Validation of ketogenic diet adherence questionnaire: Keto-check

Abstract

Background The ketogenic diet is a therapeutic option to control drug-resistant epileptic seizures and has difficult compliance standards due to adverse effects, psychosocial factors, or dietary restriction. Objective To create and validate a ketogenic diet compliance questionnaire. Methods Methodological study, convergent care. The instrument was analyzed (construct validation) by five judges during two cycles of the Delphi technique. The judges assessed the relevance and clarity by using the Likert scale with three levels and made suggestions. The validation of the instrument was calculated using the agreement rate and content validity index (CVI). The application by two nutritionists made it possible to test reproducibility using the Kappa coefficient. When comparing the classification with a template developed by the health professionals who cared for the patients in question, the Pearson correlation and Fisher exact tests were used. For the reliability test, self-applied data were collected and evaluated using Cronbach Alpha coefficient. Results The questionnaire initially created with 11 multiple choice questions on a Likert scale was reduced to 10 questions with an agreement rate and the CVI classified as excellent after two rounds with judges. In the application of the tool, a kappa of 0.6087 was obtained, a Pearson that showed no significant difference between evaluators and a Cronbach α of 0.6483, with substantial consistency. Conclusions This work resulted in the creation of an unprecedented and reliable questionnaire on adherence to the national ketogenic diet. Further studies should be performed to extrapolate the use of this questionnaire in different populations.

The Assessment of the Efficacy, Safety, and Challenges of Ketogenic Diet Therapy in Children with Epilepsy: The First Experience of a Single Center

“…Therefore, our presented results can be considered reliable [ 35 ]. In order to assess the associations between the KDT adherence and achievable outcomes, specialized questionnaires were developed and implemented into practice [ 36 , 37 ].…”

Validation of an Italian Questionnaire of Adherence to the Ketogenic Dietary Therapies: iKetoCheck

“…The process of validation was conducted in several phases: (i) the original questionnaire (Keto-check) [30,31] was initially adapted by the authors and underwent a Delphi technique for validation; (ii) reproducibility was tested in a sample of Italian patients; (iii) reliability was confirmed by factorial analysis; (iv) authors proposed a graphical representation of factors involved in adherence based on the factorial analysis.…”

“…Usually, clinicians ask parents and patients to share the food diary to check the calorie intake, the ketogenic ratio, and the nutritional composition of the diet. A 'Keto-check' questionnaire was recently developed and validated in Brazil [30,31], aiming to provide a tool to measure adherence to the KDT. There are several advantages of using the questionnaire: low-cost, easy, fast, well accepted by the patient, valid and easily reproducible questions.…”

Factor Analysis of the Brazilian Questionnaire on Adherence to Ketogenic Dietary Therapy: Keto-Check

“…Each study proposes a different way of indirectly measuring adherence to treatment, some authors through the patients' reports [32], through food records with weighted meals [33], motivations referred by the patients to start the diet [34], reports of expectations, and factors that influence the duration of the diet [35]. Just a few studies created an instrument to measure adherence [36][37][38]. In the United Kingdom, one study created a score based on the needs and concerns of patients [39].…”

“…A Brazilian questionnaire was recently published with the purpose of indirectly measuring adherence to the ketogenic diet of patients following KDT [36]. However, the article has some limitations; for example, it presented Cronbach's coefficient as a measure of the instrument's internal consistency and a factor analysis was not performed to verify the validity of the instrument.…”