Development and validation of the renal dosing questionnaire (RDQ-13) for pharmacists

Pharmacists, as an integral part of the healthcare team, can play a crucial role in preventing drug-related problems in patients with chronic kidney disease that arise due to inappropriate doses. This study aimed to develop and validate a new tool, the renal dosing questionnaire (RDQ-13), for pharmacists working across hospital, community, and retail pharmacy settings. A cross-sectional study was conducted from January to March 2023 among pharmacists working in different settings. The RDQ-13 scale consists of 3-sections, encompassing demographic details, a knowledge section with 6 domains, each having 4 questions with the choice of "yes/no," an attitude section featuring a Likert scale for 4 items, and a perception section featuring a Likert scale for 3 items. The assessment of construct and discriminative validity was performed along with testing for reliability. The average variance extracted value and the composite reliability value were used for convergent validity. A total of 65 pharmacists completed the RDQ-13, but at retest n = 2 participants were dropped (response rate at retest was 96.9%). Exploratory factor analysis revealed 3-factor loadings with 59.1% of the variance, whereas the Kaiser-Mayer-Olkin value was 0.60. The Cronbach alpha value of 0.700 indicates good internal consistency, whereas the intraclass correlation coefficient (ICC) for the test and retest showed that most domains/scores were statistically significant (P < .001), showing an excellent agreement between the test and retest. The RDQ-13 underwent extensive validation through a cross-sectional survey, demonstrating high content and face validity. The scale showed consistent responses over time (test-retest stability) and good internal consistency.