Patient-Reported Experiences with a Low-Carbohydrate Ketogenic Diet: An International Survey in Patients with McArdle Disease

Abstract

The low-carbohydrate ketogenic diet (LCKD) has attracted increased attention in recent years as a potential treatment option for individuals with McArdle disease (glycogen storage disease type V), and despite the absence of strong scientific evidence of the LCKD's benefits, increased numbers of individuals with McArdle disease have tried a LCKD. The objective of this study was to collect patient-reported experiences with a LCKD. We aimed to estimate the immediate prevalence of individuals that had tried a LCKD in an international McArdle disease cohort, and we aimed to report on the patient-reported experiences with the diet, both positive and negative. A total of 183 responses were collected from individuals with McArdle disease from 18 countries. We found that one-third of the cohort had tried a LCKD, and almost 90% experienced some degree of positive effect, with the most prominent effects on McArdle disease-related core symptoms (e.g., activity intolerance, muscle pain, and muscle fatigue). Adverse effects were rare and generally rated as mild to moderate. These patient-reported findings underline the need for randomized clinical trials to decisively determine if a LCKD is a suitable nutritional strategy for patients with McArdle disease. The results from this study can prompt and contribute to the design of such a clinical trial.

Keywords: McArdle disease; glycogen storage disease type V; ketogenic diet; low carbohydrate ketogenic diet; patient-reported experiences; survey.

Figure 1

Distribution of McArdle disease-related symptoms. PA: physical activity. Based on n = 183 responses.

Figure 2

Use of the low carbohydrate ketogenic diet. (A) Consistency of use and (B) The longest time on the diet. Based on n = 60 responses.

Figure 3

Patient-reported effects of a low-carbohydrate ketogenic diet. PA: physical activity. Based on n = 59 responses.

Figure 4

Frequency of McArdle disease-related symptoms while on and not on a low carbohydrate ketogenic diet (LCDK). The boxes illustrate the lower quartiles (Q1), medians (Q2), and upper quartiles (Q3). The cross illustrates the means. The whiskers illustrate the minimum and maximum, and the circles illustrate outliers. Statistically significant differences are illustrated with *: p < 0.05 and **: p < 0.001. Based on n = 57 responses.

Figure 5

Prevalence of adverse effects (A) (n = 57) and severity of adverse effects (B) (n = 52) experienced on a low carbohydrate ketogenic diet. AE: adverse effects; n: number of patients.

Figure 6

The balance between the efforts versus effects of the low carbohydrate ketogenic diet on overall functioning (A) and the tendency to recommend the low carbohydrate ketogenic diet to other individuals with McArdle disease (B). Based on n = 48 responses.