Outcomes for patients using mono-or dual DPP4-inhibitor therapy for Cystic Fibrosis-Related Diabetes - a regional centre's 2-year experience

Objectives: Cystic fibrosis-related diabetes (CFRD) affects 40–50% of people with cystic fibrosis (PWCF) and is associated with increased morbidity and mortality. Current guidance recommends insulin, although it is unclear what degree of glucose dysregulation requires treatment. Our regional adult CF service cares for 360 PWCF; 175 have CFRD and 118 are insulin-treated. A disadvantage of insulin is risk of hypoglycaemia. We previously reported benefits of DPP4-inhibitor (DPP4i) therapy in CFRD. This descriptive study provides a further review of outcomes. Methods: Records of all patients with CFRD currently taking DPP4i in December 2018 were reviewed (27 patients; 13F/14M; median age 31). Information regarding demographics, CFRD treatments and clinical outcomes pre-and at least 6 months post-DPP4i initiation was gathered. Results: Median duration of DPP4i therapy was 2 years (range 0.5–8.5). 8 patients commenced DPP4i as first-line, 3 patients were diet-controlled and 16 patients had previously used insulin. 20 patients used DPP4i as monotherapy, 5 patients used insulin intermittently with DPP4i and 2 used DPP4i with insulin as dual therapy. 8 patients had a documented reason for DPP4i choice; 5 were non-concordant with insulin, 2 declined insulin and 1 patient had hypoglycaemia. Mean change in % predicted FEV1 and FVC was minimal; −0.77% and 1.33%predicted respectively. Mean change in BMI after 6 months was + 0.3 kg/m2 (range −2.4–3.7 kg/m2). Mean change in HbA1c at 6 months + 2.83 mmol/mol but −0.22 mmol/mol most recently. Mean CGMS time within target range (4–8 mmol/L) pre-DDP4i was 80.2% and 87% after 6 months. Mean time below target rose from 2.6% to 5.4%. likely due to an outlier. There was insufficient data to review changes in blood pressure, albumin:creatinine ratio, neuropathy and retinopathy. Conclusion: This study provides further evidence for safe use of noninsulin therapies in CFRD in patients for whom insulin is unacceptable or concordance is problematic.