Real-world clinical and service outcomes of pre-bariatric weight loss interventions and post-bariatric outcomes among patients with insulin-treated Type 2 Diabetes living in the UK: public Health and epidemiological approach

In numerous countries globally, the morbid obesity pandemic is increasingly posing a major lifelong disorder. With one-in-four adults classed as obese, while two-thirds are overweight, obesity’s prevalence in England is among the highest in Europe. The effect of obesity and obesity-related comorbidity on the UK’s NHS public health budgets is second only to smoking, estimated to cost £44.7 billion annually. The official UK obesity management is attained via a commissioned service that adopts a four-tiered pathway. The first two tiers are outside of this study’s remit, pertaining to environmental and population-wide schemes for obesity prevention and promotion of a healthy weight and nutritional balanced diet. Tier 3 is a Multidisciplinary Weight Management Service, aimed at those whose obesity is complex and/or is accompanied by medical needs; patients in this tier may be considered for Tier 4, namely bariatric surgery. Exposure to these two clinical tiers is the focused in this thesis, which evaluates the clinical effect and health outcomes of the commissioned clinical interventions. To comprehend the comorbidities and metabolic status of individuals with severe obesity living in the UK, the Tier 3 and similar programmes were systematically reviewed. Furthermore, Tier 3 was supplemented by research conducted at a local clinic. This research extends to patients with a major comorbidity (i.e. insulin-treated T2D) and were at high risk of CV, nephropathy or hepatic disease (i.e. respectively microalbuminuria and NAFLD at baseline), who had been referred for bariatric intervention. Analysis of CV, metabolic and renal outcomes was undertaken. Additionally, this thesis presents a chapter appraising the economic effect of surgical treatment provision for the morbidly obese. It assesses the costs involved in providing clinical care, laboratory tests and pharmacotherapy (typically, antihypertensives, aspirin, insulin, GLP-1 analogues, lipids lowering and oral antidiabetic drugs). Moreover, it evaluates the likelihood of T2D remission and insulin independency in post-bariatric intervention, alongside an in-depth analysis of composite obesity-related comorbidity events—including asthma, atherosclerosis, cancers (breast, bowel or uterine), chronic kidney disease, coronary heart disease, dementia, depression, gallstones or gallbladder disease, GORD, gout, hyperlipidaemia, hypertension, liver diseases, osteoarthritis, sleep apnoea and stroke. Drawing on the systematic review results and local clinic study, a strong correlation was identified between those patients requiring Tier 3 services and their risk of developing serious comorbidities, profoundly with advanced T2D. Although subtle, the short- to mid-term effects of Tier 3 are statistically positive for patients with severe obesity. Bariatric patients with serious comorbidities (i.e. insulin-treated T2D), gained a longer-term protective effect against certain major elements of CV diseases and CKD events, while significant metabolic improvements were experienced by patients with NAFLD at baseline. Concerning the analyses of composite obesity-related comorbidities, the protective effect conferred by the Tier 4 bariatric intervention is significant, therefore justifying its cost effectiveness. Therefore, clinical interventions for preventing morbid obesity are effective in mitigating or resolving numerous comorbidities that affect patients with severe obesity living in the UK