Goals and background: Patients with Clostridium difficile infection (CDI) can experience long-term symptoms and poor quality of life due to the disease. Despite this, a health-related quality of life (HRQOL) instrument specific for patients with CDI does not exist. The aim of this study was to develop and validate a disease-specific instrument to assess HRQOL in patients with CDI.
Study: A systematic literature review was conducted to identify HRQOL instruments and questions related to general health (n=3) or gastrointestinal disease (n=12) potentially related to CDI HRQOL. Removing duplicate questions and using direct patient or clinician interviews, a 36-item survey was developed. The survey was then tested using 98 patients with CDI and compared with the RAND Short-Form 36 (SF-36) Health Survey. Psychometric analysis techniques were used to identify domains and remove redundant items.
Results: Exploratory factor analysis identified 3 major domains (physical, mental, and social) with 4 associated subdomains. Survey overall and domain scores displayed good internal consistency (Cronbach α coefficient >0.87) and concurrent validity evidenced by significant correlation with SF-36 scores. The C. difficile survey scores were better able than the SF-36 to discriminate quality-of-life score differences in patients with primary versus recurrent CDI and increasing time since last episode of CDI. The final version contained 32 items related to the physical, mental, and social health of CDI patients.
Conclusion: The properties of the newly developed Cdiff32 should make it appropriate to assess changes over time in HRQOL in patients with CDI.