Abstract
Background: Up to 40% of adult individuals with Cystic Fibrosis (CF) develop a condition known as Cystic Fibrosis Diabetes (CFRD). This co morbid condition, is secondary to insulin deficiency as a result of pancreatic islet cell damage subsequent to the underlying genetic mutation in CF. CFRD is associated with the development of microvascular complications however, little is known about the prevalence of neuropathic dysfunction in the form of cardiac autonomic neuropathy (CAN). This study examined the extent of CAN in an adult population with CF dysglycemia compared to a population with CF and normal glucose tolerance.
Methods: We performed a cross-sectional study comparing three parasympathetic function tests on 71 adults with CF, 46 of whom had CF dysglycemia. Healthy volunteers were the control group.
Results: There was no significant difference between the CF cohort with normal glucose tolerance and the CF cohort with dysglycemia in all three measures of parasympathetic function. Older individuals with dysglycemia were more likely to demonstrate a lower heart rate variability only in the deep breathing measurement (p<0.01) compared to the healthy control group. The presence of dysglycemia was not an influential factor in heart rate variability in the Valsalva maneuver and standing compared to CF individuals with normal glucose tolerance.
Conclusion: Based on these findings, the presence of dysglycemia in CF may not be a major influential factor in the development of parasympathetic cardiac dysfunction in CF. However, heart rate variability during deep breathing was lower in CF dysglycemia compared to those with normal glucose tolerance and was significantly reduced compared to healthy controls. This suggests longitudinal studies are needed to evaluate the long-term impact of dysglycemia in cardiac autonomic neuropathy in Cystic Fibrosis.
Keywords
Diabetic complications, Diabetic neuropathy, Epidemiology of diabetes