Treatment of obesity

It is difficult to determine the minimal weight quantity necessary to lose in overweighed patients, in order to reach a measurable profit for the health. A weight loss of only 5-10 % was demonstrated to be sufficient to decrease the comorbidity. Because of strong prevalence of comorbidities, even small decreases of their prevalence by the weight loss, will have a significant impact on the public health. In obese a weight loss of 10kg was associated with a decrease of 20 % of comorbidities including 30 % of diabetes. Besides the improvement of the joint and dorsal pains, the sleep apnea was improved.⁶¹ Samsa and al. demonstrated furthermore that this moderate weight loss also allowed an improvement of patients quality of life.⁶² Indeed, WHO declared a weight loss of even 5% was clinically significant.

For weight reduction, different approach such as behavioral or nutritional could be intended.

However, as adipose tissue resists to diminish, particularly on obese individuals, an important weight loss that stays stable over time is difficult to obtain in obese.

In normal weight individual as well in overweight persons, after the constitution phase of adipose tissue development, the fat mass is spontaneously maintained stable (maintenance phase). This phenomenon is due to the fact that once differentiated, adipocytes do not return to the precursor stage; and hyperplasia seems not or lightly reversible.^10,49,50 Weight loss is linked to a reduction in the size of adipocytes (hypotrophy), not the number which remains stable. Moreover, cell size cannot be maintained below a certain value; the minimum level of fat mass which can be reached is limited by the number of adipocytes. Leptin, secreted by the adipose tissue, would also be involved in this autoregulation of the fat mass during the maintenance phase. This adipose tissue resistance could explain partially, the resistances to weight loss, fast return to the initial weight after a weigh-reducing diet, or the difficulty of former obese to keep a stable weight. It would explain that only sustainable modifications permit a decrease of the long-term weight. And unfortunately most of the medical treatments based on diets, physical exercise, modifications of food behavior or drugs are often insufficient, particularly to the morbid obese individuals.⁶³

2.2.7.1 Bariatric surgery

Bariatric surgery (from Greek baros, weight; and iatrikos, being a part of the medicine) could be proposed to obese individuals that cannot lose weight with non-surgical approaches. The surgical treatment of the obesity is only justified if the morbidity and the mortality caused by the obesity are more important than those associated with the operation and its aftereffects.

Therefore, patient’s and procedure selection is primordial.

The surgical treatment of the obesity began in 1956 with Payne and De Wind⁶⁴ and since then, numerous techniques were developed. They are grouped in three categories: those reducing only the length of intestine absorption called "malabsorptives" (e.g. Scopinaro, jejuno-ileal bypass), those purely "restrictive" creating a small gastric pocket (e.g. vertical gastroplasty, adjustable gastric loop), and those who combine both principles and called "mixed" (e.g. Roux-en-Y gastric bypass (RYGBP). These operations permit a massive weight loss not only because of reduced estomac volume and intestinal absorption, but also by changing gastro-intestinal hormones and flora. Recently it has been demonstrated that bariatric surgery, influence also appetite and energetic metabolism through entero-hypothalamic pathways. Ghreline rate, considered as main appetite activator is reduced after a bariatric surgery. After RYGBP, Glucagon-like peptide-1 (GLP-1), used for diabetes treatment, and peptide YY (PYY) secretion are increased.⁶⁵

Numerous studies demonstrated that the bariatric surgery solves up to 95 % of the diabetes⁶⁶, 100% of dyslipidemia, 67,8% of blood hypertension, 92.2% of the sleep apnea syndromes⁶³ and 96% of the metabolic syndromes.⁶⁷ These improvements allow an increase of the life expectancy and a decrease of the mortality. Sjöström and al., in an important study including 7925 patients who underwent a bariatric surgery, concluded that the global mortality of the operated patients was decreased 40 % compared with the not operated group.⁶⁸ Arterburn et al. in a retrospective cohort study, confirmed that obese patients who underwent a bariatric surgery had a lower all-cause rate of death at 5 up to 10 years after the surgical procedure, compared with obese patients without surgery (13,8% vs. 23,9%)⁶⁹

With a favorable risk-profit balance, the bariatric surgery became the gold standard treatment for morbid obesity. By taking into account the disadvantages of the operation: immediate

post-operative pains, operating stress, food inconveniences, possible complications and a per-operative mortality risk of 0.04-0.16%, the advantages of the intervention are clearly superior.⁶³ In fifteen years these interventions have more that quintupled to reach more than 100'000 operations per year in the USA.⁷⁰ According to Swiss Society for the Study of Morbid Obesity and Metabolic disorders (SMOB) in 2013, more than 4000 bariatric interventions were made in Switzerland, in 51 centers (www.smob.ch).

2.2.7.2 Roux-en-Y gastric bypass

Numerous studies have already demonstrated the beneficial effect of RYGBP on the comorbidity and mortality, with a long-term efficiency in terms of weight loss.⁶³ On average patients lose 66

% of their excess of body weight (EBW) during 1-3 post-operative years, 60 % in 5 years and 50

% between 5 to 10 years.^63,71 Considering the risk/advantages balance, the RYGBP is nowadays recognized as one of the best solution for morbid obese (BMI>40 kg/m²) or those with BMI>35 kg/m² presenting more than 2 comorbidities.

For many patients the psychosocial improvement is also important, sometimes even more than the effective decrease of their weight. Indeed, the request of the patients for a medical or surgical treatment of their weight excess ensues more often from a decreased quality of life than from fears of medical comorbidities. The psychosocial distress is the main motivation of a surgical treatment for more than two thirds of the patients, against only 10 % for purely medical reasons.⁷² The purpose of the surgery treatment of obesity for the patients seems to be more the improvement of their physical image, their self-esteem and their quality of life than only the weight loss. ^73,74

Several studies demonstrated that RYGBP besides comorbidities and mortality reduction, improves patients health-related quality of life (HRQoL).^75-79 In one of our study, we demonstrated that the quality of life was evaluated as “much better” by 22 % of patients after RYGBP. This improvement concerned all sub-items of HRQoL: self-esteem, physical activity, social life, work ability and sexual activity. ⁸⁰ (Annexe. Paper 1)

However, despite a massive weight loss, HRQoL of these patients who lost a massive weight after a bariatric surgery remains always unsatisfactory in comparison with those of

non-operated persons with the same weight. The cutaneous excess appeared after a massive weight loss can be considered as a new handicap by the patients. Up to 95.6 % of patients report residual morphology dissatisfaction associated with loose sagging skin.⁸¹ This side effect of the bariatric surgery can strongly bother patient’s daily activities (e.g. mobility, clothing) and raise hygienic problems (e.g. macerations, intertrigo) requiring medical treatments. It can induce, despite considerable weight loss, severe psychosocial problems because of a lack of self-confidence and a disturbed physical image.⁸² More than two-thirds of patients who have undergone bariatric surgery consider their excess skin as a negative consequence of surgery.⁸³ This dissatisfaction motivates 74 % of patients to seek body contouring procedures after bariatric surgery, but only 21 % achieves at least one of them.⁸¹ Most of them give up the surgery for economic reasons, as often health insurances don’t cover such kind of plastic surgery.