Volume-outcome Relationship Research Articles

Volume-Outcome Relations of Percutaneous Coronary Intervention in Patients Presenting With Acute Myocardial Infarction (from the J-PCI Registry)

A lower institutional primary percutaneous coronary intervention (PCI) volume is associated with a higher risk of postprocedural poor outcomes, particularly in urgent or emergent settings (e.g., PCI for acute myocardial infarction [MI]). However, the individual prognostic impact of PCI volume stratified by indication and the relative ratio remains unclear. Using the Japanese nationwide PCI database, we investigated 450,607 patients from 937 institutions who underwent either primary PCI for acute MI or elective PCI. The primary end point was the observed/predicted in-hospital mortality ratio. The predicted mortality per patient was calculated using the baseline variables and averaged for each institution. The relation between the annual primary, elective, and total PCI volumes and institutional in-hospital mortality after acute MI was evaluated. The association between the primary-to-total PCI volume per hospital and mortality was also investigated. Of the 450,607 patients, 117,430 (26.1%) underwent primary PCI for acute MI, of whom 7,047 (6.0%) died during hospitalization. The median total PCI volume and primary-to-total PCI volume ratio were 198 (interquartile range 115 to 311) and 0.27 (0.20 to 0.36). Overall, the observed in-hospital mortality and observed/predicted mortality ratio in patients with acute MI were higher in institutions with lower primary, elective, and total PCI volumes. The observed/predicted mortality ratio was also higher in institutions with lower primary-to-total PCI volume ratios, even in high-PCI volume hospitals. In conclusion, in this nationwide registry-based analysis, lower institutional PCI volumes, regardless of setting, were associated with higher in-hospital mortality after acute MI. The primary-to-total PCI volume ratio provided independent prognostic information.

Selective referral or learning by doing? An analysis of hospital volume-outcome relationship of vascular procedures.

This paper analyzes the effects of hospital volume on outcomes of patients undergoing percutaneous transluminal angioplasty (PTA) with stent implant in Slovakia between 2014 and 2019. The volume-outcome relationship is estimated jointly using a discrete factor approach, where choice of hospital is correlated with durations until readmission or death, accounting for observed and unobserved characteristics. The results reveal the importance of controlling for between-hospital differences and selectivity in patient referral. Estimates without hospital fixed effects overstate the positive effect of volume on outcomes, but the results remain statistically significant. Once selectivity is accounted for in the joint correlated model, the positive volume-outcome relationship is not different from zero. Overall, the main driver of the volume-outcome relationship for PTA procedures appears to be related to selective referral and differences in quality of health care providers.

Effect of prostate brachytherapy case volume in the community setting on oncologic outcomes.

339 Background: A volume-outcome relationship has not yet been comprehensively established for prostate cancer brachytherapy, a treatment modality that is declining in usage, with regard to cancer-specific outcomes. The goal of this study is to describe the relationship between facility brachytherapy case volume and cancer-specific outcomes in patients with localized prostate cancer. Methods: We identified patients in CaPSURE (Cancer of the Prostate Strategic Urologic Research Endeavor) diagnosed with localized prostate cancer between 1999-2007 and treated with brachytherapy. Only community hospital settings had sufficient documented cases for inclusion. The brachytherapy case volume of each facility was based on its total number of brachytherapy-treated prostate cancer patients with facilities above the 75th percentile categorized as high-volume facilities. The primary outcome was biochemical failure based on the Phoenix definition or receipt of salvage treatment after primary brachytherapy. We used logistic regression to compute a propensity score for on high vs low volume facility based on demographic, clinical, and treatment variables. Cumulative incidence of biochemical failure and prostate cancer specific mortality of patients were assessed with lifetable estimates, log-rank test, and Cox proportional hazards regression, adjusted for propensity score and case volume. Secondary outcomes included patient-reported UCLA Prostate Cancer scores for urinary, sexual, and bowel function and bother. Results: We identified 1,282 patients with localized prostate cancer treated with brachytherapy between 1999-2007 across 18 community facilities with median follow-up of 9 years. The median number of brachytherapy cases over the 8 study years was 210. 722 patients (56.3%) received brachytherapy at high-volume (>210 cases) community facilities and 560 patients (43.7%) at low-volume (10-210 cases) facilities. High-volume facilities predominantly used Pd-103 seeds while low-volume facilities predominantly used I-125 seeds. A greater proportion of patients at low-volume facilities had pre-brachytherapy hormone therapy (47% vs 26%; p<0.01). Cumulative incidence of biochemical failure at 10 years was 10.3% for high-volume facilities and 12.5% for low-volume facilities (p=0.27). Cumulative incidence of prostate cancer specific mortality at 10 years was 4.0% for high-volume facilities and 4.5% for low-volume facilities (p=0.62). Patient-reported scores of urinary, sexual, and bowel bother at 6 months following brachytherapy were comparable between the two groups. Conclusions: Patients with localized prostate cancer treated with brachytherapy at high-volume community facilities have similar rates of biochemical failure, prostate cancer specific mortality, and trends in quality of life outcomes compared to those treated at low-volume community facilities.

The implications of surgeon case volume and hospital volume on outcomes of aortobifemoral bypasses in obese patients

BackgroundAortobifemoral (ABF) bypass is the gold standard for treating symptomatic aortoiliac occlusive disease. In the era of heightened interest in the length of stay (LOS) for surgical patients, this study aims to investigate the association of obesity with postoperative outcomes at the patient, hospital, and at surgeon levels. MethodsThis study used the Society of Vascular Surgery Vascular Quality Initiative suprainguinal bypass database from 2003 to 2021. The selected study cohort was divided into obese patients (body mass index ≥30) (group I) and nonobese patients (body mass index <30) (group II). Primary outcomes of the study included mortality, operative time, and postoperative LOS. Univariate and multivariate logistic regression analyses were performed to study the outcomes of ABF bypass in group I. Operative time and postoperative LOS were transformed into binary values by median split for regression analysis. A P value of .05 or less was deemed statistically significant in all the analyses of this study. ResultsThe study cohort consisted of 5392 patients. In this population, 1093 were obese (group I) and 4299 were nonobese (group II). Group I was found to have more females with higher rates of comorbid conditions, including hypertension, diabetes mellitus, and congestive heart failure. Patients in group I had increased odds of prolonged operative time (≥250 minutes) and an increased LOS (≥6 days). Patients in this group also had a higher chance of intraoperative blood loss, prolonged intubation, and required vasopressors postoperatively. There was also an increased odds of postoperative decline in renal function in the obese population. Patients with prior history of coronary artery disease, hypertension, diabetes mellitus, and urgent or emergent procedures were found to be risk factors for a LOS of more than 6 days in obese patients. An increase in the surgeons' case volume was associated with lesser odds of an operative time of 250 minutes or more; however, no significant impact was found on postoperative LOS. Hospitals where 25% or more of ABF bypasses were performed on obese patients were also more likely to have LOS of less than 6 days after ABF operations, compared with hospitals where less than 25% of ABF bypasses were performed on obese patients. Patients undergoing ABF for chronic limb-threatening ischemia or acute limb ischemia had a longer LOS and increased operative times. ConclusionsABF bypass in obese patients is associated with prolonged operative times and a longer LOS than in nonobese patients. Obese patients operated by surgeons with more cases of ABF bypasses have shorter operative times. A hospital's increasing proportion of obese patients was related to a decreased LOS. These findings support the known volume-outcome relationship that, with a higher surgeon case volume and increased proportion of obese patients in a hospital, there is an improvement in outcomes of obese patients undergoing ABF bypass.

Surgical volume and outcomes of surgical ablation for atrial fibrillation: a nationwide population-based cohort study

BackgroundAtrial fibrillation is the most common cardiac arrythmia and causes many complications. Sinus rhythm restoration could reduce late mortality of atrial fibrillation patients. The Maze procedure is the gold standard for surgical ablation of atrial fibrillation. Higher surgical volume has been documented with favorable outcomes of various cardiac procedures such as mitral valve surgery and aortic valve replacement. We aimed to determine the volume–outcome relationship (i.e., association between surgical volume and outcomes) for the concomitant Maze procedure during major cardiac surgeries.MethodsThis nationwide population-based cohort study retrieved data from the Taiwan National Health Insurance Research Database. Adult patients undergoing concomitant Maze procedures during 2010–2017 were identified; consequently, 2666 patients were classified into four subgroups based on hospital cumulative surgery volumes. In-hospital outcomes and late outcomes during follow-up were analyzed. Logistic regression and Cox proportional hazards model were used to analyze the volume–outcome relationship.ResultsPatients undergoing Maze procedures at lower-volume hospitals tended to be frailer and had higher comorbidity scores. Patients in the highest-volume hospitals had a lower risk of in-hospital mortality than those in the lowest-volume hospitals [adjusted odds ratio, 0.30; 95% confidence interval (CI), 0.15–0.61; P < 0.001]. Patients in the highest-volume hospitals had lower rates of late mortality than those in the lowest-volume hospitals, including all-cause mortality [adjusted hazard ratio (aHR) 0.53; 95% CI 0.40–0.68; P < 0.001] and all-cause mortality after discharge (aHR 0.60; 95% CI 0.44–0.80; P < 0.001).ConclusionsA positive hospital volume–outcome relationship for concomitant Maze procedures was demonstrated for in-hospital and late follow-up mortality. The consequence may be attributed to physician skill/experience, experienced multidisciplinary teams, and comprehensive care processes. We suggest referring patients with frailty or those requiring complicated cardiac surgeries to high-volume hospitals to improve clinical outcomes.Trial registration: the institutional review board of Chang Gung Memorial Hospital approved all data usage and the study protocol (registration number: 202100151B0C502).

The volume-outcome relationship for endoscopic transsphenoidal pituitary surgery for benign neoplasm: analysis of an administrative dataset for England

Background Setting minimum annual volume thresholds for pituitary surgery in England is seen as one way of improving outcomes for patients and service efficiency. However, there are few recent studies from the UK on whether a volume-outcome effect exists, particularly in the era of endoscopic surgery. Such data are needed to allow evidence-based decision making. The aim of this study was to use administrative data to investigate volume-outcome effects for endoscopic transsphenoidal pituitary surgery in England. Methods Data from the Hospital Episodes Statistics database for adult endoscopic transsphenoidal pituitary surgery for benign neoplasm conducted in England from April 2013 to March 2019 (inclusive) were extracted. Annual surgeon and trust volume was defined as the number of procedures conducted in the 12 months prior to the index procedure. Volume was categorised as < 10, 10–19, 20–29, 30–39 and ≥40 procedures for surgeon volume and < 20, 20–39, 40–59, 60–79 and ≥80 procedures for trust volume. The primary outcome was repeat ETSPS during the index procedure or during a hospital admission within one-year of discharge from the index procedure. Results Data were available for 4590 endoscopic transsphenoidal pituitary procedures. After adjustment for covariates, higher surgeon volume was significantly associated with reduced risk of repeat surgery within one year (odds ratio (OR) 0.991 (95% confidence interval (CI) 0.982–1.000)), post-procedural haemorrhage (OR 0.977 (95% CI 0.967–0.987)) and length of stay greater than the median (0.716 (0.597–0.859)). A higher trust volume was associated with reduced risk of post-procedural haemorrhage (OR 0.992 (95% CI 0.985–0.999)), but with none of the other patient outcomes studied. Conclusions A surgeon volume-outcome relationship exists for endoscopic transsphenoidal pituitary surgery in England.

Is hospital volume related to quality of hip fracture care? Analysis of 43,538 patients and 68 hospitals from the Dutch Hip Fracture Audit

PurposeEvidence for a hospital volume–outcome relationship in hip fracture surgery is inconclusive. This study aimed to analyze the association between hospital volume as a continuous parameter and several processes and outcomes of hip fracture care.MethodsAdult patients registered in the nationwide Dutch Hip Fracture Audit (DHFA) between 2018 and 2020 were included. The association between annual hospital volume and turnaround times (time on the emergency ward, surgery < 48 h and length of stay), orthogeriatric co-treatment and case-mix adjusted in-hospital and 30 days mortality was evaluated with generalized linear mixed models with random effects for hospital and treatment year. We used a fifth-degree polynomial to allow for nonlinear effects of hospital volume. P-values were adjusted for multiple comparisons using the Bonferoni method.ResultsIn total, 43,258 patients from 68 hospitals were included. The median annual hospital volume was 202 patients [range 1–546]. Baseline characteristics did not differ with hospital volume. Provision of orthogeriatric co-treatment improved with higher volumes but decreased at > 367 patients per year (p < 0.01). Hospital volume was not significantly associated with mortality outcomes. No evident clinical relation between hospital volume and turnaround times was found.ConclusionThis is the first study analyzing the effect of hospital volume on hip fracture care, treating volume as a continuous parameter. Mortality and turnaround times showed no clinically relevant association with hospital volume. The provision of orthogeriatric co-treatment, however, increased with increasing volumes up to 367 patients per year, but decreased above this threshold. Future research on the effect of volume on complications and functional outcomes is indicated.

The effect of minimum volume standards in hospitals (MIVOS) — protocol of a systematic review

BackgroundThe volume-outcome relationship, i.e., higher hospital volume results in better health outcomes, has been established for different surgical procedures as well as for certain nonsurgical medical interventions. Accordingly, many countries such as Germany, the USA, Canada, the UK, and Switzerland have established minimum volume standards. To date, there is a lack of systematically summarized evidence regarding the effects of such regulations.MethodsTo be included in the review, studies must measure any effects connected to minimum volume standards. Outcomes of interest include the following: (1) patient-related outcomes, (2) process-related outcomes, and (3) health system-related outcomes. We will include (cluster) randomized controlled trials ([C]RCTs), non-randomized controlled trials (nRCTs), controlled before-after studies (CBAs), and interrupted time-series studies (ITSs). We will apply no restrictions regarding language, publication date, and publication status. We will search MEDLINE (via PubMed), Embase (via Embase), CENTRAL (via Cochrane Library), CINHAL (via EBSCO), EconLit (via EBSCO), PDQ evidence for informed health policymaking, health systems evidence, OpenGrey, and also trial registries for relevant studies. We will further search manually for additional studies by cross-checking the reference lists of all included primary studies as well as cross-checking the reference lists of relevant systematic reviews.To evaluate the risk of bias, we will use the ROBINS-I and RoB 2 risk-of-bias tools for the corresponding study designs. For data synthesis and statistical analyses, we will follow the guidance published by the EPOC Cochrane group (Cochrane Effective Practice and Organisation of Care (EPOC), EPOC Resources for review authors, 2019).DiscussionThis systematic review focuses on minimum volume standards and the outcomes used to measure their effects. It is designed to provide thorough and encompassing evidence-based information on this topic. Thus, it will inform decision-makers and policymakers with respect to the effects of minimum volume standards and inform further studies in regard to research gaps.Systematic review registrationPROSPERO CRD42022318883

Volume–outcome relationship in adrenal surgery from 2009-2017 in Germany—a retrospective study

Adrenal resections are rare procedures of a heterogeneous nature. While recent European guidelines advocate a minimum annual caseload for adrenalectomies (6 per surgeon), evidence for a volume-outcome relationship for this surgery remains limited. A retrospective analysis of all adrenal resections in Germany between 2009 and 2017 using hospital billing data was performed. Hospitals were grouped into three tertiles of approximately equal patient volume. Descriptive, univariate, and multivariate analyses were applied to identify a possible volume-outcome relationship (complications, complication management, and mortality). Around 17 040 primary adrenal resections were included. Benign adrenal tumors (n = 8,213, 48.2%) and adrenal metastases of extra-adrenal malignancies (n = 3582, 21.0%) were the most common diagnoses. Six hundred and thirty-two low-volume hospitals performed an equal number of resections as 23 high-volume hospitals (median surgeries/hospital/year 3 versus 31, P < .001). Complications were less frequent in high-volume hospitals (23.1% in low-volume hospitals versus 17.3% in high-volume hospitals, P < .001). The most common complication was bleeding in 2027 cases (11.9%) with a mortality of 4.6% (94 patients). Overall in-house mortality was 0.7% (n = 126). Age, malignancy, an accompanying resection, complications, and open surgery were associated with in-house mortality. In univariate analysis, surgery in high-volume hospitals was associated with lower mortality (OR: 0.47, P < .001). In a multivariate model, the tendency remained equal (OR: 0.59, P = .104). Regarding failure to rescue (death in case of complications), there was a trend toward lower mortality in high-volume hospitals. The annual caseload of adrenal resections varies considerably among German hospitals. Our findings suggest that surgery in high-volume centers is advantageous for patient outcomes although fatal complications are rare.

Race, Insurance, and Sex-Based Disparities in Access to High-Volume Centers for Pancreatectomy

BackgroundWith a large body of literature demonstrating positive volume-outcome relationships for most major operations, minimum volume requirements have been suggested for concentration of cases to high-volume centers (HVCs). However, data are limited regarding disparities in access to these hospitals for pancreatectomy patients.MethodsThe 2005–2018 National Inpatient Sample (NIS) was queried for all elective adult hospitalizations for pancreatectomy. Hospitals performing more than 20 annual cases were classified as HVCs. Mixed-multivariable regression models were developed to characterize the impact of demographic factors and case volume on outcomes of interest.ResultsOf an estimated 127,527 hospitalizations, 79.8% occurred at HVCs. Patients at these centers were more frequently white (79.0 vs 70.8%; p < 0.001), privately insured (39.4 vs 34.2%; p < 0.001), and within the highest income quartile (30.5 vs 25.0%; p < 0.001). Adjusted analysis showed that operations performed at HVCs were associated with reduced odds of in-hospital mortality (adjusted odds ratio [AOR], 0.43; 95% confidence interval [CI], 0.34–0.55), increased odds of discharge to home (AOR, 1.17; 95% CI, 1.04–1.30), shorter hospital stay (β, −0.81 days; 95% CI, −1.2 to −0.40 days), but similar costs. Patients who were female (AOR, 0.88; 95% CI, 0.79–0.98), non-white (black: AOR, 0.66; 95% CI, 0.59–0.75; Hispanic: AOR, 0.56; 95% CI, 0.47–0.66; reference, white), insured by Medicaid (AOR, 0.63; 95% CI, 0.56–0.72; reference, private), and within the lowest income quartile (AOR, 0.73; 95% CI, 0.59–0.90; reference, highest) had decreased odds of treatment at an HVC.ConclusionsFor those undergoing pancreatectomies, HVCs realize superior clinical outcomes but treat lower proportions of female, non-white, and Medicaid populations. These findings may have implications for improving access to high-quality centers.

Restructuring of the UK Vascular Services: does the hub versus spoke model affect patient mortality in ruptured abdominal aortic aneurysms?

Background: Ruptured abdominal aortic aneurysms (AAA) are a frequently fatal vascular condition. The centralisation of vascular services in the UK was driven by the positive volume–outcome relationship witnessed within vascular surgery and other major surgical specialities. In 2018, The Get It Right First Time (GIRFT) programme officially recommended the restructuring of vascular services in England to a hub and spoke model where AAA repairs should be performed in higher volume centres, the hub sites. This study aims to assess the mortality rates in patients presenting at hub versus spoke sites in the Merseyside region. Methods: We conducted a retrospective review from 1 January 2017 to 31 December 2020, identifying 110 patients with a ruptured AAA presenting to hub and spoke sites. We determined if there was any association between mortality and the presenting site. Results: Forty-one patients presented to the hub site (Royal Liverpool University Hospital) and 69 patients to the spoke sites. 81% underwent operative intervention and 19% died in Accident and Emergency or were palliated. 57% of those who underwent an intervention survived. The overall mortality rate in hospital was 53% (58 patients). There was no association between mortality and transfer from a spoke site (p=0.585). Conclusion: This study is concordant with further published data supporting the centralisation of services for ruptured AAA.

Volume–Outcome Relationship in Cancer Survival Rates: Analysis of a Regional Population-Based Cancer Registry in Japan

There is limited data on the relationship between hospital volumes and outcomes with respect to cancer survival in Japan. The primary objective of this study was to evaluate the effect of hospital volume on cancer survival rate using a population-based cohort database. Using the Kanagawa cancer registry, propensity score matching was employed to create a dataset for each cancer type by selecting 1:1 matches for cases from high- and other-volume hospitals. The 5-year survival rate was estimated and the hazard ratio (HR) for hospital volume was calculated using a Cox proportional hazard model. Additional analyses were performed limited to cancer patients who underwent surgical operation, chemotherapy, and other treatments in each tumor stage and at the time of diagnosis. The number of cases with complete data, defined as common cancers (prostate, kidney, bladder, esophagus, stomach, liver, pancreas, colon, breast, and lung), was 181,039. Adjusted HR differed significantly among hospital volume categories for the most common cancers except bladder, and the trends varied according to cancer type. The HR ranged from 0.76 (95%CI, 0.74-0.79) for stomach cancer to 0.85 (0.81-0.90) for colon cancer. This study revealed that a relationship may exist between hospital volume and cancer survival in Japan.

Assessing the volume–outcome relationship of carotid artery stenting in nationwide administrative data: a challenge of patient population bias

BackgroundStudies have shown an association between surgical treatment volume and improved quality metrics. This study evaluated nationwide results in carotid artery stenting (CAS) procedural readmission rates, costs, and length of...

Correspondence: is there an association between centre volume and survival or neurological outcomes among out-of-hospital cardiac arrest patients?

This commentary discusses the findings of a study by Tsuchida et al. on the effect of annual hospitaladmissions of out-of-hospital cardiac arrest patients on survival and neurological outcomes in OHCA patients in thecontext of existing literature on the topic, and the implications on future studies investigating the volume-outcomerelationship in cardiac arrest.

ASO Author Reflections: The Complexity of the Volume-Outcome Relationship in Pancreatic Cancer.

ASO Author Reflections: The Complexity of the Volume-Outcome Relationship in Pancreatic Cancer.

Study within a review (SWAR).

Study within a review (SWAR).

Association of hospital volume with postoperative outcomes in Crohn's disease.

Most patients diagnosed with Crohn's disease (CD) require surgery during their lifetime. While the literature has shown that certain cancer patients have superior postoperative outcomes at high-volume hospitals, there remains a paucity of data on the hospital volume-outcome relationship in CD. Given the complexities in both medical and surgical management, this study aims to determine whether patients with CD have superior postoperative outcomes at high-volume hospitals. A retrospective analysis of patients undergoing abdominal surgery for CD in New York hospitals between 2012 and 2018 was performed using data from the Statewide Planning and Research Cooperation System. Outcomes included postoperative mortality, 30-day readmission and postoperative complications. Using a penalized B-spline plot, high-volume centres were defined as those performing more than 160 abdominal surgeries for CD each year. A total of 13,221 surgeries were performed across 176 hospital centres in New York State. Of these, 73.9% of procedures occurred at low-volume centres. High-volume hospitals had lower in-hospital mortality (0.5% vs. 1.5%; p< 0.001) and 30-day readmission rates (8.3% vs. 10.4%; p< 0.001) than low-volume centres. Major postoperative complications and reoperation rates did not differ by hospital volume. On multivariate analysis, patients at high-volume hospitals had lower odds of in-hospital mortality (OR 0.54, 95% CI 0.38-0.75) and 30-day readmission (OR 0.79, 95%CI 0.64-0.98). Hospital volume remained an independent predictor of 30-day readmission for emergent admissions (OR 0.72, 95% CI 0.61-0.85) and in-hospital mortality for nonemergent admissions (OR 0.39, 95% CI 0.19-0.82). Patients undergoing abdominal surgery for CD have lower odds of postoperative mortality and 30-day readmission when the operation occurs at a high-volume hospital. These findings suggest that surgical patients with CD may benefit from care at specialized centres.

Average treatment effect of facility hepatopancreatobiliary malignancy case volume on survival of patients with nonoperatively managed hepatobiliary malignancies

BackgroundSurgical volume-outcome relationships have been described for a variety of procedures. There is scant literature on total institutional volume and outcomes in patients who are nonoperatively managed. We examined the average treatment effect of total hepatopancreatobiliary malignancy case volume on survival outcomes of patients with nonresected hepatobiliary malignancies. MethodsWe identified patients with hepatopancreatobiliary malignancies [pancreatic adenocarcinoma, pancreatic neuroendocrine neoplasms, hepatocellular carcinoma, biliary tract cancers] within the National Cancer Database (2004–2018). We determined percentile thresholds based on the total annual hepatopancreatobiliary malignancy case volume. We then identified nonoperatively managed patients with hepatocellular carcinoma or biliary tract cancers. We used inverse probability-weighted Cox regression to estimate the effect of facility volume on overall survival. ResultsWe identified 710,988 patients with hepatopancreatobiliary malignancies. Total annual hepatopancreatobiliary malignancy case volume of 32, 71, and 177 cases/year corresponded to the 25th, 50th, and 75th percentiles. A total of 96,420 with hepatocellular carcinoma and 52,627 patients with biliary tract cancers were managed nonoperatively. In patients with hepatocellular carcinoma or biliary tract cancer, treatment at ≥25th, ≥50th, and ≥75th percentile facilities was associated with improved median, 1-, 2-, and 3-year overall survival compared with treatment at lower-percentile facilities. On inverse probability–weighted Cox analysis, treatment at higher-percentile facilities resulted in a lower hazard of death. Consistent findings were observed in patients with early or intermediate/advanced hepatocellular carcinoma or metastatic biliary tract cancers. ConclusionPatients with nonoperatively managed hepatocellular carcinoma or biliary tract cancer who receive treatment at higher-volume facilities have improved survival outcomes. These data suggest regionalization of care for patients with hepatocellular carcinoma or biliary tract cancer to high-volume centers may improve survival.

Systems of Care Factors Should Be Considered in Regionalization of Congenital Cardiac Surgery

BackgroundRegionalization of care has been proposed to optimize outcomes in congenital cardiac surgery (CCS). We hypothesized that hospital infrastructure and systems of care factors could also be considered in regionalization efforts. MethodsObserved-to-expected (O/E) mortality ratio and hospital volumes were obtained between 2015 and 2018 from public reporting data. Using a resource dependence framework, we examined factors obtained from American Hospital Association, Children’s Hospital Association, and hospital websites. Linear regression models were estimated with volume only, then with hospital factors, stratified by procedural complexity. Robust regression models were reestimated to assess the impact of outliers. ResultsWe found wide variation in the volume of congenital cardiac surgeries performed (89-3920) and in the surgical outcomes (O/E ratio range, 0.3-3.1). Six outlier hospitals performed few high-complexity cases with high mortality. Univariate analysis including all cases indicated that higher volume predicted lower O/E ratio (β = −0.02; SE = 0.008; P = .011). However, this effect was driven by the most complex cases. Models stratified by The Society of Thoracic Surgeons–European Association for Cardio-Thoracic Surgery category show that volume is a significant predictor only in category 5 cases (β = −1.707; SE = 0.663; P = .012). Robust univariate regression accounting for outliers found no effect of volume on O/E ratio (β = 0.005; SE = 0.002; P = .975). Elimination of outliers through robust multivariate regression decreased the volume-outcome relationship and found a modest relationship between health plan ownership and outcomes. ConclusionsSystems of care factors should be considered in addition to volume in designing regionalization in CCS. Patient-level data sets will better define these factors.

Volume-Outcome Relationship of Resternotomy Coronary Artery Bypass Grafting

BackgroundWe assessed volume-outcome relationships of resternotomy coronary artery bypass grafting (CABG). MethodsWe studied 1,362,218 first-time CABG and 93,985 resternotomy CABG patients reported to The Society of Thoracic Surgeons Adult Cardiac Surgery Database between 2010 and 2019. Primary outcomes were in-hospital mortality and mortality and morbidity (M&M) rates calculated per hospital and per surgeon. Outcomes were compared across 6 total cardiac surgery volume categories. Multivariable generalized linear mixed-effects models were used considering continuous case volume as the main exposure, adjusting for patient characteristics and within-surgeon and hospital variation. ResultsWe observed a decline in resternotomy CABG unadjusted mortality and M&M from the lowest to the highest case-volume categories (hospital-level mortality, 3.9% ± 0.6% to 3.3% ± 0.1%; M&M, 18.5% ± 1.1% to 15.7% ± 0.4%, P < .001; surgeon-level mortality, 4.1% ± 0.3% to 4.1% ± 1.3%; M&M, 18.5% ± 0.6% to 14.5% ± 2.2%, P < .001). Looking at outcomes vs continuous volume showed that beyond a minimum annual volume (hospital 200-300 cases; surgeon 100-150 cases, approximately), mortality and M&M rates did not further improve. Using individual-level data and adjusting for patient characteristics and clustering within surgeon and hospital, we found higher procedural volume was associated with improved surgeon-level outcomes (mortality adjusted odds ratio, 0.39/100 procedures; 95% CI, 0.24-0.61; M&M adjusted odds ratio, 0.37/100 procedures; 95% CI, 0.28-0.48; P < .001 for both). Hospital-level adjusted volume-outcomes associations were not statistically significant. ConclusionsWe observed an inverse relationship between total cardiac case volume and resternotomy CABG outcomes at the surgeon level only, indicating that individual surgeon’s experience, rather than institutional volume, is the key determinant.