The CDI-DaySyms: Content Development of a New Patient-Reported Outcome Questionnaire for Symptoms of Clostridium difficile Infection

Abstract Objectives To develop a patient-reported outcome (PRO) questionnaire for symptoms of Clostridium difficile infection (CDI) following the US Food and Drug Administration PRO guidelines. Methods Patients' experiences of CDI symptoms were elicited in open-ended discussions with patients and nurses at five US sites (stage 1). A draft PRO measure was developed after demonstration of concept saturation. Two rounds of cognitive interviews were conducted with patients at three US sites (stage 2), with revision of the draft measure after each round. All patients were 18 years or older, with confirmed CDI. The study was conducted with input from a panel of five CDI experts in Europe and North America. Results Stage 1 included interviews with 18 patients and supplementary interviews with 6 nurses; 16 additional patients were interviewed in stage 2. Patients were representative of the general CDI population and were diverse in age, sex, and disease severity. Concept saturation was reached in stage 1. Items were organized in a draft conceptual framework with five hypothesized domains: diarrhea, abdominal discomfort, tiredness, lightheadedness, and other symptoms. Stage 2 demonstrated initial content validity of the 13-item draft daily diary (CDI-DaySyms). Participants reported that the questions were clear, relevant, and comprehensive. They were able to use the instructions to complete the diary correctly and considered the 24-hour recall period appropriate. Conclusions The CDI-DaySyms captures symptoms relevant to patients undergoing CDI, demonstrating initial content validity. Final content and psychometric validity are being evaluated in a substudy comprising patients from two ongoing international clinical trials (ClinicalTrials.gov identifiers NCT01987895 and NCT01983683).