ESPE Abstracts

Introduction: Cystic fibrosis related diabetes (CFRD) is associated with a poorer nutritional status, respiratory function and an increase in mortality rate. Screening is recommended from age 10; however, prediabetic conditions are diagnosed earlier.

Objectives: 1) To characterize the degree of carbohydrate metabolism impairment (CMI) in 50 CF patients. 2) To explore the association with clinical parameters as eventual predictors of these conditions.

Patients and methods: HbA1c measurement and an oral glucose tolerance test (OGTT) for glucose and insulin were performed in 50 CF patients (27 males/23 females; mean age 12.3±3.7 years). Twenty-eight patients (56%) were normoglycemic (NG). Those with impaired glycemia at fasting [≥100 mg/dl (n=1)]; glucose tolerance [≥144 mg/dl at 120′(n=13)]; IAG: ≥200 mg/dl at 30′or 60′, (n=5)]; T2DM [≥200 mg/dl at 120′ in the OGTT or ≥126 mg/dl fasting (n=3)]) were offered continuous subcutaneous glucose monitoring (CSGM, accepted by n=16). Mutations in CFTR, age, pubertal status, clinical and anthropometric evolution, microbiologic colonisation in the previous year and exocrine pancreatic enzyme requirement at the time of study were recorded and compared between groups. HOMA index and area under the curve (AUC) for glucose and insulin in the OGTT and time (%) with glycemia above 144 mg/dl (T>144 mg/dl) in CSGM were calculated, compared between groups and their relationship with the rest of clinical parameters explored.

Results: Significant differences between groups (P<0.05 for all) were found in HbA1c, age and standardized height (the more severe the CMI, the older the patient, higher HbA1c and lower height-SDS). CFTR mutations, lung function, nutritional status and the number of exacerbations/hospital admissions in the previous year showed no differences between groups. Patients colonised by methicilin-resistant Staphiloccocus aureus (n=3) had CMI. HbA1c was positively correlated with AUC_glucose (r=+0.49; P<0.001), glycemia at 120′ (r=0.54; P<0.001) and T>144 mg/dl (r=+0.57; P<0.05). Enzime requirements (U/kg) were inversely correlated with AUC_insulin (r=−0.36; P<0.05) and directly with HbA1c (r=+0.28; P<0.05), AUC_glucose (r=+0.29; P<0.05) and T>144 mg/dl (r=+0.57; P<0.05).

Conclusions: 1) Older age and higher enzyme requirements are associated with a higher rate of CMI in CF. 2) Insulin/glucose AUC study and CSGM analysis do not afford substantial additional information to warrant the studies. 3) HbA1c is a reliable marker of the time in hyperglycaemia also in CF patients.