CF-related Diabetes Affects Girls More Often and at Younger Age than Boys, European Study Shows

Marta Figueiredo, PhD avatar

by Marta Figueiredo, PhD |

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Girls with cystic fibrosis-related diabetes (CFRD) are exposed to risk factors of early death — including chronic infections, poor lung function, and poor nutrition — at a significantly higher proportion and younger age than boys, a large European study shows.

The findings highlight the importance of early diagnosis and effective treatment of CFRD among people with cystic fibrosis (CF), particularly young girls.

The study, “Cystic fibrosis related diabetes in Europe: Prevalence, risk factors and outcome,” was published in the Journal of Cystic Fibrosis.

With the increasing life span of people with CF, non-lung complications, including CFRD, have emerged as significant contributing factors to disease burden.

While CFRD shares some features with both type 1 (impaired insulin production) and type 2 (insulin resistance) diabetes, it is a clinically distinct condition.

Several studies have shown that CFRD, which affects nearly half of all CF patients, becomes more prevalent as patients age, and is associated with poor lung function, lower weight (poor nutritional status), and higher mortality.

That is why it is relevant to determine not only CFRD’s frequency in these patients, but also to better understand its associated risk factors and effects.

Researchers evaluated the occurrence of CFRD, as well as its association with previously suggested risk factors, and outcomes in Europe and neighboring countries by analyzing data of the European Cystic Fibrosis Society Patient Registry (ECFSPR).

This registry collects demographic and clinical data of CF patients across 31 countries — those in the European Union, other European countries, and some neighboring countries, including Turkey and Israel — over a long period of time.

Researchers analyzed the data of up to 25,143 CF patients, from 2008 to 2015 (the most updated data at the time of the analysis). Patients from countries with a high percentage of missing data on CFRD status were excluded from the analysis.

Results showed that a total of 21.6% of CF patients had CFRD, and that this frequency increased by nearly 10% every decade — affecting 9.7% of those aged 10 to 19 years, 24.1% of those age 20 to 29, and 32.7% of those 30 or older. Among the included countries, the highest frequency of CFRD was found in The Netherlands for the younger group, in Czech Republic for the 20–29-year-old group, and in Denmark for the older group.

Moreover, CFRD developed significantly earlier in females than males, and occurred significantly more often in girls than boys in the younger age groups: 11.6% of girls versus 8.1% of boys age 10–19; and 27.8 versus 21.2% for those 20–29 years. However, this gender-specific difference disappeared in the older group of patients (30 or older).

The data also showed that carrying severe CF-associated mutations (both mutations of class 1–3), having pancreatic insufficiency, and being a woman increased the likelihood of developing CFRD by up to threefold.

“Severe [CF-associated mutations], pancreatic insufficiency and female gender remain considerable intrinsic risk factors for early acquisition of CFRD,” the researchers wrote.

In addition, CF patients with CFRD had a higher risk of developing chronic infections, poorer lung function, and a poorer nutritional status, than those without CF diabetes.

Overall, the findings point out that “female CFRD patients are, thus, exposed to these known risk factors for early death at a younger age and in a higher proportion,” the team wrote.

The researchers also noted that the increasing proportion of male patients with CFRD with age implies higher rates of death in women, which may explain the lack of gender differences in CFRD frequency in the older group of patients.

“Early diagnosis and aggressive treatment of CFRD are more important than ever with increasing life span,” the researchers wrote, adding that “our job as clinicians must be to diagnose, treat and further investigate this complication effectively, in order to hopefully counteract the deleterious defects presented here.”