Obesity and Type 2 Diabetes
Obesity and Type 2 Diabetes
The prevalence of type 2 diabetes is rising at a faster rate globally. This kind of a situation is primarily driven by an “obesogenic” environment that favors increasing sedentary behavior and easier access to attractive calorie-dense foods acting on susceptible genotypes1.
The most recent global predictions by the International Diabetes Federation (IDF) suggest that there are 285 million people with diabetes currently worldwide. This is set to escalate to 438 million by 2030, with a further half billion at high risk. Diabetes is looming as one of the greatest public health threats of the 21st century.
Type 2 diabetes is a risk factor for heart damage: both micro-vascular (eye failure; kidney damage and brain disease) and macro-vascular (premature and more extensive heart and brain,). Premature deaths in diabetes result from such complications.
Type 2 diabetes results from inadequate insulin production and action and results in increase in blood sugar but is also associated with multiple other dysfunctions involving fat metabolism; oxidative stress; inflammation. In addition obesity, by itself, generates similar heart and metabolic distress. Several gastrointestinal (GI) operations that were originally designed to treat morbid obesity also cause dramatic improvement of type 2 diabetes and can effectively prevent progression from impaired glucose tolerance to diabetes in severely obese individuals. In addition, surgery has been shown to substantially improve hypertension, and lack of sleep and several reports have documented an improvement of overall survival and specific reduction in diabetes-related mortality.
What is the link between obesity and type 2 diabetes?
Type 2 diabetes is a heterogeneous disorder and, while its causes have yet to be fully explained; obesity is considered the primary risk factor. It has been estimated that the risk of developing type 2 diabetes is increased 93-fold in women and 42-fold in men who are severely obese rather than of healthy weight. A small proportion of people with type 2 diabetes, approximately 15% in populations of European origin, are not overweight.
In the short term, even modest weight loss in people with type 2 diabetes who are overweight or obese is associated with improvements in sugar control and associated conditions such as hypertension and fat imbalance. However, there is strong evidence that significant weight loss achieved by using lifestyle and medical methods by obese, particularly severely obese, people is modest and rarely sustained, particularly in the severely obese. There are now few medications approved for weight loss with recent withdrawals associated with adverse events.
Why should surgery be considered in algorithms for treating obese type 2 diabetes?
- Type 2 diabetes is a progressive disease and the usual natural history is of progressive loss of insulin secretory capacity over time and the need for intensification of therapy and medications. Arresting this progression is a therapeutic challenge. Treatment for type 2 diabetes must also include active management of all heart and blood flow risk factors (increase in blood pressure, metabolic disorders, smoking and inactivity) but sugar control is very important – and not just for prevention of microvascular disease. Years of improved sugar control continue to deliver reduced risk of macrovascular disease and mortality over subsequent years
- Strategies like Lifestyle interventions to promote weight loss and increase physical activity have very limited success in controlling blood glucose levels amongst the severely obese, with many of these patients not achieving targets. A number of these medications used for treating type 2 diabetes, including insulin, themselves can result in weight gain.
- A major problem for managing type 2 diabetes is the need for continuous monitoring and intensification of therapies by adding new agents in increasing doses over time. The ADA and EASD consensus statement recommends that an HbA1c of 7% is a call to action. Some national guidelines, such as those from UK‟s NICE, support more vigorous intensification of sugar therapies in early stages of diabetes. NICE used HbA1c ≥ 6.5% to increase from monotherapy but ≥7% for increasing to triple therapies and beyond. This is very important. In one trial that randomized people with type 2 diabetes and existing cardiovascular disease to very intensive management targeting HbA1c <6.5%, mortality was higher in the intensive group, driven by deaths in those people who failed to show HbA1c improvement as treatment was intensified34. This should not be taken to mean people with early type 2 diabetes should be treated less vigorously as the legacy effect of early intervention is considerable.
A critical issue has been the rate at which health care professionals escalate therapies. Current approaches that rely on loss of sugar control and on intensifying lifestyle or other time consuming measures set clinicians up for failure to achieve targets.
It may be possible to achieve much more in terms of complication prevention – or even possibly slowed rate of progression – if treatments are started and intensified early. There have even been suggestions of starting medications at diagnosis but there is limited current evidence to demonstrate the efficacy of this.
Apart from the side effect profiles and suboptimal deployment of existing medical diabetes therapies, there remain issues around patient engagement in many aspects of their lives. Very few clinical services routinely provide psychological support to encourage life-long engagement in self-care.
The continuing deaths in persons with diabetes is a sign that the answer as to the best management for type 2 diabetes in terms of maximizing metabolic control is still elusive. Given this scenario, the option of bariatric(stomach) intervention needs to be considered in appropriately selected individuals.
What is done ?
Gastric pouch 30 ml. Part of small intestine is bypassed. Greater weight loss. Hospital stay 5-7 days Vitamin mineral supplementation required.
In this procedure a small stomach pouch is created by stapling the stomach. This causes restriction of the food intake.
Next a “Y” shaped section of the small intestine is attached to the pouch to allow food to by-pass the first part of small intestine. This causes reduced calorie and nutrient absorption.
Advantage of surgery
- rapid and sustained improvements in sugar control can be achieved within days of gastric bypass surgery, before any significant weight loss is evident
- The Swedish Obese Subjects study clearly demonstrated the prevention and sustained remission of type 2 diabetes in a group of 2037 severly obese patients electing to have bariatric surgery when compared with well-matched controls at 2 and 10 years follow-up. The extent of remission of type 2 diabetes is influenced by the extent of weight loss, weight regain, and duration of diabetes, the pre-surgery hypoglycaemic therapy requirements, and the choice of bariatric procedure. In addition each patient’s commitment to modifying their diet and levels of exercise within a framework of ongoing multidisciplinary care will influence outcomes.
- Surgery is associated with a 29% reduction in all-cause mortality after accounting for sex, age and risk factors in this severely obese group5. Bariatric surgery also led to a specific reduction in cancer incidence in women
- Specific mortality reductions in the operated group were 56% for coronary artery disease, 92% for diabetes, and 60% for cancer when compared with matched controls.
- It benefits on other aspects of their health, for example debilitating osteoarthritis or obstructive lack of sleep.
Who are eligible?
- Patients with type 2 diabetes with BMI >27 kg/m2 who are inadequately controlled by lifestyle and medical therapy. HbA1c > 7.5 despite fully optimized conventional therapy, especially if weight is increasing or other weight responsive co-morbidities not achieving targets on conventional therapies. For example blood pressure, metabolic disorders and obstructive lack of sleep The surgery for adolescents can be recommended with BMI >40 kg/m2, or >35 kg/m2 with severe co-morbidities (including type 2 diabetes), were aged 15 years or more, with Tanner pubertal stage 4 or 5 and skeletal maturity, and could provide informed consent. Potential candidates should have failed a multidisciplinary program of lifestyle +/- pharmacotherapy for 6 months, and they and their family must be motivated and understand the need to participate in post-surgical therapy and follow-up
Who are not eligible?
Patients with current drug or alcohol abuse, uncontrolled psychiatric illness, and lack of comprehension of the risks – benefits, expected outcomes, alternatives and lifestyle changes required with surgery.
Surgery for the severely obese with type 2 diabetes should be considered early as an option for eligible patients, rather than being held back as a last resort. Almost all severely obese patients are unsuccessful in their efforts to achieve sustained and significant weight loss and there is evidence that weight loss induced by surgery can lead to remission of increase in sugar level in the majority of patients with diabetes. Earlier intervention increases the likelihood of remission. In the remaining patients, residual increased sugar level is easier to manage following bariatric surgery