, SLE and MG are strongly associated together in very large databases and a large SLE cohort.

Trends in Fracture Rates Over Two Decades Among Veterans With Ankylosing Spondylitis

OBJECTIVE

There is an increased risk of fracture in individuals with ankylosing spondylitis (AS) compared to the general population, possibly due to systemic inflammatory effects. The use of tumor necrosis factor inhibitors (TNFi) may reduce fracture risk by inhibiting inflammation. We assessed fracture rates in AS versus non-AS comparators and whether these rates have changed since the introduction of TNFi.

METHODS

We used the national Veterans Affairs database to identify adults ≥18 years old with ≥1 International Classification of Diseases, Ninth Revision (ICD-9)/ICD-10 code for AS and at least 1 disease-modifying antirheumatic drug prescription. As comparators, we selected a random sample of adults without AS diagnosis codes. We calculated fracture incidence rates for AS and comparators, with direct standardization to the cohort structure in 2017. To compare fracture rates from 2000 to 2002 (pre-TNFi) versus 2004-2020 (TNFi era), we performed an interrupted time series analysis.

RESULTS

We included 3,794 individuals with AS (mean age 53 years, 92% male) and 1,152,805 comparators (mean age 60 years, 89% male). For AS, the incidence rate of fractures increased from 7.9/1,000 person-years in 2000 to 21.6/1,000 person-years in 2020. The rate also increased among comparators, although the ratio of fracture rates (AS/comparators) remained relatively stable. In the interrupted time series, the fracture rate for AS patients in the TNFi era was nonsignificantly increased compared to the pre-TNFi era.

CONCLUSION

Fracture rates have increased over time for both AS and non-AS comparators. The fracture rate in individuals with AS did not decrease after TNFi introduction in 2003.

Malignancy in ankylosing spondylitis: a cross-sectional analysis of a large population database

BACKGROUND

Increased cancer-risk has been reported with rheumatoid arthritis and systemic lupus erythematosus, but the risk is poorly studied in ankylosing spondylitis (AS). Conflicting data in AS have been reported in Asia and Europe, with lack of US population-based studies. Our objective is to study the prevalence of cancer in patients with AS in the US.

METHODS

Using the Explorys database, we performed a cross-sectional study. Data from AS patients and controls were stratified by 2 rheumatology visits, age groups, clinical characteristics, and frequency of cancers. The data were analyzed using a series of chi-square tests of independence as well as logistic regression to test for association between AS and cancer.

RESULTS

1410 AS patients (12.88%) had cancer. Female AS patients had a lower prevalence of cancer compared to controls (OR 0.840, 95% CI [0.769, 0.916]), while male AS patients had no statistically significant difference (OR 1.011, 95% CI [0.929, 1.099]). Among patients with AS, Skin cancers (squamous cell, malignant melanoma, and basal cell) and head and neck cancers were significantly increased.

CONCLUSION

Our study demonstrated that the prevalence of "any-type-cancer" was not increased in AS patients compared to controls with no rheumatic disease. Skin, head, and neck cancers were more frequently seen in AS patients.

Sjögren Syndrome and Cancer

The association between malignancy and rheumatic diseases has been demonstrated in a multitude of studies. Little is understood regarding the pathogenesis of rheumatic and musculoskeletal diseases in association with malignancy. There is strong evidence regarding the association between Sjögren syndrome and lymphoma as well as risk factors for development of lymphoma in these patients. This article discusses the accumulating data on various malignancies described in primary Sjögren syndrome, highlighting non-Hodgkin lymphoma and thyroid, multiple myeloma, and skin cancers. These reported associations may have clinical implications in daily practice and contribute to understanding of both autoimmunity and cancer.

AB0707 IS ANKYLOSING SPONDYLITIS ASSOCIATED WITH INCREASED MALIGNANCY RISK?

Background:

Increased cancer risk has been reported with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). Few studies on malignancy risk in ankylosing spondylitis (AS) patients have provided conflicting data.

Objectives:

To look at the risk of cancer in AS patients in the US and identify any risk factors associated with increased cancer frequency.

Methods:

This is a retrospective observational study using the IBM Explorys data base,a pooled de-identified clinical data base of > 60 million unique patients in the US with patient level data. The Explorys collects aggregated, standardized and normalized clinical data from different electronic health records automatically updated in near real time. In Explorys, patient records are mapped into a single set of Unified Medical Language System ontologies to facilitate searching and indexing. Diagnoses, findings and procedures are mapped into the systematized nomenclature of medicine – clinical terms (SNOMED-CT) hierarchy. Criteria of AS included at least one visit with a rheumatologist and the diagnosis code of AS (N=14,310) between 2009-2019. We further stratified the cohorts by adding the following variables to the search tool: race, gender, smoking, laboratory data (elevated ESR and CRP, HLA-B27 status), extra articular manifistations (psoriasis, inflammatory bowel disease or uveitis) and medication use (TNF inhibitor, secukinumab or NSAIDs). The index date was defined as the date of the first ever malignant neoplastic disease diagnosis occurring after the qualifying AS diagnosis.

The controls group (24,542,770) included all adults ≥ 18 years of age with exclusion of positive ANA, diagnosis of RA, SLE, AS, or vasculitis, and at least one outpatient office visit during the study period. For both groups we excluded previous diagnosis of cancer prior to 2009. A chi-square test of association was performed between the 2 groups (AS patients and controls) and the odds ratio (OR), its standard error, and the 95% confidence interval (CI) were calculated.

Results:

Of the 14,310 patients with AS, only 1300 (9.08%) patients had a cancer diagnosis compared to 2,719,240 controls (11.07%). The AS patients found to have decreased odds of cancer compared to control group (Odds ratio 0.9004, 95 % CI: 0.8502 to 0.9536, P = 0.0003). Demographics and clinical characteristic of AS patients and controls with cancer are shown in table 1. Risk factors for increased cancer risk in AS patients are shown in table 2.

Conclusion:

The study demonstrated that cancer risk was lower in the AS patients in the USA compared to the controls with no rheumatic disease. Male sex, white race, HLA-B27 positivity, history of IBD, NSAIDs use, and elevated makers of inflammation were associated with higher odds of cancer in AS patients.

Table 1.

Demographics and other features of patients with cancer.

AS patients with Cancer(n=1300)Controls with Cancer{n=2,719,240)Caucasians85.38%82.09%Males53.08 %45.53%Smokers30.00%22.22%Elevated ESR44.61%10.20%Elevated CRP44.61%10.25%NSAID use76.92%47.20%Table 2.

Risk factors for cancer in patients with AS using chi-square test.

AS with cancerN = 1300AS without cancerN=11,350P valueMale690 (53.08%)5690 (50.13%)0.04Female610 (46.92%)5650 (49.78%)0.05White1110 (85.38%)8980 (79.12%)<0.0001African American70 (5.38%)930 (8.19%)0.0004Psoriasis180 (13.85%)1510 (13.30%)0.56IBD120 (9.23%)520 (4.58%)<0.0001Uveitis180 (13.85%)1480 (13.04%)0.41Smoking390 (30%)2910 (25.64%)0.0007Elevated ESR580 (44.61%)3490 (30.75%)<0.0001Elevated CRP580 (44.61%)4240 (37.36%)<0.0001HLA B27 positivity110 (8.46%)760 (6.7%)0.018TNFi530 (40.77%)4840 (42.64%)0.2Secukinamab50 (3.85%)360 (3.17%)0.19NSAIDs1000 (76.92%)7660 (67.49%)<0.0001

Acknowledgments:

Dr. Yasir Tarabichi and Dr. David Kaelber

Disclosure of Interests:

Sali Merjanah: None declared, Mohamad Bittar: None declared, Marina Magrey Grant/research support from: AbbVie, Amgen, and UCB, Consultant of: Eli Lilly and Novartis