Abstract
Purpose
The objective of this retrospective study was to determine the feasibility of measuring frailty using patient responses to relevant EORTC QLQ-C30 items as proxy criteria for the Fried Frailty Phenotype, in a cohort of patients with Relapsed/Refractory Multiple Myeloma (RRMM).
Methods
Data were pooled from nine Phase III randomized clinical trials submitted to the FDA for regulatory review between 2010 and 2021, for the treatment of RRMM. Baseline EORTC QLQ-C30 responses were used to derive a patient-reported frailty phenotype (PRFP), based on the Fried definition of frailty. PRFP was assessed for internal consistency reliability, structural validity, and known groups validity.
Results
This study demonstrated the feasibility of adapting patient responses to relevant EORTC QLQ-C30 items to serve as proxy Fried frailty criteria. Selected items were well correlated with one another and PRFP as a whole demonstrated adequate internal consistency reliability and structural validity. Known groups analysis demonstrated that PRFP could be used to detect distinct comorbidity levels and distinguish between different functional profiles, with frail patients reporting more difficulty in walking about, washing/dressing, and doing usual activities, as compared to their pre-frail and fit counterparts. Among the 4928 patients included in this study, PRFP classified 2729 (55.4%) patients as fit, 1209 (24.5%) as pre-frail, and 990 (20.1%) as frail.
Conclusion
Constructing a frailty scale from existing PRO items commonly collected in cancer trials may be a patient-centric and practical approach to measuring frailty. Additional psychometric evaluation and research is warranted to further explore the utility of such an approach.

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Data are not available due to legal restrictions which prevent the U.S. Food and Drug Administration from sharing sponsor-submitted data with third parties. Custom code generated using R programming software for statistical analyses in this manuscript can be shared upon request.
Abbreviations
- EORTC QLQ-C30:
-
European Organization for Research and Treatment of Cancer Quality of Life 30-item Questionnaire
- RRMM:
-
Relapsed/Refractory Multiple Myeloma
- PRFP:
-
Patient-reported frailty phenotype
- CGA:
-
Comprehensive Geriatric Assessment
- PRO:
-
Patient-reported outcomes
- PROMIS:
-
Patient-reported outcomes measurement information system
- FACIT:
-
Functional assessment of chronic illness therapy
- FDA - U.S.:
-
Food and Drug Administration
- CFA:
-
Confirmatory factor analysis
- WLSMV:
-
Weighted least square means and variances
- RMSEA:
-
Root mean square error of approximation
- CFI:
-
Comparative fit index
- SRMR:
-
Standardized root mean square residual
- TLI:
-
Tucker Lewis Index
- CCI:
-
Charlson Comorbidity Index
- EQ-5D:
-
EuroQol-5 Dimension
- ECOG PS:
-
Eastern Cooperative Oncology Group Performance Status
- ISS:
-
International staging system
- IMWG:
-
International Myeloma Working Group
- HRQoL:
-
Health-related quality of life
References
Rockwood, K., Song, X., MacKnight, C., Bergman, H., Hogan, D. B., McDowell, I., & Mitnitski, A. (2005). A global clinical measure of fitness and frailty in elderly people. CMAJ, 173(5), 489–495. https://doi.org/10.1503/cmaj.050051
Xue, Q. L. (2011). The frailty syndrome: Definition and natural history. Clinics in Geriatric Medicine, 27(1), 1–15. https://doi.org/10.1016/j.cger.2010.08.009
Ethun, C. G., Bilen, M. A., Jani, A. B., Maithel, S. K., Ogan, K., & Master, V. A. (2017). Frailty and cancer: Implications for oncology surgery, medical oncology, and radiation oncology. CA: A Cancer Journal for Clinicians, 67(5), 362–377. https://doi.org/10.3322/caac.21406
Hamaker, M. E., Jonker, J. M., de Rooij, S. E., Vos, A. G., Smorenburg, C. H., & van Munster, B. C. (2012). Frailty screening methods for predicting outcome of a comprehensive geriatric assessment in elderly patients with cancer: A systematic review. The Lancet Oncology, 13(10), e437–e444. https://doi.org/10.1016/S1470-2045(12)70259-0
Handforth, C., Clegg, A., Young, C., Simpkins, S., Seymour, M. T., Selby, P. J., & Young, J. (2015). The prevalence and outcomes of frailty in older cancer patients: A systematic review. Annals of Oncology, 26(6), 1091–1101. https://doi.org/10.1093/annonc/mdu540
Makary, M. A., Segev, D. L., Pronovost, P. J., Syin, D., Bandeen-Roche, K., Patel, P., Takenaga, R., Devgan, L., Holzmueller, C. G., Tian, J., & Fried, L. P. (2010). Frailty as a predictor of surgical outcomes in older patients. Journal of the American College of Surgeons, 210(6), 901–908. https://doi.org/10.1016/j.jamcollsurg.2010.01.028
Boakye, D., Rillmann, B., Walter, V., Jansen, L., Hoffmeister, M., & Brenner, H. (2018). Impact of comorbidity and frailty on prognosis in colorectal cancer patients: A systematic review and meta-analysis. Cancer Treatment Reviews, 64, 30–39. https://doi.org/10.1016/j.ctrv.2018.02.003
Clough-Gorr, K. M., Thwin, S. S., Stuck, A. E., & Silliman, R. A. (2012). Examining five- and ten-year survival in older women with breast cancer using cancer-specific geriatric assessment. European Journal of Cancer, 48(6), 805–812. https://doi.org/10.1016/j.ejca.2011.06.016
Engelhardt, M., Ihorst, G., Duque-Afonso, J., Wedding, U., Spät-Schwalbe, E., Goede, V., Kolb, G., Stauder, R., & Wäsch, R. (2020). Structured assessment of frailty in multiple myeloma as a paradigm of individualized treatment algorithms in cancer patients at advanced age. Haematologica, 105(5), 1183–1188. https://doi.org/10.3324/haematol.2019.242958
Kumar, A., Langstraat, C. L., DeJong, S. R., McGree, M. E., Bakkum-Gamez, J. N., Weaver, A. L., LeBrasseur, N. K., & Cliby, W. A. (2017). Functional not chronologic age: Frailty index predicts outcomes in advanced ovarian cancer. Gynecologic Oncology, 147(1), 104–109. https://doi.org/10.1016/j.ygyno.2017.07.126
Corre, R., Greillier, L., Le Caër, H., Audigier-Valette, C., Baize, N., Bérard, H., Falchero, L., Monnet, I., Dansin, E., Vergnenègre, A., Marcq, M., Decroisette, C., Auliac, J.-B., Bota, S., Lamy, R., Massuti, B., Dujon, C., Pérol, M., Daurès, J.-P., … Chouaïd, C. (2016). Use of a comprehensive geriatric assessment for the management of elderly patients with advanced non-small-cell lung cancer: The phase III randomized ESOGIA-GFPC-GECP 08–02 study. Journal of Clinical Oncology, 34(13), 1476–1483. https://doi.org/10.1200/jco.2015.63.5839
Hall, P. S., Swinson, D., Waters, J. S., Wadsley, J., Falk, S., Roy, R., Tillett, T., Nicoll, J., Cummings, S., Grumett, S. A., Kamposioras, K., Garcia, A., Allmark, C., Marshall, H., Ruddock, S., Katona, E., Velikova, G., Petty, R. D., Grabsch, H. I., & Seymour, M. T. (2019). Optimizing chemotherapy for frail and elderly patients (pts) with advanced gastroesophageal cancer (aGOAC): The GO2 phase III trial. Journal of Clinical Oncology, 37(15_suppl), 4006–4006. https://doi.org/10.1200/JCO.2019.37.15_suppl.4006
Li, D., Sun, C.-L., Kim, H., Chung, V., Koczywas, M., Fakih, M., Chao, J., Chien, L., Charles, K., Hughes, S. F. D. S., Trent, M., Roberts, E., Celis, E. S. P. D., Jayani, R., Katheria, V., Moreno, J., Kelly, C., Sedrak, M. S., Hurria, A., & Dale, W. (2020). Geriatric assessment-driven intervention (GAIN) on chemotherapy toxicity in older adults with cancer: A randomized controlled trial. Journal of Clinical Oncology, 38(15_suppl), 12010–12010. https://doi.org/10.1200/JCO.2020.38.15_suppl.12010
Mohile, S. G., Mohamed, M. R., Culakova, E., Huiwen, Xu., Loh, K. P., Magnuson, A., Flannery, M. A., Ramsdale, E. E., Dunne, R. F., Gilmore, N., Obrecht, S., Patil, A., Plumb, S., Lowenstein, L. M., Janelsins, M. C., Mustian, K. M., Hopkins, J. O., Berenberg, J. L., Gaur, R., & Dale, W. (2020). A geriatric assessment (GA) intervention to reduce treatment toxicity in older patients with advanced cancer: A University of Rochester Cancer Center NCI community oncology research program cluster randomized clinical trial (CRCT). Journal of Clinical Oncology, 38(15_suppl), 12009–12009. https://doi.org/10.1200/JCO.2020.38.15_suppl.12009
Mian, H. S., Wildes, T. M., & Fiala, M. A. (2018). Development of a medicare health outcomes survey deficit-accumulation frailty index and its application to older patients with newly diagnosed multiple myeloma. JCO Clin Cancer Inform. https://doi.org/10.1200/cci.18.00043
Zweegman, S., Engelhardt, M., & Larocca, A. (2017). Elderly patients with multiple myeloma: Towards a frailty approach? Current Opinion in Oncology, 29(5), 315–321. https://doi.org/10.1097/cco.0000000000000395
Zweegman, S., & Larocca, A. (2019). Frailty in multiple myeloma: The need for harmony to prevent doing harm. The Lancet Haematology, 6(3), e117–e118. https://doi.org/10.1016/S2352-3026(19)30011-0
Mohile, S. G., Mohamed, M. R., Huiwen, Xu., Culakova, E., Loh, K. P., Magnuson, A., Flannery, M. A., Obrecht, S., Gilmore, N., Ramsdale, E., Dunne, R. F., Wildes, T., Plumb, S., Patil, A., Wells, M., Lowenstein, L., Janelsins, M., Mustian, K., Hopkins, J. O., … Dale, W. (2021). Evaluation of geriatric assessment and management on the toxic effects of cancer treatment (GAP70+): A cluster-randomised study. Lancet, 398(10314), 1894–1904. https://doi.org/10.1016/s0140-6736(21)01789-x
Clegg, A., Young, J., Iliffe, S., Rikkert, M. O., & Rockwood, K. (2013). Frailty in elderly people. Lancet, 381(9868), 752–762. https://doi.org/10.1016/s0140-6736(12)62167-9
O’Donovan, A., & Leech, M. (2020). Personalised treatment for older adults with cancer: The role of frailty assessment. Technical Innovations & Patient Support in Radiation Oncology, 16, 30–38.
Shahrokni, A., Tin, A., Alexander, K., Sarraf, S., Afonso, A., Filippova, O., Harris, J., Downey, R. J., Vickers, A. J., & Korc-Grodzicki, B. (2019). Development and evaluation of a new frailty index for older surgical patients with cancer. JAMA Network Open, 2(5), e193545–e193545. https://doi.org/10.1001/jamanetworkopen.2019.3545
Welsh, T. J., Gordon, A. L., & Gladman, J. R. (2014). Comprehensive geriatric assessment–a guide for the non-specialist. International Journal of Clinical Practice, 68(3), 290–293. https://doi.org/10.1111/ijcp.12313
Fried, L. P., Tangen, C. M., Walston, J., Newman, A. B., Hirsch, C., Gottdiener, J., Seeman, T., Tracy, R., Kop, W. J., Burke, G., & McBurnie, M. A. (2001). Frailty in older adults: Evidence for a phenotype. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 56(3), M146-156. https://doi.org/10.1093/gerona/56.3.m146
Abt, N. B., Richmon, J. D., Koch, W. M., Eisele, D. W., & Agrawal, N. (2016). Assessment of the predictive value of the modified frailty index for Clavien-Dindo grade IV critical care complications in major head and neck cancer operations. JAMA Otolaryngology—Head & Neck Surgery, 142(7), 658–664. https://doi.org/10.1001/jamaoto.2016.0707
Courtney-Brooks, M., Tellawi, A. R., Scalici, J., Duska, L. R., Jazaeri, A. A., Modesitt, S. C., & Cantrell, L. A. (2012). Frailty: An outcome predictor for elderly gynecologic oncology patients. Gynecologic Oncology, 126(1), 20–24. https://doi.org/10.1016/j.ygyno.2012.04.019
McCarthy, A. L., Peel, N. M., Gillespie, K. M., Berry, R., Walpole, E., Yates, P., & Hubbard, R. E. (2018). Validation of a frailty index in older cancer patients with solid tumours. BMC Cancer, 18(1), 892. https://doi.org/10.1186/s12885-018-4807-6
Tan, K. Y., Kawamura, Y. J., Tokomitsu, A., & Tang, T. (2012). Assessment for frailty is useful for predicting morbidity in elderly patients undergoing colorectal cancer resection whose comorbidities are already optimized. American Journal of Surgery, 204(2), 139–143. https://doi.org/10.1016/j.amjsurg.2011.08.012
Efficace, F., Gaidano, G., Petrucci, M. T., Niscola, P., Tognazzi, L., Antonioli, E., Cottone, F., Annibali, O., Tafuri, A., Califano, C., Larocca, A., Potenza, L., Palazzo, G., Fozza, C., Pastore, D., Rigolin, G. M., Offidani, M., Romano, A., Tosi, P., … Cavo, M. (2021). The accuracy of the international myeloma working group frailty score in capturing health-related quality of life profile of patients with relapsed refractory multiple myeloma. Blood, 138(Supplement 1), 115–115. https://doi.org/10.1182/blood-2021-145977
Morley, J. E., Malmstrom, T. K., & Miller, D. K. (2012). A simple frailty questionnaire (FRAIL) predicts outcomes in middle aged African Americans. The Journal of Nutrition, Health & Aging, 16(7), 601–608. https://doi.org/10.1007/s12603-012-0084-2
Papachristou, E., Wannamethee, S. G., Lennon, L. T., Papacosta, O., Whincup, P. H., Iliffe, S., & Ramsay, S. E. (2017). Ability of self-reported frailty components to predict incident disability, falls, and all-cause mortality: results from a population-based study of older British men. Journal of the American Medical Directors Association, 18(2), 152–157. https://doi.org/10.1016/j.jamda.2016.08.020
Saliba, D., Elliott, M., Rubenstein, L. Z., Solomon, D. H., Young, R. T., Kamberg, C. J., Carol Roth, R. N., MacLean, C. H., Shekelle, P. G., Sloss, E. M., & Wenger, N. S. (2001). The Vulnerable Elders Survey: A tool for identifying vulnerable older people in the community. Journal of the American Geriatrics Society, 49(12), 1691–1699. https://doi.org/10.1046/j.1532-5415.2001.49281.x
Aaronson, N. K., Ahmedzai, S., Bergman, B., Bullinger, M., Cull, A., Duez, N. J., Filiberti, A., Flechtner, H., Fleishman, S. B., Haes, J. C. JMd., Kaasa, S., Klee, M., Osoba, D., Razavi, D., Rofe, P. B., Schraub, S., Sneeuw, K., Sullivan, M., & Takeda, F. (1993). The European organization for research and treatment of cancer QLQ-C30: A quality-of-life instrument for use in international clinical trials in oncology. Journal of the National Cancer Institute, 85(5), 365–376. https://doi.org/10.1093/jnci/85.5.365
Fernandes, L. L., Zhou, J., Kanapuru, B., Horodniceanu, E., Gwise, T., Kluetz, P. G., & Bhatnagar, V. (2021). Review of patient-reported outcomes in multiple myeloma registrational trials: Highlighting areas for improvement. Blood Cancer Journal, 11(8), 148. https://doi.org/10.1038/s41408-021-00543-y
Padala, S. A., Barsouk, A., Barsouk, A., Rawla, P., Vakiti, A., Kolhe, R., Kota, V., & Ajebo, G. H. (2021). Epidemiology, staging, and management of multiple myeloma. Medical Sciences (Basel). https://doi.org/10.3390/medsci9010003
Murillo, A., Cronin, A. M., Laubach, J. P., Hshieh, T. T., Tanasijevic, A. M., Richardson, P. G., Driver, J. A., & Abel, G. A. (2019). Performance of the International Myeloma Working Group myeloma frailty score among patients 75 and older. Journal of Geriatric Oncology, 10(3), 486–489. https://doi.org/10.1016/j.jgo.2018.10.010
Myeloma XIV: Frailty-adjusted Therapy in Transplant Non-Eligible Patients With Newly Diagnosed Multiple Myeloma (FiTNEss). In Clinicaltrials.gov: NCT03720041
Palumbo, A., Bringhen, S., Mateos, M.-V., Larocca, A., Facon, T., Kumar, S. K., Offidani, M., McCarthy, P., Evangelista, A., Lonial, S., Zweegman, S., Musto, P., Terpos, E., Belch, A., Hajek, R., Heinz Ludwig, A., Stewart, K., Moreau, P., Anderson, K., … Rajkumar, V. (2015). Geriatric assessment predicts survival and toxicities in elderly myeloma patients: An International Myeloma Working Group report. Blood, 125(13), 2068–2074. https://doi.org/10.1182/blood-2014-12-615187
Engelhardt, M., Dold, S. M., Ihorst, G., Zober, A., Moller, M., Reinhardt, H., Hieke, S., Schumacher, M., & Wasch, R. (2016). Geriatric assessment in multiple myeloma patients: Validation of the International Myeloma Working Group (IMWG) score and comparison with other common comorbidity scores. Haematologica, 101(9), 1110–1119. https://doi.org/10.3324/haematol.2016.148189
Murugappan, M. N., King-Kallimanis, B. L., Bhatnagar, V., Kanapuru, B., Chen, T. Y., Horodniceanu, E. G., Singh, H., & Kluetz, P. G. (2021). Leveraging patient-reported outcomes to measure frailty in relapsed/refractory multiple myeloma. Quality of Life Research, 30(Suppl 1), S1–S177.
Brown, T. A. (2015). Confirmatory factor analysis for applied research (2nd ed.). The Guilford Press.
Weston, R., & Gore, P. A., Jr. (2006). A brief guide to structural equation modeling. The counseling psychologist, 34(5), 719–751.
Fayers, P. M., & Machin, D. (2013). Quality of life: The assessment, analysis and interpretation of patient-reported outcomes. John Wiley & Sons.
Revicki, D. (2014). Internal Consistency Reliability. In A. C. Michalos (Ed.), Encyclopedia of quality of life and well-being research (pp. 3305–3306). Netherlands: Springer. https://doi.org/10.1007/978-94-007-0753-5_1494
Davidson, M. (2014). Known-Groups Validity. In A. C. Michalos (Ed.), Encyclopedia of quality of life and well-being research (pp. 3481–3482). Netherlands: Springer. https://doi.org/10.1007/978-94-007-0753-5_1581
Comrey, A. L., & Lee, H. B. (2013). A first course in factor analysis. Psychology press.
Bean, J. (2021, 02–26–2021). Using R for Social Work Research. The Ohio State University. Retrieved 01.05.2022 from https://bookdown.org/bean_jerry/using_r_for_social_work_research/
Cook, G., Royle, K.-L., Pawlyn, C., Hockaday, A., Shah, V., Kaiser, M. F., Brown, S. R., Gregory, W. M., Anthony Child, J., Davies, F. E., Morgan, G. J., Cairns, D. A., & Jackson, G. H. (2019). A clinical prediction model for outcome and therapy delivery in transplant-ineligible patients with myeloma (UK Myeloma Research Alliance Risk Profile): a development and validation study. The Lancet Haematology, 6(3), e154–e166. https://doi.org/10.1016/S2352-3026(18)30220-5
Engelhardt, M., Domm, A.-S., Dold, S. M., Ihorst, G., Reinhardt, H., Zober, A., Hieke, S., Baayen, C., Müller, S. J., Einsele, H., Sonneveld, P., Landgren, O., Schumacher, M., & Wäsch, R. (2017). A concise revised Myeloma Comorbidity Index as a valid prognostic instrument in a large cohort of 801 multiple myeloma patients. Haematologica, 102(5), 910–921. https://doi.org/10.3324/haematol.2016.162693
Facon, T., Hulin, C., Dimopoulos, M. A., Belch, A., Meuleman, N., & Mohty, M. (2015). A frailty scale predicts outcomes of patients with newly diagnosed multiple myeloma who are ineligible for transplant treated with continuous lenalidomide plus low-dose dexamethasone on the first trial. Blood, 126(23), 4239.
Paolo Milani, S., Rajkumar, V., Merlini, G., Kumar, S., Gertz, M. A., Palladini, G., Lacy, M. Q., Buadi, F. K., Hayman, S. R., Leung, N., Dingli, D., Lust, J. A., Lin, Yi., Kapoor, P., Go, R. S., Hwa, Y. L., Gonsalves, W. I., Zeldenrust, S. R., Kyle, R. A., & Dispenzieri, A. (2016). N-terminal fragment of the type-B natriuretic peptide (NT-proBNP) contributes to a simple new frailty score in patients with newly diagnosed multiple myeloma. American Journal of Hematology, 91(11), 1129–1134. https://doi.org/10.1002/ajh.24532
Patel, B. G., Luo, S., Wildes, T. M., & Sanfilippo, K. M. (2020). Frailty in older adults with multiple myeloma: A study of US Veterans. JCO Clinical Cancer Informatics, 4, 117–127. https://doi.org/10.1200/cci.19.00094
Kellen, E., Bulens, P., Deckx, L., Schouten, H., Van Dijk, M., Verdonck, I., & Buntinx, F. (2010). Identifying an accurate pre-screening tool in geriatric oncology. Critical Reviews in Oncology Hematology, 75(3), 243–248. https://doi.org/10.1016/j.critrevonc.2009.12.002
Mohile, S. G., Bylow, K., Dale, W., Dignam, J., Martin, K., Petrylak, D. P., Stadler, W. M., & Rodin, M. (2007). A pilot study of the vulnerable elders survey-13 compared with the comprehensive geriatric assessment for identifying disability in older patients with prostate cancer who receive androgen ablation. Cancer, 109(4), 802–810. https://doi.org/10.1002/cncr.22495
Martin, F. C., & Brighton, P. (2008). Frailty: Different tools for different purposes? Age and Ageing, 37(2), 129–131. https://doi.org/10.1093/ageing/afn011
Nunes, D. P., Duarte, Y. A., Santos, J. L., & Lebrão, M. L. (2015). Screening for frailty in older adults using a self-reported instrument. Revista de Saude Publica, 49, 2. https://doi.org/10.1590/s0034-8910.2015049005516
Zhang, Y., Zhang, Y., Li, Y., Chan, P., & Ma, L. (2020). Reliability and validity of the self-reported frailty screening questionnaire in older adults. Therapeutic Advances in Chronic Disease, 11, 2040622320904278. https://doi.org/10.1177/2040622320904278
EORTC. EORTC Quality of Life. Retrieved January 24th from https://qol.eortc.org/
Roydhouse, J. K., King-Kallimanis, B. L., Howie, L. J., Singh, H., & Kluetz, P. G. (2019). Blinding and patient-reported outcome completion rates in US Food and Drug Administration cancer trial submissions, 2007–2017. Journal of the National Cancer Institute, 111(5), 459–464. https://doi.org/10.1093/jnci/djy181
Van Norman, G. A. (2021). Decentralized clinical trials: The future of medical product development? JACC Basic to Translational Science, 6(4), 384–387. https://doi.org/10.1016/j.jacbts.2021.01.011
Acknowledgements
This work was supported in part by an appointment to the Research Fellowship Program at the Center for Drug Evaluation and Research—Office of New Drugs, U.S. Food and Drug Administration, administered by the Oak Ridge Institute for Science and Education through an interagency agreement between the U.S. Department of Energy and FDA.
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This work was supported by Oak Ridge Institute for Science and Education
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Conceptualization: MNM; Methodology: MNM; Formal analysis and investigation: MNM; Writing - original draft preparation: MNM, Writing - review and editing: BLK-K, VB, BK, JFF, RDS, DDS, T-YC, EGH, PGK; Supervision: PGK
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Murugappan, M.N., King-Kallimanis, B.L., Bhatnagar, V. et al. Measuring Frailty Using Patient-Reported Outcomes (PRO) Data: A Feasibility Study in Patients with Multiple Myeloma. Qual Life Res 32, 2281–2292 (2023). https://doi.org/10.1007/s11136-023-03390-5
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DOI: https://doi.org/10.1007/s11136-023-03390-5