key: cord-0952765-td5ckxw9
authors: Verhoeff, Kevin; Mocanu, Valentin; Dang, Jerry; Wilson, Hillary; Switzer, Noah J.; Birch, Daniel W.; Karmali, Shahzeer
title: Impact of the COVID-19 pandemic on bariatric surgery in North America – A retrospective analysis of 834,647 patients
date: 2022-03-19
journal: Surg Obes Relat Dis
DOI: 10.1016/j.soard.2022.03.012
sha: 2e95aac768ed39c96f06925c56f2abbe43d96ff2
doc_id: 952765
cord_uid: td5ckxw9

BACKGROUND: COVID-19 has transformed surgical care, yet little is known regarding implications for bariatric surgery. OBJECTIVES: We sought to characterize the impact of COVID-19 on bariatric surgery delivery and outcomes. SETTING: The Metabolic and Bariatric Accreditation and Quality Improvement Program (MBSAQIP) collects data from 885 centers in North America. METHODS: The MBSAQIP database was evaluated with two cohorts described: the COVID-19 and the pre-COVID-19, receiving surgery in 2020 and 2015-2019 respectively. Yearly operative trends were characterized and bivariate analysis compared demographics and post-operative outcomes. Multivariable modelling evaluated thirty-day readmission, reintervention, reoperation, and factors associated with undergoing Roux-en-Y gastric bypass (RYGB). RESULTS: We evaluated 834,647 patients, with 155,830 undergoing bariatric surgery during the 2020 pandemic year. A 12.1% reduction in total cases (177,208 in 2019 vs 155,830 in 2020, p<0.001) and 13.8% reduction in cases per center occurred (204.2 cases/center 2019 vs 176.1 cases/center 2020, p<0.001). Patients receiving bariatric surgery during the pandemic were younger with fewer comorbidities. Use of sleeve gastrectomy increased (74.5% vs 72.5%, p < 0.001) and surgery during COVID-19 was associated with reduced RYGB procedural selection (OR 0.83, 95% CI 0.82-0.84, p < 0.001). Length of stay decreased significantly (1.4 ± 1.4 days vs 1.6 ± 1.4 days, p<0.001), yet post-operative outcomes were similar. After adjusting for comorbidities, patients during COVID-19 had decreased 30-day odds of readmission and reintervention with a small increased odds of reoperation. CONCLUSIONS: The COVID-19 pandemic dramatically changed bariatric surgery delivery. Further studies evaluating the long-term effects of these changes are warranted.

The coronavirus disease 2019 (COVID- 19) pandemic has drastically transformed delivery of surgical care worldwide (1) . With concerns regarding hospital resources, and COVID- 19 45 perioperative morbidity and mortality, millions of surgical procedures were cancelled in 2020 (1) (2) (3) . In response, patient selection, surgical techniques, and post-operative care have been affected, with substantial changes across every area of general surgery (1, (4) (5) (6) (7) (8) (9) (10) (11) (12) . These changes are expected to have pervasive long-term health and care delivery effects (13) (14) (15) . Despite substantial evidence across various surgical subspecialties, multi-centered international evaluation of the impact 50 COVID-19 has had on bariatric surgery has not been well characterized. This scarcity of evidence has occurred in spite of patients with obesity being disproportionately affected by COVID-19, alongside concerns that obesity treatments may be overlooked as we recover from the COVID-19 pandemic due to obesity stigma (16) (17) (18) (19) .

Early studies evaluating the effect of COVID-19 on bariatric surgery have reported a substantial reduction in procedures performed (16) . Unfortunately, delaying bariatric surgery due to COVID-19 has shown deleterious weight gain and psychological patient effects (20) . Other groups, including our own, have reported ongoing bariatric care delivery with careful patient selection to enable early patient discharge and limit the impact on hospital resources (21, 22) . The largest study 60 evaluating bariatric surgery patients during the COVID-19 pandemic has reported similar postoperative outcomes to historic studies but unfortunately did not characterize differences in delivery or patient selection (18) . Better understanding the consequences of COVID-19 on bariatric surgery is required to optimize future delivery during the ongoing COVID-19 waves, and potentially after if COVID-19 can be limited or eradicated. 65 J o u r n a l P r e -p r o o f Herein, we report the largest multi-centered international retrospective cohort study of prospectively collected data evaluating the impact of COVID-19 on delivery of bariatric surgery care in North America. The Metabolic and Bariatric Accreditation and Quality Improvement Program (MBSAQIP) database was used to describe surgical volume, patient demographics, 70 operative technique, and post-operative outcomes for patients undergoing bariatric surgery in accredited North American centers.

The 2015-2020 MBSAQIP database was queried to collate data for this study. This data registry prospectively collects key pre-operative, operative, and early post-operative outcomes for patients undergoing bariatric surgery from 885 centers in the United States and Canada. Data within the registry is collected based on well-defined, standardized variables and is subject to frequent review of data integrity and collection practices (23) . This study was exempt from 80 research ethics board review.

This is a retrospective cohort study of prospectively collected MBSAQIP data. The study's primary objective was to characterize bariatric surgery delivery, including case volume, during 85 the COVID-19 pandemic compared to prior. Secondary outcomes were to evaluate trends in demographics, surgical technique, and post-operative outcomes for patients undergoing bariatric J o u r n a l P r e -p r o o f surgery in North America during the COVID-19 pandemic compared to those prior to COVID-19.

Patients receiving bariatric surgery during the COVID-19 pandemic included any bariatric surgery occurring during the 2020 MBSAQIP year. Pre-COVID-19 patients were categorized by bariatric surgery before those dates and after 2015, when the MBSAQIP database began collecting data. Only patients receiving elective sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB) were included because they represent the majority of bariatric procedures 95 performed (24) . Patients with a history of a previous bariatric surgery and those where the index procedure represented emergency surgery were excluded.

Demographic data were obtained for all patients, including gender, race, and pre-operative body mass index (BMI). Pulmonary comorbidities evaluated were presence of sleep apnea, active 100 smoking, and chronic obstructive pulmonary disease (COPD). Cardiac comorbidities evaluated were hypertension, hyperlipidemia, previous myocardial infarction (MI), previous cardiac surgery, and previous percutaneous coronary intervention (PCI) . Other comorbidities evaluated were history of venous thromboembolism (VTE), gastroesophageal reflux disease (GERD), diabetes mellitus (DM), venous stasis, renal insufficiency, dialysis dependency, therapeutic 105 anticoagulation, and chronic steroid use. Information regarding the surgical technique included the operative procedure (SG versus RYGB) and operative time.

Post-operative outcomes evaluated length of inpatient hospital stay (LOS) following bariatric surgery, and outcomes including 30-day readmission to hospital, reoperation, and reintervention 110 based on MBSAQIP definitions (23) . Additionally, infectious complications such as the rate of urinary tract infection (UTI), deep, and superficial surgical site infection (SSI), wound disruption, pneumonia, and sepsis are reported. Other post-operative complications evaluated include unplanned intubation, acute renal failure (described as any renal failure requiring dialysis), myocardial infarction (MI), cerebral vascular accidents (CVA), and mortality. 115

All statistical analysis was completed using STATA 17 statistical software (StataCorp, College Station, TX, USA). Categorical data was expressed as absolute values with percentages, while continuous data were expressed as a weighted mean ± standard deviation. Between group 120 differences were evaluated using chi-squared for categorical data and ANOVA for continuous data. Trends were analyzed over time with demographics and surgical technique reported for each year from 2015 to 2020. Due to the MBSAQIP's large dataset, many statistically significant outcomes occurred; therefore, results presented in text and discussed are those with substantial differences and clinical significance. Specific cases where statistical significance occurred 125 without clinical significance are also highlighted.

To determine independent predictors of post-operative complications, including 30-day readmissions, reinterventions, and reoperations, a non-parsimonious multivariable logistic regression model was developed using a hypothesis-driven purposeful selection methodology. 130

Bivariate analysis of variables with a p-value < 0.1 or from variables previously deemed clinically relevant to our primary outcome were used to generate a preliminary main effects model. Significant variables in the multivariable model were then identified (Wald test p < 0.05) J o u r n a l P r e -p r o o f and linear assumption of continuous variables and multi-collinearity were checked using the variance inflation factors (VIF). Variables with VIF greater than 10 were explored using 135 collinearity diagnostic tests and excluded from the final model if collinear. The Brier Score and the receiver operating characteristic curve were used to assess goodness of fit. This model included the pandemic as an independent variable to assess its effect on post-operative outcomes.

A multivariable model was also developed in a similar fashion to evaluate factors independently associated with undergoing RYGB to assist with characterizing delivery of bariatric surgery 140 during COVID-19.

Patients undergoing elective bariatric surgery during the COVID-19 pandemic were marginally 145 younger (44.0 ± 11.9 COVID vs. 44.7 ± 12.0 pre-COVID, p < 0.001) and were more likely to be female (81.6% COVID vs 80.2% pre-COVID, p < 0.001) ( Table 1) . Notably, there was a large decrease in White patients receiving bariatric surgery during the COVID-19 pandemic (67.1% COVID vs 71.7% pre-COVID, p < 0.001), with ensuing increase in African American's (COVID 19 .7% vs pre-COVID 18.2%, p < 0.001, Table 1 ). 150

With regards to metabolic comorbidities, patients during the COVID-19 pandemic were less likely to have hypertension (44.4% COVID vs 47.1% pre-COVID, p < 0.001), dyslipidemia (22.4% COVID vs 23.2 pre-COVID, p < 0.001), and were more likely to not require medication for diabetes (77.2% COVID vs 74.6% pre-COVID, p < 0.001). They also had fewer systemic 155 comorbidities including less sleep apnea (36.9% COVID vs 37.4% pre-COVID, p = 0.002), and fewer cardiac comorbidities such as prior MI, prior cardiac surgery, or prior PCI ( Table 1) .

In terms of operative technique, SG was performed in a higher proportion of patients during the COVID-19 pandemic (74.5% COVID vs 72.5% pre-COVID, p < 0.001, Table 1 ). Despite that 160 change, operative duration was shorter prior to the COVID-19 pandemic by 3.2 minutes (COVID 89.9 ± 54.5 minutes vs. pre-COVID 86.7 ± 49.8, p < 0.001). had a difference >0.4%, and are unlikely to be clinically significant when comparing those undergoing bariatric surgery during COVID-19 to prior ( Table 3) . Table 4 ). The models for readmission, reintervention, and reoperation had ROC areas of 0.64, 0.67 and 0.68 and Brier Scores of 0.036, 0.012, and 0.017 respectively.

When evaluating predictors of undergoing RYGB as opposed to SG, we see few independent predictors ( Table 5) . However, undergoing bariatric surgery during the COVID-19 pandemic was independently associated with a reduced likelihood of receiving RYGB (OR 0.83, 95% CI 0.82-0.84, p < 0.001). The only patients with greater reduction in RYGB likelihood were those with renal insufficiency and those who were dialysis dependent ( 

During the COVID-19 pandemic there was a 12.1% reduction in total elective bariatric surgery cases and 13.8% reduction in cases per MBSAQIP accredited center. Less metabolically 215 comorbid patients were selected for elective surgery and there was a greater shift towards SG selection at the expense of RYGB delivery. While unadjusted outcomes were similar between cohorts, multivariable analysis revealed small differences in thirty-day readmission, reintervention, and reoperation.

Beyond the overall reduction in operative volume, patient selection and operative techniques were the most drastic changes during the COVID-19 pandemic. These outcomes partly contradict the recommendations initially proposed by Rubino et al. (2020) , suggesting that patients with severe obesity, substantial comorbidities, and risk of deterioration from obesity J o u r n a l P r e -p r o o f related complications should be prioritized for bariatric surgery (19) . Regardless, both the trend 225 towards SG and less comorbid patient selection appears to have begun prior to the COVID-19 pandemic but were emphasised during the pandemic. It is likely that recent data showing favourable outcomes and long-term benefits in patients with obesity but without comorbidities led to selection of these patients during the pandemic considering the limited operative time, hospital occupancy, and post-operative follow-up (16, 21) . Similarly, favourable outcomes, shorter 230 hospital stay, and reduced post-operative complications with SG in recently-published SM-BOSS and SLEEVEPASS trials likely explain its increased use during the COVID-19 pandemic (25) (26) (27) . The advent and success of bariatric day surgery, again prior to the COVID-19 pandemic, has also likely contributed to these findings (28, 29) . On the other hand, the reason for pandemic likely contributed to surgeons and centers directing delivery towards patients more 240 likely to be fit for day or short-stay surgery.

Fortunately, despite changes in delivery, bariatric surgery procedures during the COVID-19 pandemic did not appear to have substantially worse outcomes. However, when adjusting for comorbidities the COVID-19 was associated with decreased odds of readmission and 245 reintervention, and a small increased odds of reoperation. While our study design does not allow us to evaluate reasons for these findings, a potential reason could be earlier discharge during J o u r n a l P r e -p r o o f COVID-19 and increased post-operative management of non-life threatening complications via telehealth solutions (30, 31) . Overall, outcomes during the COVID-19 pandemic were similar to prior, which is in keeping with the largest international retrospective study by Singhal et al. (18) . 250

This study and ours support continuation of bariatric surgery during the COVID-19 pandemic with careful patient selection in order to provide care for patients with obesity, who also happen to be at substantial risk of morbidity and mortality from COVID-19 (17, 32) . Long-term outcomes are warranted and careful scrutiny of these practices is encouraged, especially considering the ongoing trend towards use of SG despite novel studies suggesting that RYGB outperforms SG in 255 terms of long-term weight loss and comorbidity resolution, particularly in patients with superobesity (25, (33) (34) (35) (36) (37) .

Considering the decrease in bariatric surgeries performed, the COVID-19 pandemic has created a substantial deficit in care for thousands of patients with obesity. Further, considering the shift 260 towards selecting less comorbid patients who can successfully be managed with SG, patients with super-obesity or substantial comorbidities are likely at a further deficit. Unfortunately, it is these patients that also stand to benefit most from bariatric intervention (37) (38) (39) . We hypothesize that as COVID-19 is eliminated or becomes endemic, a transition back towards operating on patients with increased comorbidities may occur. Studies evaluating delivery of bariatric surgery 265 care in the next year will be critical to further evaluate the impact and long-term effect of COVID-19. This would further characterize trends that are specific to COVID-19, and others that have occurred secondary to bariatric surgery optimization over time. Regardless, while surgical delays and deficits are often discussed in the oncologic setting, a similar call to action to J o u r n a l P r e -p r o o f prioritize surgical care of patients with obesity is needed considering the social, financial, and 270 functional benefits offered with these interventions (40) (41) (42) (43) .

Limitations of this study are primarily related to its retrospective nature and data limitations from MBSAQIP. In this study, the COVID-19 pandemic cohort was defined by any surgery occurring during the 2020 MBSAQIP data collection year. However, as we have all experienced, waves of 275 the pandemic has differed drastically and the effect on bariatric surgery delivery likely also varied during that time. Similarly, the COVID-19 pandemic has had variable effects on different countries, regions, and municipalities; because center specific data is not collected, the variability of those effects could not be evaluated. Additionally, because the COVID-19 pandemic began in 2019, some of the reported patients from 2019 may have also received 280 bariatric surgery during the pandemic. On the other hand, the beginning of 2020 had fewer cases, restrictions, and health care effects than other periods of the year and this temporal variability is summarized as an average throughout the year in this study. Comparing patients receiving bariatric surgery during COVID-19 to all patients from 2015-2019 also presents substantial limitations considering changes that occurred over time; to limit that effect we presented all 285 operative trends by year in order to put differences in context. Finally, as detailed above, the MBSAQIP database does not characterize outpatient management or other changes that likely occurred during the COVID-19 pandemic, which may represent substantial confounders in this study. Data from this study are also limited to 30 days following operation. Studies evaluating the effect of COVID-19 on outpatient management of bariatric surgery patients and long-term 290 outcomes following bariatric surgery during the COVID-19 pandemic are warranted. Despite these limitations, this study characterizes important trends and effects on bariatric surgery in North America secondary to the COVID-19 pandemic that will prove useful in evaluation of next steps as we continue to improve surgical care in the setting of health care resource limitations.

Understanding the impact that COVID-19 has elicited on bariatric surgery delivery in North America is crucial to evaluating future patient and technique selection. This is especially true as subsequent waves of the COVID-19 pandemic occur. During the COVID-19 pandemic, patients undergoing bariatric surgery have had fewer metabolic comorbidities and received SG at an unprecedented rate. It remains uncertain whether these changes will continue in the future and 300 how these changes will affect future bariatric surgery care. Regardless of COVID-19's trajectory, a growing trend towards SG has been hastened by the COVID-19 pandemic and ongoing evaluation of long-term outcomes as well as the socioeconomic consequences of this impacted delivery are warranted.

The COVID-19 pandemic has dramatically changed the landscape of bariatric delivery in North America. During the COVID-19 pandemic there was a 13.8% reduction in elective bariatric surgery cases despite increased reporting centers. Patients receiving surgery were less comorbid and more likely to receive SG, while outcomes were similar to prior. Future studies evaluating 310 persistent changes that occur following the COVID-19 pandemic, and further work characterizing the long-term effect of the COVID-19 pandemic on outcomes and the socioeconomic consequences of this impacted delivery are warranted. 

Surgery and COVID-19

Mortality and pulmonary complications in 320 patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Elective surgery cancellations due to the COVID-19 pandemic: global predictive modelling to inform surgical recovery plans

COVID-19: impact on 325 colorectal surgery

COVID-19 and the Global Impact on Colorectal Practice and Surgery

Practice Patterns of Colorectal Surgery During the COVID-19 Pandemic. Diseases of the Colon & Rectum

Effect of COVID-19 pandemic lockdowns on planned cancer surgery for 15 tumour types in 61 countries: an international, prospective, cohort study. The Lancet Oncology

The Impact of the COVID-19 Pandemic on Surgical Management of Breast Cancer: Global Trends and Future Perspectives

Impact of the COVID-19 Pandemic on Acute General Surgical Admissions in a District General Hospital in the United Kingdom: A Retrospective Cohort Study

Impact of the COVID-19 Pandemic on Emergency Adult Surgical Patients and Surgical Services: An International Multi-center Cohort Study and 340 Department Survey

At a glance: The impact of COVID-19 on emergency general surgery

Delivery of hepato-pancreato-biliary surgery during the COVID-19 pandemic: an European-African Hepato-Pancreato-Biliary 345

Association (E-AHPBA) cross-sectional survey. HPB : the official journal of the International Hepato Pancreato Biliary Association

Short-term Effects of Canceled Elective Procedures Due to COVID-19: Evidence From the Veterans Affairs Healthcare System

Impact of the COVID-19 pandemic on the detection 350 and management of colorectal cancer in England: a population-based study

Immediate and long-term impact of the COVID-19 pandemic on delivery of surgical services

Effect of COVID-19 pandemic on global Bariatric 355 surgery PRActiceS -The COBRAS study

Obesity and COVID-19: a call for action from people living with obesity

Global 30-day outcomes after bariatric surgery during the COVID-19 pandemic (GENEVA): an international cohort study. The Lancet Diabetes & 360 Endocrinology

Bariatric and metabolic surgery during and after the COVID-19 pandemic: DSS recommendations for management of surgical candidates and postoperative patients and prioritisation of access to surgery

Serious Impacts of Postponing Bariatric Surgery as a Result of the COVID-19 Pandemic: The Patient Perspective

The effect of the COVID-19 pandemic on bariatric surgery delivery in Edmonton, Alberta: a single-centre experience

Bariatric surgery during COVID-19 in the UK: a British Obesity and Metabolic Surgery Society (BOMSS) survey. Surgical Endoscopy

American College of Surgeons. MBSAQIP Participant Use Data File (PUF)

National Trends in Bariatric Surgery

Effect of Laparoscopic Sleeve Gastrectomy vs Laparoscopic Roux-en-Y Gastric Bypass on Weight Loss in Patients With Morbid Obesity: The SM-BOSS Randomized Clinical Trial

Trends and Outcomes of Laparoscopic Sleeve Gastrectomy Between 2015 and 2018 in the USA and Canada

Effect of Laparoscopic Sleeve Gastrectomy vs Laparoscopic Roux-en-Y Gastric Bypass on Weight Loss at 5 Years Among Patients With Morbid Obesity: The SLEEVEPASS Randomized Clinical Trial

Laparoscopic sleeve gastrectomy as day-case surgery (without overnight hospitalization)

Laparoscopic sleeve gastrectomy as day-case surgery: a case-matched study

The Impact of Telemedicine Adoption on a 390

Multidisciplinary Bariatric Surgery Practice During the COVID-19 Pandemic

Use of Telehealth by Surgical Specialties During the COVID-19 Pandemic

Associations between body-mass index and COVID-19 395 severity in 6&#xb7;9 million people in England: a prospective, community-based, cohort study

Systematic Review and Meta-Analysis of Randomised Controlled Trials Comparing Long-Term Outcomes of Roux-En-Y Gastric Bypass and Sleeve Gastrectomy

Long-term and midterm outcomes of laparoscopic sleeve gastrectomy versus Roux-en-Y gastric bypass: a systematic review and meta-analysis of comparative studies

Is There a Better Design for a Bariatric Procedure? The Case for a Single Anastomosis Duodenal Switch

Surgical management of supersuper obese patients: Roux-en-Y gastric bypass versus sleeve gastrectomy

Five Years of MBSAQIP Data: Characteristics, Outcomes, 410 and Trends for Patients with Super-obesity

Diabetes and hypertension in severe obesity and effects of gastric bypass-induced weight loss

Cost-effectiveness of bariatric surgery and non-surgical weight management programmes for adults with severe obesity: a decision analysis model

The real-world cost-effectiveness of bariatric surgery for the treatment of severe obesity: a cost-utility analysis

Impact of bariatric surgery on quality of life, functional capacity, and symptoms in patients with heart failure

Association of Bariatric Surgery With Vascular Outcomes

BMI, body mass index

GERD, gastroesophageal reflux disease; COPD, chronic obstructive pulmonary disease

PCI, percutaneous coronary intervention

*data on race combinations or other race was not captured in the MBSAQIP database prior

UTI, urinary tract infection

SSI, surgical site infection