Bariatric surgery given to woman with CF and diabetes due to weight

Obese patient's mild CF not seen as likely cause of type 2 diabetes

Joana Vindeirinho, PhD avatar

by Joana Vindeirinho, PhD |

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Type 2 diabetes in a 49-year-old woman with cystic fibrosis (CF) went into remission after bariatric surgery, given to help her lose weight after obesity was seen as the likely cause of her blood-sugar levels.

She had a mild form of CF, stable pulmonary function and pancreatic sufficiency, supporting suspicions of diabetes due to excessive weight and an unhealthy lifestyle rather than CF-related diabetes (CFRD).

“To the best of our knowledge, this is the first report of an individual with CF to be diagnosed with [type 2 diabetes] due to obesity instead of CFRD … [and] the first published description of the effect of bariatric surgery in CF,” the researchers wrote.

It “demonstrates that patients with CF may present with type 2 diabetes instead of CF-related diabetes. Differential diagnosis of these two types of diabetes is essential for optimal treatment and quality of life,” they added.

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CF related diabetes not suspected due to patient’s mild disease, high BMI

The report, “Bariatric surgery in a patient with cystic fibrosis and diabetes: A case report,” was published in the Journal of Cystic Fibrosis.

CF is caused by mutations in the CFTR gene that lead to an absent or poorly working CFTR protein, which acts like a channel in the cell membrane to help regulate the flow of water and salts. As a result, thick mucus accumulates in organs, including the lungs and the pancreas.

Mucus accumulating in the pancreas can result in insufficient production of insulin, the hormone responsible for controlling sugar levels in the blood, leading to CFRD. It is estimated that nearly half of all adults with CF will develop disease-related diabetes.

The woman was diagnosed at age 23 with a mild form of CF based on her mutations and overall health, and she was considered obese at age 42, the scientists in the Netherlands reported. She did not use corticosteroids.

“Her energy intake exceeded the expenditure due to no exercise and unhealthy diet,” they wrote.

Despite diet and exercise coaching and psychological advice, her condition continued to deteriorate. Over the following four years, her weight increased, reaching a body mass index — a measure of body fat based on weight and height — of 35.2 kg/m2, and she developed diabetes.

A healthy weight is generally considered as a BMI ranging from 18.5 to 24.9.

Medical assessments showed stable pulmonary function and no evidence of pancreatic insufficiency that could point to a CFRD diagnosis, apart from a reduced vitamin D concentration. She had normal bone density, normal kidney, liver, and thyroid function, and no signs of hypertension or dyslipidemia (abnormally high lipids, or fats, in the blood, such as cholesterol).

“Based on these results, her treating physicians strongly suspected that her diabetes was not CF-related diabetes (CFRD) and more likely to be T2D [type 2 diabetes],” the researchers wrote.

The patient was started on metformin, an initial type 2 diabetes treatment, but both her blood-sugar levels and weight continued to rise, leading her doctors to suggest bariatric surgery.

In January 2020, at age 49, she underwent a laparoscopic sleeve gastrectomy, a surgical procedure that removes about 80% of the stomach, without complications.

Six months later, she had lost 22.7% of her body weight (a BMI of 27.2 kg/m2) and her blood-sugar levels improved enough so that metformin was stopped. She reported feeling well. About one year later, she started treatment with CFTR modulators (Symkevi, known as Symdeko in the U.S., later switching to Trikafta ).

In June 2022, both her body weight (24.1 kg/m2) and blood-sugar levels had fallen further and were holding stable.  Her pulmonary health also improved, as seen in a higher forced expiratory volume in one second, a measure of how much air quickly can be expelled from the lungs.

These results suggest that “patients with overweight and CF may also have T2D [type 2 diabetes],” the scientists wrote, adding that “with good diagnostics and treatment,” such diabetes “can go into remission.”

A rise in “diagnoses of mild CF coupled with the increase in overweight/obese patients” make it more “likely that T2D in CF patients will increase,” they added.

“In overweight CF patients, bariatric surgery may be considered as an option to achieve and maintain weight loss, and, if necessary, to treat diabetes. However, bariatric surgery must be considered carefully given the potential cause of adverse effects, such as malabsorption, vitamin and mineral deficiencies,” the team concluded.

Researchers recommended further study into the potential benefits and drawbacks of bariatric surgery in these patients. “In our view, both T2D and bariatric surgery are new phenomena in CF that will both require further research to determine their effects on the quality of life of patients with CF,” they wrote.

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