A SYSTEMATIC APPROACH TO

Transcription

1 A SYSTEMATIC APPROACH TO OBESITY Robert B. Baron MD MS Professor and Associate Dean UCSF School of Medicine Declaration of full disclosure: No conflict of interest Prevalence of Obesity (Adults): 2008 Obesity: 33.8% Men: 32.2% Women: 35.5% Overweight + obesity: 68% Men: 72.3% Women: 64.1% Severe Obesity: 6% Flegal JAMA 2010 Men and Women Aged 40 to 59 Years in and Prevalence of Obesity (Children): 2008 Severe obesity (97 percentile): 11.9% Obesity (95 percentile): 16.9% Overweight (85 percentile): 31%. No increase from 1999 to 2008 (except severe obesity in boys) Flegal JAMA

2 Obesity Disparities: 2008 Women, Black: 52%, Hispanic: 47%, Whites: 36% Teens Black: 29%, Hispanic: 17.5%, Whites: 14.5% Mental illness Overweight + obese: 83% For a 40 yo woman, which BMI is associated with the lowest allcause mortality? % 39% Flegal JAMA % % 2% 38 CLASSIFICATION OF OVERWEIGHT AND OBESITY BY BMI Obesity Class BMI (kg/m 2 ) Underweight <18.5 Normal Overweight Obesity I II Extreme Obesity III >40 BMI AND MORTALITY: Overall Combined NHANES I, II, and III data set BMI y y 70 y < < to < to < Flegal, JAMA,

3 Excess Deaths Trends Over NHANES Surveys I, II, and II Body Weight and Mortality Overweight (unlike obesity) is not associated with increased all cause mortality. It may be associated with decreased mortality. Overweight (like obesity) is associated with increased mortality from diabetes, but not from CV disease and cancer (unlike obesity). Flegal, JAMA 2007 For a 40 yo woman, which BMI is associated with the lowest allcause mortality? 40 yo woman, BMI 33. Which abnormality best predicts her 10 year mortality? Waist circumference: 36 inches 2. Fasting blood sugar: 110 mg/dl 3. Systolic BP: 140 mm Hg 4. Triglycerides: 185 mg/dl 5. Exercise test: early stage 2 (fatigue) 16% 11% 16% 5% 53% Waist circumfe... Fasting blood... Systolic BP: 1... Triglycerides:... Exercise test:... 3

4 FITNESS AND MORTALITY Aerobics Center Longitudinal Study 25,714 men, 44 years old, 14 year observational study CV death (RR) normal overweight obese Fit Not fit Total death (RR) normal overweight obese Fit Not fit Wei, JAMA 1999 Relative Risk* of Death According to Body Mass and Physical Activity ** 1.00 Physical activity level 1.18 > 3.5 hours/week hours/week < 1 hour/week < > 30 Body mass index (BMI) * RR s adjusted for age, smoking status, family history, menopausal status, hormone use, and other factors ** Reference group = women with 3.5 or > hours/week of physical activity and BMI of 25 or less Hu FB, et al. N Engl J Med 2004;351: yo woman, BMI 33. Which abnormality best predicts 10 year all cause mortality? 1. Waist circumference: 36 inches 2 Fasting blood sugar: Systolic BP: Triglycerides: Exercise test: early stage 2 (fatigue) 60% US adults don t exercise regularly 25% are sedentary Epidemic of Inactivity 4

5 EXERCISE FOR OBESITY Meta-analysis analysis of 43 RCTs: 3476 participants Exercise vs no Rx small weight losses 40 yo woman, BMI 36. Motivated to begin diet therapy. Which of the following is contraindicated: Exercise plus diet vs diet alone -1.1 kg Increased intensity of exercise -1.5 kg Exercise without weight loss -BP, -TG, -FBS 1. Meal replacement, very low calorie diet 2. Atkins diet 3. Ornish diet 4. Zone diet 5. All are contraindicated 6. None are contraindicated 20% 75% 2% 2% 0% 0% Shaw, Cochrane, 2006 Meal replaceme... Atkins diet Ornish diet Zone diet All are contra... None are contr... COMPARISON OF DIETS WITH DIFFERENT MACRONUTRIENTS RCT of 811 patients, 4 diets: fat/protein/carbs 20/15/65; 20/25/55; 40/15/45; 40/25/35 6 months: 6kg, 7% weight; at 2 years: completers lost 4kg; 15% lost 10% of weight Results similar for: 15% pro v. 25% pro 20% fat v. 40% fat 35% carbs v. 65% carbs Heterogeneity of Response to Weight Loss Diets: Insulin Resistance Insulin sensitive: low carb and high carb both effective for weight loss Insulin resistant: low carb more effective Attendance highly correlated with weight loss; satiety, hunger, lipids, insulin all equal Sacks, NEJM,

6 40 yo woman, BMI 36. Motivated to begin diet therapy. Which of the following is contraindicated: 1. Meal replacement, very low calorie diet 2 Atkins diet 3 Ornish diet 4. Zone diet 5. All are contraindicated 6. None are contraindicated Very Low Calorie Diets (VLCD) vs Low Calorie Diets (LCD): Meta-analysis analysis of 6 RCTs Trials with direct comparisons Short-term: mean 12.7 weeks Long-term: mean 1.9 years Weight loss (as % of initial weight): short-term long-term LCDs VLCDs (p) (0.001) (0.2) 40 yo woman, BMI 36. Much to your surprise (and satisfaction), she has lost 35 pounds. In order to maintain her new weight, her lifelong daily calorie intake should 35% be: 33% kcals kcals kcals kcals kcals 8% 23% 3% Tsai and Wadden, Obesity, kcals 1800 kcals 1600 kcals 1400 kcals 1200 kcals 6

7 SUCCESSFUL WEIGHT LOSS MAINTENANCE 3000 subjects in National Weight Control Registry: 30-lb weight loss for 1-year Average weight loss 33 kg (10 BMI units less), average weight maintenance 5.5 years 45 years old, 80% women, 97% Caucasian 46% overweight as child, 46% one parent obese, 27% both parents SUCCESSFUL WEIGHT LOSS MAINTENANCE High levels of physical activity Women 2545 kcal/week, men 3293 kcal/week (1-hour moderate intensity per day Only 9% report no physical activity Diet low in fat, high in carbohydrate 1381 kcal day, 24% fat, 19% protein, 56% CHO 4.87 meals or snacks/day Fast food 0.74/week Regular self-monitoring of weight 44% weigh once per day; 31% once per week Wing, Am J Clin Nutr, 2005 Wing, Am J Clin Nutr, yo woman, BMI 36. Much to your surprise, she has lost 35 pounds. In order to maintain her new weight, her lifelong daily calorie intake should be: kcals kcals kcals kcals kcals BEHAVIOR THERAPY Key elements Goal setting Self-monitoring Stimulus control Cognitive skills Fabricatore, J Am Diet Assoc,

8 BEHAVIOR THERAPY Meta-Analysis of 36 Studies Behavioral vs placebo -2.5 kg more weight lost Behavior plus diet and exercise Better in 5 of 6 studies -4.9 kg more weight lost In the last year, I have prescribed a medication for weight loss. 1. Yes 2. No Shaw, Cochrane Database, 2005 The medication I most commonly prescribe for weight loss is: 1. Phentermine 2. Sibutramine 3. Orlistat 4. Topiramate 5. Exenatide 6. Other LONG TERM PHARMACOTHERAPY OF OBESITY Review of all RCT s more than 36 weeks published since 1960 Weight loss in excess of placebo: % of initial kg s Phen-fen 11.0% 9.6 kg Phentermine 8.1% 7.9 kg Sibutramine 5.0% 4.3 kg Orlistat 3.4% 3.4 kg Dexfenfluramine 3.0% 2.5 Kg Fluoxetine -0.4% -0.4 kg Diethyproprion -1.5% -1.5 kg 8

9 The Neuroendocrinology of Energy Balance RIMONABANT Meta-analysis of 4 studies Rimonobant plus diet vs diet alone, for 1 year or more Rimonabant kg loss (5%) Improved waist circ, BP, HDL, TG Attrition 40%: GI, psychiatric, neuro Rimonobant 5 mg -1.3 kg loss Curioni, Cochrane, 2006 RIMONABANT June 2007 FDA advisory committee recommends that rimonabant not be sold in the US pending further study of depression and suicidality. Sanofi withdraws bid to sell rimonabant in US INVESTIGATIONAL DRUGS Buproprion/zonisamide (Empatic ) Buproprion/naltrexone (Contrave ) Phentermine/topiramate (Qnexa ) Lorcaserin (No brand name yet) (selective serotonin receptor agonist, more specific than fenfluramine) 9

10 PRINCIPLES OF DRUG THERAPY NIH: BMI > 30 kg/m 2 or 27 kg/m 2 with co-morbidity (but in practice almost never) Wouldn t It Be Easier Just To Have Surgery? Motivated to begin structured exercise and low calorie diet Begin medications at completion of one month successful diet and exercise Continue medications only if additional weight loss achieved in first month with meds 57 yo woman, BMI 42 with diabetes, hypertension, and creatinine 1.4 asks about bariatric surgery. Her risk of mortality 30 days post-op is 1. 1 in in in in in 10 Restrictive Types of Surgery Horizontal Gastroplasties Vertical Banded Gastroplasty (VGB) Silastic Ring Vertical Gastroplasty (SRVG) Adjustable Lap-Band Malabsorptive Jejunoileal Bypass (JIB) Biliopancreatic Diversion (BPD) Duodenal Switch Long Limb Gastric Bypass Restrictive with Malabsorptive Component Roux-en-Y Gastric Bypass (RYGPB) 10

11 Restrictive and Mixed Procedures Resolution of Comorbidities Bariatric Surgery A Systematic Review and Meta-analysis Buchwald H. et al. JAMA. 2004; 292(14): VBG Adjustable Gastric Banding Roux-en-Y GB % Resolution Comorbidity Diabetes Hyperlipidemia HTN Sleep apnea Band VBG GBP D Switch COMPLICATIONS OF BARIATRIC SURGERY: EARLY COMPLICATIONS OF BARIATRIC SURGERY: EARLY Anastomotic leak 1-7% Stable line disruption 1.8% Gastric pouch dilation 1% DVT/PE 1.5% Anastomotic stricture 1.6-7% SBO/internal hernia 2-9% Cardiopulmonary failure 1.5% Marginal ulcer 1-13% Staple line hemorrhage 3% Subphrenic abcess 1% Wound: Infection 4.4% Hernia 3-25% Dehiscence 1% 11

12 SBO COMPLICATIONS OF BARIATRIC SURGERY: LATE Dumping Bile reflux Failed weight loss Nutrient Deficiencies B1 and B6 Pellagra, beriberi, Wernicke-Korsikoff Pernicious anemia (B12) Iron deficiency Calcium GASTRIC BANDING OR BYPASS Systematic review of 14 comparative studies (1 RCT) Roux-en Y gastric bypass associated with: More weight loss (76% vs. 48% excess weight) More resolution of co-morbidities (diabetes resolved 78% vs. 50%) More peri-op complications (9% vs 5%) Fewer re-operation rates (16% vs. 24%) Lab band associated with: Less OR time and shorter hospitalization Gastric bypass should remain the primary bariatric procedure Tice, Am J Med 2008 BARIATRIC SURGERY OUTCOMES: BARIATRIC SURGERY OUTCOMES: Ten sites, 4776 patients. 3/4 roux-en-y (87% lap); 1/4 lap band 30 Day overall mortality: 0.3% -lap band 0.0% -roux-en-y (lap) 0.2% -roux-en-y (open) 2.1% Composite (death, DVT, reintervention, 30 + days in hosp): 4.1% -lap band 1.0% -roux-en-y (lap) 4.8% -roux-en-y (open) 7.8% Predictors of poor outcomes: History of DVT or PE Obstructive sleep apnea Impaired functional status (can t walk 200 feet) Extremes of BMI (75 vs 53) Age, sex, race/ethnicity, other conditions were not LABS Consortium, NEJM, 2009 LABS Consortium, NEJM,

13 Weight Loss Before Bariatric Surgery Mortality Rate After Bariatric Surgery 881 patients with gastric bypass; 6 month program to achieve 10% weight loss; 2/3 lost 5%; 1/2 lost 10% Weight Change Complications % Gain 5% 28.4 Gain 0-5% 27.9 Loss 0-5% 23.5 Loss 6-10% 14.2 Loss 10% 18.0 (p for trend = 0.004) Benotti, Arch Surg, 2009 Flum, JAMA yo woman, BMI 42 with diabetes, hypertension, and creatinine 1.4 asks about bariatric surgery. Her risk of mortality 30 days post-op is 1. 1 in in in in in 10 Bariatric Surgery and Mortality Swedish Obese Subjects Study 4047 subjects, surgery vs. matched control years f/u Max weight loss % Final weight loss % Control 2 Gastric bypass Vertical banded Gastroplasty Banding Sjostrom, NEJM,

14 Bariatric Surgery and Mortality Swedish Obese Subjects Study OBESITY IN PRIMARY CARE Primary Care MDs have 4 options to treat activated patients: Deaths HR Rate MI deaths Cancer deaths Control Surgery (p = 0.04) PCP provides weight management (behavioral counseling ± meds) PCP and other professional (RD/RN) ± meal replacement PCP refer to community program (self help or commercial) NNT 77 over 11 years (approx 850 per year) PCP refers to obesity specialist (medically supervised program, surgery) Sjostrom, NEJM, 2007 Tsai, JGIM, 2009 OBESITY IN PRIMARY CARE OBESITY IN PRIMARY CARE Review of 10 RCTs of weight loss in primary care PCP counseling alone: kg PCP counseling + pharmacotherapy: kg Collaborative obesity care (RD/RN): kg Conclusions: low to moderate intensity counseling rarely leads to meaningful weight loss. Outcomes of referral for obesity treatment in activated patient: Commercial programs (Jenny Craig, Weight Watchers): 5-7% Intensive programs: 7-10% Medically supervised programs (Optifast, HMR): 15-25% (but not sustained) Pharmacotherapy: 4-5% Pharmacotherapy plus intensive lifestyle: 8-12% Surgery: 15% (banding) - 25% (bypass) PCP counseling plus meds, or intensive counseling (more than 2 visits/ month) with RD/RN plus meal replacements may achieve goal Tsai, JGIM, 2009 Tsai, JGIM,

15 GOALS OF MANAGEMENT Be as fit as possible at current weight The Magic Formula Prevent further weight gain If successful at 1 and 2, begin weight loss 15