Background: Insulin therapy is recommended by the Cystic Fibrosis Foundation when cystic fibrosis-related diabetes has been diagnosed. Diagnosis is based on an elevated fasting blood glucose level greater than 6.94 mmol/liter (125 mg/deciliter) or symptomatic diabetes for random glucose levels greater than 11.11 mmol/liter (200 mg/deciliter).
Objectives: To examine the evidence that, when treated with agents for managing diabetes, people with cystic fibrosis improve their sugar metabolic control resulting in beneficial impact on lung function and the ability to maintain optimal weight.
Search strategy: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. We also handsearched abstracts from pulmonary and North American Cystic Fibrosis Conference symposia. Date of the most recent search of the Group's Trials Register: December 2004.
Selection criteria: Randomized controlled trials comparing all methods of diabetes therapy for one month or longer in people with cystic fibrosis.
Data collection and analysis: No studies were found which were eligible for inclusion in this review.
Main results: Six references to four studies were identified by the searches, but none were eligible for inclusion in the review as they were not randomized controlled trials.
Authors' conclusions: While some cystic fibrosis centers use oral medications to help control diabetes, a condition which complicates the course of cystic fibrosis, insulin therapy is the recommended and most widely used treatment method. Lung function has been reported to improve with the use of insulin, but this has not been correlated to the degree in which sugar metabolism has been affected. While the Cystic Fibrosis Foundation recommends insulin therapy be used in managing diabetes, this systematic review identifies the need for a multicentre randomized controlled trial assessing both the efficacy of insulin or other insulin-releasing or insulin-sensitizing medications and their possible adverse effects in managing cystic fibrosis-related diabetes.