ESPE Abstracts

Objective: Cystic fibrosis (CF) associated diabetes (CFRD) is a common comorbid condition in individuals with CF and its prevalence increases with age. There are reports in children aged 10 years and younger. The aimof this study was to estimate insulin resistance by HOMA-IR (Homeostatic Model Assessment) with oral glucose tolerance test (OGTT) data and Matsuda index to test glucose metabolism in relation to Matsuda insulin secretion in children with CF.

Materials and Methods: Fifty patients aged 6 years and older with a diagnosis of CF who underwent OGTT were included. 24(48%) patients were prepubertal. Anthropometric measurements, OGTT, HbA1c, HOMA-IR andMatsuda Index were obtained. Matsuda index ≤ 4.5 was accepted as the threshold value to differentiate insulin resistant and non-insulin resistant individuals.

Results: The mean age of the patients was 11.24±2.64 years, there were 18 (36%) patients under 10 years of age, the age range was 6-16 years. Weight SDS:-1.29±1.74 BMD-SDS:-0.72±1.59 2 of them were obese. INDET (1st hour glucose value ≥ 200 mg/dl during OGTT: Indeterminate) was detected in 5(10%) patients. 2(6%) patients, both aged 13 years, were found to have CFRD and one of the patients had HbA1c value ≥6.5 and Matsuda index (1.7) was low and the other was normal. HOMA-IR was low in both. One patient had impaired glucose tolerance (BGT) and one patient had impaired fasting glucose (BAG). 2 (4%) patients had reactive and/or spontaneous hypoglycemia. In 11(22%) patients with Matsuda value below 4.5, insulin values at 60 and 120 min were statistically significantly higher (p:0.008, p:0.002). Matsuda index and insulin values at (0,1,2). We found a moderate and strong negative correlation between Matsuda index and insulin values at 0, 1, 2 hours (r:-0.56, r-0.35, r:-0.32). We found a moderate negative correlation between Matsuda and HOMA-IR(r:-0.52). Under 10 years of age, the mean Matsuda index was significantly lower (18.81±12.13) and over 10 years of age(11.16±9.99)(P:0.033).

Discussion: According to the guidelines, screening for CFRD in children with CF is recommended above the age of 10 years. There are no studies on the Matsuda index in children with CF, and in our study, the Matsuda value was found to be lower in children older than 10 years compared to children younger than 10 years. This gives us an idea about insulin sensitivity.