Diabetes Provides More Challenges for Cystic Fibrosis Patients

Not long ago patients diagnosed with cystic fibrosis (CF) would have faced not only a much different quality of life, but also a much shorter lifespan.

In 1959, a child born with CF in the United States was expected to live 6 months. Today, life expectancy is closer to 35 years. Earlier diagnosis, better treatments, and improved access to healthcare have been credited with the improvements.

Because of these changes, endocrinologists are faced with a different CF patient population—approximately half of all CF patients are now adults—and the inherent challenges that come with it including more long-term complications.. Among those complications is diabetes mellitus (DM), which affects 40% to 50 % of adults with CF.

The August 2014 issue of Current Diabetes Reports contains a review article that covers cystic fibrosis-related diabetes (CFRD), which differs from the garden variety type 1 (T1DM) and type 2 diabetes (T2DM) seen in other populations. The disease is described as a non-autoimmune, progressive condition in which destruction of pancreatic β cells leads to relative insulin deficiency.

Often, CF patients develop concurrent insulin resistance pursuant to chronic inflammation and acute infection, which compounds the insulin deficiency. Unlike T1DM or T2DM, CFRD does not increase cardiovascular risk, nor does it cause microvascular complications to the extent T1DM or T2DM do. Dylipidemia is also rare in patients. The authors found only 2 reported cases of diabetic ketoacidosis in CFRD patients in the literature they reviewed.

Once diabetes is diagnosed in CF patients, outcomes have been shown to worsen and mortality increases. Standard oral glucose tolerance tests may also miss postprandial hyperglycemia. In light of these and other factors, the entire medical approach to CFRD is unique.

In this population, clinicians use insulin therapy early to preserve or improve lung function and encourage weight restoration. The authors stressed appropriate screening and early treatment, but also identified gaps in our collective knowledge.