Hydroxychloroquine in lupus or rheumatoid arthritis pregnancy and risk of major congenital malformations: a population-based cohort study.

OBJECTIVES: To assess the infant risk of major congenital malformations (MCM) associated with first-trimester exposure to hydroxychloroquine (HCQ) among mothers with systemic lupus erythematosus (SLE) or rheumatoid arthritis (RA). METHODS: This population-based cohort study utilised Swedish nationwide registers and included all singleton births (2006-2021) among individuals with prevalent SLE or RA in Sweden. The exposure was filling ≥1 HCQ prescription during the first trimester. The outcome was infant MCM within one year of birth. Inverse probability of treatment weighting was applied to adjust for potential confounders (e.g. maternal smoking, body mass index, pregestational diabetes, and corticosteroids). Modified Poisson regression models with robust variance estimated risk ratios and 95% confidence intervals (RR 95%CI). RESULTS: We included 1,007 births (453 exposed) and 2,500 births (144 exposed) in the SLE and RA cohorts, respectively. The MCM risks in the SLE overall cohort, exposed, and unexposed groups were 3.6%, 3.7%, and 3.4%, respectively. The corresponding figures in the RA cohort were 4.4%, 5.6%, and 4.3%, respectively. The adjusted RRs (95%CI) were 1.29 (0.65-2.56) in the SLE cohort, 1.32 (0.56-3.13) in the RA cohort, and 1.30 (0.76-2.23) in the pooled analysis. The adjusted risk difference (exposed vs unexposed) was small (0.9% in SLE and 1.3% in RA). Sensitivity analyses examining different exposure and outcome windows yielded similar findings. CONCLUSIONS: First-trimester exposure to HCQ was not associated with a significantly increased risk of MCM. HCQ's benefits may outweigh the risks in managing SLE or RA during pregnancy.

Familial autoimmunity in patients with idiopathic inflammatory myopathies.

BACKGROUND: Familial associations can be indicators of shared genetic susceptibility between two diseases. Previous data on familial autoimmunity in patients with idiopathic inflammatory myopathies (IIM) are scarce and inconsistent. OBJECTIVES: To investigate which autoimmune diseases (ADs) may share genetic susceptibility with IIM, we examined the familial associations between IIM and different ADs. METHODS: In this Swedish population-based family study, we assembled 7615 first-degree relatives (FDRs) of 1620 patients with IIM and 37,309 relatives of 7797 matched individuals without IIM. Via register linkages, we ascertained rheumatoid arthritis, other rheumatic inflammatory diseases (RIDs), multiple sclerosis, inflammatory bowel diseases (IBD), type 1 diabetes mellitus, autoimmune thyroid diseases (AITD), coeliac disease (CeD) and myasthenia gravis among the FDRs. We estimated the familial association between IIM and each AD using conditional logistic regression and performed subgroup analyses by kinship. RESULTS: Patients with IIM had significantly higher odds of having ≥1 FDR affected by other RIDs (adjusted odds ratio [aOR] = 1.40, 95% confidence interval [CI] 1.11-1.78) and greater odds of having ≥2 FDRs affected by CeD (aOR = 3.57, 95% CI 1.28-9.92) compared to the individuals without IIM. In the analyses of any FDR pairs, we observed familial associations for other RIDs (aOR = 1.34, 95% CI 1.14-1.56), IBD (aOR = 1.20, 95% CI 1.02-1.41), AITD (aOR = 1.10, 95% CI 1.02-1.19) and CeD (aOR = 1.37, 95% CI 1.08-1.74) while associations for other ADs were not statistically significant. CONCLUSION: The observed familial associations may suggest that IIM shares genetic susceptibility with various ADs, information that may be useful for clinical counselling and guiding future genetic studies of IIM.

Cancer risks with JAKi and biological disease-modifying antirheumatic drugs in patients with rheumatoid arthritis or psoriatic arthritis: a national real-world cohort study.

OBJECTIVE: Assess cancer risks with Janus kinase inhibitors (JAKi) versus biological disease-modifying antirheumatic drugs (bDMARDs) in clinical practice. METHODS: Cohort study of patients with rheumatoid arthritis (RA) or psoriatic arthritis (PsA) initiating treatment with JAKi, tumour necrosis factor inhibitors (TNFi) or other (non-TNFi) bDMARDs 2016-2020 using prospectively collected data from the Swedish Rheumatology Quality Register linked to other registers including the Cancer Register. We estimated incidence rates, and HRs via Cox regression, for all cancers excluding non-melanoma skin cancer (NMSC), and for individual cancer types including NMSC. RESULTS: We identified 10 447 patients with RA and 4443 patients with PsA who initiated treatment with JAKi, a non-TNFi bDMARD or a TNFi. Median follow-up times in RA were 1.95, 2.83 and 2.49 years, respectively. In RA, based on 38 incident cancers other than NMSC with JAKi vs 213 with TNFi the overall HR was 0.94 (95% CI 0.65 to 1.38). Based on 59 vs 189 incident NMSC, the HR was 1.39 (95% CI 1.01 to 1.91). At 2 or more years since treatment start, the HR for NMSC was 2.12 (95% CI 1.15 to 3.89). In PsA, based on 5 vs 73 incident cancers other than NMSC, and 8 vs 73 incident NMSC, the corresponding HRs were 1.9 (95% CI 0.7 to 5.2) and 2.1 (95% CI 0.8 to 5.3). CONCLUSION: In clinical practice, the short-term risk of cancer other than NMSC in individuals initiating treatment with JAKi is not higher than for TNFi, but we found evidence of increased risk for NMSC.

Pregnancy outcomes in relation to disease activity and anti-rheumatic treatment strategies in women with rheumatoid arthritis: a matched cohort study from Sweden and Denmark.

OBJECTIVES: To explore the association of maternal RA to pregnancy outcomes, especially preterm birth (PTB) and small for gestational age (SGA), in relation to disease activity and anti-rheumatic treatment before and during pregnancy. METHODS: By linking prospective clinical rheumatology registers (CRR) in Sweden (the Swedish Rheumatology Quality Register, SRQ) and Denmark (the Danish clinical quality register, DANBIO) with medical birth registers, we identified 1739 RA-pregnancies and 17 390 control-pregnancies (matched 1:10 on maternal age, birth year, parity) with delivery 2006-18. Disease activity (DAS28, CRP, HAQ score) and anti-rheumatic treatment 9 months before and during pregnancy were identified through CRR and prescribed drug registers. Using logistic regression, we estimated adjusted odds ratios (aOR) with 95% CI for PTB and SGA overall and stratified by disease activity and anti-rheumatic treatment before and during pregnancy, adjusting for maternal characteristics. RESULTS: We found increased aOR of PTB [1.92 (1.56-2.35)] and SGA [1.93 (1.45-2.57)] in RA-pregnancies vs control-pregnancies. For RA-pregnancies with DAS28-CRP ≥4.1 vs <3.2 during pregnancy, aOR was 3.38 (1.52-7.55) for PTB and 3.90 (1.46-10.4) for SGA. Use of oral CS (yes/no) during pregnancy resulted in an aOR of 2.11 (0.94-4.74) for PTB. The corresponding figure for biologics was 1.38 (0.66-2.89). Combination therapy, including biologics before pregnancy, was a marker of increased risk of both PTB and SGA. CONCLUSION: During pregnancy, disease activity rather than treatment seems to be the most important risk factor for PTB and SGA in RA. Women with RA should be carefully monitored during pregnancy, especially if they have moderate to high disease activity or/and are treated with extensive anti-rheumatic treatment.

Familial aggregation and heritability: a nationwide family-based study of idiopathic inflammatory myopathies.

OBJECTIVES: The magnitude of the genetic contribution to idiopathic inflammatory myopathies (IIMs) is unknown. In this project, we aimed to investigate the familial aggregation and heritability of IIM. METHODS: This is a family-based study using nationwide healthcare register data in Sweden. We matched each patient with IIM to individuals without IIM, identified their first-degree relatives and determined the IIM status among all first-degree relatives. We estimated the adjusted ORs (aORs) of familial aggregation of IIM using conditional logistic regression. In addition, we used tetrachoric correlation to estimate the heritability of IIM. RESULTS: We included 7615 first-degree relatives of 1620 patients with IIM diagnosed between 1997 and 2016 and 37 309 first-degree relatives of 7797 individuals without IIM. Compared with individuals without IIM, patients with IIM were more likely to have ≥1 first-degree relative affected by IIM (aOR=4.32, 95% CI 2.00 to 9.34). Furthermore, the aOR of familial aggregation of IIM in full siblings was 2.53 (95% CI 1.62 to 3.96). The heritability of IIM was 22% (95% CI 12% to 31%) among any first-degree relatives and 24% (95% CI 12% to 37%) among full siblings. CONCLUSIONS: IIM has a familial component with a risk of aggregation among first-degree relatives and a heritability of about 20%. This information is of importance for future aetiological studies and in clinical counselling.

Lymphoma risks in patients with rheumatoid arthritis treated with biological drugs-a Swedish cohort study of risks by time, drug and lymphoma subtype.

OBJECTIVES: To estimate the association between biological DMARDs (bDMARDs; overall and by drug) as used in RA and the risk of malignant lymphomas including subtypes. METHODS: By linking nationwide Swedish registers we identified cohorts of patients with RA initiating treatment with a bDMARD (n = 16 392), bDMARD-naïve (n = 55 253), an age- and sex-matched general population comparator cohort (n = 229 047), and all incident lymphomas 2001-16. We used Cox regression to calculate hazard ratios (HRs) of lymphoma taking calendar period and other factors into account. RESULTS: There were 82 lymphomas among the bDMARD-treated patients with RA, crude incidence rate 76/100 000 person-years, and 310 lymphomas among the bDMARD-naïve patients with RA, crude incidence rate 90/100 000 person-years. This resulted in an adjusted HR (aHR) associated with bDMARD treatment (vs not) of 1.08 (95% CI: 0.83, 1.41). The corresponding aHR for bDMARD-treated and bDMARD-naïve vs the general population was 1.65 (95% CI: 1.31, 2.08) and 1.56 (95% CI: 1.37, 1.78) respectively. Restricting follow-up period to after 2006, the aHR of lymphoma for patients with RA starting a first bDMARD vs bDMARD-naïve was 0.69 (95% CI: 0.47, 1.00), and for bDMARD treated vs patients with RA switching from one conventional synthetic DMARDs to another, aHR was 0.46 (95% CI: 0.28, 0.73). There were no signals of different risks with any particular TNF inhibitor (TNFi) agent. We found no different lymphoma subtype pattern following bDMARD therapy. CONCLUSION: Treatment with bDMARDs, including both TNFi and non-TNFi bDMARDs, does not further increase the lymphoma risk in RA; instead, bDMARD treatment may actually reduce the excess lymphoma risk in RA.

Risk of solid cancers overall and by subtypes in patients with psoriatic arthritis treated with TNF inhibitors - a Nordic cohort study.

OBJECTIVES: To investigate whether TNF inhibitors (TNFi) are associated with increased risk of solid cancer in patients with psoriatic arthritis (PsA). METHODS: From the Nordic clinical rheumatology registers (CRR) here: SRQ/ARTIS (Sweden), DANBIO (Denmark), NOR-DMARD (Norway), ROB-FIN (Finland) and ICEBIO (Iceland) we identified PsA patients who started a first TNFi 2001-2017 (n = 9655). We identified patients with PsA not treated with biologics from (i) the CRR (n = 14 809) and (ii) the national patient registers (PR, n = 31 350). By linkage to the national cancer registers, we collected information on incident solid cancer overall and for eight cancer types. We used Cox regression to estimate hazard ratio (HR) with 95% CI of cancer (per country and pooled) in TNFi-exposed vs biologics-naïve, adjusting for age, sex, calendar period, comorbidities and disease activity. We also assessed standardized incidence ratios (SIR) in TNFi-exposed PsA vs the general population (GP). RESULTS: We identified 296 solid cancers among the TNFi-exposed PsA patients (55 850 person-years); the pooled adjusted HR for solid cancer overall was 1.0 (0.9-1.2) for TNFi-exposed vs biologics-naïve PsA from the CRR, and 0.8 (0.7-1.0) vs biologics-naïve PsA from the PRs. There were no significantly increased risks for any of the cancer types under study. The pooled SIR of solid cancer overall in TNFi treated PsA vs GP was 1.0 (0.9-1.1). CONCLUSION: In this large cohort study from five Nordic countries, we found no increased risk of solid cancer in TNFi-treated PsA patients, neither for solid cancer overall nor for eight common cancer types.

Familial aggregation and heritability of ankylosing spondylitis - a Swedish nested case-control study.

OBJECTIVES: AS is known to be a highly heritable disease, but previous studies on the magnitude of the familial aggregation and heritability of AS have been small and inconclusive, with familial relative risks ranging from 17 to 94. We aimed to improve estimates of these factors by studying families of all subjects diagnosed with AS in Sweden over a period of 16 years and to investigate if familial risks vary by sex or type of relative. METHODS: In a nested case-control study, we identified AS index patients from the National Patient Register (NPR) and the Swedish Rheumatology Quality Register (SRQ) between 2001 and 2016. Each index patient was matched on age and sex to up to 50 general population controls. First-degree relatives of index patients and controls were identified through the Multi-Generation Register, with disease status ascertained in the NPR and SRQ. Familial risks were defined as odds ratios (ORs) of having AS when exposed to a first-degree relative with AS, using conditional logistic regression. RESULTS: The overall familial OR for AS was 19.4 (95% CI 18.1, 20.8). Estimates were similar for different relative types and by sex, but having more than one affected relative resulted in a higher risk [OR 68.0 (95% CI 51.3, 90.1)]. Heritability, estimated by assuming sibling risks were completely due to genetics, was 77% (95% CI 73, 80). CONCLUSION: Although the familial risk and heritability of AS are higher than for most other diseases, we report estimates that are substantially lower than commonly referenced numbers for AS from other populations.

Pregnancy outcomes in women with idiopathic inflammatory myopathy, before and after diagnosis-a population-based study.

OBJECTIVES: To examine pregnancy outcomes among births to women with idiopathic inflammatory myopathy (IIM) in relation to time of IIM diagnosis using population-based data. METHODS: This study used Swedish nationwide registers to identify all singleton births that occurred between 1973 and 2016 among women diagnosed with IIM between 1998 and 2016 and among women unexposed to IIM. We classified births according to the IIM status of the mother at time of delivery: post-IIM (n = 68), 1-3 years pre-IIM (n = 23), >3 years pre-IIM (n = 710) and unexposed to IIM (n = 4101). Multivariate regression models were used to estimate relative risks of adverse pregnancy outcomes in post-IIM births and pre-IIM births separately, in comparison with their non-IIM comparators. RESULTS: We found that post-IIM births had increased risks of caesarean section [adjusted relative risk (aRR) = 1.98; 95% CI: 1.08, 3.64], preterm birth (aRR = 3.35; 95% CI: 1.28, 8.73) and low birth weight (aRR = 5.69; 95% CI: 1.84, 17.55) compared with non-IIM comparators. We also noticed higher frequencies of caesarean section and instrumental delivery in 1-3 years pre-IIM births than in the non-IIM comparators. CONCLUSION: Women who gave birth after IIM diagnosis had higher risks of caesarean section, preterm birth and low birth weight. These results further underline the importance of special care and close monitoring of women with IIM. Higher frequencies of caesarean section and instrumental delivery in pre-IIM births highlight the need for future research on the influence of subclinical features of IIM on pregnancy outcomes.

Anti-TNF treatment during pregnancy and birth outcomes: A population-based study from Denmark, Finland, and Sweden.

PURPOSE: To study the risk of preterm birth, caesarean section, and small for gestational age after anti-tumor necrosis factor agent treatment (anti-TNF) in pregnancy. METHODS: Population-based study including women with inflammatory bowel disease, rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, and psoriasis, and their infants born 2006 to 2013 from the national health registers in Denmark, Finland, and Sweden. Women treated with anti-TNF were compared with women with nonbiologic systemic treatment. Adalimumab, etanercept, and infliximab were compared pairwise. Continuation of treatment in early pregnancy was compared with discontinuation. Odds ratios with 95% confidence intervals were calculated in logistic regression models adjusted for country and maternal characteristics. RESULTS: Among 1 633 909 births, 1027 infants were to women treated with anti-TNF and 9399 to women with nonbiologic systemic treatment. Compared with non-biologic systemic treatment, women with anti-TNF treatment had a higher risk of preterm birth, odds ratio 1.61 (1.29-2.02) and caesarean section, 1.57 (1.35-1.82). The odds ratio for small for gestational age was 1.36 (0.96-1.92). In pairwise comparisons, infliximab was associated with a higher risk of severely small for gestational age for inflammatory joint and skin diseases but not for inflammatory bowel disease. Discontinuation of anti-TNF had opposite effects on preterm birth for inflammatory bowel disease and inflammatory joint and skin diseases. CONCLUSIONS: Anti-TNF agents were associated with increased risks of preterm birth, caesarean section, and small for gestational age. However, the diverse findings across disease groups may indicate an association related to the underlying disease activity, rather than to agent-specific effects.

Cancer risk in patients with spondyloarthritis treated with TNF inhibitors: a collaborative study from the ARTIS and DANBIO registers.

BACKGROUND: Safety data on cancer risks following tumour necrosis factor α inhibitors (TNFi) in patients with spondyloarthritis (SpA) (here defined as ankylosing spondylitis (AS), undifferentiated spondarthropaties (SpA UNS), psoriatic arthritis (PsA)) are scarce. Our objective was to assess risks for cancer overall and for common subtypes in patients with SpA treated with TNFi compared with TNFi-naïve patients with SpA and to the general population. METHODS: From the Swedish (Anti-Rheumatic Therapy in Sweden (ARTIS)) and Danish (DANBIO) biologics registers, we assembled 8703 (ARTIS=5448, DANBIO=3255) patients with SpA initiating a first TNFi 2001-2011. From the Swedish National Patient and Population Registers we assembled a TNFi-naïve SpA cohort (n=28,164) and a Swedish age-matched and sex-matched general population comparator cohort (n=131 687). We identified incident cancers by linkage with the nationwide Swedish and Danish Cancer Registers 2001-2011, and calculated age-standardised and sex-standardised incidence ratios as measures of relative risk (RR). RESULTS: Based on 1188 cancers among the TNFi-naïve patients with SpA, RR of cancer overall was 1.1 (95% CI 1.0 to 1.2). Based on 147 cancers among TNFi initiators with SpA, RR versus TNFi-naïve was 0.8 (95% CI 0.7 to 1.0) and results were similar for AS and PsA when analysed separately. Site-specific cancer RRs: prostate 0.5 (95% CI 0.3 to 0.8), lung 0.6 (95% CI 0.3 to 1.3), colorectal 1.0 (95% CI 0.5 to 2.0), breast 1.3 (95% CI 0.9 to 2.0), lymphoma 0.8 (95% CI 0.4 to 1.8) and melanoma 1.4 (95% CI 0.7 to 2.6). CONCLUSIONS: In patients with SpA, treatment with TNFi was not associated with increased risks of cancer, neither overall nor for the six most common cancer types.

Spectrum of lymphomas across different drug treatment groups in rheumatoid arthritis: a European registries collaborative project.

BACKGROUND: Lymphomas comprise a heterogeneous group of malignant diseases with highly variable prognosis. Rheumatoid arthritis (RA) is associated with a twofold increased risk of both Hodgkin's lymphoma (HL) and non-Hodgkin's lymphoma (NHL). It is unknown whether treatment with biologic disease-modifying antirheumatic drugs (bDMARDs) affect the risk of specific lymphoma subtypes. METHODS: Patients never exposed to (bionaïve) or ever treated with bDMARDs from 12 European biologic registers were followed prospectively for the occurrence of first ever histologically confirmed lymphoma. Patients were considered exposed to a bDMARD after having received the first dose. Lymphomas were attributed to the most recently received bDMARD. RESULTS: Among 124 997 patients (mean age 59 years; 73.7% female), 533 lymphomas were reported. Of these, 9.5% were HL, 83.8% B-cell NHL and 6.8% T-cell NHL. No cases of hepatosplenic T-cell lymphoma were observed. Diffuse large B-cell lymphoma (DLBCL) was the most frequent B-cell NHL subtype (55.8% of all B-cell NHLs). The subtype distributions were similar between bionaïve patients and those treated with tumour necrosis factor inhibitors (TNFi). For other bDMARDs, the numbers of cases were too small to draw any conclusions. Patients with RA developed more DLBCLs and less chronic lymphocytic leukaemia compared with the general population. CONCLUSION: This large collaborative analysis of European registries has successfully collated subtype information on 533 lymphomas. While the subtype distribution differs between RA and the general population, there was no evidence of any modification of the distribution of lymphoma subtypes in patients with RA treated with TNFi compared with bionaïve patients.

Low Risk of Birth Defects for Infants Whose Mothers Are Treated With Anti-Tumor Necrosis Factor Agents During Pregnancy.

BACKGROUND & AIMS: Safety data on anti-tumor necrosis factor (anti-TNF) treatment during pregnancy are limited. We studied the risk of birth defects after anti-TNF treatment in early pregnancy. METHODS: We collected data on 1,272,424 live-born infants identified from the Danish (2004-2012) and Swedish (2006-2012) population-based health registers. We determined the prevalence of birth defects among infants born to women with chronic inflammatory disease (inflammatory bowel disease, rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, or psoriasis), with (n = 683) and without (n = 21,549) anti-TNF treatment during early pregnancy, and in the general population. We compared the risk of any major birth defect and birth defect by organ system for infants born to women with chronic inflammatory disease, with and without anti-TNF treatment. Risks were presented as odds ratios (ORs) with 95% confidence intervals (CIs). We adjusted for maternal age, parity, smoking, body mass index, multiple gestation, country, and chronic inflammatory diagnosis. RESULTS: Birth defects were more prevalent among infants born to women with chronic inflammatory disease, regardless of anti-TNF treatment status, than in the general population (4.8% vs 4.2%). Birth defects occurred in 43 of the infants born to the 683 women who received anti-TNF treatment (6.3%), and 1019 of the infants born to women with chronic inflammatory disease (4.7%). The OR for any defect in women receiving anti-TNF therapy was 1.32 (95% CI, 0.93-1.82); the OR for a cardiovascular defect was 1.60 (95% CI, 0.93-2.58), and the OR for a urinary defect was 2.22 (95% CI, 0.86-4.71). CONCLUSIONS: Based on an analysis of data from the health registries in Denmark and Sweden, women who received anti-TNF agents during pregnancy had a slightly (but not significantly) higher risk of having children with birth defects. Although larger studies are needed, the heterogeneity of the observed birth defects did not indicate a common etiology.

Familial aggregation of arthritis-related diseases in seropositive and seronegative rheumatoid arthritis: a register-based case-control study in Sweden.

OBJECTIVES: Our objective was to estimate the risk of developing rheumatoid arthritis (RA) associated with a family history of non-RA arthritis-related diseases. This familial co-aggregation is of clinical interest since it is often encountered when assessing family history of RA specifically, but also informative on the genetic overlap between these diseases. Since anticitrullinated peptide antibodies/rheumatoid factor (RF)-positive and RF-negative RA have both specific and shared genetic factors, the familial co-aggregation was assessed separately for seropositive and seronegative disease. METHODS: Nested case-control study in prospectively recorded Swedish total population data. The Multi-Generation Register identified first-degree relatives. RA and arthritis-related diseases were ascertained through the nationwide patient register. RA serology was based on International Classification of Diseases tenth revision coded diagnoses, mainly reflecting RF. Familial risks were calculated using conditional logistic regression. Results were replicated using the Swedish rheumatology register. RESULTS: Familial co-aggregation was found between RA and every studied arthritis-related disease, but the magnitude varied widely, from juvenile idiopathic arthritis (JIA) (seropositive RA OR=3.98 (3.01 to 5.26); seronegative RA OR=5.70 (3.47 to 9.36)) to osteoarthritis (seropositive RA OR=1.03 (1.00 to 1.06); seronegative RA OR=1.05 (1.00 to 1.09)). The familial co-aggregation pattern of non-RA arthritis-related diseases was overall similar for seropositive and seronegative RA. Among those with family history of RA, relatives' other arthritis-related diseases conferred little or no additional risk. CONCLUSIONS: Although family history of several arthritis-related diseases may be useful to predict RA (eg, lupus and JIA), others (eg, osteoarthritis and arthralgia) are less useful. Seropositive and seronegative RA had rather similar familial co-aggregation patterns with arthritis-related diseases, suggesting that the two RA subsets are similar in the genetic factors that overlap with these diseases.

Prevalence of coeliac disease in patients with systemic lupus erythematosus: a systematic review and meta-analysis.

BACKGROUND: There is some evidence of a higher prevalence of coeliac disease (CD) among patients with SLE than in the general population. However, the prevalence estimates vary substantially. OBJECTIVE: To investigate the prevalence of CD among patients with SLE through systematic review and meta-analysis. METHODS: We performed searches in the databases of Medline, Embase, Cochrane and Web of Science Core Collection between 1 January 1990 and 9 July 2023. A total of 2053 publications were rendered in the searches, of which 68 were reviewed in full text and 14 included in the analyses. Primary analysis estimated the pooled prevalence of biopsy-verified CD in patients with SLE. In the secondary analysis, the prevalence of serological markers indicative of CD was investigated. The quality of studies was appraised using the Joanna Briggs Institute Critical Appraisal Tool. We conducted meta-regression analyses to investigate associations between the prevalence of CD in individuals with SLE and publication year, study population size, CD prevalence in the general population, proportion of females and quality assessment score. RESULTS: A total of 14 studies met the inclusion criteria, of which 11 were included in the primary analysis of biopsy-verified CD. Among 1238 patients with SLE, 14 had CD. The weighted pooled prevalence of CD was 0.7% (95% CI 0.0 to 1.8). The weighted pooled prevalence of CD serological markers in 1063 patients with SLE was 3.7% (95% CI 1.4 to 6.7). In meta-regression analyses, no associations between CD prevalence and study characteristics, demographics and quality assessment scores were found. CONCLUSIONS: In this meta-analysis, we found a weighted pooled prevalence of biopsy-verified CD in patients with SLE comparable with the prevalence in the general population. Our findings do not support routine screening for CD in patients with SLE. However, individual screening could be considered in cases of clinical suspicion and additional risk factors for CD. PROSPERO REGISTRATION NUMBER: CRD42022339594.

Association of childhood infections and perinatal factors with ankylosing spondylitis: a Swedish nationwide case-control and sibling study.

OBJECTIVES: To identify perinatal and early-life risk factors for ankylosing spondylitis (AS), controlling for family-shared confounding with a sibling comparison design. METHODS: In this nationwide, register-based case-control study, we identified 5612 AS cases from the Swedish National Patient Register, and matched them with 22 042 individuals without inflammatory arthritis from the general population. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) of AS in relation to childhood infections and a broad range of perinatal factors including fetal growth. Significant associations were further tested in a sibling comparison analysis, including 3965 patients with AS and their 6070 siblings without a diagnosis of spondyloarthritis. RESULTS: We found no statistically significant associations between any studied fetal growth-related factor or other perinatal factors and the risk of developing AS. In contrast, having older siblings (adjusted OR 1.12; 95% CI 1.04 to 1.22 for one vs no older sibling) and history of a childhood tonsillectomy (adjusted OR 1.30; 95% CI 1.13 to 1.49) were associated with AS in the case-control analysis, results that also held in the sibling comparison. Serious childhood infection and multiple birth were significantly associated with AS in the case-control sample, but estimates were attenuated in the sibling comparison. CONCLUSIONS: Having older siblings and a history of tonsillectomy in childhood were independently associated with development of AS, even after adjustment for family-shared factors in a sibling comparison analysis. This strengthens the hypothesis that childhood infections play a role in the aetiology of AS.

Temporal trends in adverse pregnancy outcomes in axial spondyloarthritis in Sweden: a cohort study.

BACKGROUND: Evidence on the risks associated with pregnancy and childbirth in women with axial spondyloarthritis is scarce and conflicting, with more research needed to guide policy and clinical practice. We aimed to assess the risks of adverse pregnancy outcomes in a large cohort of women with axial spondyloarthritis, and to investigate how outcomes varied over time and in relation to anti-rheumatic treatment. METHODS: In this register-based cohort study, we included births in Sweden between April 1, 2007, and Dec 31, 2020, to women with axial spondyloarthritis and general population comparators, matched 1:10 on year of delivery, maternal age, and parity. Our main data source was the Medical Birth Register (MBR), which includes over 98% of births in Sweden and prospectively collects data on antenatal care, delivery, and foetal outcomes. The information in MBR was linked to other registers, including the National Patient Register, the Prescribed Drug Register, and registers with demographic data. Our main outcomes were the relative risks of adverse pregnancy outcomes, analysed using modified Poisson regression. We also studied how the frequency of certain adverse outcomes, as well as disease-modifying antirheumatic drug (DMARD) and non-steroidal anti-inflammatory drug treatments, changed over the study period by linear regression and loess plots. FINDINGS: Between April 1, 2007, and Dec 31, 2020, 1580 births in women with axial spondyloarthritis recorded in MBR fulfilled the inclusion criteria and were matched with 15 792 comparator births. Among the 1580 births in women with axial spondyloarthritis, we found increased risks of preterm birth (risk ratio 1·43, 95% CI 1·13-1·80), pre-eclampsia (1·44, 1·08-1·92), elective caesarean delivery (1·59, 1·37-1·84), and serious infant infection (1·29, 1·05-1·59) compared with births in general population comparators. The risks of preterm birth, infant infection, and caesarean delivery decreased by around 0·5 percentage points annually during the study period, while the use of tumour necrosis factor inhibitors during pregnancy increased. INTERPRETATION: In view of remaining concerns regarding safety of the use of biological DMARDs during pregnancy, we saw a reassuring trend in which pregnancy outcomes improved over time in the axial spondyloarthritis group, concurrent with increased use of biological DMARDs. If the current rate of improvement is maintained, women with axial spondyloarthritis treated in accordance with clinical guidelines might eventually not be at an increased risk of adverse pregnancy outcomes. FUNDING: Swedish Research Council and The Swedish Rheumatism Association.

Familial Co-Aggregation of Idiopathic Inflammatory Myopathies and Cancer: A Swedish Population-Based Study.

OBJECTIVE: To examine if idiopathic inflammatory myopathies (IIMs) share familial susceptibility with cancer, we estimated the familial co-aggregation of these diseases. METHODS: This Swedish population-based family study with data from national registers included 8,460 first-degree relatives of patients with IIM and 41,127 relatives of matched individuals without IIM. We modeled the adjusted odds ratios (ORs) of familial co-aggregation of IIM and cancer using conditional logistic regressions and adjusted for sex and birth year of index individuals and their first-degree relatives. We examined the associations for cancer overall and stratified by several factors of interest. We also performed exploratory analyses for specific cancer types. RESULTS: We observed no statistically significant familial associations between IIM and cancer overall. However, there was a familial association in male relative pairs of patients with dermatomyositis (adjusted OR for familial association 1.39 [95% confidence interval (95% CI) 1.15-1.68]). The association remained statistically significant after controlling for multiple testing. Moreover, this finding was consistent between kinships. Familial co-aggregation of IIM and cancer diagnosed before 50 years of age was only observed in offspring. In exploratory analyses, only the familial associations for myeloid malignancies (adjusted OR 2.27 [95% CI 1.43-3.60]) and liver cancer (adjusted OR 2.01 [95% CI 1.21-3.33]) in male relative pairs remained significant after controlling for multiple testing. CONCLUSION: We found little evidence of shared familial susceptibility as a major pathologic mechanism contributing to the co-occurrence of IIM and cancer overall. There could be subsets of patients and cancer types for which familial factors including genetics and shared environments are of more importance, but these findings need replication.

Exposure to specific tumour necrosis factor inhibitors and risk of demyelinating and inflammatory neuropathy in cohorts of patients with inflammatory arthritis: a collaborative observational study across five Nordic rheumatology registers.

OBJECTIVE: To compare incidences of neuroinflammatory events, including demyelinating disease (DML), inflammatory polyneuropathies (IPN) and multiple sclerosis (MS), in patients with rheumatoid arthritis (RA) or spondyloarthritis (SpA; including psoriatic arthritis) starting a tumour necrosis factor inhibitor (TNFi), investigating whether monoclonal TNFi antibodies (other TNFis (oTNFis)) confer higher risk than etanercept. METHODS: This is an observational cohort study including patients from the five Nordic countries starting a TNFi in 2001-2020. Time to first neuroinflammatory event was identified through register linkages. We calculated crude incidence rates (cIR) per 1000 person-years and used multivariable-adjusted Cox regression to compare incidences of neuroinflammatory events overall and for DML, IPN and MS with oTNFi versus etanercept. We further examined individual TNFis and indications. RESULTS: 33 883 patients with RA and 28 772 patients with SpA were included, initiating 52 704 and 46 572 treatment courses, respectively. In RA, we observed 135 neuroinflammatory events (65% DML) with cIR of 0.38 with oTNFi and 0.34 with etanercept. The HR of oTNFi versus etanercept was 1.07 (95% CI 0.74 to 1.54) for any neuroinflammatory event, 0.79 (95% CI 0.51 to 1.22) for DML, 2.20 (95% CI 1.05 to 4.63) for IPN and 0.73 (95% CI 0.34 to 1.56) for MS. In SpA, we observed 179 events (78% DML) with cIR of 0.68 with oTNFi and 0.65 with etanercept. The HR for any neuroinflammatory event, DML, IPN and MS was 1.06 (95% CI 0.75 to 1.50), 1.01 (95% CI 0.68 to 1.50), 1.28 (95% CI 0.61 to 2.69) and 0.94 (95% CI0.53 to 1.69), respectively. CONCLUSION: The cIRs of neuroinflammatory events are higher in SpA than in RA, but the choice of specific TNFi does not seem to play an important role in the risk of neuroinflammatory events.

Search for the molecular basis of ultra-rapid CYP2C9-catalysed metabolism: relationship between SNP IVS8-109A>T and the losartan metabolism phenotype in Swedes.

AIM: To search for a relationship between ultra-rapid metabolism catalysed by cytochrome P450 2C9 (CYP2C9) and its genotypes. METHODS: DNA from a Swedish ultra-rapid metaboliser patient [losartan metabolic ratio (MR) <0.13] and three healthy Swedes with normal CYP2C9 activity and a MR of about 1 were assessed for variation in the CYP2C9 gene. Direct DNA sequencing was performed for all exons and exon-intron junctions and also for -2100 bp of the 5'-flanking regions of the CYP2C9 gene. This analysis revealed four intronic mutations [single nucleotide polymorphisms (SNPs) 1-4] in the three samples with normal MR while no variation was observed in the ultra-rapid metaboliser. PCR/restriction fragment length polymorphism and allele-specific PCR methods were subsequently developed to screen 85 Swedes and 128 Koreans without CYP2C9*2 or *3. RESULTS: We found a significant relationship between SNP 4 (IVS8-109A>T) and CYP2C9 activity (χ²-test, p=0.011) in the Swedes. Twenty Swedes with the lowest MR were compared with 20 Swedes with the highest MR, revealing a strong association (p00.001) between SNP4 and higher MR. For homozygous SNP 1 (IVS1+83T>C), SNP 2 (IVS2+73T>C), and SNP 3 (IVS6+95A>G), no phenotype and genotype relationships were found, but theMRwas generally higher among the Swedes compared to the Koreans (Mann-Whitney test, p<0.05). CONCLUSIONS: We found that the SNP 4 IVS8-109T allele is associated with a higher CYP2C9 MR in healthy Swedish subjects, but further investigations need to be carried out to establish a molecular explanation for ultra-rapid CYP2C9- catalysed metabolism. Haplotype based on SNPs 1-4 did not seem to contribute to variation in the MR of the Korean subjects nor play a role in determining the MR of the Swedish ones.