Purpose A well-defined and reliable patient-reported outcome instrument for COVID-19 is important for assessing symptom severity and supporting research studies. The InFLUenza Patient-Reported Outcome (FLU-PRO) instrument has been expanded to include loss of taste and smell in the FLU-PRO Plus, to comprehensively cover COVID-19 symptoms. Our studies were designed to evaluate and validate the FLU-PRO Plus among patients with COVID-19. Methods Two studies were conducted: (1) a qualitative, non-interventional, cross-sectional study of patients with COVID-19 involving hybrid concept elicitation and cognitive debriefing interviews; (2) a psychometric evaluation of the measurement properties of FLU-PRO Plus, using data from COMET-ICE (COVID-19 Monoclonal antibody Efficacy Trial—Intent to Care Early). Results In the qualitative interviews (n = 30), all 34 items of the FLU-PRO Plus were considered relevant to COVID-19, and participants determined the questionnaire was easily understood, well written, and comprehensive. In the psychometric evaluation (n = 845), the internal consistency reliability of FLU-PRO Plus total score was 0.94, ranging from 0.71 to 0.90 for domain scores. Reproducibility (Day 20–21) was 0.83 for total score, with domain scores of 0.67–0.89. Confirmatory factor analysis with the novel smell/taste domain demonstrated an acceptable fit to the data. Conclusion The content, reliability, validity, and responsiveness of the FLU-PRO Plus in the COVID-19 population were supported. Our results suggest that FLU-PRO Plus is a content- and psychometrically-valid, fit-for-purpose measure which is easily understood by patients. FLU-PRO Plus is a suitable PRO measure for evaluating symptoms of COVID-19 and treatment benefit directly from the patient perspective. Trial Registration: ClinicalTrials.Gov: NCT04545060, September 10, 2020; retrospectively registered.

Purpose To explore symptoms and disease impacts of Crohn’s disease and to develop a new patient-reported outcomes (PRO) measure according to industry best practices. Methods A conceptual model of relevant symptoms experienced by patients with Crohn’s disease was developed following a literature review. Three rounds of combined qualitative semi-structured concept elicitation and cognitive debriefing interviews with 36 patients (≥ 16 years) with Crohn’s disease and 4 clinicians were conducted to further explore the most commonly reported and most bothersome symptoms to patients. Interview results were used to update the conceptual model as well as items and response options included in The Crohn’s Disease Diary, a new PRO measure. Results All patients (N = 36) reported abdominal pain, loose or liquid bowel movements, and high or increased frequency of bowel movements, with most reporting these symptoms spontaneously (100%, 92%, and 75%, respectively). All patients reported bowel movement urgency, but 61% reported this symptom only when probed. Most also reported that symptoms impacted activities of daily living, work/school, and emotional, social, and physical functioning (overall, 78%–100%; spontaneously, 79% – 92%). Data regarding core symptoms of Crohn’s disease from clinician concept elicitation interviews supported patient data. The 17-item Crohn’s Disease Diary assesses core symptoms and impacts of Crohn’s disease over 24 h, and extraintestinal manifestations over 7 days. The content validity of the diary was confirmed during cognitive debriefing interviews. Conclusion The Crohn’s Disease Diary is a new PRO measure for the assessment of Crohn’s disease symptoms and impacts, developed according to industry best practices.