Patient Reported Outcome Measures in Otology and the Development, Validation, and Implementation of the Otology Questionnaire Amsterdam

In this dissertation, the development, validation, and implementation of the Otology Questionnaire Amsterdam (OQUA) is described. The OQUA is a Patient-Reported Outcome Measure (PROM), a questionnaire completed directly by patients to capture health, symptoms, functioning, and quality of life without interpretation by clinicians. PROMs are crucial in evaluating outcomes, monitoring disease, and tailoring care to what matters most to patients. Selecting appropriate PROMs in otology has been challenging, as many questionnaires are symptom-specific.

Chapter 2 provides an overview of existing PROMs in otology through a systematic review. A total of 155 unique questionnaires were identified, including 84 for hearing loss, 33 for tinnitus, 23 for vertigo, and 15 addressing multiple complaints. Despite many ear diseases producing multiple symptoms, most instruments were single-symptom focused.

Chapter 3 describes the multicentre development of the OQUA. In phase 1, interviews identified relevant ear complaints, and pilot studies refined items. In phase 2, field-testing and item reduction led to 34 items grouped into two subscales: complaints and their impact on daily life. Explorative factor analysis produced nine factors: eight reflecting frequency and severity of complaints and one reflecting impact. The complaints subscale was considered formative, while the impact subscale was reflective.

Chapter 4 reports on validity, reliability, and responsiveness. Construct validity was confirmed. A new cohort of 194 patients assessed responsiveness, while 50 surgical patients were included for test–retest reliability. A scoring system was developed to calculate subscale scores for eight ear complaints and their impact on quality of life.

We argue that while most PROMs are questionnaires, not all questionnaires are PROMs. Patient involvement is essential to ensure relevant aspects are included. Chapter 5 repeats the earlier search and evaluates the quality of PROMs for multiple ear complaints using the COSMIN checklist. Twelve such questionnaires were assessed; most lacked robust design, patient input, or concept elicitation. Many were modifications or combinations of existing tools, often undergoing ongoing validation despite methodological shortcomings. This underlines the need for the OQUA.

Chapter 6 focuses on normative data for the OQUA. A representative sample of 500 Dutch adults without ENT history completed the questionnaire; 496 responses were analyzed. Percentiles were calculated for all subscales, with the 95th percentile defining the threshold between normal and abnormal scores. These normative data provide valuable context in shared decision-making, allowing clinicians and patients to compare individual results to the general population.

Implementation is key to ensuring the OQUA contributes to standard care. Broader use generates more data, improving precision, interpretability, and usefulness in quality improvement and shared decision-making.

Chapter 7 explores implementation through qualitative analysis. Focus groups and interviews with ENT professionals (n=15) and patients (n=25) identified enablers and barriers. Both groups were motivated to use the OQUA: patients valued reflecting on their complaints and clinicians appreciated the detailed insights. Barriers included patient-level challenges (language, digital literacy), provider-level issues (awareness, workload), and organizational barriers (workflow integration). An implementation strategy was proposed, focusing on education and training, adapting digital systems, and ensuring engagement and feedback mechanisms so that OQUA results are effectively used at all levels.

In conclusion, the OQUA is the first validated, comprehensive PROM addressing multiple ear complaints and their impact on daily life. It is supported by normative data and a proposed implementation framework. Its use can advance patient-centred care in otology by enhancing understanding, supporting shared decision-making, and improving quality of care.