Assessing the Content Validity of Preference-Based Measures in Cancer

This study assessed the content validity of generic and condition-specific preference-based measures (PBMs) with patients treated for cancer, evaluated against ten COSMIN criteria for good content validity, to best inform measurement strategies regarding the use of PBMs in oncology development programs as well as real-world applications. Individual, semi-structured interviews were conducted with patients who received drug treatment for cancer in the UK (n=47) and US (n=49). During the interview, patients completed three generic PBMs (EQ-5D-5L, EQ-HWB-S, CS-Base) and two condition-specific PBMs (QLU-C10D, FACT-8D). Interviews were conducted via teleconference, audio recorded and transcribed verbatim. Transcripts were coded using thematic and content analysis methods. Condition-specific measures were evaluated as having better relevancy than generic PBMs. Overall, the FACT-8D was evaluated as holding the best content validity in terms of relevancy, and the EQ-HWB-S received the most favourable evaluation of relevancy for generic PBMs. All measures demonstrated comparable comprehensiveness, with all suggested by patients to be missing concepts. The EQ-5D-5L was evaluated best in terms of comprehensibility. This was followed by the QLU-C10D and FACT-8D; both received similar evaluations. All measures were generally seen by patients as adequate in capturing appropriate aspects of HRQoL for measuring cancer outcomes, although together, condition specific measures were evaluated as having better relevancy than generic PBMs. Further HRQoL instrument development is encouraged, particularly with regards to the longer-term detrimental impacts of cancer and treatment side effects. Other developments could include new cancer-specific tools inclusive of conventional health items, treatment impacts, and psychological items. •What is already known about the topic? Generic preference-based measures (PBM) are recommended to assess patient reported outcomes across interventions and to allow for comparative assessments across unrelated health conditions and interventions. Generic PBMs may exclude dimensions relevant to specific conditions, whereas condition-specific PBMs can contain items related to specific symptoms. Recent work has identified several concepts that are relevant to health-related quality of life and psychological well-being which are not measured by existing outcome measures.•What does the paper add to existing knowledge? Patients who had received drug treatm