Evidence-Based Classification for Post-bariatric Weight Regain from a Benchmark Registry Cohort of 18,403 Patients and Comparison with Current Criteria

INTRODUCTION

There is a need for a standardized, evidence-based classification of post-bariatric weight-regain, to investigate and compare revision procedures and to advice and treat patients in an evidence-based way.

METHODS

We used standard deviations (SD) of the highest (1-2 years) and latest (> 2 years) percentage total weight loss (%TWL) results after primary bariatric surgery from the Dutch Audit for Treatment of Obesity (DATO) bariatric registry as benchmarks for (above) average (≥ - 1SD), poor (- 1SD to - 2SD) and insufficient (< - 2SD) weight loss. Weight regain maintaining (above) average weight loss was called grade 1, weight regain towards poor weight loss grade 2, towards insufficient weight loss grade 3, with subgrades 2a/3a for below average weight loss from the start, and 2b/3b for weight regain from (above) average to below average weight loss. Patient characteristics and diabetes improvement/impairment were compared. Sensitivity and specificity of 14 existing weight regain criteria were calculated.

RESULTS

We analyzed 93,465 results from 38,830 patients (77.1% gastric bypass, 22.5% sleeve gastrectomy). The - 1SD thresholds for early and late weight loss approximated 25%TWL and 20%TWL, the - 2SD threshold for late weight loss 10%TWL. Weight regain could be analyzed for 18,403 patients (2.5-5.2 years follow-up). They regained mean 6.7 kg (5.4%TWL), with 66.8% grade 1 weight regain, 7.2% grade 2a, 7.4% grade 2b, 2.1% grade 3a, and 0.6% grade 3b. There were significant differences in comorbidities, gender, age, weight regain, diabetes impairment, and diabetes improvement across grades. Weight regain criteria from literature were extremely divers. None had high sensitivity.

CONCLUSION

The DATO classification for post-bariatric weight regain combines the extent of weight regain with evidence-based endpoints of weight loss. It differentiated weight regain maintaining (above) average weight loss, two intermediate grades, gradual weight regain with below average weight loss from the start (primary non-response) and steep weight regain towards insufficient weight loss (secondary non-response). The classification is superior to existing criteria and well supported by evidence.

Predicting serious complication risks after bariatric surgery: external validation of the Michigan Bariatric Surgery Collaborative risk prediction model using the Dutch Audit for Treatment of Obesity

BACKGROUND

Risk-prediction tools can support doctor-patient (shared) decision making in clinical practice by providing information on complication risks for different types of bariatric surgery. However, external validation is imperative to ensure the generalizability of predictions in a new patient population.

OBJECTIVE

To perform an external validation of the risk-prediction model for serious complications from the Michigan Bariatric Surgery Collaborative (MBSC) for Dutch bariatric patients using the nationwide Dutch Audit for Treatment of Obesity (DATO).

SETTING

Population-based study, including all 18 hospitals performing bariatric surgery in the Netherlands.

METHODS

All patients registered in the DATO undergoing bariatric surgery between 2015 and 2020 were included as the validation cohort. Serious complications included, among others, abdominal abscess, bowel obstruction, leak, and bleeding. Three risk-prediction models were validated: (1) the original MBSC model from 2011, (2) the original MBSC model including the same variables but updated to more recent patients (2015-2020), and (3) the current MBSC model. The following predictors from the MBSC model were available in the DATO: age, sex, procedure type, cardiovascular disease, and pulmonary disease. Model performance was determined using the area under the curve (AUC) to assess discrimination (i.e., the ability to distinguish patients with events from those without events) and a graphical plot to assess calibration (i.e., whether the predicted absolute risk for patients was similar to the observed prevalence of the outcome).

RESULTS

The DATO validation cohort included 51,291 patients. Overall, 986 patients (1.92%) experienced serious complications. The original MBSC model, which was extended with the predictors "GERD (yes/no)," "OSAS (yes/no)," "hypertension (yes/no)," and "renal disease (yes/no)," showed the best validation results. This model had a good calibration and an AUC of .602 compared with an AUC of .65 and moderate to good calibration in the Michigan model.

CONCLUSION

The DATO prediction model has good calibration but moderate discrimination. To be used in clinical practice, good calibration is essential to accurately predict individual risks in a real-world setting. Therefore, this model could provide valuable information for bariatric surgeons as part of shared decision making in daily practice.

Measuring quality of life in bariatric surgery: a multicentre study

BACKGROUND

Current studies mainly focus on total weight loss and comorbidity reduction. Only a few studies compare Quality of Life (QoL) after sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB). This study was conducted to examine the extent of improvement in QoL on different domains after primary bariatric surgery and compare these results to Dutch reference values.

METHODS

The study included prospectively collected data from patients who underwent primary bariatric surgery in five Dutch hospitals. The RAND-36 questionnaire was used to measure the patient's QoL; preoperatively and twelve months postoperatively. Postoperative scores were compared to Dutch reference values, standardized for age, using t-test. A difference of more than 5% was considered a minimal important difference. A multivariate linear regression analysis was used to compare SG and RYGB on the extent of improvement, adjusted for case-mix factors.

RESULTS

In total, 4864 patients completed both the pre- and postoperative questionnaire. Compared with Dutch reference values, patients postoperatively reported clinically relevant better physical functioning (RYGB + 6.8%), physical role limitations (SG + 5.6%; RYGB + 6.2%) and health change (SG + 77.1%; RYGB + 80.0%), but worse general health perception (SG - 22.8%; RYGB - 17.0%). Improvement in QoL was similar between SG and RYGB, except for physical functioning (β 2.758; p-value 0.008) and general health perception (β 2.607; p-value < 0.001) for which RYGB patients improved more.

CONCLUSIONS

SG and RYGB patients achieved a better postoperative score in physical functioning, physical role limitations and health change compared to Dutch reference values, and a worse score in general health perception.

Perioperative Outcomes of Primary Bariatric Surgery in North-Western Europe: a Pooled Multinational Registry Analysis

Introduction

The global prevalence of obesity has increased in recent decades, and bariatric surgery has become a part of the treatment algorithm of obesity. National high-quality registries enable large-scale evaluations of the use and outcome of bariatric surgery and may allow for improved knowledge. The main objective was to evaluate the rate and type of complications after primary bariatric surgery in three North-Western European countries using nationwide registries.

Materials and Methods

Data from three registries for bariatric surgery were used (January 2015–December 2016). All registries have nationwide coverage with data on patient characteristics, obesity-related diseases, surgical technique, complications, grading of complications, reinterventions, readmissions, and mortality. Eligibility criteria for bariatric surgery were similar and included body mass index of ≥ 40.0 or ≥ 35.0 kg/m², with one or more obesity-associated diseases.

Results

A total of 35,858 procedures (32,177 primary) were registered. The most common procedure was gastric bypass in the Netherlands (78.9%) and Sweden (67.0%), and sleeve gastrectomy in Norway (58.2%). A total of 904 (2.8%) patients developed major complications after primary surgery and 12 patients (0.04%) died within 30 days. Total number of complications between the registries were comparable (p = 0.939). However, significant differences were seen for Clavien-Dindo Classification grades IIIb and IV (p < 0.001). Pooled readmission rates were 4.3% (n = 1386).

Discussion

Bariatric surgery is safely performed in the three evaluated countries. Standardization of registries and consensus of variables are essential for international comparison and may contribute to improved quality of treatment across nations.

A Dutch Nationwide Bariatric Quality Registry: DATO

INTRODUCTION

In the Netherlands, the number of bariatric procedures increased exponentially in the 90s. To ensure and improve the quality of bariatric surgery, the nationwide Dutch Audit for Treatment of Obesity (DATO) was established in 2014. The audit was coordinated by the Dutch Institute for Clinical Auditing (DICA). This article provides a review of the aforementioned process in establishing a nationwide registry in the Netherlands.

MATERIALS AND METHODS

In collaboration with the DATO's scientific committee and other stakeholders, an annual list of several external quality indicators was formulated. This list consists of volume, process, and outcome indicators. In addition to the annual external indicators, the database permits individual hospitals to analyze their own data. The dashboard provides several standardized reports and detailed quality indicators, which are updated on a weekly base.

RESULTS

Since the start, all 18 Dutch bariatric centers participated in the nationwide audit. A total of 21,941 cases were registered between 2015 and 2016. By 2016, the required variables were registered in 94.3% of all cases. A severe complicated course was seen in 2.87%, and mortality in 0.05% in 2016. The first-year follow-up shows a > 20% TWL in 86.1% of the registered cases.

DISCUSSION

The DATO has become rapidly a mature registry. The well-organized structure of the national audit institution DICA and governmental funding were essential. However, most important were the bariatric teams themselves. The authors believe reporting the results from the registry has already contributed to more knowledge and acceptance by other health care providers.