Effect of Contemporary Bariatric Surgical Procedures on Type 2 Diabetes Remission. A Population-Based Matched Cohort Study

Clinical outcomes and adverse events of bariatric surgery in adults with severe obesity in Scotland: the SCOTS observational cohort study

Background

Bariatric surgery is a common procedure worldwide for the treatment of severe obesity and associated comorbid conditions but there is a lack of evidence as to medium-term safety and effectiveness outcomes in a United Kingdom setting.

Objective

To establish the clinical outcomes and adverse events of different bariatric surgical procedures, their impact on quality of life and the effect on comorbidities.

Design

Prospective observational cohort study.

Setting

National Health Service secondary care and private practice in Scotland, United Kingdom.

Participants

Adults (age >16 years) undergoing their first bariatric surgery procedure.

Main outcome measures

Change in weight, hospital length of stay, readmission and reoperation rate, mortality, diabetes outcomes (HbA1c, medications), quality of life, anxiety, depression.

Data sources

Patient-reported outcome measures, hospital records, national electronic health records (Scottish Morbidity Record 01, Scottish Care Information Diabetes, National Records Scotland, Prescription Information System).

Results

Between December 2013 and February 2017, 548 eligible patients were approached and 445 participants were enrolled in the study. Of those, 335 had bariatric surgery and 1 withdrew from the study. Mean age was 46.0 (9.2) years, 74.7% were female and the median body mass index was 46.4 (42.4; 52.0) kg/m2. Weight was available for 128 participants at 3 years: mean change was -19.0% (±14.1) from the operation and -24.2% (±12.8) from the start of the preoperative weight-management programme. One hundred and thirty-nine (41.4%) participants were readmitted to hospital in the same or subsequent 35 months post surgery, 18 (5.4% of the operated cohort) had a reoperation or procedure considered to be related to bariatric surgery gastrointestinal complications or revisions. Fewer than five participants (<2%) died during follow-up. HbA1c was available for 93/182 and diabetes medications for 139/182 participants who had type 2 diabetes prior to surgery; HbA1c mean change was -5.72 (±16.71) (p = 0.001) mmol/mol and 65.5% required no diabetes medications (p < 0.001) at 3 years post surgery. Physical quality of life, available for 101/335 participants, improved in the 3 years post surgery, mean change in Rand 12-item Short Form Survey physical component score 8.32 (±8.95) (p < 0.001); however, there was no change in the prevalence of anxiety or depression.

Limitations

Due to low numbers of bariatric surgery procedures in Scotland, recruitment was stopped before achieving the intended 2000 participants and follow-up was reduced from 10 years to 3 years.

Conclusions

Bariatric surgery is a safe and effective treatment for obesity. Patients in Scotland, UK, appear to be older and have higher body mass than international comparators, which may be due to the small number of procedures performed.

Future work

Intervention studies are required to identify the optimal pre- and post surgery pathway to maximise safety and cost-effectiveness.

Study registration

This study is registered as ISRCTN47072588.

Funding details

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 10/42/02) and is published in full in Health Technology Assessment; Vol. 28, No. 7. See the NIHR Funding and Awards website for further award information.

A review on the beneficial effects of bariatric surgery in the management of obesity

INTRODUCTION

Obesity is a chronic disease with a complex interplay of multiple factors such as genetic, metabolic, behavioral, and environmental factors. The management of obesity includes; lifestyle modification, psychological therapy, pharmacological therapy, and bariatric surgery. To date, bariatric surgery is the most effective treatment for obesity by offering a long-term reduction in weight, remission of obesity-related complications, and improving quality of life. However, bariatric surgery is not equally effective in all patients. Thus, if we can predict who would benefit most, it will improve the risk versus benefit ratio of having surgery.

AREAS COVERED

In this narrative review, we explore the question on who will benefit the most from bariatric surgery by examining the recent evidence in the literature. In addition, we investigate the predisposing predictors of bariatric surgery response. Finally, we offer the best strategies in the clinic to explain the potential benefits of bariatric surgery to patients.

EXPERT OPINION

Bariatric surgery is an effective obesity management approach. Despite its efficacy, considerable variation of individual response exists. Thus, it is important to recognize patients that will benefit most, but at present very few predictors are available which can be clinically useful.

Which predictors could effect on remission of type 2 diabetes mellitus after the metabolic surgery: A general perspective of current studies?

BACKGROUND

The alarming rise in the worldwide prevalence of obesity is paralleled by an increasing burden of type 2 diabetes mellitus (T2DM). Metabolic surgery is the most effective means of obtaining substantial and durable weight loss in individual obese patients with T2DM. There are randomized trials that justify the inclusion of metabolic surgery into the treatment algorithm for patients with T2DM, but remission rates of T2DM after metabolic surgery can display great variability.

AIM

To discuss the most commonly used surgical options including vertical sleeve gastrectomy, adjustable gastric banding, Roux-en-Y gastric bypass, and biliopancreatic diversion with duodenal switch.

METHODS

We also report from observational and randomized controlled studies on rate of remission of T2DM after the surgical procedures.

RESULTS

In light of the recent findings, metabolic surgery is a safe and effective treatment option for obese patient with T2DM, but further studies are needed to clarify better the rate of diabetes remission.

CONCLUSION

In light of the recent findings, metabolic surgery is a safe and effective treatment option for obese patients with T2DM, but further studies are needed to clarify better the rate of diabetes remission.

Validity of bariatric surgery codes in the UK Clinical Practice Research Datalink (CPRD) GOLD compared with Hospital Episodes Statistics

OBJECTIVES

To assess completeness and validity of bariatric surgery codes in the UK Clinical Practice Research Datalink (CPRD) GOLD compared with Hospital Episodes Statistics (HES).

METHODS

We conducted a validation study among patients in the UK-based CPRD GOLD with linkage to HES (1998 to 2017). Since the same surgery codes are used for bariatric and other gastrointestinal surgery we assessed code distribution patterns used in patients with bariatric versus other gastrointestinal surgery by presence of other conditions such as obesity and gastrointestinal cancer. We developed algorithms to identify bariatric surgery and calculated validity measures (ie, positive/negative predictive value [PPV/NPV], sensitivity, and specificity) of each in CPRD GOLD compared with HES (gold standard).

RESULTS

Among 7 357 007 available patients we identified 10 190 patients who had a total of 14 046 potential bariatric surgery codes in CPRD GOLD and/or HES. Surgery code patterns differed between bariatric surgery and assumed other gastrointestinal surgery. The sensitivity of CPRD GOLD bariatric surgery coding improved from an overall of 56% to 69-71% when applying stricter algorithms (ie, in obese patients or obese, gastrointestinal disease/complication free patients) but PPVs remained at 53%-55%. NPVs and specificities of CPRD GOLD bariatric surgery coding achieved ≥99.8% for all algorithms.

CONCLUSION

Our results suggest that using CPRD GOLD and HES data and a wide selection of surgery codes will result in the most complete and accurate capture of bariatric surgery events. Validity measures of CPRD GOLD bariatric surgery codes were identical in obese patients and more restrictive populations.

Long-Term Quality of Life Outcomes After Laparoscopic Sleeve Gastrectomy and Roux-en-Y Gastric Bypass-a Comparative Study

Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) have been shown to improve metabolic comorbidities as well as quality of life (QoL) in the obese population. The vast majority of previous studies have investigated the metabolic effects of bariatric surgery and there is a dearth of studies examining long-term QoL outcomes post bariatric surgery. The outcomes of 43 patients who underwent bariatric surgery were prospectively assessed, using BAROS questionnaires to quantify QoL and metabolic status pre-operatively, at 1 year and at 8 years. Total weight loss and comorbidity resolution were similar between RYGB and SG. The RYGB cohort experienced greater QoL improvement from baseline and had higher BAROS scores at 8 years. RYGB may provide more substantial and durable long-term benefits as compared to SG.

Attrition Bias in an Observational Study of Very Low-Energy Diet: A Cohort Study

OBJECTIVE

Obesity treatment is plagued by attrition. Estimates of attrition bias are needed. Thus, in this study, percent change from baseline BMI at 1, 2, and 3 years following enrollment in a 2-year weight management program using a very low-energy diet was calculated. Program data were supplemented with information from medical records.

METHODS

Attrition was classified as occurring early (<6 months), late (6-21 months), at program completion (22-28 months), and after program completion (>28 months). Stepwise multivariable regression examined attrition and other covariates.

RESULTS

A total of 881 subjects had ≥3 years of follow-up. BMI decreased by a mean (SD) of 11.8 (9.2), 8.6 (9.3), and 5.2 (10.0) kg/m2 at 1, 2, and 3 years after enrollment, respectively. At year 1, every 10-kg/m2 increase in baseline BMI was associated with a 2% (95% CI: 1%-3%) decrease in BMI. Individuals with early attrition decreased their mean BMI by 13% (11%-15%) less than program completers and by 9% (7%-11%) at 2 years. At 3 years, there was no significant difference in BMI between individuals with early attrition and program completers. However, BMI decreased 5% (3%- 8%) more in individuals who extended participation compared with program completers.

CONCLUSIONS

Reported outcomes of weight management programs must account for program attrition.

Bariatric surgery for patients with type 2 diabetes mellitus requiring insulin: Clinical outcome and cost-effectiveness analyses

BACKGROUND

Although bariatric surgery is well established as an effective treatment for patients with obesity and type 2 diabetes mellitus (T2DM), there exists reluctance to increase its availability for patients with severe T2DM. The aims of this study were to examine the impact of bariatric surgery on T2DM resolution in patients with obesity and T2DM requiring insulin (T2DM-Ins) using data from a national database and to develop a health economic model to evaluate the cost-effectiveness of surgery in this cohort when compared to best medical treatment (BMT).

METHODS AND FINDINGS

Clinical data from the National Bariatric Surgical Registry (NBSR), a comprehensive database of bariatric surgery in the United Kingdom, were extracted to analyse outcomes of patients with obesity and T2DM-Ins who underwent primary bariatric surgery between 2009 and 2017. Outcomes for this group were combined with data sourced from a comprehensive literature review in order to develop a state-transition microsimulation model to evaluate cost-effectiveness of bariatric surgery versus BMT for patients over a 5-year time horizon. The main outcome measure for the clinical study was insulin cessation at 1-year post-surgery: relative risks (RR) summarising predictive factors were determined, unadjusted, and after adjusting for variables including age, initial body mass index (BMI), duration of T2DM, and weight loss. Main outcome measures for the economic evaluation were total costs, total quality-adjusted life years (QALYs), and incremental cost-effectiveness ratio (ICER) at willingness-to-pay threshold of GBP£20,000. A total of 2,484 patients were eligible for inclusion, of which 1,847 had 1-year follow-up data (mean age of 51 years, mean initial BMI 47.2 kg/m2, and 64% female). 67% of patients no longer required insulin at 1-year postoperatively: these rates persisted for 4 years. Roux-en-Y gastric bypass (RYGB) was associated with a higher rate of insulin cessation (71.7%) than sleeve gastrectomy (SG; 64.5%; RR 0.92, confidence interval (CI) 0.86-0.99) and adjustable gastric band (AGB; 33.6%; RR 0.45, CI 0.34-0.60; p < 0.001). When adjusted for percentage total weight loss and demographic variables, insulin cessation following surgery was comparable for RYGB and SG (RR 0.97, CI 0.90-1.04), with AGB having the lowest cessation rates (RR 0.55, CI 0.40-0.74; p < 0.001). Over 5 years, bariatric surgery was cost saving compared to BMT (total cost GBP£22,057 versus GBP£26,286 respectively, incremental difference GBP£4,229). This was due to lower treatment costs as well as reduced diabetes-related complications costs and increased health benefits. Limitations of this study include loss to follow-up of patients within the NBSR dataset and that the time horizon for the economic analysis is limited to 5 years. In addition, the study reflects current medical and surgical treatment regimens for this cohort of patients, which may change.

CONCLUSIONS

In this study, we observed that in patients with obesity and T2DM-Ins, bariatric surgery was associated with high rates of postoperative cessation of insulin therapy, which is, in turn, a major driver of overall reductions in direct healthcare cost. Our findings suggest that a strategy utilising bariatric surgery for patients with obesity and T2DM-Ins is cost saving to the national healthcare provider (National Health Service (NHS)) over a 5-year time horizon.

Options in Bariatric Surgery: Modeled Decision Analysis Supports One-Anastomosis Gastric Bypass as the Treatment of Choice when Type 2 Diabetes Is Present

BACKGROUND

Obesity and type 2 diabetes mellitus (T2DM) represent significant healthcare burdens. Surgical management is superior to traditional medical therapy. Laparoscopic sleeve gastrectomy (LSG) and gastric bypass (both Roux-en-Y (RYGB) and one anastomosis gastric bypass (OAGB) are the most commonly performed metabolic procedures. It remains unclear which gives the optimal quality-of-life pay-off in the context of T2DM. This study compares LSG, RYGB, and OAGB in the management of T2DM and obesity using modeled decision analysis. Alternative approaches were assessed considering efficacy of interventions, post-operative complications, and quality of life outcomes to determine the optimal approach.

METHODS

Modeled decision analysis was performed from the patent's perspective comparing best medical management (MM), SG, RYGB, OAGB, and LAGB. The base case is a 40-year-old female with a body mass index (BMI) of 40 and T2DM. Input variables were calculated based on published decision analyses and a literature review. Utilities were based on previous studies. Sensitivity analysis was performed. The payoff was quality-adjusted life years (QALYs) 5 years from intervention. TreeAge Pro modeling software was used for analysis.

RESULTS

In 5-years post-procedure, OAGB gave the optimal QALY payoff of 3.65 QALYs (reviewer 2). RYGB gave 3.47, SG gave 3.08, LAGB gave 2.62 and MM 2.45 QALYs. Three input variables proved sensitive. RYGB is optimal if its metabolic improvement rates exceed 86%. It is also optimal if metabolic improvement rates in OAGB drop below 71.8% or if the utility of OAGB drops below 0.759.

CONCLUSION

OAGB gives the optimal QALY payoff in treatment of T2DM. RYGB and SG also improve metabolic outcomes and remain viable options in selected patients.

The Effect of Attrition on Reported Diabetes Remission Rates Following Roux-en-Y Gastric Bypass: a Sensitivity Analysis

OBJECTIVE

Attrition, or loss to follow-up, is a common problem in studies of type 2 diabetes remission following roux-en-Y gastric bypass (RYGB) and is often correlated with weight loss. Thus, reported rates of remission may be inflated by attrition bias. We investigate the effect of attrition bias on reported diabetes remission rates following RYGB.

METHODS

Using sensitivity analyses, we identified sets of attrition and remission rates that produced simulated outcomes within 95% confidence intervals of the reported outcomes from five studies of diabetes remission following RYGB.

RESULTS

Potential attrition bias varied greatly, yielding possible remission rates of diabetes ranging from 20 to 40% at 1 year. For studies with the attrition greater than ~ 20%, estimates that ignored attrition overestimated diabetes remission rates. Kaplan-Meier estimates were less affected by attrition. Potential for bias was most evident in the study with the largest sample size.

CONCLUSION

Researchers, clinicians, and policymakers can measure potential attrition bias in clinical studies. In the case of remission of diabetes following RYGB, the potential bias in reported remission rates is generally less than 10%, varies considerably among studies, and is primarily driven by attrition rate and study size. Studies with very large sample sizes may provide a narrow confidence interval around a biased estimate.

Costs and Outcomes of Increasing Access to Bariatric Surgery: Cohort Study and Cost-Effectiveness Analysis Using Electronic Health Records

OBJECTIVES

To estimate costs and outcomes of increasing access to bariatric surgery in obese adults and in population subgroups of age, sex, deprivation, comorbidity, and obesity category.

METHODS

A cohort study was conducted using primary care electronic health records, with linked hospital utilization data, for 3,045 participants who underwent bariatric surgery and 247,537 participants who did not undergo bariatric surgery. Epidemiological analyses informed a probabilistic Markov model to compare bariatric surgery, including equal proportions with adjustable gastric banding, gastric bypass, and sleeve gastrectomy, with standard nonsurgical management of obesity. Outcomes were quality-adjusted life-years (QALYs) and net monetary benefits at a threshold of £30,000 per QALY.

RESULTS

In a UK population of 250,000 adults, there may be 7,163 people with morbid obesity including 1,406 with diabetes. The immediate cost of 1,000 bariatric surgical procedures is £9.16 million, with incremental discounted lifetime health care costs of £15.26 million (95% confidence interval £15.18-£15.36 million). Patient-years with diabetes mellitus will decrease by 8,320 (range 8,123-8,502). Incremental QALYs will increase by 2,142 (range 2,032-2,256). The estimated cost per QALY gained is £7,129 (range £6,775-£7,506). Net monetary benefits will be £49.02 million (range £45.72-£52.41 million). Estimates are similar for subgroups of age, sex, and deprivation. Bariatric surgery remains cost-effective if the procedure is twice as costly, or if intervention effect declines over time.

CONCLUSIONS

Diverse obese individuals may benefit from bariatric surgery at acceptable cost. Bariatric surgery is not cost-saving, but increased health care costs are exceeded by health benefits to obese individuals.

Reconciliation of Type 2 Diabetes Remission Rates in Studies of Roux-en-Y Gastric Bypass

OBJECTIVE

Bariatric surgery may induce remission of type 2 diabetes in obese patients. However, estimates of remission rates reported in the literature range from 25 to 81%, contributing to the uncertainty patients and physicians both face as they assess treatment options. This analysis attempts to reconcile the seemingly disparate rates of diabetes remission reported in studies of Roux-en-Y gastric bypass (RYGB) surgery. It examines variation in the methodologies used to derive the estimates and proposes outcomes that should be reported by all studies.

RESEARCH DESIGN AND METHODS

A literature review yielded 10 large (n > 100), recent (index surgery since 2000) studies of diabetes remission after RYGB. These studies differed in definitions of remission (partial vs. complete), lengths of follow-up (1 year vs. ≥3 years), reported outcomes (cumulative vs. prevalent remission), and risks of attrition bias.

RESULTS

Reported rates of partial remission were 10-30 percentage points higher than rates of complete remission. Study duration explained 69% of the variability in cumulative remission rates, plateauing at 3 years. Adjustment for attrition increased the explained variability to 87%. Attrition-adjusted, 3-year cumulative, complete remission rates ranged from 63 to 65%; however, this does not account for relapse. Attrition-adjusted, 3-year prevalent complete remission rates that accounted for relapse were 23%.

CONCLUSIONS

Variations in reported rates of diabetes remission after RYGB are primarily related to definitions and study duration. Future studies should report both cumulative and prevalent remission to aid decision making and more easily compare studies.

Perfil farmacoterapêutico de pacientes obesos no pós-operatório de cirurgia bariátrica

Contexto

A obesidade pode estar relacionada a doenças como diabetes, hipertensão arterial e dislipidemia. A cirurgia bariátrica é um dos tratamentos mais eficazes, levando à diminuição de peso e comorbidades.

Objetivo

Avaliar o perfil metabólico e farmacoterapêutico de pacientes obesos após cirurgia bariátrica.

Métodos

Trata-se de um estudo observacional transversal retrospectivo, realizado em um hospital localizado na cidade de Porto Alegre, RS, Brasil. Foram avaliados 70 prontuários de pacientes que realizaram cirurgia bariátrica, nos períodos de antes de 2 meses e mais de 6 meses após a cirurgia bariátrica. A análise estatística foi realizada no programa SPSS 17.0®.

Resultados

A pressão arterial inicial foi de 130/85 mmHg, passando para 120/80 mmHg (p < 0,01). Com relação ao perfil metabólico antes de dois meses, o HDL foi de 34 mg/dL, o colesterol total foi de 195,07 ± 40,17 mg/dL, o LDL foi de 118,22 ± 41,28 mg/dL, os triglicerídeos foram de 141,09 ± 43,39 mg/dL, e a glicemia de jejum foi de 90 mg/dL. Após 6 meses de cirurgia, os valores passaram para 43 mg/dL, 133,67 ± 28,14 mg/dL, 65,53 ± 24,3 mg/dL, 104,41 ± 29,6 mg/dL, e 77 mg/dL, respectivamente (p < 0,01). Com relação ao uso de medicamentos, 41% utilizaram anti-hipertensivos, 39% utilizaram hipolipemiantes, 10% utilizaram hipoglicemiantes orais e 97% utilizaram suplementos antes dos 2 meses de cirurgia. Após os 6 meses, os percentuais foram alterados para 21%, 19%, 9% e 99%, respectivamente.

Conclusões

O estudo mostra o sucesso da cirurgia bariátrica em pacientes obesos com comorbidades, revelando melhora no perfil metabólico e redução na utilização de medicamentos para tratamento de comorbidades.