Cardiopulmonary Exercise Testing Provides Additional Prognostic Information in Cystic Fibrosis.

RATIONALE: The prognostic value of cardiopulmonary exercise testing (CPET) for survival in cystic fibrosis (CF) in the context of current clinical management, when controlling for other known prognostic factors, is unclear. OBJECTIVES: To determine the prognostic value of CPET-derived measures beyond peak oxygen uptake ( V. o2peak) following rigorous adjustment for other predictors. METHODS: Data from 10 CF centers in Australia, Europe, and North America were collected retrospectively. A total of 510 patients completed a cycle CPET between January 2000 and December 2007, of which 433 fulfilled the criteria for a maximal effort. Time to death/lung transplantation was analyzed using Cox proportional hazards regression. In addition, phenotyping using hierarchical Ward clustering was performed to characterize high-risk subgroups. MEASUREMENTS AND MAIN RESULTS: Cox regression showed, even after adjustment for sex, FEV1% predicted, body mass index (z-score), age at CPET, Pseudomonas aeruginosa status, and CF-related diabetes as covariates in the model, that V. o2peak in % predicted (hazard ratio [HR], 0.964; 95% confidence interval [CI], 0.944-0.986), peak work rate (% predicted; HR, 0.969; 95% CI, 0.951-0.988), ventilatory equivalent for oxygen (HR, 1.085; 95% CI, 1.041-1.132), and carbon dioxide (HR, 1.060; 95% CI, 1.007-1.115) (all P < 0.05) were significant predictors of death or lung transplantation at 10-year follow-up. Phenotyping revealed that CPET-derived measures were important for clustering. We identified a high-risk cluster characterized by poor lung function, nutritional status, and exercise capacity. CONCLUSIONS: CPET provides additional prognostic information to established predictors of death/lung transplantation in CF. High-risk patients may especially benefit from regular monitoring of exercise capacity and exercise counseling.

CFTR Genotype and Maximal Exercise Capacity in Cystic Fibrosis: A Cross-sectional Study.

RATIONALE: Cystic fibrosis transmembrane conductance regulator (CFTR) is expressed in human skeletal muscle cells. Variations of CFTR dysfunction among patients with cystic fibrosis may be an important determinant of maximal exercise capacity in cystic fibrosis. Previous studies on the relationship between CFTR genotype and maximal exercise capacity are scarce and contradictory. OBJECTIVES: This study was designed to explore factors influencing maximal exercise capacity, expressed as peak oxygen uptake (V.O2peak), with a specific focus on CFTR genotype in children and adults with cystic fibrosis. METHODS: In an international, multicenter, cross-sectional study, we collected data on CFTR genotype and cardiopulmonary exercise tests in patients with cystic fibrosis who were ages 8 years and older. CFTR mutations were classified into functional classes I­V. RESULTS: The final analysis included 726 patients (45% females; age range, 8­61 yr; forced expiratory volume in 1 s, 16 to 123% predicted) from 17 cystic fibrosis centers in North America, Europe, Australia, and Asia, all of whom had both valid maximal cardiopulmonary exercise tests and complete CFTR genotype data. Overall, patients exhibited exercise intolerance (V.O2peak, 77.3 ± 19.1% predicted), but values were comparable among different CFTR classes. We did not detect an association between CFTR genotype functional classes I­III and either V.O2peak (percent predicted) (adjusted ß = −0.95; 95% CI, −4.18 to 2.29; P = 0.57) or maximum work rate (Wattmax) (adjusted ß = −1.38; 95% CI, −5.04 to 2.27; P = 0.46) compared with classes IV­V. Those with at least one copy of a F508del-CFTR mutation and one copy of a class V mutation had a significantly lower V.O2peak (ß = −8.24%; 95% CI, −14.53 to −2.99; P = 0.003) and lower Wattmax (adjusted ß = −7.59%; 95% CI, −14.21 to −0.95; P = 0.025) than those with two copies of a class II mutation. On the basis of linear regression analysis adjusted for relevant confounders, lung function and body mass index were associated with V.O2peak. CONCLUSIONS: CFTR functional genotype class was not associated with maximal exercise capacity in patients with cystic fibrosis overall, but those with at least one copy of a F508del-CFTR mutation and a single class V mutation had lower maximal exercise capacity.

Clinical stress testing in the pediatric age group: a statement from the American Heart Association Council on Cardiovascular Disease in the Young, Committee on Atherosclerosis, Hypertension, and Obesity in Youth.

This statement is an updated report of the American Heart Association's previous publications on exercise in children. In this statement, exercise laboratory requirements for environment, equipment, staffing, and procedures are presented. Indications and contraindications to stress testing are discussed, as are types of testing protocols and the use of pharmacological stress protocols. Current stress laboratory practices are reviewed on the basis of a survey of pediatric cardiology training programs.

Very high-dose ergocalciferol is effective for correcting vitamin D deficiency in children and young adults with cystic fibrosis.

Approximately 10-80% of patients with Cystic Fibrosis (CF) have vitamin D deficiency. Obtaining therapeutic vitamin D levels has been a challenge for CF care providers using current recommended high-dose oral ergocalciferol (400,000 IU over 2 months). The objective of this study was to evaluate the safety and efficacy of a 2-week, very high dose ergocalciferol (700,000 IU over 14 days) repletion strategy in children and young adults with CF. As part of a quality improvement initiative, a prospective cohort study was performed from January through May 2007. Phase I included identifying individuals with CF who were subtherapeutic in 25-OH D. In phase II, 50,000 IU of ergocalciferol was prescribed for a 14 day term and administered daily. During phase III, a post treatment 25-OH D level was obtained to determine improvement. Baseline demographics and clinical characteristics were obtained at study entry. Stratification of the post 25-OHD levels was defined. Eighteen individuals with CF participated in the study. The mean age was 17+/-5 years (range 6-25 years). One hundred percent were pancreatic insufficient and required pancreatic enzyme replacement. All 18 had 25-OHD levels less than 30 ng/mL pre-treatment. Seventeen of the 18 (94%) participants became therapeutic in the 2-week interval. No patients had values considered high abnormal (100-150 ng/mL) or toxic (>150 ng/mL). Mean change was noted at an increase of 37.3+/-22 ng/mL in the 2-week period (p<0.001). Pre and peripubertal individuals had a significantly greater increase in 25-OH D levels. The results of this study demonstrate that very high dosing of vitamin D using oral ergocalciferol over a 14 day period is an effective strategy in achieving therapeutic levels of 25-OH vitamin D in children and young adults with CF. We believe this regimen deserves further study.

EUR-1008 pancreatic enzyme replacement is safe and effective in patients with cystic fibrosis and pancreatic insufficiency.

BACKGROUND: EUR-1008 (Zenpep [pancrelipase]) is a new, enteric-coated, porcine-derived pancreatic enzyme product (PEP) developed for the treatment of cystic fibrosis (CF) patients with malabsorption associated with exocrine pancreatic insufficiency (EPI). Unlike currently marketed PEPs, EUR-1008 contains the label-claimed lipase content. Safety and efficacy were assessed in younger (<7 years) and older (> or =7 years) CF patients with EPI. METHODS: Two multicenter studies were conducted: a randomized, double-blind, placebo-controlled, crossover trial in patients > or =7 years of age (N=34) and a supplemental, open-label study in children <7 years of age (N=19). Use of any medications altering gastric pH/motility was prohibited during the studies. Outcome measures in the randomized trial included changes in the coefficient of fat absorption (CFA), coefficient of nitrogen absorption (CNA), and signs/symptoms of malabsorption for EUR-1008 vs. placebo. Outcome measures in the supplemental study included safety and response (defined as no steatorrhea and no overt signs/symptoms of malabsorption) to EUR-1008 vs. previous enzyme treatment. RESULTS: In the randomized trial, EUR-1008 treatment compared to placebo resulted in a significantly higher mean CFA (88.3% vs. 62.8%, respectively) and CNA (87.2% vs. 65.7%, respectively) (both p<0.001) and reduced the incidence of malabsorption signs and symptoms in 32 evaluable patients. In the supplemental study, 11 of 19 patients met the criteria for responder with EUR-1008 at the end of the study vs. 10 of 19 patients at screening (previous PEP), and improvements in clinical symptoms were reported with EUR-1008 treatment. EUR-1008 was safe and well tolerated, and no serious drug-related AEs were reported in either study. CONCLUSIONS: EUR-1008 was safe, well tolerated, and effective in CF patients of all ages with EPI-associated malabsorption in two clinical trials. Treatment led to clinically and statistically significant improvements in CFA and CNA in the randomized study, and control of malabsorption and clinical symptoms in both studies.