Comparison of body adiposity index (BAI) and BMI with estimations of % body fat in clinically severe obese women.

OBJECTIVE: Body adiposity index (BAI), a new surrogate measure of body fat (hip circumference/(height(1.5) - 18)), has been proposed as an alternative to body mass index (BMI). We compared BAI with BMI, and each of them with laboratory measures of body fat-derived from bioimpedance analysis (BIA), air displacement plethysmography (ADP), and dual-energy X-ray absorptiometry (DXA) in clinically severe obese (CSO) participants. DESIGN AND METHODS: Nineteen prebariatric surgery CSO, nondiabetic women were recruited (age = 32.6 ± 7.7 SD; BMI = 46.5 ± 9.0 kg/m(2) ). Anthropometrics and body fat percentage (% fat) were determined from BIA, ADP, and DXA. Scatter plots with lines of equality and Bland-Altman plots were used to compare BAI and BMI with % fat derived from BIA, ADP, and DXA. BAI and BMI correlated highly with each other (r = 0.90, P < 0.001). RESULTS: Both BAI and BMI correlated significantly with % fat from BIA and ADP. BAI, however, did not correlate significantly with % fat from DXA (r = 0.42, P = 0.08) whereas BMI did (r = 0.65, P = 0.003). BMI was also the single best predictor of % fat from both BIA (r(2) = 0.80, P < 0.001) and ADP (r(2) = 0.65, P < 0.001). The regression analysis showed that the standard error of the estimate (SEE), or residual error around the regression lines, was greater for BAI comparisons than for BMI comparisons with BIA, ADP, and DXA. Consistent with this, the Bland and Altman plots indicated wider 95% confidence intervals for BAI difference comparisons than for BMI difference comparisons for their respective means for BIA, ADP, and DXA. CONCLUSIONS: Thus, BAI does not appear to be an appropriate proxy for BMI in CSO women.

Factors affecting morbidity and mortality of Roux-en-Y gastric bypass for clinically severe obesity: an analysis of 1,000 consecutive open cases by a single surgeon.

INTRODUCTION: Determinants of perioperative risk for RYGB are not well defined. METHODS: Retrospective analysis of comorbidities was used to evaluate predictors of perioperative risk in 1,000 consecutive patients having open RYGB by univariate analyses and logistic regression. RESULTS: One hundred forty-six men, 854 women; average age 38.3+/-11.2 years; mean BMI 51.8+/-10.5 (range 24-116) were evaluated. Average hospital stay (LOS) was 3.8 days; 87%<3 days. 91.3% of procedures were without major complication. The most common complications were incisional hernia 3.5%, intestinal obstruction 1.9%, and leak 1.6%. 31 patients required reoperation within 30 days (3.1%). A 30-day mortality was 1.2%. Logistic regression evaluating predictors of operative mortality correlated strongly with coronary artery disease (CAD) (p<0.01), sleep apnea (p=0.03), and age (p=0.042). BMI>50 (0.6 vs 2.3%, p=0.03) and male sex were associated with increased mortality (1.3 vs. 4.0%, p=0.02). Sex-specific logistic regression demonstrated males with angiographically proven CAD were more likely to die (p=0.028) than matched cohorts. Age (p=0.033) and sleep apnea (p=0.040) were significant predictors of death for women. CONCLUSION: Perioperative mortality after RYGB appears to be affected by sex, BMI, age, CAD, and sleep apnea. Strategies employing risk stratification should be developed for bariatric surgery.

Nonalcoholic fatty liver disease in severely obese subjects.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) has been consistently associated with obesity and insulin resistance. Nonalcoholic steatohepatitis (NASH) is a histological entity within NAFLD that can progress to cirrhosis. The exact prevalence of NASH in severe obesity is unknown. It is unclear whether differences in insulin sensitivity exist among subjects with NASH and simple fatty liver. OBJECTIVE: To evaluate the prevalence and correlates of NASH and liver fibrosis in a racially diverse cohort of severely obese subjects. DESIGN: Ninety-seven subjects were enrolled. Liver biopsies, indirect markers of insulin resistance, metabolic parameters, and liver function tests were obtained. RESULTS: Thirty-six percent of subjects had NASH and 25% had fibrosis. No cirrhosis was diagnosed on histology. Markers of hyperglycemia, insulin resistance, and the metabolic syndrome but not body mass index were associated with the presence of NASH and fibrosis. Elevated transaminase levels correlated strongly with NASH and fibrosis but 46% subjects with NASH had normal transaminases. Subjects with NASH had more severe insulin resistance when compared to those with simple fatty liver. A signal detection model incorporating AST and the presence of diabetes predicted the presence of NASH while another incorporating ALT and HbA1C predicted the presence of fibrosis. CONCLUSIONS: NAFLD is associated with the metabolic syndrome rather than excess adipose tissue in severe obesity. Insulin resistance is higher in subjects with NASH versus those with simple fatty liver. Statistical models incorporating markers of liver injury and hyperglycemia may be useful in predicting the presence of liver pathology in this population.

Preoperative nutritional status of patients undergoing Roux-en-Y gastric bypass for morbid obesity.

Few data exist concerning preoperative nutritional status in patients undergoing bariatric surgery. We retrospectively analyzed the preoperative values of serum albumin, calcium, 25-OH vitamin D, iron, ferritin, hemoglobin, vitamin B12, and thiamine in 379 consecutive patients (320 women and 59 men; mean body mass index 51.8 +/- 10.6 kg/m2; 25.8% white, 28.4% African American, 45.8% Hispanic) undergoing bariatric surgery between 2002 and 2004. Preoperative deficiencies were noted for iron (43.9%), ferritin (8.4%), hemoglobin (22%; women 19.1%, men 40.7%), thiamine (29%), and 25-OH vitamin D (68.1%). Low ferritin levels were more prevalent in females (9.9% vs. 0%; P = 0.01); however, anemia was more prevalent in males (19.1% vs. 40.7%; P < 0.005). Patients younger than 25 years were more likely to be anemic than patients over 60 years (46% vs. 15%; P < 0.005). This correlated with iron deficiency, which was more prevalent in younger patients (79.2% vs. 41.7%; P < 0.005). Whites (78.8%) and African Americans (70.4%) had a higher prevalence of vitamin D deficiency than Hispanics (56.4%), P = 0.01. Whites were the least likely group to be thiamine deficient (6.8% vs 31.0% African Americans and 47.2% Hispanics; P < 0.005). Nutritional deficiencies are common in patients undergoing Roux-en-Y gastric bypass, and these deficiencies should be detected and corrected early to avoid postoperative complications.

Initial experience with bariatric surgery in asymptomatic human immunodeficiency virus-infected patients.

BACKGROUND: Performance of bariatric surgery in patients with human immunodeficiency virus (HIV) infection is controversial. The advent of highly active antiretroviral treatment (HAART) has dramatically reduced the progression of HIV/AIDS, so that these individuals live longer, with nearly undetectable viral loads, and thus may develop obesity and similar obesity-related comorbidity as occurs in the general population. However, HAART also causes lipodystrophy, placing these patients at increased risk for coronary artery disease. METHODS: This was a retrospective study of 6 patients from a prospectively maintained database of 892 patients (0.71%) undergoing bariatric surgery between June 1999 and December 2003. RESULTS: Six HIV-infected patients (4 women, 2 men; mean age, 43 years [range, 28-56 years]; mean preoperative weight, 142 kg [range, 110-174 kg]; mean preoperative body mass index, 50 [range, 42-59) underwent Roux-en-Y gastric bypass (RYGB). The mean duration of HIV infection was 9 years; 33% were receiving HAART at the time of surgery, which was discontinued perioperatively for 2-3 days. Average CD4 cell count was 619 cells/mm3 (range, 361-1096 cells/mm3). Preoperative comorbidities included type 2 diabetes mellitus/impaired glucose tolerance (3 cases), hypertension (2 cases), dyslipidemia (2 cases), coronary artery disease/chronic heart failure (1 case), sleep apnea (4 cases), asthma (2 cases), gastroesophageal reflux disease (3 cases), arthritis (5 cases), and depression (3 cases). Average preoperative length of hospital stay was 4.2 days (range, 3-5 days). There were no deaths or postoperative infectious complications. Mean percent excess body weight loss was 33% at 3 months, 47% at 6 months, and 61% at 12 months. Mean percent initial body weight lost was 19% at 3 months, 26% at 6 months, and 33% at 12 months. CONCLUSION: RYGB can be safely performed in HIV-infected individuals. Initial results appear to be comparable to those in noninfected controls. Well-controlled HIV infection should not be an absolute contraindication to bariatric surgery.

Surgical management of obese patients with eating disorders: a survey of current practice.

BACKGROUND: This study examined the current practice of bariatric surgeons and their colleagues regarding patients with binge eating disorder (BED) and night eating syndrome (NES) who present for Roux-en-Y gastric bypass (RYGBP) for obesity. METHOD: We conducted a 9-item internet survey of American Society for Bariatric Surgery (ASBS) members. For each item, the numbers of respondents endorsing each possible response, including "Other" and "Unknown or not applicable," were tabulated, and percentages of the total sample of respondents were calculated. RESULTS: Most respondents' screening process included mental health (82.0%) and nutritional (78.0%) evaluations. Most inquired about binge eating (88.0%) and other eating disturbances (83.3%), while fewer respondents (52.7%) screened for night eating. Management of patients with eating disorders varied widely. For patients with binge eating, 20.0% of respondents proceeded with surgery, 2.7% recommended against surgery, and 27.3% postponed surgery, with the remainder (50.0%) reporting that their management varied. For night eating and other eating disturbances, responses were similarly diverse. Respondents who postponed surgery reported a wide range of estimates of how often patients with eating disorders follow through with treatment for their eating problem and return for surgery: 16% (always/almost always), 36% (usually), 24% (sometimes), 12% (occasionally), and 12% (never/almost never). CONCLUSION: Although bariatric surgeons commonly screen for eating disorders such as BED, there are limited empirical data and no consensus regarding the optimal management of these patients.

Calorie intake and meal patterns up to 4 years after Roux-en-Y gastric bypass surgery.

BACKGROUND: Roux-en-Y gastric bypass (RYGBP) is the most popular surgical treatment for morbid obesity in the U.S.A., producing significant and durable weight loss with improvement in co-morbidities. Although a greater number of patients are undergoing surgical treatment for obesity, little data are available regarding their food intake after surgery. This study was undertaken to evaluate the caloric amount, nutrient composition and meal patterns of patients 18 months to 4 years after RYGBP. Ethnic differences in food intake were also investigated. METHODS: Questionnaires were mailed to 360 patients who had undergone RYGBP at least 18 months prior to the onset of the study. RESULTS: Data were available from 69 patients, 52% Caucasian, 25% African-American, 23% Hispanic. 30 months after surgery, the average daily calorie intake was 1733 +/- 630 kcal (n=68, range 624-3486 kcal), with 44% of calories from carbohydrates, 22% from protein and 33% from fat. Sugar-sweetened beverages represented 7% of total caloric intake. Patients consumed 3 meals and 3 snacks per day on average. Food intake from dinner and an evening snack represented 40% of the daily caloric intake. Snacks accounted for 37% of the daily intake. Percent excess weight loss (%EWL) was 58 +/- 17% and was not different among ethnic groups. However, Hispanics reported consuming fewer snacks and fewer calories. %EWL correlated with the total daily caloric intake (r= .446, P <0.001). Follow-up attendance was 54% at 1 year after surgery but fell to 10% at 3 years. Only 77% of patients were taking vitamin supplements. CONCLUSION: RYGBP resulted in significant weight loss. Caloric intake was quite variable. Long-term follow-up remained low, putting patients at risk for metabolic and vitamin deficiencies. The relationship between caloric intake and long-term weight changes remains to be studied.

Mechanisms of weight loss after bariatric surgery.

The surgical treatment of clinically severe obesity is becoming more popular. To date, little has been published concerning the mechanisms by which each of the commonly employed bariatric surgical procedures induces weight loss. This article reviews the physiology of weight loss induced by semi-starvation and other proposed mechanisms of surgically induced weight loss.

Prevalence of co-morbidities in obese patients before bariatric surgery: effect of race.

BACKGROUND: We evaluated the prevalence of co-morbidities, in particular diabetes, in a diverse population of morbidly obese patients who underwent gastric bypass surgery at our institution in New York City. METHODS: A retrospective study of 300 patients who had bariatric surgery between January 2001 and April 2002 was conducted. RESULTS: 57% of the patients had at least one metabolic complication, 30% had diabetes, 38% hypertension and 35% dyslipidemia. Our population was ethnically diverse, with 40% Hispanic, 34% Caucasian, 25% African-American and 1% Asian. There was no difference in the prevalence of diabetes among races. However, Caucasians had the highest prevalence of hyperlipidemia, and the Hispanic patients were the least hypertensive. Among patients with diabetes, one-third were undiagnosed and 50% untreated. Similarly, 45% of the hypertensive patients and 51% of those with hyperlipidemia remained undiagnosed. Men had more co-morbidities than women. CONCLUSION: These results suggest a high prevalence of co-morbid conditions in severely obese patients undergoing bariatric surgery. Age, ethnicity and gender influence the type of co-morbid conditions. More research is needed to understand why diabetes and other metabolic complications remain undiagnosed and untreated in a large number of these high risk patients.

Obese patients have inadequate protein intake related to protein intolerance up to 1 year following Roux-en-Y gastric bypass.

BACKGROUND: Inadequate protein intake is a concern following Roux-en-Y gastric bypass (RYGBP). The small gastric pouch and bypass restrict energy intake and may lead to insufficient protein intake and absorption, and excess loss of lean tissue. METHODS: We evaluated protein intake in 93 (77 F, 16 M) morbidly obese individuals (BMI = 52.0 +/- 12.9 [SD]) who underwent RYGBP at our medical center. Participants completed 24-hr food recalls and received nutritional counseling at 3, 6, and 12 months following surgery. RESULTS: Daily energy intake (kcal/day) increased from 849 +/- 329 (SD) at 3 months to 1,101 +/- 400 at 12 months (P = .009). Protein intake also increased (g/day) from 45.6 +/- 14.2 at 3 months to 58.5 +/- 17.1 at 12 months (P = .04), and as a percentage of goal protein intake from 55.1% +/- 23.0 at 3 months to 73.5% +/- 38.0 at 12 months (P = .02). Although energy and protein intake increased significantly over the 12-month period, protein intake at 12 months remained significantly lower (P = .01) than the daily recommended guidelines (1.5 g/kg IBW) for a low-energy restrictive diet. Energy intake did not differ in those who reported food intolerances at 3 months (P = .77) or 6 months (P = .65), but was lower in them at 12 months (trend, P = .06). Also at 12 months, protein intake (P = .02) and percentage of protein intake goal (P = .04) were significantly lower in those with protein intolerance. CONCLUSIONS: These results suggest that postoperative patients consume insufficient amounts of protein, possibly mediated by protein intolerance. Protein supplementation following RYGBP deserves further consideration.

Depression score predicts weight loss following Roux-en-Y gastric bypass.

BACKGROUND: The prevalence of obesity is increasing in the United States. Bariatric surgery is the only intervention that can reliably induce and maintain significant weight loss in obese patients. The association between pre-surgical severity of depression and success at weight loss following Roux-en-Y gastric bypass (RYGBP) has not yet been fully elucidated. METHODS: 145 charts of patients who underwent RYGBP for morbid obesity were reviewed. 47 patients who filled out the Beck Depression Inventory (BDI) before surgery and completed 1 year of follow-up were studied. The relationship between pre-surgical severity of depression and success at weight loss was examined through multivariate regression analysis using percent excess weight loss (%EWL) as a dependent variable and BDI score as one of the predictors. RESULTS: Weight loss at 1 year was significantly related to the BDI score before surgery (P =0.014). BDI score was also found to be a significant predictor of the amount of weight lost (kg) 1 year after surgery (P =0.027). Age (P =0.03) and initial body mass index (BMI) (P =0.011) were the only other variables with significant independent relations to %EWL. CONCLUSIONS: Our data show a positive correlation between pre-surgical severity of depression as measured by BDI score and the 1-year success at weight loss after RYGBP as measured by %EWL. More depressed individuals tend to lose greater amounts of weight compared with less depressed individuals. Future prospective studies should examine possible mechanisms and effects of depression and other psychiatric disturbances on long-term weight loss after RYGBP.

The effect of Roux limb lengths on outcome after Roux-en-Y gastric bypass: a prospective, randomized clinical trial.

BACKGROUND: The effect of limb-length on weight loss after Roux-en-Y gastric bypass (RYGBP) is controversial; hence, the optimal limb-lengths have not been determined. This study evaluated the effect of different limb-lengths on weight loss after RYGBP. METHODS: The study was a prospective randomized clinical trial in which patients undergoing RYGBP (110 F, 24 M; mean age 39.7) were randomized as follows: BMI < or = 50 (N = 69): A-75 cm (N = 35) vs B-150 cm alimentary limb (N = 34) and C-150 cm (N = 33) vs D-250 cm alimentary limb (N = 31). All other aspects of the operation were identical. Patients were followed at 2 weeks, 6 weeks, 6 months, 12 months, 18 months, 24 months and yearly thereafter. RESULTS: There were no significant differences in age, sex, race, initial BMI, or excess weight between patients assigned to groups A vs B and C vs D. Postoperative nutritional intake was also similar between groups. Within each weight category, there were no differences in mean weight loss, change in BMI, and % excess weight lost (EWL) over time. When the number of patients achieving 50% EWL was evaluated, there was no difference between groups with a BMI < or = 50 kg/m2; however, among patients with a BMI > 50 kg/m2, a significantly greater percentage of those having a 250-cm limb achieved > 50% EWL at 18 months postoperatively. This difference was lost at 24 and 36 months, possibly due to the small sample size. CONCLUSIONS: In patients with a BMI < or = 50, there appears to be no advantage to longer limb-lengths. In patients with BMI > 50, however, these data suggest that longer alimentary limb-lengths may be associated with a higher percent of patients achieving > 50% EWL. Longer follow-up studies of the effects of limb-length on success of RYGBP are indicated.

Liver pathology in morbidly obese patients undergoing Roux-en-Y gastric bypass surgery.

BACKGROUND: Non-alcoholic fatty liver disease is common. However, little is known about liver disease in the morbidly obese. METHODS: 75 subjects (78% female, mean BMI 57 [40-108]) who had intra-operative liver biopsies at the time of Roux-en-Y gastric bypass surgery were studied. RESULTS: 84% of subjects had steatosis while only about 20% had moderate to severe inflammation and fibrosis. 8% had bridging fibrosis or cirrhosis. The presence of fibrosis correlated strongly with the presence of inflammation (p < 0.001) and steatosis (p = 0.0011), but weakly with ALT (p = 0.02) and not with AST (p = 0.12) or with BMI (p = 0.34). Steatosis correlated with AST (p = 0.04) and ALT (p = 0.055), but not with BMI. CONCLUSION: Liver disease is not rare in the morbidly obese. The exact causes and mechanisms that lead from the very common isolated steatosis to inflammation and fibrosis remain unclear. Intra-operative liver biopsies during bariatric surgery may be helpful to screen for the presence of steatohepatitis and fibrosis.