BGBjorn Gudbjornsson

Bjorn Gudbjornsson

*This is an algorithmically generated author record based on publicly available information.

Current Organizations / Institutes

The organizations/institutes from the scholar's latest article

Previous Organizations / Institutes

The organizations / institutes from the scholar's other articles in the past ten years


Bjorn Gudbjornsson has a total of 437 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Difficult-to-manage axial spondyloarthritis–an analysis in five Nordic registries inspired by recent ASAS definitions

    by Daniela Di Giuseppe, Louise M Nielung, Merete Lund Hetland, Johan Askling, Dan C Nordstrom, Sella A Provan, Bjorn Gudbjornsson, Olafur Palsson, Bénédicte Delcoigne, Brigitte Michelsen, et al.

  • Open Access

    MRI-assessed structural damage progression in sacroiliac joints of European routine care patients with axial spondyloarthritis receiving biological or conventional therapy

    by Annik Steimer, Jonas Brändli, Raphael Micheroli, Anna E.F. Hadsbjerg, Simon Krabbe, Nora Vladimirova, Iris Eshed, Torsten Diekhoff, Robert G.W. Lambert, Susanne Juhl Pedersen, et al.

  • Open Access

    Progression of sacroiliac joint structural lesions in axial spondyloarthritis: a longitudinal comparative study of MRI and radiography among European patients in routine clinical care

    by Annik Steimer, Raphael Micheroli, Claudia Lourenço Rodrigues, Jonas Brändli, Anna E. F. Hadsbjerg, Simon Krabbe, Nora Vladimirova, Iris Eshed, Torsten Diekhoff, Robert G. W. Lambert, et al.

    Background: To compare the performances of magnetic resonance imaging (MRI) and radiography in detecting changes in structural lesions of the sacroiliac joints (SIJs) in routine care patients with axial spondyloarthritis (axSpA). Methods: SIJ MRIs and radiographs of routine care patients with axSpA in four European countries were collected as part of the EuroSpA Imaging Project. Patients were included if both MRIs and radiographs (≤ 6 months apart) were available at two time points (≥ 1 year apart). Images were evaluated centrally and independently by two trained readers (blinded to chronology and other imaging), applying the Spondyloarthritis Research Consortium of Canada SIJ scores (MRI) and the modified New York criteria (mNY, radiography). Intermodality agreement was assessed cross-sectionally and for change. Results: One-hundred-and-five patients (65 male, mean (SD) age 38.1 (10.9) years, symptom duration 9.1 (9.7) years), with a follow-up interval of 2.6 (1.4) years) were included. Baseline agreement between radiography and MRI was slight-to-fair for erosion detection (kappa = 0.12 to 0.42), poor to slight for sclerosis (− 0.04 to 0.07), and substantial to almost perfect for ankylosis (0.66–0.86). Agreement for change over time was poor-to-slight (− 0.04 to 0.20). While lesions remained largely stable on radiography (≤ 6 patients showing change in scores, per lesion type), MRI detected change in at least one lesion in ≥ 50% of patients (positive/negative change in scores (“progression”/”regression”): sclerosis 27/30, erosion 51/38, ankylosis 14/5). A composite MRI score of damage correlated well with mNY grades (Spearman rho = 0.65–0.69). Conclusions: Compared to radiography, MRI detected more SIJ structural lesion changes over time, reflecting its ability to capture dynamic changes not readily visible on radiography.

  • Open Access

    Influence of national socioeconomic status on treatment retention and disease activity in psoriatic arthritis and axial spondyloarthritis: evidence over 2 years in 13 European countries

    by Brigitte Michelsen, Christos Polysopoulos, Michael J. Nissen, Adrian Ciurea, Burkhard Möller, Lykke Midtbøll Ørnbjerg, Catalin Codreanu, Corina Mogosan, Gary J. Macfarlane, Gareth T. Jones, et al.


  • Overall and Sex-Specific Predictors of Secukinumab Effectiveness in European Patients With Psoriatic Arthritis: Results From the EuroSpA Collaboration

    by Jette Heberg, Stylianos Georgiadis, Zohra Faizy Ahmadzay, Bente Glintborg, Isabel Castrejón, Mehrdad Shoae Kazemi, Anne Gitte Loft, Brigitte Michelsen, Simon Horskjær Rasmussen, Karin Laas, et al.

    Objective: Identifying patient characteristics that predict treatment response in psoriatic arthritis (PsA) may help optimize treat-to-target strategies. We aimed to explore overall and sex-specific predictors of secukinumab (SEC) effectiveness in European patients with PsA treated in routine care. Methods: We analyzed data from 14 registries in the European Spondyloarthritis (EuroSpA) Research Collaboration. Patients aged ≥ 18 years at diagnosis, initiating SEC treatment from January 2015 to January 2021, were included. Multiple imputation was used for missing covariates at treatment start (baseline) and Disease Activity Index for Psoriatic Arthritis based on 28 joints (DAPSA28) at 6 months. Overall and sex-stratified analyses were performed by logistic and Cox regressions to identify baseline predictors of the following treatment outcomes: (1) DAPSA28 low disease activity (LDA; DAPSA28 ≤ 14) at 6 months, (2) DAPSA28 moderate response at 6 months, and (3) SEC discontinuation within 12 months. Results: In total, 2790 patients (43% male) were included. Median age was 43 years (IQR 34-52), and SEC was the first-line biologic/targeted synthetic disease-modifying antirheumatic drug (b/tsDMARD) in 665 patients (24%). Positive predictors for both DAPSA28 LDA and DAPSA28 moderate response were male sex, fewer previous b/tsDMARDs, C-reactive protein (CRP) > 10 mg/L, and lower Health Assessment Questionnaire (HAQ) score. Absence of psoriasis, higher patient fatigue, and tender joint counts predicted SEC discontinuation within 12 months. For some outcomes, sex-specific predictors were fewer previous b/tsDMARDs and CRP > 10 mg/L among male patients and lower patient fatigue score among female patients. Conclusion: We identified overall and sex-specific predictors of SEC effectiveness in European patients with PsA. Our findings may support personalized treatment decisions.

  • Open Access

    Impact of cardiometabolic comorbidities on clinical characteristics, prescription patterns and retention rate of first b/tsDMARD treatment in 5299 European real-world patients with psoriatic arthritis

    by Zohra Faizy Ahmadzay, Lykke Midtbøll Ørnbjerg, Mikkel Østergaard, Kasper Yde Jensen, Jacob Brauner Jørgensen, Jette Heberg, Anne Gitte Loft, Brigitte Michelsen, Gareth T Jones, Pasoon Hellamand, et al.

    Objectives: To investigate associations between cardiometabolic comorbidities and clinical characteristics, prescription patterns and retention of first biologic/targeted synthetic disease-modifying anti-rheumatic drug (b/tsDMARD) in patients with psoriatic arthritis (PsA). Methods: Patients with PsA initiating a first b/tsDMARD treatment in 2015 or later were identified in eight European rheumatology registries. Patients with information on five cardiometabolic comorbidities (obesity, dyslipidaemia, diabetes, hypertension, ischaemic heart disease) at treatment start (baseline) were included. All analyses were conducted according to patients’ comorbidity burden (count: 0/1/≥2) and status (presence/absence of each comorbidity). Patient characteristics and prescription patterns were described. Twelve-month treatment retention rates were estimated and compared using Kaplan-Meier plots, log-rank tests and multivariable Cox regression analyses. Results: Among 5299 patients, 36% had at least one cardiometabolic comorbidity. Patients with comorbidity were older, had higher disease activity and more disability. Regardless of comorbidity, most patients were prescribed a tumour necrosis factor inhibitor (76%). The use of interleukin-17 inhibitors increased with comorbidity burden (0/1/≥2 comorbidities: 13%/18%/19%), whereas Janus kinase inhibitor use declined (2.3%/1.6%/0.8%). Retention rates were marginally lower with higher comorbidity burden (80%/76%/78%) (log-rank, p=0.036) and obesity (absent 79% vs present 77%) (log-rank, p=0.04). The risk of treatment withdrawal was only marginally higher in patients with higher comorbidity burden (one comorbidity: HR 1.19; 95% CI 1.02 to 1.40; ≥2 comorbidities: HR 1.18; 0.98 to 1.42). Conclusion: Patients with cardiometabolic comorbidities had higher disease activity at treatment initiation of the first b/tsDMARD. Prescription patterns varied with comorbidity burden. Cardiometabolic comorbidity burden, especially obesity, was associated with marginally lower treatment retention.

  • Open Access

    The impact of smoking and obesity on secukinumab effectiveness in psoriatic arthritis: real-world evidence from 1202 European patients

    by Zohra Faizy Ahmadzay, Stylianos Georgiadis, Mikkel Østergaard, Bente Glintborg, Marion Pons, Jette Heberg, Signe Møller-Bisgaard, Sara Nysom Christiansen, Simon Horskjær Rasmussen, Anne Gitte Loft, et al.

  • Open Access

    Antimicrobial Use and Serious Infections Among Patients With Psoriatic Arthritis After Initiating Tumor Necrosis Factor Inhibitors: A Nationwide Matched Cohort Study

    by Telma Thrastardottir, Aron Hjalti Bjornsson, Alexis Ogdie, Arna Hauksdottir, Sigurdur Yngvi Kristinsson, Bjorn Gudbjornsson, Thorvardur Jon Love

    In Table 1, the units for the last row were labelled incorrectly. The value in the parentheses represents the number of individuals affected by serious infections, as some individuals had > 1 event of a serious infection. The revised variable is “No. of serious infections (n individuals).” We apologize for this error. This correction applies to the August 1 2025 First Release and print issue. The online version has been corrected. J Rheumatol 2025; doi: 10.3899/jrheum.2025-0029

  • Open Access

    Defining Bath Ankylosing Spondylitis Disease Activity Index Cut‐off Values for Disease Activity States in a Multinational European Cohort of Patients With Axial Spondyloarthritis

    by Stylianos Georgiadis, Lykke Midtbøll Ørnbjerg, Brigitte Michelsen, Tore K. Kvien, Mehrdad Shoae Kazemi, Jakub Závada, Karel Pavelka, Bente Glintborg, Anne Gitte Loft, Andreas Reich, et al.

    Objective: The Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) is widely used for assessing disease activity in patients with axial spondyloarthritis (axSpA), particularly in settings where markers of inflammation are unavailable. As no consensus on BASDAI cut‐off values exists for disease activity states in axSpA, we aimed to develop and validate such cut‐offs against external criteria. Methods: Routine care patients with axSpA initiating a biologic disease‐modifying antirheumatic drug in eight European registries were included. Receiver operating characteristic analyses against external criteria were performed to determine optimal BASDAI values for separating remission, low disease activity (LDA), high disease activity (HDA), and very high disease activity (VHDA). Follow‐up data at 6 months were used to select BASDAI cut‐off values between remission and LDA and between LDA and HDA, whereas baseline data were used to select the cut‐off for VHDA. The level of agreement between disease activity states based on BASDAI and Axial Spondyloarthritis Disease Activity Score (ASDAS) cut‐off values was assessed using the proportion of discordance and weighted kappa. Results: In this cohort of 4,633 patients, the optimal BASDAI cut‐off values between remission, LDA, HDA and VHDA were estimated to be 4,600 patients. These cut‐off values can be used for assessing disease activity and monitoring patients with axSpA, particularly when laboratory markers are unavailable.


  • Open Access

    Assessing internal construct validity of DAPSA and DAPSA28 in psoriatic arthritis: a European observational study using confirmatory factor analysis and additional psychometric testing

    by Jacob Brauner Jørgensen, Karl Bang Christensen, Brigitte Michelsen, Anne Gitte Loft, Simon Horskjær Rasmussen, Jette Heberg, Merete Lund Hetland, Jakub Zavada, Karel Pavelka, Florenzo Iannone, et al.

    Objectives: The Disease Activity index for Psoriatic Arthritis (DAPSA) was developed to assess disease activity in patients with psoriatic arthritis (PsA). A modified version, DAPSA28, uses 28 joints instead of 66/68. This study evaluated key psychometric properties of DAPSA and DAPSA28. Methods: Data from 1865 patients with PsA in the European Spondyloarthritis (EuroSpA) Research Collaboration Network, having DAPSA and DAPSA28 scores at baseline and follow-up, were analysed. Tests included assessment of internal construct validity by scree plots, confirmatory factor analysis (CFA) and structural equation modelling (SEM), supplemented by tests of differential item functioning (DIF) and evaluation of internal consistency reliability by Cronbach’s α (CA). A subset of 625 patients was used for most analyses, except descriptive statistics, correlation matrix and CA. Results: One-dimensional CFA models for DAPSA and DAPSA28 showed acceptable model fit at baseline (root mean square error of approximation, RMSEA: 0.020, 0.034). However, model fit at 6 months follow-up was poor (RMSEA: 0.057, 0.063). SEM combining baseline and follow-up data could not identify an acceptable model fit. DIF was found for sex and country. CA indicated acceptable internal consistency (DAPSA: 0.65; DAPSA28: 0.63). Heterogeneity across countries was observed. Conclusions: Overall, the model fit was acceptable across model fit statistics, supporting internal construct validity, but some evidence of misfit at country level was disclosed. Our findings support acceptable internal consistency reliability, but DIF was found for sex and country. Based on mixed results of model fit and DIF, further investigation of these and other PsA disease activity measures is warranted.