Cystic fibrosis-related diabetes: links, challenges, and future directions

Figures & data

Table 1 Screening and diagnosis of CFRD

OGTT	Annually ≥ 10 years
	Glucose tolerance category	1-hour PG	2-hour PG
	Normal (NGT) Impaired (IGT)	< 140 mg/dL NA	< 140 mg/dL > 140 and <200 mg/dL
	Indeterminate (INDET) CFRD	>200 mg/dL NA	< 140 mg/dL > 200 mg/dL
HbA1c	≥6.5% for diagnosis <6.5% does not exclude diagnosis
Fasting and 2-hour post-prandial glucose	During hospitalizations or intercurrent illnesses, systemic glucocorticoid use monthly during and after continuous overnight feeds
Random glucose	CFRD ≥200 mg/dL + polyuria and polydipsia

Abbreviations: CFRD, cystic fibrosis-related diabetes; HbA_1c, hemoglobin; A_1c; IGT, impaired glucose tolerance; INDET, indeterminate glucose tolerance; NA, not applicable; NGT, normal glucose tolerance; OGTT, oral glucose tolerance test; PG, plasma glucose.

Figure 1 Patient 1 is an 18 years and 4 months old female who underwent CGM and OGTT testing during a 2 week period.

Note: Glucose excursions on CGM are milder compared to those seen on OGTT.
Abbreviations: CGM, continuous glucose monitoring; min, minute; OGTT, oral glucose tolerance test; PG, plasma glucose.

Figure 2 Improvements in BMI on insulin treatment among two individuals with normal OGTT but elevated random post-prandial blood glucose (BG) monitoring.

Notes: Patient 1 (A) is a male, 13 years and 4 months old with pancreatic insufficient CF on long-term G-tube supplementation who showed BG results in the mid-300s mg/dL on overnight feeds. Patient 2 (B) is a female, 11 years and 6 months old who demonstrated BG >200 mg/dL immediately during overnight feeds.
Abbreviations: BMI, body mass index; OGTT, oral glucose tolerance test; CF, cystic fibrosis; G-tube, gastrostomy tube.

Figure 3 Patient with one G551D mutation, diagnosed with CFRD at 9 years and 5 months who initiated ivacaftor at 13 years 4 months old.

Note: The patient’s BMI and BG on home glucose monitoring improved and CFRD treatment was stopped; the individual subsequently has remained off CFRD treatment with improvements in OGTT plasma glucose (PG; fasting, 1- and 2-hours).
Abbreviations: CFRD, cystic fibrosis-related diabetes; BMI, body mass index; BG, blood glucose; OGTT, oral glucose tolerance test.