Kristin Bjordal

Kristin Bjordal

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Current Organizations / Institutes

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Previous Organizations / Institutes

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Kristin Bjordal has a total of 377 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    Association between symptom experience and long-term survival in people treated for cancer

    by K. Hofsø, T. Rustøen, K. Bjordal, M. Hagen, B. Aouizerat, G.L. Astrup

  • Open Access

    The SISAQOL-IMI glossary: harmonising terminology for patient-reported outcomes in cancer clinical trials

    by Kenth Louis Joseph, Francesca Martinelli, Lisa M. Wintner, Silène Ten Seldam, Vincent Claus, Andrej Belančić, Ragnhild S. Falk, Cecilie D. Amdal, Micha J. Pilz, Corneel Coens, et al.

    Background: This study presents the development of a glossary designed to harmonize terminology, foster consensus and support the successful implementation of the Setting International Standards in Analysing Patient-Reported Outcomes and Quality of Life Endpoints in Cancer Clinical Trials-Innovative Medicines Initiative (SISAQOL-IMI) guidelines. Methodology: SISAQOL-IMI consortium representatives from 41 international organisations were invited to participate in the development of the glossary. From 2021 to 2024, the glossary was developed through iterative processes, guided by consortium members input and formally updated twice yearly. A template with categories for term, acronym, topic, scientific definition, plain language definition, examples and references/sources was applied and were accessible for input throughout the process. As project documents such as draft guideline recommendations were updated, new terms for the glossary were identified. Definition of terms were primarily sought from a predefined hierarchical list of references and acknowledged resources, such as existing glossaries, prior to seeking other references. Patient representatives and patient advocates from The Workgroup of European Cancer Patient Advocacy Networks contributed to plain language definitions. Results: The glossary development resulted in 227 terms with scientific and plain language definitions, which are integrated into the online SISAQOL-IMI guidelines. During the initial development phase, of 205 terms, the project’s work package teams agreed on 166 (81%) and had diverging views on 39 (19%). Discussions were organized to reconcile disagreements. The glossary proved essential in 1) helping patient representatives better understand and engage in the consensus process, 2) aligning terminology during the pre-testing of preliminary recommendations, and 3) clarifying terms during the final language harmonisation of the recommendations. Conclusions: The glossary was pivotal in ensuring a common understanding of terminology throughout the SISAQOL-IMI project. It serves as a critical resource for enhancing clarity and successful implementation of the SISAQOL-IMI recommendations, ultimately advancing the role of patient-reported outcomes in improving the quality of cancer clinical trials.

  • Open Access

    Unmet supportive care needs among head and neck cancer survivors beyond 5 years after diagnosis: a multinational cohort study

    by Femke Jansen, Simone Ej. Eerenstein, Katherine J. Taylor, Cecilie D. Amdal, Kristin Bjordal, Guro L. Astrup, Bente B. Herlofson, Fréderic Duprez, Ricardo R. Gama, Alexandre A. Jacinto, et al.


  • Open Access

    Late Toxicity and Long‐Term Quality of Life in Survivors of Cancer of the Major Salivary Glands More Than 5 Years After Diagnosis: A Multi‐National Study

    by Susanne Singer, Cecilie Delphin Amdal, Kristin Bjordal, Bente Brokstad Herlofson, Guro Lindviksmoen Astrup, Andreas Boehm, Ulrike Wöhner, Eva Hammerlid, Ricardo Ribeiro Gama, Alexandre Arthur Jacinto, et al.

    Background: Because salivary gland cancers (SGC) are rare and include different tumor subtypes, data on their long‐term quality of life and late toxicities are sparse. Methods: Multi‐national study including SGC survivors more than 5 years after diagnosis. They completed the European Organisation for Research and Treatment of Cancer (EORTC) quality of life core questionnaire together with its head and neck cancer module and reported problems that were most bothering for them. Toxicity was clinically assessed. Results: Altogether, 60 survivors from nine countries participated and reported dry mouth (mean score 37.2), use of painkillers (35.0), problems with sexuality (30.1), insomnia (28.9), fatigue (27.8), trismus (24.9), and sticky saliva (23.3). The most frequently mentioned long‐term problem was dry mouth , mentioned by a third of all participants. The most frequent toxicities were hearing impairment , soft tissue fibrosis , dry mouth , and cranial neuropathies . Conclusions: Dry mouth is a frequent and disturbing problem in SGC survivors.

  • Open Access

    Serious Long-Term Effects of Head and Neck Cancer from the Survivors’ Point of View

    by Katherine J. Taylor, Cecilie D. Amdal, Kristin Bjordal, Guro L. Astrup, Bente B. Herlofson, Fréderic Duprez, Ricardo R. Gama, Alexandre Jacinto, Eva Hammerlid, Melissa Scricciolo, et al.

    The long-term problems of head and neck cancer survivors (HNCS) are not well known. In a cross-sectional international study aimed at exploring the long-term quality of life in this population, 1114 HNCS were asked to state their two most serious long-term effects. A clinician recorded the responses during face-to-face appointments. A list of 15 example problems was provided, but a free text field was also available. A total of 1033 survivors responded to the question. The most frequent problems were ‘dry mouth’ (DM) (n = 476; 46%), ‘difficulty swallowing/eating’ (DSE) (n = 408; 40%), ‘hoarseness/difficulty speaking’ (HDS) (n = 169; 16%), and ‘pain in the head and neck’ (PHN) (n = 142; 14%). A total of 5% reported no problems. Logistic regression adjusted for age, gender, treatment, and tumor stage and site showed increased odds of reporting DM and DSE for chemo-radiotherapy (CRT) alone compared to surgery alone (odds ratio (OR): 4.7, 95% confidence interval (CI): 2.5–9.0; OR: 2.1, CI: 1.1–3.9), but decreased odds for HDS and PHN (OR: 0.3, CI: 0.1–0.6; OR: 0.2, CI: 0.1–0.5). Survivors with UICC stage IV at diagnosis compared to stage I had increased odds of reporting HDS (OR: 1.9, CI: 1.2–3.0). Laryngeal cancer survivors had reduced odds compared to oropharynx cancer survivors of reporting DM (OR: 0.4, CI: 0.3–0.6) but increased odds of HDS (OR: 7.2, CI: 4.3–12.3). This study provides evidence of the serious long-term problems among HNCS.


  • Open Access

    A multicenter international prospective study of the validity and reliability of a COVID-19-specific health-related quality of life questionnaire

    by Cecilie Delphin Amdal, Ragnhild Sørum Falk, Susanne Singer, Madeline Pe, Claire Piccinin, Andrew Bottomley, Lambert Tetteh Appiah, Juan Ignacio Arraras, Oliver Bayer, Eirik Alnes Buanes, et al.

    Purpose: To develop and validate a health-related quality of life (HRQoL) questionnaire for patients with current or previous coronavirus disease (COVID-19) in an international setting. Methods: This multicenter international methodology study followed standardized guidelines for a four-phase questionnaire development. Here, we report on the pretesting and validation of our international questionnaire. Adults with current or previous COVID-19, in institutions or at home were eligible. In the pretesting, 54 participants completed the questionnaire followed by interviews to identify administration problems and evaluate content validity. Thereafter, 371 participants completed the revised questionnaire and a debriefing form to allow preliminary psychometric analysis. Validity and reliability were assessed (correlation-based methods, Cronbach’s α, and intra-class correlation coefficient). Results: Eleven countries within and outside Europe enrolled patients. From the pretesting, 71 of the 80 original items fulfilled the criteria for item-retention. Most participants (80%) completed the revised 71-item questionnaire within 15 min, on paper (n = 175) or digitally (n = 196). The final questionnaire included 61 items that fulfilled criteria for item retention or were important to subgroups. Item-scale correlations were > 0.7 for all but nine items. Internal consistency (range 0.68–0.92) and test–retest results (all but one scale > 0.7) were acceptable. The instrument consists of 15 multi-item scales and six single items. Conclusion: The Oslo COVID-19 QLQ-W61© is an international, stand-alone, multidimensional HRQoL questionnaire that can assess the symptoms, functioning, and overall quality of life in COVID-19 patients. It is available for use in research and clinical practice. Further psychometric validation in larger patient samples will be performed.


  • Open Access

    Health-related quality of life in patients with COVID-19; international development of a patient-reported outcome measure

    by Cecilie Delphin Amdal, Katherine Taylor, Dagmara Kuliś, Ragnhild Sørum Falk, Andrew Bottomley, Juan Ignacio Arraras, James Harold Barte, Anne Sophie Darlington, Kristin Hofsø, Bernard Holzner, et al.

    Background: We aimed to create a questionnaire to assess the health-related quality of life including functioning, symptoms, and general health status of adult patients with current or previous COVID-19. Here, we report on Phase I and II of the development. Methods: Internationally recognized methodology for questionnaire development was followed. In Phase I, a comprehensive literature review was performed to identify relevant COVID-19 issues. Decisions for inclusion, exclusion, and data extraction were completed independently in teams of two and then compared. The resulting issues were discussed with health care professionals (HCPs) and current and former COVID-19 patients. The input of HCPs and patients was carefully considered, and the list of issues updated. In Phase II, this updated list was operationalized into items/questions. Results: The literature review yielded 3342 publications, 339 of which were selected for full-text review, and 75 issues were identified. Discussions with 44 HCPs from seven countries and 52 patients from six countries showed that psychological symptoms, worries, and reduced functioning lasted the longest for patients, and there were considerable discrepancies between HCPs and patients concerning the importance of some of the symptoms. The final list included 73 issues, which were operationalized into an 80-item questionnaire. Conclusion: The resulting COVID-19 questionnaire covers health–related quality of life issues relevant to COVID-19 patients and is available in several languages. The next steps include testing of the applicability and patients’ acceptability of the questionnaire (Phase IIIA) and preliminary psychometric testing (Phase IIIB).


  • Open Access

    Comparing the use of patient-reported outcomes in clinical studies in Europe in 2008 and 2018: a literature review

    by Guro Lindviksmoen Astrup, Gudrun Rohde, Stein Arne Rimehaug, Marit Helen Andersen, Tomm Bernklev, Kristin Bjordal, Ragnhild Sørum Falk, Nina Marie Høyning Jørgensen, Knut Stavem, Anita Tollisen, et al.

    Purpose: Several guidelines for the use of patient-reported outcomes (PROs) in clinical studies have been published in the past decade. This review primarily aimed to compare the number and compliance with selected PRO-specific criteria for reporting of clinical studies in Europe using PROs published in 2008 and 2018. Secondarily, to describe the study designs, PRO instruments used, patient groups studied, and countries where the clinical studies were conducted. Methods: A literature search was conducted in MEDLINE to identify eligible publications. To assess the number of publications, all abstracts were screened for eligibility by pairs of reviewers. Compliance with PRO-specific criteria and other key characteristics was assessed in a random sample of 150 eligible full-text publications from each year. Randomized controlled trials (RCTs) were assessed according to the full CONSORT-PRO checklist. Results: The search identified 1692 publications in 2008 and 4290 in 2018. After screening of abstracts, 1240 from 2008 and 2869 from 2018 were clinical studies using PROs. By full-text review, the proportion of studies discussing PRO-specific limitations and implications was higher in 2018 than in 2008, but there were no differences in the other selected PRO-specific criteria. In 2018, a higher proportion of studies were longitudinal/cohort studies, included ≥ 300 patients, and used electronic administration of PRO than in 2008. The most common patient groups studied were those with cancer or diseases of the musculoskeletal system or connective tissue. Conclusion: The number of clinical studies from Europe using PROs was higher in 2018 than in 2008, but there was little difference in compliance with the PRO-specific criteria. The studies varied in terms of study design and PRO instruments used in both publication years.


  • Open Access

    Methodological approach for determining the Minimal Important Difference and Minimal Important Change scores for the European Organisation for Research and Treatment of Cancer Head and Neck Cancer Module (EORTC QLQ-HN43) exemplified by the Swallowing scale

    by Susanne Singer, Eva Hammerlid, Iwona M. Tomaszewska, Cecilie Delphin Amdal, Kristin Bjordal, Bente Brokstad Herlofson, Marcos Santos, Joaquim Castro Silva, Hisham Mehanna, Amy Fullerton, et al.

    Purpose: The aim of this study was to explore what methods should be used to determine the minimal important difference (MID) and minimal important change (MIC) in scores for the European Organisation for Research and Treatment of Cancer Head and Neck Cancer Module, the EORTC QLQ-HN43. Methods: In an international multi-centre study, patients with head and neck cancer completed the EORTC QLQ-HN43 before the onset of treatment (t1), three months after baseline (t2), and six months after baseline (t3). The methods explored for determining the MID were: (1) group comparisons based on performance status; (2) 0.5 and 0.3 standard deviation and standard error of the mean. The methods examined for the MIC were patients' subjective change ratings and receiver-operating characteristics (ROC) curves, predictive modelling, standard deviation, and standard error of the mean. The EORTC QLQ-HN43 Swallowing scale was used to investigate these methods. Results: From 28 hospitals in 18 countries, 503 patients participated. Correlations with the performance status were |r|< 0.4 in 17 out of 19 scales; hence, performance status was regarded as an unsuitable anchor. The ROC approach yielded an implausible MIC and was also discarded. The remaining approaches worked well and delivered MID values ranging from 10 to 14; the MIC for deterioration ranged from 8 to 16 and the MIC for improvement from − 3 to − 14. Conclusions: For determining MIDs of the remaining scales of the EORTC QLQ-HN43, we will omit comparisons of groups based on the Karnofsky Performance Score. Other external anchors are needed instead. Distribution-based methods worked well and will be applied as a starting strategy for analyses. For the calculation of MICs, subjective change ratings, predictive modelling, and standard-deviation based approaches are suitable methods whereas ROC analyses seem to be inappropriate.