Body mass index, cardiac surgery and clinical outcome. A single-center experience with 9125 patients

The effect of body mass index on short-term outcomes in patients undergoing off-pump coronary artery bypass grafting surgery: a retrospective study from a single cardiovascular center

OBJECTIVE

This study is designed to investigate the impact of body mass index (BMI) on the short-term outcomes of patients undergoing off-pump coronary artery bypass graft (OPCAB) surgery.

METHODS

Data was obtained from 1006 Chinese patients who underwent isolated, primary OPCAB at a high-traffic cardiovascular center during 2020. Subjects were categorized, by BMI, into a low & normal weight (LN) group (BMI < 24 kg/m2), an overweight (OVW) group (24 ≤ BMI < 28 kg/m2), and an obese (OBS) group (BMI ≥ 28 kg/m2). Information pertaining to patients' short-term outcomes (including incidence of mortality and morbidities; duration of postoperative mechanical ventilation; length of stay in the ICU and hospital; postoperative bleeding; etc.) were extracted, and the data from each group were compared.

RESULTS

The incidences of in-hospital mortality and morbidities were similar for all three groups. The volume of fluid infusion, postoperative bleeding within 24 h and total bleeding in LN group were higher than those in the OBS group (P < 0.001). The hemoglobin level was lower in the LN group than that in the OBS group (P < 0.001). Duration of mechanical ventilation and length of stay in the ICU in the LN group were longer than those in the OBS group (P < 0.001).

CONCLUSIONS

Our results demonstrate that BMI is not significantly related with short-term outcomes in OPCAB patients. However, we suggest that OPCAB patients with low-normal BMI are more susceptible to post-operative blood loss.

Association of body mass index with perioperative blood transfusion and short-term clinical outcomes in patients undergoing isolated coronary artery bypass grafting

BACKGROUND

Few studies have considered outcomes among low body mass index (BMI) cohorts undergoing coronary artery bypass grafting (CABG). This study aims to investigate the effects of low body weight on blood transfusion and perioperative outcomes in patients undergoing isolated CABG.

METHODS

This retrospective study enrolled consecutive cases from a single-center between January 2008 and December 2018. Low body weight/underweight was defined as a BMI < 18.5 kg/m², while normal BMI was defined as 18.5 ≤ BMI < 24.0 kg/m². The primary endpoint was the perioperative red blood cell (RBC) transfusion rate. Secondary endpoints include platelet and plasma transfusion rates, transfusion volume for all blood components, hospital length of stay, and the occurrence of adverse events including prolonged mechanical ventilation, re-intubation, re-operation, acute kidney injury, and 30-day all-cause mortality.

RESULTS

A total of 7,620 patients were included in this study. After 1:1 propensity score matching, 130 pairs were formed, with 61 pairs in the on-pump group and 69 pairs in the off-pump group. Baseline characteristics were comparable between the matched groups. Low body weight independently increased the risk of RBC transfusion (on-pump: OR = 3.837, 95% CI = 1.213-12.144, p = 0.022; off-pump: OR = 3.630, 95% CI = 1.875-5.313, p < 0.001). Moreover, within the on-pump group of the original cohort, BMI of < 18.5 kg/m² was independently correlated with increased risk of re-intubation (OR = 5.365, 95% CI = 1.159 to 24.833, p = 0.032), re-operation (OR = 4.650, 95% CI = 1.019 to 21.210, p = 0.047), and 30-day all-cause mortality (OR = 10.325, 95% CI = 2.011 to 53.020, p = 0.005).

CONCLUSION

BMI < 18.5 kg/m² was identified as an independent risk factor for increased perioperative RBC transfusion rate in patient underwent isolated CABG with or without CPB. Only on-pump underweight patients in the original cohort exhibited an increased risk for re-intubation, re-operation, and 30-day all-cause mortality. Physicians and healthcare systems should consider these findings to improve management for this population.

The Relationship Between Body Mass Index and In-Hospital Mortality in Patients Following Coronary Artery Bypass Grafting Surgery

Background: The association between Body Mass Index (BMI) and clinical outcomes following coronary artery bypass grafting (CABG) remains controversial. Our objective was to investigate the real-world relationship between BMI and in-hospital clinical course and mortality, in patients who underwent CABG. Methods: A sampled cohort of patients who underwent CABG between October 2015 and December 2016 was identified in the National Inpatient Sample (NIS) database. Outcomes of interest included in-hospital mortality, peri-procedural complications and length of stay. Patients were divided into 6 BMI (kg/m²) subgroups; (1) under-weight ≤19, (2) normal-weight 20-25, (3) over-weight 26-30, (4) obese I 31-35, (5) obese II 36-39, and (6) extremely obese ≥40. Multivariable logistic regression model was used to identify predictors of in-hospital mortality. Linear regression model was used to identify predictors of length of stay (LOS). Results: An estimated total of 48,710 hospitalizations for CABG across the U.S. were analyzed. The crude data showed a U-shaped relationship between BMI and study population outcomes with higher mortality and longer LOS in patients with BMI ≤ 19 kg/m² and in patients with BMI ≥40 kg/m² compared to patients with BMI 20-39 kg/m². In the multivariable regression model, BMI subgroups of ≤19 kg/m² and ≥40 kg/m² were found to be independent predictors of mortality. Conclusions: A complex, U-shaped relationship between BMI and mortality was documented, confirming the "obesity paradox" in the real-world setting, in patients hospitalized for CABG.

Weight impacts 1-year congenital heart surgery outcomes independent of race/ethnicity and payer

Body mass index, race/ethnicity, and payer status are associated with operative mortality in congenital heart disease (CHD). Interactions between these predictors and impacts on longer term outcomes are less well understood. We studied the effect of body mass index, race/ethnicity, and payer on 1-year outcomes following elective CHD surgery and tested the degree to which race/ethnicity and payer explained the effects of body mass index. Patients aged 2-25 years who underwent elective CHD surgery at our centre from 2010 to 2017 were included. We assessed 1-year unplanned cardiac re-admissions, re-interventions, and mortality. Step-wise, multivariable logistic regression was performed.Of the 929 patients, 10.4% were underweight, 14.9% overweight, and 8.5% obese. Non-white race/ethnicity comprised 40.4% and public insurance 29.8%. Only 0.5% died prior to hospital discharge with one additional death in the first post-operative year. Amongst patients with continuous follow-up, unplanned re-admission and re-intervention rates were 14.7% and 12.3%, respectively. In multivariable analyses adjusting for surgical complexity and surgeon, obese, overweight, and underweight patients had higher odds of re-admission than normal-weight patients (OR 1.40, p = 0.026; OR 1.77, p < 0.001; OR 1.44, p = 0.008). Underweight patients had more than twice the odds of re-intervention compared with normal weight (OR 2.12, p < 0.001). These associations persisted after adjusting for race/ethnicity, payer, and surgeon.Pre-operative obese, overweight, and underweight body mass index were associated with unplanned re-admission and/or re-intervention 1-year following elective CHD surgery, even after accounting for race/ethnicity and payer status. Body mass index may be an important modifiable risk factor prior to CHD surgery.

Overweight is associated with better one-year survival in elderly patients after cardiac surgery: a retrospective analysis of the MIMIC-III database

Background

The relationship of body mass index (BMI) to short- and long-term outcomes after cardiac surgery remains controversial, and the dose-response relationship between BMI and mortality in patients receiving cardiac surgery is unclear. Furthermore, the influence of age, concomitant disease, and types of surgery on the prognostic role of BMI has yet to be determined.

Methods

A retrospective cohort study with 6,473 adult patients receiving cardiac surgery was conducted using the Multiparameter Intelligent Monitoring in Intensive Care (MIMIC-III) database. Multivariate Cox proportional hazard analysis and multivariate logistic regression analysis were used to assess the association of BMI with 1-year and in-hospital mortality. Restricted cubic regression splines were used to evaluate the effect of BMI as a continuous variable and to determine appropriate cut points. Subgroup analyses were performed based on age, hypertension and types of surgery.

Results

The baseline characteristics of patients differed between BMI categories. On multivariable analysis, overweight patients (BMI 25–30 kg/m²) had a lower 1-year mortality [hazard ratio (HR) =0.660, 95% confidence interval (CI): 0.516–0.843, P=0.001] when compared with normal weight patients (BMI 18.5–25 kg/m²). For patients with BMI <30 kg/m², each 1 kg/m² BMI increase was independently associated with a significant decrease in the 1-year mortality risk (HR =0.936, 95% CI: 0.899–0.975, P=0.002), while in patients with BMI ≥30 kg/m², an increase in BMI did not increase the 1-year mortality risk (HR =1.032, 95% CI: 0.998–1.067, P=0.064). Subgroup analyses suggested the protective effect of overweight on post-cardiac surgery survival was confined to patients with advanced age (>60 years), hypertension and those undergoing isolated coronary artery bypass grafting (CABG).

Conclusions

Overweight was associated with better 1-year survival in patients after cardiac surgery when compared to normal weight. The protective effect of overweight on post-cardiac surgery survival was confined to elderly patients (>60 years).

Prognostic Impact of Underweight (Body Mass Index <20 kg/m2) in Patients With Severe Aortic Valve Stenosis Undergoing Transcatheter Aortic Valve Implantation or Surgical Aortic Valve Replacement (from the German Aortic Valve Registry [GARY])

According to the Valve Academic Resortium, underweight is one parameter in the definition of frailty, which is associated with increased mortality after transcatheter aortic valve implantation (TAVI) and surgical aortic valve replacement (SAVR). Aims of our study were (1) to examine the impact of underweight on mortality after TAVI and SAVR and (2) to determine the effect of intervention mode (TAVI vs SAVR) on mortality in underweight patients from the German Aortic Valve Registry. Overall, 35,109 patients treated with TAVI or SAVR were studied. Outcomes of underweight (body mass index [BMI] <20 kg/m²) TAVI and SAVR patients were compared using propensity score weighting. Prevalence of underweight was 5.7% in patients who underwent TAVI and 2.9% in patients who underwent SAVR. Underweight patients had significantly increased mortality rates for both treatment strategies compared with normal weight patients (BMI 20 to 30 kg/m²). Comparing underweight TAVI and SAVR-patients using propensity score weighting, no statistically significant differences regarding mortality rates were observed. Subgroup analysis of severely underweight patients (BMI <18.5 kg/m²) revealed no significant increase of mortality after TAVI compared with underweight patients (BMI <20 kg/m²), whereas severely underweight SAVR patients showed twofold increased mortality rates. In conclusion, underweight in patients who underwent TAVI or SAVR is rare, but it is associated with increased mortality. Especially severely underweight SAVR patients showed excess mortality rates.

Dose-Response Meta-Analysis of the Impact of Body Mass Index on Mortality in the Intensive Care Unit

INTRODUCTION

Both low and high body mass index (BMI) are associated with mortality in the intensive care unit (ICU). Although many studies have been done to determine the relationship between BMI and risk of mortality in the ICU, their results were inconsistent. This study aimed to conduct a dose-response meta-analysis of published observational studies to assess the effect of BMI on the risk of mortality in patients admitted to the ICU.

METHODS

PubMed, Scopus, and Google Scholar were searched to identify articles up to May 2019. A total of 31 relevant articles, with 238,961 patients and a follow-up period of 1 month to 11 years, were analyzed.

RESULTS

Linear analysis showed a 0.6% decrease in mortality rate per unit (kg/m² ) increase in BMI (odds ratio: 0.99; 95% CI, 0.98-0.99). In addition, nonlinear analysis showed a decrease in risk of mortality for a BMI of 35 (P < .001) and then increased the risk of mortality with a BMI > 35 (P < .001).

CONCLUSION

This dose-response meta-analysis revealed that a BMI ≤ 35 can be a protective agent against mortality, but a BMI > 35 is a life-threatening factor in patients admitted to the ICU.

Association of body mass index and all-cause mortality in patients after cardiac surgery: A dose-response meta-analysis

Ample studies have reported the effect of body mass index (BMI) on the prognosis of patients undergoing cardiac surgery, but the results remain inconsistent. Therefore, we aimed to conduct a dose-response meta-analysis to clarify the relationship between BMI and all-cause mortality in this population. A systematic search was performed in the PubMed and Embase databases through April 2019 for studies that reported the impact of BMI on all-cause mortality in patients after cardiac surgery. Pooled risk ratios (RRs) were calculated using a random-effects model. Non-linear associations were explored with restricted cubic spline models. Forty-one studies with a total of 54,300 cases/1,774,387 patients were included. The pooled RR for all-cause mortality was 0.93 (95% CI 0.89-0.97) for every 5-unit increment in BMI, indicating that higher BMI did not increase the risk of all-cause mortality in patients after cardiac surgery. A U-shaped association with the nadir of risk at a BMI of 25-27.5 kg/m² was observed, as well as a higher mortality risk for the underweight and the extremely obese patients. The subgroup analysis revealed that this phenomenon remained regardless of mean age, surgery type, geographic location and number of cases. Overall, for patients after cardiac surgery, a slightly higher BMI may be instrumental in survival, whereas underweight and extreme obesity is associated with a worse prognosis.

Maternal factors and preoperative nutrition in children with mild cases of congenital heart disease

AIM

The preoperative poor nutrition of children with congenital heart disease (CHD) impacts the postoperative rehabilitation process of pediatric CHD cases. The factors of these children's preoperative poor nutrition, excluding the disease, have been underreported. The aim was to investigate the preoperative nutritional status of children with CHD who required a simple surgical repair and to analyze the maternal characteristics that are associated with poor nutrition in these sick children.

METHODS

This was a cross-sectional survey. The weight and height of the children were measured, maternal data were collected via a questionnaire and a univariate analysis and multivariate logistic regression were used to analyze the association between maternal factors and the preoperative poor nutrition of the children with CHD.

RESULTS

A total of 119 children with simple CHD were recruited to the study. The prevalence of poor nutrition was higher in the children with CHD ("cases") than in the healthy children ("controls"). An increased risk of poor nutrition was associated with lower mothers' perception, education level, understanding of the disease, and higher anxiety.

CONCLUSIONS

Paying attention to maternal anxiety, depression, and knowledge and providing interventions for the mothers of children with CHD are important in order to promote the nutritional status of these children.

Hyperglycemic Episodes Are Associated With Postoperative Infections After Cardiac Surgery

BACKGROUND AND AIMS

To describe the incidence of and risk factors for postoperative infections and the correlation between postoperative hyperglycemia despite tight blood glucose control with infectious and other complications after contemporary cardiac surgery.

MATERIAL AND METHODS

The study comprised 1356 consecutive adult patients who underwent cardiac surgery between January 2013 and December 2014 and were followed up for 6 months. Patients surviving the first 2 days were included in the analysis. Preoperative demographic information, medical history, procedural details, and the postoperative course were recorded. The target range for blood glucose levels was 4-7 mmol/L and repeated arterial blood samples were obtained during the intensive care unit stay. The associations of blood glucose levels during the first postoperative day and the occurrence of postoperative infections and other significant complications were analyzed.

RESULTS

Of the study cohort, 9.8% developed infectious complications which were classified as major surgical site infections in 2.2%, minor surgical site infections in 1.1%, lung infections in 2.0%, unclear fever or bacteremia in 0.3%, cannula or catheter related in 2.6%, multiple in 1.5%, and other in 0.2%. The incidence of deep sternal wound infection was 2.0%. Repeated hyperglycemia occurred in 39.7% of patients and was associated with increased rates of postoperative infections, 12.1% versus 8.2%, p = 0.019; stroke, 4.9% versus 1.5%, p < 0.001; and mortality, 6.1% versus 2.1%, p < 0.001, when compared to patients with single or no hyperglycemia.

CONCLUSION

Every 10th patient develops infectious complications after cardiac surgery. Repeated hyperglycemia is associated with increased rates of infectious complications, stroke, and mortality.

Body Mass Index and Mortality Among Adults Undergoing Cardiac Surgery: A Nationwide Study With a Systematic Review and Meta-Analysis

BACKGROUND

In an apparent paradox, morbidity and mortality are lower in obese patients undergoing cardiac surgery, although the nature of this association is unclear. We sought to determine whether the obesity paradox observed in cardiac surgery is attributable to reverse epidemiology, bias, or confounding.

METHODS

Data from the National Adult Cardiac Surgery registry for all cardiac surgical procedures performed between April 2002 and March 2013 were extracted. A parallel systematic review and meta-analysis (MEDLINE, Embase, SCOPUS, Cochrane Library) through June 2015 were also accomplished. Exposure of interest was body mass index categorized into 6 groups according to the World Health Organization classification.

RESULTS

A total of 401 227 adult patients in the cohort study and 557 720 patients in the systematic review were included. A U-shaped association between mortality and body mass index classes was observed in both studies, with lower mortality in overweight (adjusted odds ratio, 0.79; 95% confidence interval, 0.76-0.83) and obese class I and II (odds ratio, 0.81; 95% confidence interval, 0.76-0.86; and odds ratio, 0.83; 95% confidence interval, 0.74-0.94) patients relative to normal-weight patients and increased mortality in underweight individuals (odds ratio, 1.51; 95% confidence interval, 1.41-1.62). In the cohort study, a U-shaped relationship was observed for stroke and low cardiac output syndrome but not for renal replacement therapy or deep sternal wound infection. Counter to the reverse epidemiology hypotheses, the protective effects of obesity were less in patients with severe chronic renal, lung, or cardiac disease and greater in older patients and in those with complications of obesity, including the metabolic syndrome and atherosclerosis. Adjustments for important confounders did not alter our results.

CONCLUSIONS

Obesity is associated with lower risks after cardiac surgery, with consistent effects noted in multiple analyses attempting to address residual confounding and reverse causation.

Do acute hospitalised patients in Australia have a different body mass index to the general Australian population: a point prevalence study?

Objective The aim of the present study was to provide a current snapshot of the body mass index (BMI) of the entire patient cohort of an Australian tertiary hospital on one day and compare these data with current published Australian and state (Western Australia) population norms. Methods A single-centre prospective point prevalence study was performed whereby BMI was calculated following actual measurement of patient weight (nurse) and height (physiotherapist) on one day during 2015. Variables were summarised descriptively, and one-way analysis of variance was used to investigate the relationship between continuous BMI and hospital speciality. Multivariate Cox proportional hazards regression was used to analyse the time to leaving hospital, where those who died were censored at their date of death. Results Data were collected from 416 patients (96% of the hospital population on that day). The mean (± s.e.m.) BMI across the whole hospital population was 26.6±2.2kgm-2, with 37% of patients having normal BMI, 8% being underweight, 32% being overweight, 19% being obese and 4% being severely obese. Comparison with both national and state population norms for 2014-15 reflected higher proportions of the hospital population in the underweight and extremely obese categories, and lower proportions in the overweight and obese categories. There was no significant difference in BMI across medical specialties. Conclusions Despite health warnings about the direct relationship between illness and being overweight or obese, the results of the present study reveal fewer hospitalised patients in these BMI categories and more underweight patients than in the non-hospitalised general Australian population. Being overweight or obese may offer some protection against hospitalisation, but there is a point where the deleterious effect of obesity results in more extremely obese individuals being hospitalised than the proportion represented in the general population. What is known about the topic? Although there is significant current published data relating to general Australian population BMI, there is little pertaining specifically to the hospitalised population. Accordingly, although we know that as an affluent Western country we are seeing growing rates of overweight and obese people and relatively few underweight or undernourished people in the general population, we do not know whether these trends are mirrored or magnified in those who are sick in hospital. We also know that although caring for obese patients carries a significant burden, there is the suggestion in some healthcare literature of an 'obesity paradox', whereby in certain disease states being overweight actually decreases mortality and promotes a faster recovery from illness compared with underweight people, who have poorer outcomes. What does this paper add? This paper is the first of its kind to actually measure and calculate the BMI of a whole tertiary Australian hospital population and provide some comparison with published Australian norms. On average, the hospital cohort was overweight, with a mean (± s.e.m.) BMI of 26.6±2.2kgm-2, but less so than the general population, which had a mean BMI of 27.5±0.2kgm-2. The results also indicate that compared with state and national norms, underweight and extremely obese patients were over-represented in the hospitalised cohort, whereas overweight or obese patients were under-represented. What are the implications for practitioners? Although only a single-centre study, the case-mix and socioeconomic catchment area of the hospital evaluated in the present study suggest that it is a typical tertiary urban West Australian facility and, as such, there may be some implications for practitioners. Primarily, administrators need to ensure that we are able to accommodate people of increasing weight in our hospital facilities and have the resources with which to do so, because, on average, hospitalised patients were overweight. In addition, resources need to be available for managing the extremely obese if numbers in this subset of the population increase. Finally, practitioners may also need to consider that although the management of underweight and undernourished patients may be less of a physical burden, there are actually more of these patients in hospital compared with the general population, and they may require a different package of resource utilisation.

Obesity Does Not Impact Perioperative or Postoperative Outcomes in Patients with Inflammatory Bowel Disease

BACKGROUND

While the prevalence of obesity in IBD patients is rapidly increasing, it is unclear if obesity impacts surgical outcomes in this population. We aim to investigate the effects of BMI on perioperative and postoperative outcomes in IBD patients by stratifying patients into BMI groups and comparing outcomes between these groups.

METHODS

This is a retrospective cohort study where IBD patients who underwent intestinal surgeries between the years of 2000 to 2014 were identified. The patients were divided into groups based on BMI: underweight (BMI <18.5), normal weight (BMI 18.5-24.9), overweight (BMI 25-29.9), and obese (BMI ≥30). Preoperative patient demographics, operative variables, and postoperative complications were collected and compared between BMI groups.

RESULTS

A total of 391 surgeries were reviewed (34 underweight, 187 normal weight, 105 overweight, and 65 obese) from 325 patients. No differences were observed in preoperative patient demographics, type of IBD, preoperative steroid or biologic mediator use, or mean laboratory values. No differences were observed in percent operative procedures with anastomosis, surgeries converted to open, estimated blood loss, intraoperative complications, and median operative time. Thirty-day postoperative complication rates including total complications, wound infection, or anastomotic leak were similar between groups. There was a statistically significant increased postoperative bleeding risk (p = 0.029) in underweight patients. The relative percent for increased postoperative bleeding risk between BMI groups was as follows: 2.9% in underweight, zero in normal weight, 2.9% in overweight, and zero in obese.

CONCLUSION

Obesity does not appear to impact intraoperative variables nor does obesity appear to worsen postoperative complication rates in IBD patients.

Impact of Body Mass Index on Outcomes in Cardiac Surgery

OBJECTIVES

Body mass index (BMI) commonly is used in obesity classification as a surrogate measure, and obesity is associated with a cluster of risk factors for cardiovascular disease. The aim of this study was to investigate the impact of BMI on short-term outcomes after cardiac surgery.

DESIGN

A retrospective cohort study.

SETTING

University teaching hospital, 2 centers.

PARTICIPANTS

The study comprised 4,740 patients who underwent cardiac surgery at 2 hospitals-from July 1, 2001, to June 30, 2013, in 1 hospital and from September 1, 2003, to August 31, 2014, in a second hospital.

INTERVENTIONS

No changes to standard practice were required.

MEASUREMENTS AND MAIN RESULTS

Patients were assigned into 6 BMI groups as follows: underweight (BMI<18.5 kg/m(2)), normal weight (≥18.5 to<25 kg/m(2)), overweight (≥25 to<30 kg/m(2)), class I obese (≥30 to<35 kg/m(2)), class II obese (≥35 to<40 kg/m(2)), and class III obese (BMI≥40 kg/m(2)). Short-term major postoperative complications (postoperative stroke, cardiac arrest, new atrial fibrillation/flutter, permanent rhythm device insertion, deep sternal infection, sepsis, prolonged ventilation, pneumonia, renal dialysis, renal failure, intensive care unit readmission, total intensive care unit hours, and readmission in 30 days, and mortalities (in-hospital mortality, 30-day mortality, surgical mortality) were compared among various BMI groups after cardiac surgery. Age, sex, surgery type, family history of coronary artery disease, diabetes, hypertension, heart failure, and lipid-lowering medication were the risk factors for early outcomes. Multiple logistic regression analysis indicated that the underweight and class III obese BMI groups demonstrated significant, adverse differences in some short-term outcomes, including deep sternal infection, prolonged ventilation, new atrial fibrillation/flutter, and renal failure. However, being in the overweight or class I obese group demonstrated a positive effect on discharge and surgical mortality.

CONCLUSIONS

The results of this study demonstrated that extreme obesity and underweight were significantly associated with early major adverse clinical outcomes. However, there was an "obese paradox" in short-term mortality after cardiac surgery.

Obesity, regardless of comorbidity, influences outcomes after colorectal surgery-time to rethink the pay-for-performance metrics?

An elevated body mass index (BMI) is associated with increased morbidity and mortality after colorectal surgery. While coexistent comorbid conditions are captured in some determinations of case-severity, BMI itself is not factored into pay for performance (P4P) initiatives. From the National Surgical Quality Improvement Program database 2006-2011, obese (BMI ≥30 kg/m(2)) and nonobese (BMI <30 kg/m(2)) patients with and without comorbidity undergoing colorectal resection were identified. Pre- and intraoperative factors as well as postoperative outcomes were compared. Of 130,415 patients, 31.3 % were obese. 80.4 % of obese and 72.9 % of nonobese patients had comorbid conditions. Among obese patients, overall rates of surgical site infection (SSI), wound dehiscence, and various medical complications were significantly higher for those with comorbidity compared to those without (p < 0.001 for all). Obese patients with comorbidity overall had greater risk of renal failure and urinary tract infection than nonobese patients. Regardless of comorbidity, obese patients more commonly had pulmonary embolism, failure to wean from the ventilator, overall SSI, and wound dehiscence. Comorbid factors associated with obesity influence outcomes; however, obesity itself in their absence is associated with worse outcomes. This supports inclusion of obesity as an independent determinant of case-severity, quality, and reimbursement after colorectal surgery.