The impact of plasma 25-hydroxyvitamin D on pulmonary function and exercise physiology in cystic fibrosis: A multicentre retrospective study.

BACKGROUND: A 25-hydroxyvitamin D (25OHD) may exert immunomodulatory effects on respiratory health, which may translate to improvements in exercise physiology. Thus, we aimed to investigate whether plasma 25OHD is associated with lung function and aerobic fitness in people with cystic fibrosis (pwCF). METHODS: A multicentre retrospective review of pwCF (> 9 years old) attending the Royal Hospital for Sick Children (Edinburgh) or Wessex CF-Unit (Southampton) was performed between July 2017 and October 2019. Demographic and clinical data were collected. Plasma 25OHD measured closest in time to clinical cardiopulmonary exercise testing and/or spirometry [forced expiratory volume (FEV1 )% predicted] was recorded. Pancreatic insufficiency was diagnosed based on faecal elastase of < 100 µg g-1 . We performed multiple-regression analysis with aerobic fitness outcomes [peak oxygen uptake (VO2 peak )] and FEV1 % predicted as primary outcomes. RESULTS: Ninety pwCF [mean ± SD age: 19.1 ± 8.6 years, 54 (60%) children, 48 (53%) males and 88 (98%) Caucasian] were included. 25OHD deficiency and insufficiency was 15 (17%) and 44 (49%), respectively. 25OHD deficiency and insufficiency was significantly associated with pancreatic insufficiency (χ2  = 4.8, p = 0.02). Plasma 25OHD was not significantly associated with FEV1 % predicted (r2  = 0.06, p = 0.42, 95% CI = -0.09 to 0.19) or VO2 peak (r2  = 0.04, p = 0.07, 95% CI = -011 to 0.005) in all pwCF. However, 25OHD was significantly associated with both FEV1 % (r2  = 0.15, p = 0.02, 95% CI = 1.99-2.64) and VO2 peak (r2  = 0.13, p = 0.05, 95% CI = -0.26 to -0.005) in the paediatric cohort. CONCLUSIONS: We showed that 25OHD is associated with improved lung function and aerobic fitness in children and adolescents with CF. Mechanistic and high-quality prospective studies including both lung function and aerobic fitness as primary outcomes are now warranted.

The implications of dysglycaemia on aerobic exercise and ventilatory function in cystic fibrosis.

BACKGROUND: The development of cystic fibrosis (CF)-related diabetes (CFRD) in paediatric groups is associated with a reduced aerobic fitness. However, this has yet to be investigated in adults with more severe lung disease. METHODS: Cardiopulmonary exercise and glycaemic control tests were retrospectively analysed in 46 adults with CF (age: 26.9 y [range: 16.3-66.5 y]; forced expiratory volume in 1s: 65.3% [range: 26.8-105.7%]; 26 males), diagnosed with CFRD (n = 19), impaired glucose tolerance (IGT; n = 8) or normal glucose tolerance (NGT; n = 19). RESULTS: Maximal oxygen uptake (V˙O2max) was reduced in adults with IGT and CFRD compared to their age- and gender-matched counterparts with NGT (p < 0.05); however, there was no difference when lung function was included as a covariate (all p > 0.05). V˙O2max was greater in adults who experienced post-reactive hypoglycaemia vs. NGT without hypoglycaemia (p < 0.05). The frequency of ventilatory limitation (84%, 63% and 37%, respectively; p < 0.05) but not ventilation-perfusion mismatch (42%, 38% and 16%, respectively; p > 0.05), was greater with CFRD and IGT vs. NGT. There was also no difference in arterial oxygen saturation changes between groups (p > 0.05). Gender and body mass index were significant predictors of V˙O2max (adjusted R2 = 0.37, p < 0.01), but glycaemic control did not explain additional variance (p > 0.05). CONCLUSIONS: Adults with CF-related dysglycaemia had a reduced V˙O2max compared to age- and gender-matched counterparts, due to a greater degree of CF lung disease in these populations.

Postoperative chyle leak after major pancreatic resections in patients who receive enteral feed: risk factors and management options.

BACKGROUND: Chyle leak complicates 1.3-10.8 % of pancreatic resections. Universal use of parenteral nutrition following pancreatic resection may reduce the incidence of chyle leak. However, this denies the majority of patients who do not develop chyle leak the benefits of enteral nutrition (EN). The present study aimed to identify risk factors for chyle leak following pancreatic resection within a single institution where EN was used universally. METHODS: All patients who underwent pancreatic resection between January 2007 and December 2010 were identified retrospectively. The patients had been treated according to a common unit protocol of enteral feeding; those developing chyle leak were switched to a medium-chain triglyceride (MCT) regimen. Clinical progress and recovery after surgery was evaluated. Multivariate analysis was performed to identify factors associated with chyle leak. RESULTS: A total of 245 patients underwent major pancreatic resection (231 pancreatoduodenectomy, 14 total pancreatectomy). Chyle leak complicated 40 cases (16.3 %). After multivariate analysis, both extensive lymphadenectomy (P = 0.002) and postoperative portal/mesenteric venous thrombosis (PVT) (P = 0.009) were independently linked with a higher incidence of chyle leak. The development of chyle leak was not associated with poorer survival or prolonged duration of hospital stay. It was associated with a significantly increased duration of abdominal drainage and reduced likelihood of early hospital discharge (P = 0.026). CONCLUSIONS: Universal use of enteral feeding is associated with a high rate of chyle leak following pancreatic resection. Patients undergoing extensive lymphadenectomy or those who develop PVT postoperatively are at increased risk. Development of chyle leak was not associated with additional morbidity or mortality following implementation of an MCT regimen. The implication is that reactive management of chyle leak with conversion to a MCT predominant diet is safe.