Does Improved Mortality at Low- and Medium-Volume Hospitals Lead to Attenuation of the Volume to Outcomes Relationship for Major Visceral Surgery?

Dynamic volume-outcome association for esophagectomies: Do current volume thresholds still apply?

BACKGROUND

It is unknown if the current minimum case volume recommendation of 20 cases per year per hospital is applicable to contemporary practice.

METHODS

Patients undergoing esophageal resection between 2005 and 2015 were identified in the National Cancer Database. High, medium, and low-volume hospital strata were defined by quartiles. Adjusted odds ratios and adjusted 30-day mortality between low-, medium-, and high-volume hospitals were calculated using logistic regression analyses and trended over time.

RESULTS

Only 1.1% of hospitals had ≥20 annual cases. The unadjusted 30-day mortality for esophagectomy was 3.8% overall. Unadjusted and adjusted 30-day mortality trended down for all three strata between 2005 and 2015, with disproportionate decreases for low-volume and medium-volume versus high-volume hospitals. By 2015, adjusted 30-day mortality was similar in medium- and high-volume hospitals (odds ratio 1.35, 95% confidence interval 0.96-1.91). For hospitals with 20 or more annual cases the adjusted 30-day mortality was 2.7% overall. To achieve this same 30-day mortality the minimum volume threshold had lowered to 7 annual cases by 2015.

CONCLUSION

Only 1.1% of hospitals meet current volume recommendations for esophagectomy. Differential improvements in postoperative mortality at low- and medium- versus high-volume hospitals have led to 7 cases in 2015 achieving the same adjusted 30-day mortality as 20 cases in the overall cohort. Lowering volume thresholds for esophagectomy in contemporary practice would potentially increase the proportion of hospitals able to meet volume standards and increase access to quality care without sacrificing quality.

Effect of General Surgery Resident Participation in Thoracic Surgery on Oncologic Outcomes: An Observational Cohort Study

Background: Despite increasing sub-specialization, general surgeons continue to perform oncologic thoracic surgeries. Our objective was to determine whether general surgery resident participation in thoracic surgery affects surgical quality or oncologic outcomes. We hypothesized that patient outcomes with and without resident participation would be similar. Methods: We retrospectively reviewed the electronic health records of patients with stage 0-IV lung cancer undergoing oncologic pulmonary resection at BLINDED FOR REVIEW during an 11-year period (2012-2022). Patients younger than 18 years or older than 85 years were excluded, as were those who had incomplete follow-up data or were unregistered in our institutional cancer registry. Patients were divided into groups based on whether residents or staff surgeons completed >50% of the critical portions of the operation. We compared 30-day morbidity outcomes, overall survival (OS), and disease-free survival (DFS). Results: Three hundred thirteen patients met inclusion criteria. Demographic and clinical characteristics were similar between groups, as were types of surgical resection and median operative times. A statistical difference was found in the distribution of surgical approach. The odds of morbidity were 65% higher in the Staff group (OR=1.65; 95% CI, 1.007-2.71). Resident participation was not significantly associated with OS or DFS (P =.32 and P =.54, respectively). Discussion: General surgery resident involvement in lung cancer operations is not associated with longer operative times but is associated with a higher likelihood of a thoracotomy. General surgery resident involvement was associated with decreased postoperative morbidity and did not significantly affect OS or DFS.

Variation in Hospital Mortality After Complex Cancer Surgery: Patient, Volume, Hospital or Social Determinants?

INTRODUCTION

We sought to define the individual contributions of patient characteristics (PCs), hospital characteristics (HCs), case volume (CV), and social determinants of health (SDoH) on in-hospital mortality (IHM) after complex cancer surgery.

METHODS

The California Department of Health Care Access and Information database identified patients who underwent esophagectomy (ES), pneumonectomy (PN), pancreatectomy (PD), or proctectomy (PR) for a malignant diagnosis between 2010 and 2020. Multi-level multivariable regression was performed to assess the proportion of variance explained by PCs, HCs, CV and SDoH on IHM.

RESULTS

A total of 52,838 patients underwent cancer surgery (ES: n = 2,700, 5.1%; PN: n = 30,822, 58.3%; PD: n = 7530, 14.3%; PR: n = 11,786, 22.3%) across 294 hospitals. The IHM for the overall cohort was 1.7% and varied from 4.4% for ES to 0.8% for PR. On multivariable regression, PCs contributed the most to the variance in IHM (overall: 32.0%; ES: 21.6%; PN: 28.0%; PD: 20.3%; PR: 39.9%). Among the overall cohort, CV contributed 2.4%, HCs contributed 1.3%, and SDoH contributed 1.2% to the variation in IHM. CV was the second highest contributor to IHM among ES (5.3%), PN (5.3%), and PD (5.9%); however, HCs were a more important contributor among patients who underwent PR (8.0%). The unexplained variance in IHM was highest among ES (72.4%), followed by the PD (67.5%) and PN (64.6%) patient groups.

CONCLUSIONS

PCs are the greatest underlying contributor to variations in IHM following cancer surgery. These data highlight the need to focus on optimizing patients and exploring unexplained sources of IHM to improve quality of surgical care.

Understanding Variation in In-hospital Mortality After Major Surgery in the United States

OBJECTIVES

We aimed to quantify the contributions of patient characteristics (PC), hospital structural characteristics (HC), and hospital operative volumes (HOV) to in-hospital mortality (IHM) after major surgery in the United States (US).

BACKGROUND

The volume-outcome relationship correlates higher HOV with decreased IHM. However, IHM after major surgery is multifactorial, and the relative contribution of PC, HC, and HOV to IHM after major surgery is unknown.

STUDY DESIGN

Patients undergoing major pancreatic, esophageal, lung, bladder, and rectal operations between 2006 and 2011 were identified from the Nationwide Inpatient Sample linked to the American Hospital Association survey. Multilevel logistic regression models were constructed using PC, HC, and HOV to calculate attributable variability in IHM for each.

RESULTS

Eighty thousand nine hundred sixty-nine patients across 1025 hospitals were included. Postoperative IHM ranged from 0.9% for rectal to 3.9% for esophageal surgery. Patient characteristics contributed most of the variability in IHM for esophageal (63%), pancreatic (62.9%), rectal (41.2%), and lung (44.4%) operations. HOV explained < 25% of variability for pancreatic, esophageal, lung, and rectal surgery. HC accounted for 16.9% and 17.4% of the variability in IHM for esophageal and rectal surgery. Unexplained variability in IHM was high in the lung (44.3%), bladder (39.3%), and rectal (33.7%) surgery subgroups.

CONCLUSIONS

Despite recent policy focus on the volume-outcome relationship, HOV was not the most important contributor to IHM for the major organ surgeries studied. PC remains the largest identifiable contributor to hospital mortality. Quality improvement initiatives should emphasize patient optimization and structural improvements, in addition to investigating the yet unexplained sources contributing to IHM.

Mortality factors in pancreatic surgery: A systematic review. How important is the hospital volume?

BACKGROUND

How the extent of confounding adjustment impact (hospital) volume-outcome relationships in published studies on pancreatic cancer surgery is unknown.

METHODS

A systematic literature search was conducted for studies that investigated the relationship between volume and outcome using a risk adjustment procedure by querying the following databases: PubMed, Cochrane Central Register of Controlled Trials, Livivo, Medline and the International Clinical Trials Registry Platform (last query: 2020/09/16). Importance of risk-adjusting covariates were assessed by effect size (odds ratio, OR) and statistical significance. The impact of covariate adjustment on hospital (or surgeon) volume effects was analyzed by regression and meta-regression models.

RESULTS

We identified 87 studies (75 based on administrative data) with nearly 1 million patients undergoing pancreatic surgery that included in total 71 covariates for risk adjustment. Of these, 33 (47%) had statistically significant effects on short-term mortality and 23 (32%) did not, while for 15 (21%) factors neither effect size nor statistical significance were reported. The most important covariates for short term mortality were patient-specific factors. Concerning the covariates, single comorbidities (OR: 4.6, 95% CI: 3.3 to 6.3) had the strongest impact on mortality followed by hospital volume (OR: 2.9, 95% CI: 2.5 to 3.3) and the procedure (OR: 2.2, 95% CI: 1.9 to 2.5). Among the single comorbidities, coagulopathy (OR: 4.5, 95% CI: 2.8 to 7.2) and dementia (OR: 4.2, 95% CI: 2.2 to 8.0) had the strongest influence on mortality. The regression analysis showed a significant decrease hospital volume effect with an increasing number of covariates considered (OR: 0.06, 95% CI: 0.10 to -0.03, P < 0.001), while such a relationship was not observed for surgeon volume (P = 0.35).

CONCLUSIONS

This analysis demonstrated a significant inverse relationship between the extent of risk adjustment and the volume effect, suggesting the presence of unmeasured confounding and overestimation of volume effects. However, the conclusions are limited in that only the number of included covariates was considered, but not the effect size of the non-included covariates.

Comparison of surgical outcomes for colostomy closure performed by acute care surgeons versus a dedicated colorectal surgery service

BACKGROUND

Despite colostomy closure being a common procedure, it remains highly morbid. Previous literature suggests that complication rates, including surgical site infections, intra-abdominal abscess, and anastomotic failures, reach as high as 50%. With the creation of a dedicated colorectal service, colostomy reversals have been largely migrated from the acute care surgery services. This study analyzes the differences in outcomes in colostomy closures performed between colorectal surgeons and acute care surgeons.

METHODS

We retrospectively analyzed our experience with 127 colostomy closures performed in our hospital system by acute care surgeons and colorectal surgeons from 2016 through 2020. Demographic data, operative data, and outcomes such as abscess formation, anastomotic leak, and readmission were analyzed. Multivariate regression analysis was performed for intraabdominal abscesses and anastomotic leaks.

RESULTS

In total, 71 colostomy closures were performed by colorectal surgeons (56%) and 56 by acute care surgeons (43%). The majority of colostomy reversals were after Hartmann's procedure for perforated diverticulitis. No differences in demographics were identified, except for a shorter interval to closure in the acute care surgeons group (10.0 vs 7.2 months; P = .049). Two (3.6%) acute care surgeon patients required colorectal surgeon consultation during the definitive repair. Regression analysis identified body mass index (odds ratio 2.43; P = .001), male gender (odds ratio -2.39; P = .18), and colorectal surgeons (odds ratio -2.28; P = .025) as significant risk factors for anastomotic leak.

CONCLUSION

Analysis of the current series identified female gender and increased body mass index as higher risk, while procedures performed by colorectal surgeons were at decreased risk for anastomotic leak. Our study identified colostomy reversals performed by a dedicated colorectal service decreased the rate of anastomotic leak.

Identifying the Optimal case-volume threshold for pancreatectomy in contemporary practice

BACKGROUND

The volume-mortality association led to regionalization recommendations for pancreatic surgery. Mortality following pancreatectomy has declined, but case-volume thresholds remain unchanged.

METHODS

Patients undergoing pancreatectomy from 2004 to 2013 were identified in the National Cancer Database (NCDB). Hospitals were divided into low (LV), medium (MV), and high-volume (HV) strata using 30-day mortality quartiles and logistic regression with cubic splines. Adjusted absolute difference and odds of 30-day mortality between strata were calculated.

RESULTS

Annual volumes for LV, MV, and HV were <4, 4-18 and > 18 cases using quartiles and <6, 6-18 and > 18 using cubic splines. Absolute 30-day mortality trended downwards, with differential improvements for MV and LV. Benchmark 30-day mortality for hospitals with >18 cases was 2.8%. For this benchmark, the case-volume threshold decreased from 31 in 2004 to 6 in 2013.

CONCLUSION

Differential improvement in 30-day mortality at LV and MV hospitals led to similar 30-day mortality odds at MV and HV hospitals by 2013.

The adequacy of lymph node clearance in colon cancer surgery performed in a non-specialist centre; implications for practice

BACKGROUND

Despite recent medical advances, surgery remains the mainstay treatment in colon cancer. It is well established that better patient outcomes are achieved when complex surgery including pancreatic, oesophageal and rectal surgeries are carried out in high-volume centres. However, it is unclear as to whether or not colon cancer patients receive the same benefit. Lymph node adequacy is a key performance indicator of successful oncological colonic resection which impacts on patient outcome.

AIM

To assess the adequacy of lymph node clearance during colonic resection performed with curative intent in a non-specialist centre post introduction of the National Cancer Strategy.

METHODS

Retrospective analysis was performed of a prospectively maintained database examining the lymph node clearance of all oncological resections for colon cancer over a 7-year period (Nov 2010-Dec 2017) at a satellite unit with links to a regional specialist centre. Primary outcome measured was the number of lymph nodes retrieved. Secondary outcomes included resection margins, 30-day complication rate and survival at 1 year. Statistical analysis was performed using SPSS Statistics for Windows, version 24.0 (IBM Corp, Armonk, N.Y., USA).

RESULTS

One hundred sixty-seven patients were included. Mean age was 71.0 ± 11.6 years. Majority were male (n = 90, 53.6%). The majority of resections was right sided (n = 112.66.7%) with 78.6% of all resections being undertaken electively. All margins were free of tumour. The average lymph node count was 19.93 ± 8.63 (4.62) with only 17 (10.2%) of specimens containing < 12 nodes. The anastomotic leak rate was 3.3%. There was no association between surgeon or pathologist volume, nor emergent status and achieving oncological lymph node count (p = 0.14, 0.29, 0.97). 90.5% of patients were alive at 1 year.

CONCLUSIONS

This study demonstrates that colonic cancer surgery can be safely performed in a non- specialist centre with technical outcomes comparable to nationally reported figures.