Carbohydrate counting accuracy in adults with cystic fibrosis related diabetes

Poorly controlled Cystic Fibrosis-Related Diabetes (CFRD) is associated with adverse impacts on lung function and nutritional status. Insulin therapy is the only recommended medical treatment. Carbohydrate Counting (CC) is used to guide insulin doses and can assist in achieving optimal postprandial blood glucose levels. This study aimed to determine the prevalence of individuals with CFRD who carbohydrate count, explore barriers to its use and assess the accuracy of CC in hospitalised patients.

A cross-sectional, mixed-methods, descriptive study recruited individuals with CFRD hospitalised at an Australian tertiary hospital. Consenting patients completed a questionnaire. Patients were asked to estimate the carbohydrate content of their ordered meals provided by hospital foodservices. The study dietitian assessed each meal's estimation against the actual content.

17 individuals were recruited to this study and five declined. Seven had a fixed insulin regimen, and ten had a flexible insulin regimen and used CC. Patients in the fixed insulin group reported lower levels of confidence in their ability to carbohydrate count (P < .001) and placed less importance on CC (P < .001). 53% of the fixed insulin group's and 41.7% of the flexible insulin group's estimations of the carbohydrate content of the hospital food items were accurate.

Of those patients recruited to this study, 59% used CC as a tool to guide insulin dosing, and patients estimated accurate carbohydrate values in only 46% of meals. Further research is warranted to investigate the most suitable method to assist accurate carbohydrate content estimations in a hospital setting.