Constructing bi-plots for random forest: Tutorial.

Current technological developments have allowed for a significant increase and availability of data. Consequently, this has opened enormous opportunities for the machine learning and data science field, translating into the development of new algorithms in a wide range of applications in medical, biomedical, daily-life, and national security areas. Ensemble techniques are among the pillars of the machine learning field, and they can be defined as approaches in which multiple, complex, independent/uncorrelated, predictive models are subsequently combined by either averaging or voting to yield a higher model performance. Random forest (RF), a popular ensemble method, has been successfully applied in various domains due to its ability to build predictive models with high certainty and little necessity of model optimization. RF provides both a predictive model and an estimation of the variable importance. However, the estimation of the variable importance is based on thousands of trees, and therefore, it does not specify which variable is important for which sample group. The present study demonstrates an approach based on the pseudo-sample principle that allows for construction of bi-plots (i.e. spin plots) associated with RF models. The pseudo-sample principle for RF. is explained and demonstrated by using two simulated datasets, and three different types of real data, which include political sciences, food chemistry and the human microbiome data. The pseudo-sample bi-plots, associated with RF and its unsupervised version, allow for a versatile visualization of multivariate models, and the variable importance and the relation among them.

Prediction model development of women's daily asthma control using fitness tracker sleep disruption.

BACKGROUND: Night-time wakening with asthma symptoms is an important indicator of disease control and severity, with no gold-standard objective measurement. OBJECTIVE: The study objective was to use fitness tracker sleep data to develop predictive models of daily disease control-related asthma-specific wakening and FEV1 in working-aged women with poorly controlled asthma. METHODS: A repeated measures panel design included data from 43 women with poorly controlled asthma. Two components of asthma control were the primary outcomes, measured daily as (1) self-reported asthma-specific wakening and (2) self-administered spirometry to measure FEV1. Data were analyzed using generalized linear mixed models. RESULTS: Our models demonstrated predictive value (AUC=0.77) for asthma-specific night-time wakening and good predictive value (AUC=0.83) for daily FEV1. CONCLUSIONS: Fitness tracker sleep efficiency and wake counts demonstrate clinical utility as predictive of asthma-specific night-time wakening and daily FEV1. Fitness tracker sleep data demonstrated predictive capability for daily asthma outcomes.

Validation of fitness tracker for sleep measures in women with asthma.

OBJECTIVE: Nighttime wakening with asthma symptoms is a key to assessment and therapy decisions, with no gold standard objective measure. The study aims were to (1) determine the feasibility, (2) explore equivalence, and (3) test concordance of a consumer-based accelerometer with standard actigraphy for measurement of sleep patterns in women with asthma as an adjunct to self-report. METHODS: Panel study design of women with poorly controlled asthma from a university-affiliated primary care clinic system was used. We assessed sensitivity and specificity, equivalence and concordance of sleep time, sleep efficiency, and wake counts between the consumer-based accelerometer Fitbit Charge™ and Actigraph wGT3X+. We linked data between devices for comparison both automatically by 24-hour period and manually by sleep segment. RESULTS: Analysis included 424 938 minutes, 738 nights, and 833 unique sleep segments from 47 women. The fitness tracker demonstrated 97% sensitivity and 40% specificity to identify sleep. Between device equivalence for total sleep time (15 and 42-minute threshold) was demonstrated by sleep segment. Concordance improved for wake counts and sleep efficiency when adjusting for a linear trend. CONCLUSIONS: There were important differences in total sleep time, efficiency, and wake count measures when comparing individual sleep segments versus 24-hour measures of sleep. Fitbit overestimates sleep efficiency and underestimates wake counts in this population compared to actigraphy. Low levels of systematic bias indicate the potential for raw measurements from the devices to achieve equivalence and concordance with additional processing, algorithm modification, and modeling. Fitness trackers offer an accessible and inexpensive method to quantify sleep patterns in the home environment as an adjunct to subjective reports, and require further informatics development.

Patient travel for bariatric surgery: does distance matter?

BACKGROUND: Increasingly, patients are faced with greater travel distances to undergo bariatric surgery at high-volume centers. OBJECTIVES: This study sought to evaluate the impact of travel distance on access to care and outcomes after bariatric surgery. SETTING: Patients who underwent Roux-en-Y gastric bypass at an academic bariatric surgery center from 1985 to 2004 were examined and stratified by patient travel distance. METHODS: Univariate analyses were performed for preoperative risk factors, 30-day complications, and long-term (10-yr) weight loss between "local," defined as<1 hour of travel time, and "regional," defined as>1 hour of travel time. Survival analysis was performed with Kaplan-Meier and Cox proportional hazards models. RESULTS: A total of 650 patients underwent Roux-en-Y gastric bypass, of whom 316 (48.6%) traveled<1 hour to undergo surgery and 334 (51.4%) traveled>1 hour. Median body mass index was equivalent between the groups (local, 52.9 kg/m2; regional, 53.2 kg/m2; P = .76). Patients who traveled longer distances had higher rates of preoperative co-morbidities, including chronic obstructive pulmonary disease, congestive heart failure, diabetes, and sleep apnea (all P<.05). Complications within 30 days of surgery and long-term reduction of excess body mass index were equivalent between groups. Travel time was an independent predictor of risk-adjusted reduced long-term survival (hazard ratio, 1.23, P = .0002). CONCLUSIONS: A majority of patients who underwent bariatric surgery at our center traveled>1 hour. Despite longer travel time for care, 30-day complications and long-term weight loss were equivalent with that of local patients. As expected, patients who lived in close proximity were more likely to adhere to yearly follow-up in surgery clinic. Travel time was an independent predictor of risk-adjusted reduced long-term survival.

Type 2 Diabetes Remission Rates After Laparoscopic Gastric Bypass and Gastric Banding: Results of the Longitudinal Assessment of Bariatric Surgery Study.

OBJECTIVE: The goals of this study were to determine baseline and postbariatric surgical characteristics associated with type 2 diabetes remission and if, after controlling for differences in weight loss, diabetes remission was greater after Roux-en-Y gastric bypass (RYGBP) than laparoscopic gastric banding (LAGB). RESEARCH DESIGN AND METHODS: An observational cohort of obese participants was studied using generalized linear mixed models to examine the associations of bariatric surgery type and diabetes remission rates for up to 3 years. Of 2,458 obese participants enrolled, 1,868 (76%) had complete data to assess diabetes status at both baseline and at least one follow-up visit. Of these, 627 participants (34%) were classified with diabetes: 466 underwent RYGBP and 140 underwent LAGB. RESULTS: After 3 years, 68.7% of RYGBP and 30.2% of LAGB participants were in diabetes remission. Baseline factors associated with diabetes remission included a lower weight for LAGB, greater fasting C-peptide, lower leptin-to-fat mass ratio for RYGBP, and a lower hemoglobin A1c without need for insulin for both procedures. After both procedures, greater postsurgical weight loss was associated with remission. However, even after controlling for differences in amount of weight lost, relative diabetes remission rates remained nearly twofold higher after RYGBP than LAGB. CONCLUSIONS: Diabetes remission up to 3 years after RYGBP and LAGB was proportionally higher with increasing postsurgical weight loss. However, the nearly twofold greater weight loss-adjusted likelihood of diabetes remission in subjects undergoing RYGBP than LAGB suggests unique mechanisms contributing to improved glucose metabolism beyond weight loss after RYGBP.

Pulmonary embolism and gastrointestinal leak following bariatric surgery: when do major complications occur?

BACKGROUND: Complications following bariatric surgery are uncommon but potentially life threatening. OBJECTIVES: The aim of this study was to assess the timing of gastrointestinal leaks (GIL) and pulmonary embolism (PE) in patients undergoing bariatric surgery. SETTING: Retrospective analysis of the nationwide American College of Surgeons National Surgical Quality Improvement Program database from 2006 to 2011. METHODS: Data on patient demographic characteristics, baseline co-morbidities, procedural events, and postoperative occurrences were analyzed. Thirty-day morbidity was assessed. Median (interquartile range) and frequencies are reported. RESULTS: We identified 71,694 bariatric surgery patients; median age was 45 years (range 36-54 yr), and median body mass index was 44.8 kg/m(2) (range 40.8-50.3 kg/m(2)). Laparoscopic Roux-en-Y gastric bypass was performed in 39,480 patients, laparoscopic adjustable band in 21,104, laparoscopic sleeve gastrectomy in 3225, open Roux-en-Y gastric bypass in 4243, duodenal switch in 1064, revisional surgery in 1182, and other procedures in 1396 patients. Of these patients, 95.2% had no complications. GIL was found in 441 (.6%), deep vein thrombosis in 184 (.3%), and PE in 134 (.2%). These complications occurred 10 (5-15), 13 (7-20), and 11 (4-19) days after surgery, respectively. GIL and PE developed after discharge in 275 (62.4%) and 96 (71.6%), respectively. Only 35 (26.1%) of the patients who developed PE had deep vein thrombosis. There were no differences in patient characteristics between the groups of early PE versus postdischarge PE. Patients diagnosed with in-hospital GIL were more obese with more severe systemic disease compared with patients with postdischarge diagnosis. CONCLUSIONS: The majority of GILs and PEs after bariatric surgery occur after discharge. This finding goes against the routine use of contrast studies to rule out GIL. The risk of PE remains after discharge from bariatric surgery.

Following Bariatric Surgery: an Exploration of the Couples' Experience.

BACKGROUND: Bariatric surgery is the most effective intervention for morbid obesity, resulting in substantial weight loss and the resolution of co-morbid conditions. It is not clear what impact bariatric surgery and the subsequent life-style changes have on patients' couple relationships. The purpose of this phenomenological study was to examine the lived experience of couples after one member of the couple underwent bariatric surgery. METHODS: This study utilized a phenomenological approach of semi-structured interviews of the couples jointly (n = 10 couples). Colaizzi's method of analysis for phenomenological studies was utilized to elucidate the central themes and distill the essence of the participants' experience. RESULTS: All of the couples felt their post-operative success was due to a joint effort on both members of the couples' part. The participant couples described the following five emerging thematic experiences: (a) changes in physical health, (b) changes in emotional health, (c) changes in eating habits, (d) greater intimacy in the relationship, and (e) the joint journey. CONCLUSIONS: This research provides greater insight into the experience of the couple than has been previously reported. The use of qualitative research techniques offer new approaches to examine the biopsychosocial outcomes and needs of bariatric surgery patients. Further research is warranted in order to develop culturally appropriate interventions to improve the patient's surgical and biopsychosocial outcomes.

Validation of the Behavioral Risk Factor Surveillance System Sleep Questions.

STUDY OBJECTIVES: leep problems may constitute a risk for health problems, including cardiovascular disease, depression, diabetes, poor work performance, and motor vehicle accidents. The primary purpose of this study was to assess the validity of the current Behavioral Risk Factor Surveillance System (BRFSS) sleep questions by establishing the sensitivity and specificity for detection of sleep/ wake disturbance. METHODS: Repeated cross-sectional assessment of 300 community dwelling adults over the age of 18 who did not wear CPAP or oxygen during sleep. Reliability and validity testing of the BRFSS sleep questions was performed comparing to BFRSS responses to data from home sleep study, actigraphy for 14 days, Insomnia Severity Index, Epworth Sleepiness Scale, and PROMIS-57. RESULTS: Only two of the five BRFSS sleep questions were found valid and reliable in determining total sleep time and excessive daytime sleepiness. CONCLUSIONS: Refinement of the BRFSS questions is recommended.

Urinary Incontinence Before and After Bariatric Surgery.

IMPORTANCE: Among women and men with severe obesity, evidence for improvement in urinary incontinence beyond the first year after bariatric surgery-induced weight loss is lacking. OBJECTIVES: To examine change in urinary incontinence before and after bariatric surgery and to identify factors associated with improvement and remission among women and men in the first 3 years after bariatric surgery. DESIGN, SETTING, AND PARTICIPANTS: The Longitudinal Assessment of Bariatric Surgery 2 is an observational cohort study at 10 US hospitals in 6 geographically diverse clinical centers. Participants were recruited between February 21, 2005, and February 17, 2009. Adults undergoing first-time bariatric surgical procedures as part of clinical care by participating surgeons between March 14, 2006, and April 24, 2009, were followed up for 3 years (through October 24, 2012). INTERVENTION: Participants undergoing bariatric surgery completed research assessments before the procedure and annually thereafter. MAIN OUTCOMES AND MEASURES: The frequency and type of urinary incontinence episodes in the past 3 months were assessed using a validated questionnaire. Prevalent urinary incontinence was defined as at least weekly urinary incontinence episodes, and remission was defined as change from prevalent urinary incontinence at baseline to less than weekly urinary incontinence episodes at follow-up. RESULTS: Of 2458 participants, 1987 (80.8%) completed baseline and follow-up assessments. At baseline, the median age was 47 years (age range, 18-78 years), the median body mass index was 46 kg/m2 (range, 34-94 kg/m2), and 1565 of 1987 (78.8%) were women. Urinary incontinence was more prevalent among women (49.3%; 95% CI, 46.9%-51.9%) than men (21.8%; 95% CI, 18.2%-26.1%) (P < .001). After a mean 1-year weight loss of 29.5% (95% CI, 29.0%-30.1%) in women and 27.0% (95% CI, 25.9%-28.6%) in men, year 1 urinary incontinence prevalence was significantly lower among women (18.3%; 95% CI, 16.4%-20.4%) and men (9.8%; 95% CI, 7.2%-13.4%) (P < .001 for all). The 3-year prevalence was higher than the 1-year prevalence for both sexes (24.8%; 95% CI, 21.8%-26.5% among women and 12.2%; 95% CI, 9.0%-16.4% among men) but was substantially lower than baseline (P < .001 for all). Weight loss was independently related to urinary incontinence remission (relative risk, 1.08; 95% CI, 1.06-1.10 in women and 1.07; 95% CI, 1.02-1.13 in men) per 5% weight loss, as were younger age and the absence of a severe walking limitation. CONCLUSIONS AND RELEVANCE: Among women and men with severe obesity, bariatric surgery was associated with substantially reduced urinary incontinence over 3 years. Improvement in urinary incontinence may be an important benefit of bariatric surgery.

Delayed repair of obstructing ventral hernias is associated with higher mortality and morbidity.

BACKGROUND: Patients presenting with ventral hernia-related obstruction are commonly managed with emergent ventral hernia repair (VHR). Selected patients with resolution of obstruction may be managed in a delayed manner. This study sought to assess the effect of delay on VHR outcomes. METHODS: The American College of Surgeons' National Surgical Quality Improvement Program database from 2005 to 2011 was queried using diagnosis codes for ventral hernia with obstruction. Those who underwent repair over 24 hours after admission were classified as delayed repair. Preoperative comorbid conditions, American Society of Anesthesiology (ASA) scores, and 30-day outcomes were evaluated. RESULTS: We identified 16,881 patients with a mean age of 58 ± 15 years and body mass index of 36 ± 10. Delayed repair occurred in 27.7% of the patients. After controlling for comorbidities and ASA score, delayed VHR was independently associated with mortality (odds ratio [OR] 1.9, 95% confidence interval [CI] 1.41 to 2.48, P < .001), morbidity (OR 1.4, 95% CI 1.24 to 1.50, P < .001), surgical site infection (OR 1.2, 95% CI 1.03 to 1.35, P = .016), and concurrent bowel resection (OR 1.2, 95% CI 1.03 to 1.34, P = .016). CONCLUSIONS: VHR for obstructed patients is frequently performed over 24 hours after admission. After adjusting for comorbid conditions and ASA score, delayed VHR is independently associated with worse outcomes. Prompt repair after appropriate resuscitation should be the management of choice.

Bariatric Surgery in Patients with Dialysis-Dependent Renal Failure.

BACKGROUND: Laparoscopic procedures for the treatment of morbid obesity are commonly offered to patients with comorbidities previously thought to carry prohibitive operative risk. In this study, we reviewed characteristics and perioperative outcomes of patients with dialysis-dependent renal failure (DDRF) who underwent laparoscopic bariatric procedures. METHODS: The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database from 2006 to 2011 was reviewed. Preoperative characteristics and 30-day outcome data of patients who underwent three common laparoscopic procedures were analyzed using ANOVA and Pearson chi-squared tests. RESULTS: One hundred thirty-eight patients (52.5 % female) with DDRF and a median body mass index (BMI) of 45.5 kg/m(2) were identified; 33.8 % (n = 47) underwent laparoscopic banding (LAGB), 48.9 % (n = 68) laparoscopic Roux-en-Y gastric bypass (RYGB), and 16.5 % (n = 23) laparoscopic sleeve gastrectomy (LSG). No differences were found among groups in age, prevalence of American Society of Anesthesiology IV classification, BMI, weight, gender, prevalence of diabetes, and vascular or neurologic comorbidities. Total operation time and length of hospital stay were significantly different between groups. Mortality was 0.7 %, and overall morbidity was 5.8 %. The case mix reflected a decrease in LAGB procedures from 45.5 to 23.3 % from 2006-2009 to 2010-2011 and an increase in LSG procedures from 9.1 to 24.7 % (p < 0.006). CONCLUSIONS: When performed in selected DDRF patients, bariatric surgery is safe. An increase in LSG with a concurrent decline in LAGB procedures was demonstrated over the period of the study.

Synchronous Ventral Hernia Repair in Patients Undergoing Bariatric Surgery.

BACKGROUND: Obesity predisposes patients to abdominal wall hernias. Patients undergoing bariatric surgery are not uncommonly found to have ventral hernias. Synchronous ventral hernia repair (S-VHR) has been reported in 2-5% of patients undergoing bariatric surgery. Studies reporting on the outcomes of S-VHR are limited by sample size. The aim of this study was to assess the effect of S-VHR on surgical site infection (SSI) rate. METHODS: The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database from 2010 to 2011 was queried using Current Procedural Terminology codes for bariatric surgery. Data on patient demographics, comorbidities, procedural events, and postoperative occurrences were analyzed. Thirty-day mortality and morbidity were assessed. Comparisons between laparoscopic Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) were performed. RESULTS: We identified 17,117 patients who underwent RYGB or SG. S-VHR was performed in 503 (2.94%) patients. S-VHR was independently associated with SSI (odds ratios (OR) 1.65, 95% confidence interval (CI) 1.06-2.58), but not overall morbidity (OR 1.33, 95% CI 0.96-1.86). Four hundred thirty-three patients with RYGB and 70 with SG had S-VHR. Serious morbidity (3.5 vs. 5.7%, p = 0.32) and overall morbidity (8.3 vs. 8.6%, p = 0.942) were similar. After controlling for baseline comorbidities, there was no significant effect of procedure type on SSI (OR 0.38, 95% CI 0.05-2.91). CONCLUSIONS: S-VHR is associated with an increase in SSI but not overall morbidity. There is no significant difference in the SSI rate between RYGB and SG. Larger studies are needed to definitively assess a potential difference in the wound infection rate between RYGB and SG.

Validation of Capturing Sleep Diary Data via a Wrist-Worn Device.

Paper sleep diaries are the gold standard for assessment of sleep continuity variables in clinical practice as well as research. Unfortunately, paper diaries can be filled out weekly instead of daily, lost, illegible or destroyed; and are considered out of date according to the newer technology savvy generations. In this study, we assessed the reliability and validity of using a wrist-worn electronic sleep diary. Design. A prospective design was used to compare capturing 14 days of sleep continuity data via paper to a wrist-worn electronic device that also captured actigraphy data. Results. Thirty-five healthy community dwelling adults with mean (sd) age of 36 (15), 80% Caucasians, and 74% females were enrolled. All sleep continuity variables via electronic and paper diary capture methods were significantly correlated with moderate, positive relationships. Assessment of validity revealed that electronic data capture had a significant relationship with objective measure of sleep continuity variables as measured by actigraphy. Paper diary variables were not significantly associated with objective measures. Conclusions. The use of a wrist-worn device to capture daily sleep diary data is as accurate as and for some variables more accurate than using paper diaries.

Eating behavior and eating disorders in adults before bariatric surgery.

OBJECTIVE: To describe eating patterns, prevalence of problematic eating behaviors, and determine factors associated with binge eating disorder (BED), before bariatric surgery. METHOD: Before surgery, 2,266 participants (median age 46 years; 78.6% female; 86.9% white; median body mass index 45.9 kg/m(2) ) of the Longitudinal Assessment of Bariatric Surgery-2 (LABS-2) study completed eating behavior survey items in the self-administered LABS-2 Behavior form. Other measures included the Alcohol Use Disorder Identification Test, the LABS-2 Psychiatric and Emotional Test Survey, the Beck Depression Inventory, the Interpersonal Support Evaluation List-12, the Short Form-36 Health Survey, and Impact of Weight Quality of Life-Lite Survey. RESULTS: The majority (92.1%) of participants reported eating dinner regularly, whereas just over half (54.0%) reported eating breakfast regularly. Half of the participants reported eating at least four meals/week at restaurants; two meals/week were fast food. Loss of control eating was reported by 43.4%, night eating syndrome by 17.7%; 15.7% satisfied criteria for binge eating disorder (BED), 2% for bulimia nervosa. Factors that independently increased the odds of BED were being a college graduate, eating more times per day, taking medication for psychiatric or emotional problems, and having symptoms of alcohol use disorder, lower self-esteem and greater depressive symptoms. DISCUSSION: Before undergoing bariatric surgery a substantial proportion of patients report problematic eating behaviors. Several factors associated with BED were identified, most suggesting other mental health problems, including higher levels of depressive symptomotology. The strengths of this study include the large sample size, the multi-center design and use of standardized assessment practices.

Hyperinsulinemic syndrome: the metabolic syndrome is broader than you think.

BACKGROUND: Type 2 diabetes mellitus (T2DM) is characterized by hyperinsulinemia. In 2011 we showed that gastric bypass (RYGB) corrects these high levels even though insulin resistance remains high, ie, the operation "dissociates" hyperinsulinemia from insulin resistance. RYGB produces reversal of T2DM along with other diseases associated with the metabolic syndrome. This observation led us to examine whether these illnesses also were characterized by hyperinsulinemia. METHODS: A systematic review was performed to determine whether hyperinsulinemia was present in disorders associated with the metabolic syndrome. We reviewed 423 publications. 58 were selected because of appropriate documentation of insulin measurements. Comparisons were based on whether the studies reported patients as having increased versus normal insulin levels for each metabolic disorder. RESULTS: The presence (+) or absence (-) of hyperinsulinemia was documented in these articles as follows: central obesity (4+ vs 0-), diabetes (5+ vs 0-), hypertension (9+ vs 1-), dyslipidemia (2+ vs 0-), renal failure (4+ vs 0-), nonalcoholic fatty liver disease (5+ vs 0-), polycystic ovary syndrome (7+ vs 1-), sleep apnea (7+ vs 0-), certain cancers (4+ vs 1-), atherosclerosis (4+ vs 0-), and cardiovascular disease (8+ vs 0-). Four articles examined insulin levels in the metabolic syndrome as a whole (4+ vs 0-). CONCLUSION: These data document that disorders linked to the metabolic syndrome are associated with high levels of insulin, suggesting that these diseases share a common etiology that is expressed by high levels of insulin. This leads us to propose the concept of a "hyperinsulinemic syndrome" and question the safety of insulin as a chronic therapy for patients with T2DM.

Hepatic pathology among patients without known liver disease undergoing bariatric surgery: observations and a perspective from the longitudinal assessment of bariatric surgery (LABS) study.

Liver biopsy is not routine during bariatric surgery. Alanine aminotransferase (ALT) is widely used to screen for liver disease. We assessed the relationship between ALT and pathology in biopsies from Longitudinal Assessment of Bariatric Surgery (LABS) patients with normal preoperative ALTs. Biopsies from the LABS-1 and LABS-2 studies were scored using the NASH CRN and Ishak systems. Diagnosis and histology were examined in relation to alanine aminotransferase (ALT) values. Six-hundred ninety-three suitable biopsies were evaluated. Biopsied patients had a median age of 45 years; 78.6% were female and 35.1% diabetic; median body mass index was 46 kg/m(2). Six-hundred thirty-five biopsied patients had preoperative ALTs. Median ALT was 25 IU/L (interquartile range [IQR] 19-36 IU/L); 26.6% had an ALT > 35 IU/L and 29.9% exceeded the more restrictive Prati criteria for normal. Using the Prati criteria, 7.9% of participants with normal ALT had steatohepatitis and 5.3% had ≥ stage 2 fibrosis. Logistic regression models were used to predict the probabilities of having bridging fibrosis/cirrhosis or a diagnosis of borderline/definite steatohepatitis in the unbiopsied LABS-2 sample. The proportion of biopsied participants with these findings was very similar to the modeled results from the unbiopsied cohorts. We estimated that 86.0% of participants with advanced fibrosis and 88.1% of participants with borderline/definite steatohepatitis were not biopsied and went undiagnosed. As ALT did not reliably exclude significant obesity-related liver disease in bariatric surgery patients, consideration should be given to routine liver biopsy during bariatric surgery and medical follow-up of significant hepatic pathology.

Course of depressive symptoms and treatment in the longitudinal assessment of bariatric surgery (LABS-2) study.

OBJECTIVE: To examine changes in depressive symptoms and treatment in the first 3 years following bariatric surgery. METHODS: The longitudinal assessment of bariatric surgery-2 (LABS-2) is an observational cohort study of adults (n = 2,458) who underwent a bariatric surgical procedure at 1 of 10 US hospitals between 2006 and 2009. This study includes 2,148 participants who completed the Beck depression inventory (BDI) at baseline and ≥ one follow-up visit in years 1-3. RESULTS: At baseline, 40.4% self-reported treatment for depression. At least mild depressive symptoms (BDI score ≥ 10) were reported by 28.3%; moderate (BDI score 19-29) and severe (BDI score ≥30) symptoms were uncommon (4.2 and 0.5%, respectively). Mild-to-severe depressive symptoms independently increased the odds (OR = 1.75; P = 0.03) of a major adverse event within 30 days of surgery. Compared with baseline, symptom severity was significantly lower at all follow-up time points (e.g., mild-to-severe symptomatology was 8.9%, 6 months; 8.4%, 1year; 12.2%, 2 years; 15.6%, 3 years; ps < 0.001), but increased between 1 and 3 years postoperatively (P < 0.01). Change in depressive symptoms was significantly related to change in body mass index (r = 0.42; P < 0001). CONCLUSION: Bariatric surgery has a positive impact on depressive features. However, data suggest some deterioration in improvement after the first postoperative year. LABS-2, #NCT00465829, http://www.clinicaltrials.gov/ct2/show/NCT00465829.

Metabolic syndrome prevalence and associations in a bariatric surgery cohort from the Longitudinal Assessment of Bariatric Surgery-2 study.

BACKGROUND: Metabolic syndrome is associated with higher risk for cardiovascular disease, sleep apnea, and nonalcoholic steatohepatitis, all common conditions in patients referred for bariatric surgery, and it may predict early postoperative complications. The objective of this study was to determine the prevalence of metabolic syndrome, defined using updated National Cholesterol Education Program criteria, in adults undergoing bariatric surgery and compare the prevalence of baseline co-morbid conditions and select operative and 30-day postoperative outcomes by metabolic syndrome status. METHODS: Complete metabolic syndrome data were available for 2275 of 2458 participants enrolled in the Longitudinal Assessment of Bariatric Surgery-2 (LABS-2), an observational cohort study designed to evaluate long-term safety and efficacy of bariatric surgery in obese adults. RESULTS: The prevalence of metabolic syndrome was 79.9%. Compared to those without metabolic syndrome, those with metabolic syndrome were significantly more likely to be men, to have a higher prevalence of diabetes and prior cardiac events, to have enlarged livers and higher median levels of liver enzymes, a history of sleep apnea, and a longer length of stay after surgery following laparoscopic Roux-en-Y gastric bypass (RYGB) and gastric sleeves but not open RYGB or laparoscopic adjustable gastric banding. Metabolic syndrome status was not significantly related to duration of surgery or rates of composite end points of intraoperative events and 30-day major adverse surgical outcomes. CONCLUSIONS: Nearly four in five participants undergoing bariatric surgery presented with metabolic syndrome. Establishing a diagnosis of metabolic syndrome in bariatric surgery patients may identify a high-risk patient profile, but does not in itself confer a higher risk for short-term adverse postsurgery outcomes.