Cystic fibrosis‐related diabetes compared with type 1 and type 2 diabetes in adults

BACKGROUND: With increasing life expectancy of patients with cystic fibrosis (CF), secondary diabetes becomes more prevalent. It appears to be the most common co-morbidity in persons with cystic fibrosis. Therefore, the objective of our study was to describe characteristics of cystic fibrosis-related diabetes compared with type 1 and 2 diabetes (T1DM/T2DM) in adults. METHODS: Data from 218 436 patients >18 years with cystic fibrosis (n = 401), T1DM (n = 32,409) or T2DM (n = 185 626) in the multicenter Diabetes-Patienten-Verlaufsdokumentation or prospective documentation of diabetes patients registry were analysed. RESULTS: Diabetes onset [median (interquartile range)] in cystic fibrosis [18.70 (15.50-25.30) years] was between T1DM [16.40 (10.50-31.80) years] and T2DM [58.50 (48.80-68.00) years], with female preponderance. Body mass index (BMI) and glycosylated haemoglobin (HbA1c ) were lowest (19.6 [18.1-21.5] kg/m(2) )/50 mmol/mol (6.73%) versus T1DM (24.4 [22.1-27.4])/62 mmol/mol (7.83%) vs. T2DM (29.6 [26.1-33.9])/54 mmol/mol (7.06%); all p < 0.01. A total of 78.6% of cystic fibrosis patients with diabetes received insulin. Insulin dose (0.74 IE/kg bodyweight) was not significantly different from T1DM (0.73) and T2DM (0.76). Frequency of vascular complications, adjusted for confounding effects, across the groups was different: Hypertension (CFRD 16.1% vs. T1DM 24.0% vs. T2DM 32.2%; all p < 0.01), retinopathy (CFRD 10.7% vs. T1DM 10.4% vs. T2DM 10.5%, not significant), nephropathy (CFRD 25.2% vs. T1DM 17.2% vs. T2DM 24.7%; only T1DM/T2DM; p < 0.01). CONCLUSION: CFRD is a uniquely complex entity with clear differences from T1DM and T2DM in adults.