Background: Patients with CF are at risk for gestational diabetes/CFRD, which is challenging to treat. Traditional insulin regiments with fixed prandial and high basal insulin increase hypoglycemia.

Case: A 23 year old woman with CF was diagnosed with gestational diabetes and started on NPH 18 units qAM/8 at HS, and Lispro 6 units TID. She had a blood glucose of 36 mg/dL in clinic, with which she was asymptomatic, suggesting hypoglycemia unawareness. NPH was discontinued and a 1:12 carb ratio was started, reducing glycemic excursions and hypoglycemia.

Discussion: Patient rapidly developed hypoglycemia on a basal-predominant regimen. By decreasing basal insulin and targeting prandial insulin coverage we more closely approximated CFRD physiology, improving glycemic excursions and hypoglycemia.

Conclusion: Due to physiology of CFRD, basal-predominant regiments may cause fasting hypoglycemia and post-prandial hyperglycemia. Providers should be aware that patients with gestational diabetes/CFRD have minimal basal insulin requirements and glycemic control should focus on flexible prandial coverage of their high in carbohydrates diet.


M. Litvin: None.

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