A clinical guide for a special kind of diabetes

Cystic fibrosis, a genetic disease that attacks the lungs, affects roughly one in 3,000 people, and cystic fibrosis-related diabetes (CFRD) is its most common complication, a rare and unique type that differs from more common forms such as type 1 and type 2 diabetes.

CFRD results from damage to the pancreas caused by thick mucus obstructing the pancreatic ducts. It becomes more common with age, with prevalence increasing from three per cent in children with cystic fibrosis to 50 per cent in adults over age 35.

Trikafta, a drug approved for use in Canada in 2021 that dramatically improves the functioning of the lungs, has revolutionized treatment and significantly increased the life expectancy of people with cystic fibrosis.

As a result, the number of people living with CFRD is growing, and with the rapid evolution of treatment options, the clinical recommendations for dealing with the disease have had to be updated.

To that end, a team of scientists led by Université de Montréal nutrition assistant professor Adèle Coriati and professor Rémi Rabasa-Lhoret, who is also director of the Metabolic Diseases Research Unit and of the Diabetes Clinic at the Montreal Clinical Research Institute (IRCM), have come up with a first for Canadian clinicians: a set of practice guidelines for treating CFRD.

They’re published in the Canadian Journal of Diabetes.

To develop their guide, the research team first held several sessions with patient-partners across Canada to identify existing gaps and needs in the detection, management and treatment of CFRD.

“Patients expressed a desire for a better understanding of the issues surrounding CFRD and for early management to avoid complications from two chronic diseases overlapping,” said Coriati, a researcher with the CIUSSS du Nord-de-l’Île-de-Montréal research centre, the Hôpital du Sacré-Cœur-de-Montréal and the Centre Jean-Jacques-Gauthier.

Based on these discussions, the clinical guidelines call for four sets of improvements: to coordinate care through an interdisciplinary team, to simplify screening, to personalize lifestyle recommendations and to incorporate new blood-glucose monitoring tools and treatments for other types of diabetes.

Coriati and Rabasa-Lhoret recommend a holistic approach to treating CFRD, including maintaining a healthy lifestyle (physical activity and diet), taking medication (such as Trikafta) and undergoing insulin therapy if necessary.

Dietary recommendations for people with CFRD differ significantly from those for people with other types of diabetes: they depend on the person’s weight and lung function, since cystic fibrosis tends to cause weight loss and reduced lung function, while Trikafta has the opposite effect.

“The recommendations must be individualized,” said Coriati. “We want to prevent weight loss but also obesity, which is becoming more common in this population. For example, we advise spreading carbohydrate intake over the meals of the day, eating a high-fibre diet to prevent dyslipidemia and limiting ultra-processed foods.”

It is therefore important to be supported by a care team that can help people choose the treatment plan that best suits their needs and their physical and mental condition, the researchers say.