To investigate if patients with cutaneous lupus erythematosus (CLE) or systemic lupus erythematosus (SLE) have an increased risk of cancer compared with the general population, and furthermore to identify specific cancer types associated with increased risk. This is an observational cohort study of 5310 patients with CLE or SLE identified in the Danish National Patient Register from 1 January 1995 to 31 December 2014. The cohort was followed up for cancer by linkage to the Danish Cancer Registry. Based on the age, sex, and calendar specific cancer rates of the general population of Denmark, standardised incidence ratios (SIRs) were calculated. The patients with CLE or SLE were followed for 40.724 person-years, each group’s average duration of follow-up being 6.9 and 8.1 years. The SIR for overall cancer (except non-melanoma skin cancer (NMSC)) was increased in patients with CLE 1.35 (95%CI 1.15 to 1.58) and patients with SLE 1.45 (95%CI 1.30 to 1.62). Both groups had high risks of hematological – including a 3–4-fold increased risk of non-Hodgkin lymphoma –, pancreatic, and lung cancers. Several cancers associated with oncogenic viruses as liver and tongue/mouth/pharynx were increased in the SLE group, while the risk of ovarian cancer was increased 2–4-fold only in the CLE group. The overall risk of cancer was significantly increased in both patients with CLE and SLE. SIRs for hematological, pancreatic and lung cancers were elevated in both groups. Extra awareness of cancer in patients with SLE and patients with CLE should be considered.

Objectives: We aimed to investigate the risk of first primary cancer in patients with RA treated with janus kinase inhibitors (JAKi) compared with those who received biologic DMARDs (bDMARDs) in a real-world setting. Methods: We performed an observational cohort study using the nationwide registers in Denmark. Patients with RA aged 18+ years, without a previous cancer diagnosis, and who initiated treatment with JAKi or bDMARDs from 1 January 2017 to 31 December 2020 were followed for any cancer (except non-melanoma skin cancer). We applied inverse probability of treatment weighting (IPTW) to account for covariate differences between treatment groups. IPTW-generated weights were used with cause-specific Cox (CSC) models to calculate hazard ratios (HRs) for cancer incidence in JAKi-treated compared with bDMARD-treated patients with RA. Results: We identified 875 and 4247 RA patients treated with JAKi and bDMARDs, respectively. The JAKi group contributed 1315 person years (PYRS) and 19 cancers, the bDMARD group contributed 8597 PYRS and 111 cancers, with corresponding crude incidence rates per 1000 PYRS of 14.4 and 12.9. Comparing the two groups using weighted CSC models, a HR of 1.41 (95% CI 0.76, 2.37, 95% CIs) was seen for JAKi- vs bDMARD-treated patients with RA. Conclusion: JAKi treatment in real-world patients with RA was not associated with a statistically significant increased risk of first primary cancer compared with those who received bDMARDs. However, several numerically increased risk estimates were detected, and a clinically important excess risk of cancer among JAKi recipients cannot be dismissed.

Background: Patients with systemic lupus erythematosus (SLE) have an increased risk of infections due to impaired immune functions, disease activity, and treatment. This study investigated the impact of having SLE on the incidence of hospitalisation with COVID-19 infection. Methods: This was a nationwide cohort study from Denmark between 1 March 2020 to 2 February 2021, based on the linkage of several nationwide registers. The adjusted incidence of COVID-19 hospitalisation was estimated for patients with SLE compared with the general population in Cox-regression models. Among SLE patients, the hazard ratio (HR) for hospitalisation was analysed as nested case-control study. Results: Sixteen of the 2533 SLE patients were hospitalised with COVID-19 infection. The age-sex adjusted rate per 1000 person years was 6.16 (95% CI 3.76–10.08) in SLE patients, and the corresponding hazard ratio was 2.54 (95% CI 1.55–4.16) compared with the matched general population group after adjustment for comorbidities. Among SLE patients, hydroxychloroquine treatment was associated with a HR for hospitalisation of 0.61 (95% CI 0.19–1.88), and 1.06 (95% CI 0.3–3.72) for glucocorticoid treatment. Conclusion: Patients with SLE were at increased risk of hospitalisation with COVID-19.

Objectives: The objectives of this study were to investigate the incidence of COVID-19 hospitalization in unvaccinated and vaccinated patients with RA compared with matched controls, and in patients with RA according to DMARD treatment. Methods: This was a Danish nationwide matched-cohort study from January to October 2021. Patients with RA were identified in the DANBIO register and matched 1:20 with individuals from the general population on age, sex, and vaccination status. Primary and secondary outcomes were COVID-19 hospitalization (Danish National Patient Register) and first-time positive SARS-CoV-2 PCR test (Danish COVID-19 Surveillance Register), respectively. Stratified by vaccination status, incidence rates (IRs) per 1000 person years (PYs) and comorbidity-adjusted hazard ratios (aHRs) in cause-specific Cox models were calculated with 95% confidence intervals. Results: In total, 28 447 unvaccinated patients and 568 940 comparators had IRs for COVID-19 hospitalization of 10.4 (8.0–13.4) and 4.7 (4.3–5.1) per 1000 PYs, respectively (aHR 1.88, 1.44–2.46). When fully vaccinated, corresponding IRs were 0.9 (0.5–1.6) and 0.5 (0.4–0.6) per 1000 PYs (aHR 1.94, 1.03–3.66). Unvaccinated RA patients had an aHR of 1.22 (1.09–1.57) for testing positive for SARS-CoV-2 and 1.09 (0.92–1.14) among vaccinated RA patients. Vaccinated rituximab-treated patients had increased crude IR of COVID-19 hospitalization compared with conventional DMARD–treated patients. Conclusion: The incidence of COVID-19 hospitalization was increased for both unvaccinated and vaccinated patients with RA compared with controls. Importantly, the parallel decreasing risk for patients with RA suggests a comparable relative benefit of vaccination in most patients.

To investigate cancer risk in rheumatoid arthritis (RA) patients treated with tocilizumab/sarilumab, abatacept, or rituximab compared with those who received tumour necrosis factor inhibitors (TNFi) and compared with biological disease-modifying anti-rheumatic drugs (bDMARD) naïve RA patients. Nationwide registry-based cohort study of RA patients initiating treatment with tocilizumab/sarilumab, abatacept, rituximab, TNFi, and bDMARD-naive patients their second type of conventional synthetic DMARD (csDMARD). Patients were identified in DANBIO and followed for cancer from 2006–2020. Patients could contribute multiple treatments, with person years (PYRS), deaths, and cancers allocated to each treatment group in a ‘latest type of treatment’ manner. Inverse probability of treatment weighting and weighted cause-specific Cox models were used to calculate hazard ratios (HRs) for cancer in each tocilizumab/sarilumab, abatacept, and rituximab group compared with TNFI and bDMARD naïve groups, respectively. In total, 21 982 treatment initiations, 96 475 PYRS, and 1423 cancers were identified. There were no statistically significant increased HRs for overall cancer in tocilizumab/sarilumab, abatacept, or rituximab treatment groups (HRs ranged from 0.7–1.1). More than five years of abatacept exposure showed a non-significantly increased HR compared with TNFi (HR 1.41, 95% confidence intervals CI 0.74–2.71). For hematological cancers, rituximab treatment showed non-significantly reduced HRs: vs TNFi (HR 0.09; 95%CI 0.00–2.06) and bDMARD-naïve (HR 0.13; 95%CI 0.00–1.89). Treatment with tocilizumab/sarilumab, abatacept, or rituximab in RA patients was not associated with increased risks of cancer compared with TNFi-treated and with bDMARD-naïve RA patients in a real-world setting.

Objective: To investigate the risk of cancer recurrence in patients with rheumatoid arthritis (RA) and a prior solid cancer in remission treated with biological disease-modifying antirheumatic drugs (bDMARDs) compared with those who received only conventional synthetic DMARDs (csDMARDs). Methods: Nationwide registry-based cohort study of Danish patients with RA and one of the six algorithm-specific solid cancers in remission (breast, colorectal, melanoma, bladder, endometrial and lung) who initiated treatment with a bDMARD or a csDMARD. Three bDMARD exposure groups were defined according to the type(s) of bDMARD initiated: (1) any bDMARD, (2) tumour necrosis factor inhibitors (TNFi) and (3) rituximab. Patients were identified in Danish Rheumatology Quality Register and followed for cancer recurrence from 2002 to 2021 using validated cancer-specific recurrence algorithms. Inverse probability of treatment weighting and weighted cause-specific Cox models were used to calculate HRs for cancer recurrence in each bDMARD exposure group compared with a csDMARD-treated group. Results: Among 720 unique patients with RA and an algorithm-specific solid cancer in remission, 170 any bDMARD, 81 TNFi, 99 rituximab and 651 csDMARD initiators were identified. No statistically significant increased HRs for cancer recurrence were found with any type of bDMARD 0.92 (95% CI 0.38 to 1.73), TNFi 1.10 (95% CI 0.21 to 3.16) or rituximab 0.94 (95% CI 0.32 to 2.11). Also, no increased HRs were shown for breast cancer recurrence specifically. Conclusion: No indications of increased cancer recurrence risk were found for bDMARDs as used in clinical practice in patients with RA and a solid cancer in remission when compared with csDMARD treatment.