Study design (if review, criteria of inclusion for studies)
Randomised controlled trials (RCT) and nonârandomised studies of interventions (NRSI) (controlled trials in which allocation was performed by randomisation or a quasiârandom rule, e.g. by alternation or Patient ID Number).
Participants
People with cystic fibrosis (pwCF) over five years of age, who have also been diagnosed with either CFâimpaired glucose tolerance (IGT) or CFârelated diabetes (CFRD). Pregnant women or pwCF post lung transplant not include.
Interventions
Any dietary intervention (e.g. low glycaemic index (GI) diet, carbohydrate counting) assigned for a minimum of two months to manage glucose abnormalities in nonâhospitalised pwCF, with or without the use of insulin therapy. The comparators are standard CF dietary therapy (energy dense, highâfat, highâsalt diet) for individuals with CFâIGT, and standard CF dietary therapy plus insulin therapy for individuals with CFRD.
Outcome measures
Primary outcomes: Glycaemic control before and after dietary intervention (measured by standard clinical methods: oral glucose tolerance test (OGTT); glycated haemoglobin (HbA1c); percentage of continuous glucose monitoring (CGM) time above 7.8 mmol/L (Hameed 2010)). Secondary outcomes. Nutritional status. Lung functionFEVâ (L). Adverse events. Acceptability of dietary intervention. Quality of life (measured by a validated diseaseâspecific tool, e.g. CF Questionnaireârevised (CFQâR (Quittner 2005)))