A teenage girl with cystic fibrosis-related diabetes, diabetic ketoacidosis, and cerebral edema

Cystic Fibrosis-Related Diabetes in Children: An Update

Cystic fibrosis-related diabetes mellitus (CFRD) is the most common endocrine complication of cystic fibrosis (CF), affecting more than 50% of patients by the 4th decade of life. CFRD is often preceded by worsening pulmonary status and nutritional decline. Treatment of CFRD is associated with improvements in body weight and pulmonary function and a reduction in pulmonary exacerbations. Because of the clinical significance of CFRD, diabetes screening with an oral glucose tolerance test (OGTT) is recommended annually for all patients with CF starting at age 10 years. The OGTT detects CFRD with greater sensitivity than random glucose or hemoglobin A1c testing. The first-line treatment for CFRD is insulin. The use of other treatments such as oral medications remains under study. [Pediatr Ann. 2016;45(9):e321-e326.].

Does β-Cell Autoimmunity Play a Role in Cystic Fibrosis-Related Diabetes? Analysis Based on the German/Austrian Diabetes Patienten Verlaufsdokumentation Registry

OBJECTIVE

Research on β-cell autoimmunity in cystic fibrosis (CF)-related diabetes (CFRD) is still rare. We aimed to analyze the frequency of β-cell autoimmunity and the influence on age at diabetes onset, insulin requirement, type of insulin therapy, and hypoglycemic or ketoacidotic events in patients with CFRD compared with antibody-negative patients with CFRD in the Diabetes Patienten Verlaufsdokumentation (DPV) registry.

RESEARCH DESIGN AND METHODS

We analyzed data of 837 patients with CFRD in the German/Austrian DPV database by multivariable mixed-regression modeling.

RESULTS

In our cohort, 8.5% of patients with CFRD (n = 72) were found to be β-cell antibody positive. There was a female preponderance in this patient group: 65.3 vs. 57.6%. Diabetes onset (median [interquartile range]) was earlier (14.00 [10.15-15.90] vs. 16.10 [13.50-21.20] years; P < 0.005), and insulin dose/kg body weight was higher (0.95 [0.61-1.15] vs. 0.67 [0.33-1.04] IU/kg; P < 0.05). There were also differences in the type of insulin treatment. Insulin pump therapy was used significantly more often in patients with CFRD with β-cell autoimmunity (18.2 vs. 6.4%; P < 0.05). The differences for multiple daily injections (ICT) and conventional therapy (CT) were not significant (ICT: 67.7 vs. 79.0%; CT: 15.2 vs. 14.6). Oral antidiabetic agents were rarely used in both groups. Rate of severe hypoglycemia with coma and rate of ketoacidosis were higher in antibody-positive patients (hypoglycemia with coma: 8.0 vs. 1.4, P < 0.05; ketoacidosis: 9.3 vs. 0.9, P < 0.05).

CONCLUSIONS

Presence of β-cell autoantibodies in our cohort of patients with CFRD (8.5%) appeared to be greater than in the general population and was associated with female sex, earlier onset of diabetes, and higher insulin requirement. Insulin pump therapy was used significantly more often in patients with β-cell antibodies. Severe hypoglycemia and ketoacidosis were significantly more frequent in CFRD with β-cell autoimmunity compared with β-cell antibody-negative patients with CFRD.

Cystic fibrosis related diabetes

Improved life expectancy in cystic fibrosis (CF) has led to an expanding population of adults with CF, now representing almost 50 % of the total CF population. This creates new challenges from long-term complications such as diabetes mellitus (DM), a condition that is present in 40 %-50 % of adults with CF. Cystic fibrosis-related diabetes (CFRD) results from a primary defect of insulin deficiency and although sharing features with type 1 (DM1) and type 2 diabetes (DM2), it is a clinically distinct condition. Progression to diabetes is associated with poorer CF clinical outcomes and increased mortality. CFRD is not associated with an increased risk of cardiovascular disease and the prevalence of microvascular complications is lower than DM1 or DM2. Rather, the primary goal of insulin therapy is the preservation of lung function and optimization of nutritional status. There is increasing evidence that appropriate screening and early intervention with insulin can reverse weight loss and improve pulmonary function. This approach may include targeting postprandial hyperglycemia not detected by standard diagnostic tests such as the oral glucose tolerance test. Further clinical research is required to guide when and how much to intervene in patients who are already dealing with the burden of one chronic illness.

New insights into cystic fibrosis-related diabetes in children

Cystic fibrosis-related diabetes (CFRD) is the most common complication of cystic fibrosis. It is associated with significantly increased morbidity and mortality in adults and children. Adolescents with cystic fibrosis have a much higher prevalence of diabetes than any other similar age population. Glucose abnormalities that precede diabetes are even more common, especially in children younger than 10 years. The pathophysiology of glucose metabolic abnormalities is poorly understood, but insulin insufficiency is clearly the main component. Findings from animal studies have provided insight into the pathophysiology of CFRD, and imply that carbohydrate metabolic abnormalities might begin at much younger ages than was previously thought in patients with cystic fibrosis, and might be related to the basic cystic fibrosis chloride channel defect. In this Review we explore present knowledge of CFRD in children and adolescents, and new data that indicate that the pathophysiology of CFRD begins in very young patients.

Update on diagnosis and monitoring of cystic fibrosis-related diabetes mellitus (CFRD)

Cystic fibrosis (CF) is the most common recessive autosomal disease among Caucasian. Children with CF have benefitted from advances in medical and nutritional treatments, and this can be gleaned from the improvement in the survival of these patients. The increase in the survival rate brought with it the appearance of co-morbidities related to CF. Nowadays cystic fibrosis-related diabetes (CFRD) is considered the most common complication associated with CF. It can appear as early as infancy or adolescence, and its prevalence can be as high as 50% in adult patients. Because of its high prevalence, difficulties in early detection and the risks involved, in recent years several studies and consensuses have focused on this condition, adding information about the epidemiology, pathophysiology, prognosis and treatment of CFRD. The main aspects of these new concepts, as well as the current recommendations for its diagnosis and follow-up, will be presented in this study.

Cystic fibrosis related diabetes (CFRD)--the end stage of progressive insulin deficiency

In cystic fibrosis, gradual pancreatic destruction causes progressive insulin deficiency, culminating in cystic fibrosis related diabetes (CFRD). As a consequence of insulin deficiency, elevated glucose levels can be detected (well before the diagnosis of CFRD), by continuous ambulatory subcutaneous interstitial fluid glucose monitoring or 30-min sampled oral glucose tolerance test (OGTT). Current diagnostic criteria for CFRD (based on 0 and 120-min OGTT blood glucose levels) were originally designed to forecast microvascular disease in type 2 diabetes, rather than CF-specific outcomes such as declining weight or lung function. In CF, decline in either weight or lung function predicts early mortality. Both may precede the diagnosis of CFRD by several years. Insulin, a potent anabolic hormone, is recommended treatment for CFRD, but use in earlier stages of insulin deficiency is not established. Conventional dosing (with four or more insulin injections per day) is burdensome and carries substantial risk of hypoglycemia. However, recent uncontrolled trials suggest that once-daily injection of intermediate or long-acting insulin improves weight and lung function, with minimal hypoglycemia risk, in CFRD and also in early insulin deficiency. It is plausible that insulin may be of greater benefit to respiratory function when given prior to the diagnosis of CFRD, after which structural lung disease may be irreversible. It is also plausible that early insulin treatment may prolong the lifespan of the remaining insulin-secreting β-cells. Randomized controlled trials are now needed to determine whether or not current clinical practice should be altered toward the earlier commencement of insulin in CF.

Managing diabetes in cystic fibrosis

Cystic fibrosis related diabetes (CFRD) is the most common co-morbidity in persons with cystic fibrosis (CF). As the life expectancy of persons with CF continues to increase, the need to proactively diagnose and aggressively treat CFRD and its potential complications has become more apparent. CFRD negatively impacts lung function, growth and mortality, making its diagnosis and management crucial in a population already at high risk for early mortality. Compared to type 1 and type 2 diabetes, CFRD is a unique entity, requiring a thorough understanding of its unique pathophysiology to facilitate the creation and utilization of an effective medical treatment plan. The physiology of CFRD is complex, likely consisting of a combination of insulin deficiency, insulin resistance and a genetic predisposition towards the development of diabetes. However, the hallmark of CFRD is insulin deficiency, necessitating the use of exogenous insulin as the mainstay of therapy. Insulin administration, in combination with a multidisciplinary team of health professionals with expertise in the care of patients with CF and CFRD, is the cornerstone of the care for these patients. The goals of treatment of the CFRD population are to reverse protein catabolism, maintain a healthy weight, and reduce acute and chronic diabetes complications. Creating a partnership between the treatment team and the patient is the ideal way to accomplish these goals and is essential for successful diabetes care.