Abstract
Exclusive enteral nutrition (EEN) is a first line treatment for active paediatric Crohn’s disease (CD) but is used less frequently in adult patients. A meta-analysis of six controlled trials in adults found EEN to be less efficacious than corticosteroids at inducing CD remission. In contrast, paediatric studies have found EEN to be an effective treatment. Paediatric EEN regimens often use a polymeric nutrition formula provided orally; this regimen has not been studied in a cohort of adults with active CD.
This research aimed to investigate patient acceptability of EEN, the efficacy of EEN and a sequential EEN and partial enteral nutrition (PEN) regimen in young adults, and the impact of these treatments on disease activity, inflammatory and nutrition markers, quality of life and the gut microbiota. This research also aimed to investigate health professional awareness and perception of EEN in the treatment of CD.
Thirty five patients with CD attending hospital outpatient appointments were surveyed. Patients blind tasted an elemental and a polymeric formula then ranked them on measures of palatability. Patients were also asked whether they would consider using EEN, if it could induce disease remission, to treat active CD. Patients rated polymeric formula more palatable and the majority of patients would consider using EEN to treat moderate to severe CD symptoms.
Two prospective non-randomised clinical trials of eight weeks of EEN or a sequential EEN and PEN regimen were undertaken. Thirty-eight patients aged 16 to 40 years old with active CD were recruited. Twenty-five patients started EEN of which 17 (68 %) responded or achieved disease remission. Thirteen patients started PEN and eight (62 %) responded or achieved disease remission. There were significant improvements in serum CRP and insulin like growth factor-1. EEN or PEN treatment was completed by 23/38 (61 %) and resulted in significant reductions in anxiety and depression and improvements in quality of life.
Faecal samples were collected prior, during and after EEN or PEN treatment. The faecal microbiota of six patients who used EEN was characterised. EEN treatment shifted the phylogenetic structure of the faecal microbiota and changes in the abundance of specific species were observed.
An electronic survey was completed by 58 dietitians and 42 gastroenterologists working in New Zealand. Most dietitians and gastroenterologists had limited experience using EEN but believe EEN is an appropriate treatment option for some adult CD patients. Health professionals would like more guidance on how to use EEN and more evidence to supports its use with adults.
Based on the findings in this thesis, EEN effectively induces disease remission in young adults with active CD and its use should be considered within the profession and presented as an option to patients. There is also a need for further research investigating therapies, such as PEN, which may be more appealing and efficacious for a greater number of adult patients. Patients who are interested in an alternative to corticosteroids should be offered nutrition therapy with the support of an IBD multidisciplinary team.