Therapeutic Approaches to Obesity Treatment

Transcription

1 Therapeutic Approaches to Obesity Treatment Sherif Hafez MD, FACP CONTENTS Summary. Aim. Aim of weight reduction and target body mass index. o Optimal weight for cardiovascular health Outline of therapeutic approaches. Therapeutic targets. - Body weight and waist circumference. - Other cardiometabolic risk factors. Role of behavior modification. High risk abdominally obese patient. 1

2 SUMMARY The therapeutic approaches to obesity treatment include lifestyle changes, pharmacotherapy and bariatric surgery. These therapeutic approaches are outlines in this chapter stressing on their indications and on the therapeutic targets. The benefits of moderate weight loss in improving cardiometabolic risks and on other co-morbidities are discussed. Abdominal obesity in particular is considered as an independent cardiometabolic risk factors, and is linked to multiple cardiometabolic risk factors. AIM OF THIS CHAPTER To outline the therapeutic approaches to obesity treatment, the aim of weight reduction and the therapeutic targets and benefits of moderate weight loss. AIM OF WEIGHT REDUCTION AND TARGET BODY MASS INDEX Optimal weight for cardiovascular health Effective weight management does not simply mean organizing a slimming process. It is a completely different concept geared to ensuring that the long-term health of the patient is the key concern. (1) The World Health Organization and the National Institute of Health have classified weight status based on Body Mass Index (BMI) (Table 1) (2,3). Table (1): Classification of overweight and obesity by BMI Weight Status BMI (Kg/m 2 ) Obesity class Under weight <18.5 Normal Overweight Obesity I II Extreme obesity = 40 III Men and women who have a BMI = 30 Kg/m 2 are considered obese and are at a higher risk for adverse health outcomes than those who are overweight (BMI Kg/m 2 ) or lean (BMI ) (4,5) 2

3 Therefore, BMI has become the gold standard for identifying patients at increased cardiometabolic risk. Furthermore, intra-abdominal adiposity (IAA) is considered an independent cardiometabolic risk factor. Waist circumference (WC) is strongly correlated with IAA measurement by CT or MRI, therefore, WC measurement should be a part of routine clinical examination emphasizing the importance of IAA. Thus, it is logic to consider the optimal BMI (and not the weight) to be less than 30 Kg/m 2 for good cardiovascular health. In addition, several studies have provided evidence for a positive impact of moderate weight reduction on cardiometabolic outcomes (6,7,8). Benefits of weight loss: weight loss is the key factor in the control and prevention of hypertension, coronary heart disease, type 2 diabetes mellitus, dyslipidemia, cardiorespiratory failure and chronic degenerative osteoarthritic disease. This can be achieved by modest weight loss (9). Weight loss and cardiovascular risk: o The American Heart Association (AHA) recognized obesity as a modifiable risk factor for Coronary Heart Disease (CHD). o Adipose tissue secrets cytokines that contribute to cardiovascular risk. o Moderate weight loss favorably changes serum adipocytokines and adiponectin (10). OUTLINE OF THERAPEUTIC APPROACHES Treatment of obesity: o Lifestyle modification Dietary management Physical activity Behavior modification o Pharmacotherapy o Bariatric surgery 3

4 INTERNATIONAL OBESITY TASK FORCE (IOTF) RECOMMENDATIONS IN TREATMENT OF OBESITY Diet, physical activity and behavioral therapy are recommended for obese patients with BMI = 30 kg/m 2 they are also recommended for overweight individuals (BMI > 25 and < 30 kg/m 2 ), if associated with co-morbidities. Pharmacotherapy are recommended for obese patients with BMI > 30 kg/m 2 and overweight individual with BMI > 27 and < 30 kg/m 2. Bariatric surgery is recommended for extremely obese patients with BMI = 40 kg/m 2 and also for those patients with BMI > 35 kg/m 2 if associated with comorbidities (Table 2). Table (2): International Obesity Task Force (IOTF) Recommendations in treatment of obesity Treatment BMI category (kg/m 2 ) =40 Diet, physical activity With comorbiditiemorbidities With co & behavior therapy Pharmacotherapy With comorbidities Surgery With comorbidities + Source: Dr. Karim Said Co-morbidities include diabetes, hypertension and atherosclerotic heart disease. Diet Generally speaking a reduction of caloric intake in the diet by Kcal/day will result in the recommended weight loss of about half to one kilogram per week. Physical activity Physical activity helps to decrease body fat and to prevent the decrease in muscle mass with dieting. Physical activity plays an integral role in weight maintenance. 4

5 According to the 2005 dietary guidelines, weight reduced adults need an estimated minutes/day of moderate physical activity to avoid weight regain (11). However, adopting a lower calorie dietary pattern may reduce the amount of physical activity that is necessary for weight maintenance. Behavior therapy Behavior therapy helps to improve compliance since life style modificatio n is very difficult to maintain especially in adulthood. Pharmacotherapy Approved prescription anti-obesity drugs: Rimonabant (Accomplia) Orlistat (Xenical) Sibutramine (Meridia) Over The Counter (OTC) anti-obesity drugs: The following agents are sometimes used and have no scientific proof of efficacy or safety. Compounds with positive weight loss Ma Huang(Ephedra) Green Tea 5-HTP/Tryptophan Calcium/Vitamin D Cimetidine Conjugated linoleic acid Compounds with questionable weight loss Chitosan Chromium Garcinia cambogia Melatonine Safety Regulation of OTC Labels on OTC weight Loss Pills are not Always Accurate OTC weight Loss Pills May Contain Unlisted Ingredients 5

6 Many experts stated that any compound containing ephedra "should not be called a dietary supplement; it is a drug." (12) The use of the previous agents is not recommended in the treatment of obesity. Bariatric surgery Types of Bariatric surgery: o Vertical gastric banding. o Adjustable gastric banding. o Gastric bypass surgery. o Duodenal switch. o Sleeve gastrectomy. Indications: o Morbid obesity BMI = 40Kg/m 2, after failure of lifestyle modification and pharmacologic therapy. o Moderate obesity BMI = 35Kg/m 2 but associated with a co-morbid condition, e.g. diabetes, hypertension, after failure of lifestyle modification and pharmacologic therapy. NB. Liposuction is not a treatment for generalized obesity but may be used for shaping or for cosmetic reasons. Therapeutic targets The achievement of weight normalization (BMI < 25 kg/ m 2 ) is not realistic and does not have to be the goal or target of a weight reduction policy. Moderate weight loss (5-10% of original body weight) can have a good beneficial health effects. Moderate weight loss has been shown to help: o Reduce CV risk. o Prevent Diabetes. o Lower BP o Decrease Mortality o Improve quality of life 6

7 Therefore, the recommended goals for obesity therapy are: o Reduction of body weight: 5-6 Kg or 10% of initial body weight over 6 months. o Maintaining BMI < 25 Kg/m 2 is ideal, yet maintaining BMI < 30 Kg/m 2 is still beneficial. NB: Each one Kg weight loss is associated with a one cm decrease in waist circumference. High risk abdominally obese patients Abdominal obesity in particular is regarded as an independent cardiometabolic risk factor. There is a subset of abdominally obese patients at increased risk of future CV event in spite of the absence of other established risk factors or cardiovascular disease. Fig. 1. Central obesity, sedentary lifestyles, inflammation and coronary heart disease Central obesity fl Physical activity Small dense LDL TG /fl HDL NEFA Proinsulin Proinflammatory cytokines (micro -inflammation) Endothelial dysfunction Hypertension Microalbuminuria PAI-1 Insulin resistance IGT/DM CRP Fibrinogen CHD This figure summarizes the metabolic consequences of abdominal obesity and sedentary lifestyle in terms of the component of the dysmetabolic syndrome (13). 7

8 REFERNCES 1. James P (1998). 2. World Health Organization: Obesity: Preventing and managing the global epidemic. Report of WHO consultation on Obesity. Geneva, Switzerland. World Health Organization, National Institute of Health. National Heart Lung and Blood Institute. Clinical guidelines on the identification, evaluation and treatment of overweight and obesity in adults - the evidence report. Obs Res, 1998; 6(Suppl 2): 51S-209s. 4. Golditz GA, Willett WC, Rotnitzky A, Manson JE. Weight gain as a risk factor for clinical diabetes mellitus in women. Ann Intern Med, 1995; 341: Calle EE, Thun MJ, Petrelli JM, Rodriguez C, Heath CW. Body mass index and mortality ina prospective cohort of US adult. N Engl. J Med, 1999; 341: DPP. N Engl of Med 2000; 346: Aucott L et al.: Hypertension 2005; 45: Elmer PJ et al.: Ann Intern Med, 2006; 144: Vidal J. Int. J Obes, 2002; 26 (Suppl. 4) S25-S Doukets JD et al.: Int. J Obes, 2005; 29: US Department of Health and Human Services: Dietary Guidelines for Americans. 6 th ed. Washington, DC: US Department of Agriculture, US Dietary Guidelines Advisory Committee, Am. Fam Physician, 2000; 62: Yudkin et al. Arterioscler Throm Vasc Biol 1999; 19: