The Leuven questionnaire on patient knowledge of chemotherapy (L-PaKC): instrument development and psychometric evaluation

Abstract

Purpose: Evidence suggests that patients who gain knowledge perform better self-care, cope better and are more satisfied. Today, up-to-date and valid instruments for evaluating patient knowledge on chemotherapy are unavailable. Hence, our aim was to develop a valid instrument to assess patients' knowledge on chemotherapy.

Method: We performed a literature review to develop a topic list for the construct. Using a triple Delphi procedure, an expert panel of nine oncologists and oncology nurses evaluated the face and content validity of the topic list and the generated items. A preliminary psychometric evaluation of 144 patients allowed to identify and remediate items having limited applicability and item validity. A convenience sample of 440 patients was used to evaluate item statistics (item difficulty), reliability (Cronbach alpha) and construct validity (exploratory factor analysis) of the final instrument.

Results: We developed a 20-item instrument reflecting 14 relevant themes of patient knowledge on chemotherapy in 13 questions. Twelve items cover general chemotherapy aspects, eight items cover treatment-specific knowledge. Three questions are facultative and address oral chemotherapy. Content validity was excellent (CVI = 0.78-1.00). Item difficulty ranged from 0.25 to 0.95. Internal consistency was acceptable (Cronbach's alpha = 0.67). Exploratory factor analysis defined four underlying factors: general aspects of chemotherapy treatment, negative treatment-related events, information resources and intake of oral chemotherapy.

Conclusions: The Leuven Questionnaire on Patient Knowledge of Chemotherapy (L-PaKC) demonstrated good content validity and psychometric properties, permitting application in both research and practice for evaluating patient knowledge on chemotherapy.