Sex disparities in effects of cystic fibrosis-related diabetes on clinical outcomes: A matched study

Background: Cystic fibrosis-related diabetes (CFRD) is an increasingly prevalent comorbidity factor for patients with cystic fibrosis (CF). CFRD has been associated with an accelerated decline in clinical parameters and an increased mortality rate. Objectives: To investigate the clinical impact of CFRD on pulmonary function and clinical status using a matched study design to further explore potential causality. Methods: Charts from the adult CF clinic at St Paul's Hospital (Vancouver, British Columbia) were retrospectively reviewed. Forty CFRD patients with and without fasting hyperglycemia were matched to CF patients with nondiabetic glucose tolerance based on sex, age and forced expiratory volume in 1 s (FEV₁). Results: Sixteen of 40 CFRD patients (40%) died compared with nine of 40 patient controls (23%) (P=0.13). CFRD patients were more likely to experience declines in FEV₁ (P<0.01), especially women (P<0.01). Patients with CFRD were not more likely to be hospitalized (P=0.39). Body mass index did not differ between groups. Conclusions: Patients with CFRD had higher rates of FEV₁ deterioration than nondiabetic patients with CF, and showed a trend toward increased mortality. The present study suggests that CFRD has a significant clinical impact and should be carefully considered when evaluating the status of CF patients.