Implementation of the Short-Form 36 (SF-36) in childhood cancer survivors: An analysis on measurement properties across 5 European countries

Purpose The Short Form-36 (SF-36) is widely used in many research contexts and cultures to assess health-related quality of life (HRQOL). We investigated the measurement properties of the SF-36 in a large cohort study among childhood cancer survivors living in 5 European countries. Methods The PanCareLIFE project includes adult survivors of childhood cancer living in the Czech Republic, France, Germany, The Netherlands, and Switzerland. We invited 19,268 survivors aged >18 years, and 10,077 (53%) returned questionnaires. Of these, 9,871 (98%) were included in the analyses. We assessed HRQOL with the SF-36 version 1 (V1) or version 2 (V2) and investigated its performance. We analysed data completeness, floor and ceiling effects, item-internal consistency, item-discriminant validity, reliability, and scaling assumptions focusing on country-and version-specific differences. Results Data completeness was high but differed between countries (90% in the Czech Republic to 96% in France). Floor effects were negligible, but ceiling effects in 5 out of 8 SF-36 scales were present (50-70%). V2 had slightly fewer ceiling effects than V1 in 2 scales. Item-internal consistency, item-discriminant validity, and reliability were good. Scaling assumptions were met, with 4 scales representing strong mental health content, and the other 4 representing strong physical health content. Conclusion The SF-36 (V1 and V2) provided robust measurement properties among childhood cancer survivors, and differences in study design across the 5 European countries did not affect measurement properties. Researchers need to take into account that ceiling effects exist which might limit sensitivity among participants who fared particularly well. PLAIN ENGLISH SUMMARY This study investigated how well the Short Form-36 (SF-36), a commonly used tool for assessing health-related quality of life, performs in childhood cancer survivors from five different European countries. We looked at the amount of survivors answering to all of the SF-36 questions, how many indicated the most positive or the most negative answer category, whether the questions were consistent within the different aspects of the questionnaire and how consistent and dependable it measured quality of life in the survivors. We found that overall, the SF-36 measured health-related quality of life well in all the countries. This is reassuring for researchers considering its use in studies involving multiple centers across Europe. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement In the Czech Republic, we received funding from the University Hospital of Brno from the Ministry of Education, Youth and Sports of the Czech Republic, under grant agreement No. 7E13061; and the University Hospital of Prague from the foundation Narod detem ([www.naroddetem.cz][1]). In France, we received funding from The Wyeth Foundation; the French National Institute of Cancer (INCa); and the French League against Cancer. In Germany, we received funding from the German Cancer Aid (Grant No. 110298). In Switzerland, we also received funding from the Swiss Cancer League and Swiss Cancer Research (Grant no. KLS-3412-02-2014, HSR‐4951‐11‐2019, KFS-5302-02-2021, KLS/KFS- 5711-01-2022); the Bernese Cancer League, Kinderkrebs Schweiz, and Stiftung fuer krebskranke Kinder Regio Basiliensis. The work of the Childhood Cancer Registry in Switzerland is supported by the Federal Office of Public Health. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: PanCareLIFE is a multinational collaborative research project that has harmonized and combined data from regional and national cohorts across Europe. Data collection and analysis for each cohort was approved by the responsible ethics committee in each participating country. For Germany this is the Ethics Committee of the Medical Association of Westphalia-Lippe and the Medical faculty of the Westphalian Wilhelms University (2012-530-f-S), for Switzerland the Cantonal Ethics Committee of the Canton of Bern (KEK-BE: 166/2014; 2021-01462), for the Czech Republic the Ethics Committee for Multi-Centric Clinical Trials of the University Hospital Motol (EK-1723/13) and the Multi-Centric Ethics Committee of the University Hospital Brno (approval date: 2014/10/22), for France the Personal Protection Committee South East 1 (CPP: 2015-23) and for the Netherlands the Medical Ethical Review Committee of the Academic Medical Center, University of Amsterdam (2010_332#B2015108). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes The data that support the information of this manuscript were accessed on secured servers of the Institute of Social and Preventive Medicine at the University of Bern. Individual-level sensitive data can only be made available for researchers who fulfil the respective legal requirements. All data requests should be communicated to the corresponding author. [1]: https://www.naroddetem.cz