Bariatric surgery : a literature review and results from the BaSE study : a grounded theory of constructing success for bariatric patients : a thesis presented in partial fulfilment for the requirements of the degree of Master of Science in Human Nutrition at Massey University, Palmerston North, New Zealand

Abstract

Background: In New Zealand, around one-third of adults are categorised as medically ‘obese’ and at risk of related comorbidities such as cardiovascular disease, diabetes, sleep apnoea and certain cancers. Obesity is complex, with an elaborate aetiology that encompasses physical, psychological and socio-economic domains. It has proved a tough challenge for health agencies to address, with lifestyle and pharmaceutical interventions consistently showing underwhelming to nil results, particularly for those classified as having class III obesity. Bariatric surgery is now widely accepted as the only effective treatment for severe obesity and related comorbidities with numbers of surgeries worldwide increasing exponentially each year. Objective: The aim of this review was to document an overview of the current knowledge base around bariatric surgery including its effectiveness, the accepted or proposed mechanisms of action and known issues, while also identifying areas of special interest, findings that could be incorporated into best practice and deficits in the research. Method: A focused non-systematic literature review was conducted through the Web of Science and PubMed databases using keywords relevant to each section of the review. Preference was given to apers that were recent, had large sample numbers, long follow-up times and that had been published in respected journals. Less prestigious papers were also included where they added to the depth and interest of the review. Results: A number of topics were identified which may be of interest to clinicians and provide direction for future research. These included the emerging area of the influence of gut hormones and the microbiome on surgery outcomes, the ongoing problem of pre- and post-surgical nutrient deficiencies and the crucial impact of psychological states and conditions on bariatric outcomes. Recommendations include more intensive physical and psychological screening and preparation, longer and more thorough follow-up protocols, managing patient expectations and expanding the definition of bariatric ‘success’ so that, as well as weight loss and improvement of physical comorbidities, it includes measurable psychological and psychosocial variables as well as subjective eating behaviours.