Volume-outcome Association Research Articles

The association between hospital volume and overall survival in adult AML patients treated with intensive chemotherapy.

Acute myeloid leukemia (AML) requires specialized care, particularly when administrating intensive remission induction chemotherapy (ICT). High-volume hospitals are presumed more adept at delivering this complex treatment, resulting in better overall survival (OS) rates. Despite its potential implications for quality improvement, research on the volume-outcome relationship in ICT administration for AML is scarce. This nationwide, population-based study in the Netherlands explored the volume-outcome relationship in AML. Data from the Netherlands Cancer Registry on adult (≥18 years of age) ICT-treated AML patients, diagnosed between 2014 and 2018, were analyzed. Hospital volume was assessed against OS using mixed-effects Cox regression, adjusting for patient and disease characteristics (i.e. case mix), with hospital as a random effect. Our study population consisted of a total of 1761 patients (57% male), with a median age of 61 years. The average annual number of ICT-treated patients varied across the 24 hospitals (range 1-56, median 13, and interquartile range 8-20 patients per hospital per year). Overall, an increase of 10 ICT-treated patients annually was associated with an 8% lower mortality risk [hazard ratio (HR) 0.92, 95% confidence interval (CI) 0.87-0.98, P= 0.01]. This association was not significant at 30-day (HR 1.02, 95% CI 0.89-1.17, P= 0.75) and 42-day (HR 0.96, 95% CI 0.85-1.08, P= 0.54) OS but became apparent after 100-day OS (HR 0.91, 95% CI 0.83-0.99, P= 0.05). There is a volume-outcome association within AML care. This finding could support hospital volume as a metric in AML care. However, it should be acknowledged that centralizing care is a complex process with implications for health care providers and patients. Therefore, any move toward centralization must be judiciously balanced.

Changes in the volume-outcome association and implications for minimum case volume recommendations for cancer surgery in the United States

Changes in the volume-outcome association and implications for minimum case volume recommendations for cancer surgery in the United States

Procedural volume is linearly associated with mortality, major complications, and readmissions in patients undergoing malignant brain tumor resection.

Improved outcomes have been noted in patients undergoing malignant brain tumor resection at high-volume centers. Studies have arbitrarily chosen high-volume dichotomous cutoffs and have not evaluated volume-outcome associations at specific institutional procedural volumes. We sought to establish the continuous association of volume with patient outcomes and identify cutoffs significantly associated with mortality, major complications, and readmissions. We hypothesized that a linear volume-outcome relationship can estimate likelihood of adverse outcomes when comparing any two volumes. The patient cohort was identified with ICD-10 coding in the Nationwide Readmissions Database(NRD). The association of volume and mortality, major complications, and 30-/90-day readmissions were evaluated in multivariate analyses. Volume was used as a continuous variable with two/three-piece splines, with various knot positions to reflect the best model performance, based on the Quasi Information Criterion(QIC). From 2016 to 2018, 34,486 patients with malignant brain tumors underwent resection. When volume was analyzed as a continuous variable, mortality risk decreased at a steady rate of OR 0.988 per each additional procedure increase for hospitals with 1-65 cases/year(95% CI 0.982-0.993, p < 0.0001). Risk of major complications decreased from 1 to 41 cases/year(OR 0.983, 95% CI 0.979-0.988, p < 0.0001), 30-day readmissions from 1 to 24 cases/year(OR 0.987, 95% CI 0.979-0.995, p = 0.001) and 90-day readmissions from 1 to 23 cases/year(OR 0.989, 95% CI 0.983-0.995, p = 0.0003) and 24-349 cases/year(OR 0.9994, 95% CI 0.999-1, p = 0.01). In multivariate analyses, institutional procedural volume remains linearly associated with mortality, major complications, and 30-/90-day readmission up to specific cutoffs. The resulting linear association can be used to calculate relative likelihood of adverse outcomes between any two volumes.

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

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

Assessing the Ambulatory Surgery Center Volume-Outcome Association

In surgical patients, it is well known that higher hospital procedure volume is associated with better outcomes. To our knowledge, this volume-outcome association has not been studied in ambulatory surgery centers (ASCs) in the US. To determine if low-volume ASCs have a higher rate of revisits after surgery, particularly among patients with multimorbidity. This matched case-control study used Medicare claims data and analyzed surgeries performed during 2018 and 2019 at ASCs. The study examined 2328 ASCs performing common ambulatory procedures and analyzed 4751 patients with a revisit within 7 days of surgery (defined to be either 1 of 4735 revisits or 1 of 16 deaths without a revisit). These cases were each closely matched to 5 control patients without revisits (23 755 controls). Data were analyzed from January 1, 2018, through December 31, 2019. Seven-day revisit in patients (cases) compared with the matched patients without the outcome (controls) in ASCs with low volume (less than 50 procedures over 2 years) vs higher volume (50 or more procedures). Patients at a low-volume ASC had a higher odds of a 7-day revisit vs patients who had their surgery at a higher-volume ASC (odds ratio [OR], 1.21; 95% CI, 1.09-1.36; P = .001). The odds of revisit for patients with multimorbidity were higher at low-volume ASCs when compared with higher-volume ASCs (OR, 1.57; 95% CI, 1.27-1.94; P < .001). Among patients with multimorbidity in low-volume ASCs, for those who underwent orthopedic procedures, the odds of revisit were 84% higher (OR, 1.84; 95% CI, 1.36-2.50; P < .001) vs higher-volume centers, and for those who underwent general surgery or other procedures, the odds of revisit were 36% higher (OR, 1.36; 95% CI, 1.01-1.83; P = .05) vs a higher-volume center. The findings were not statistically significant for patients without multimorbidity. In this observational study, the surgical volume of an ASC was an important indicator of patient outcomes. Older patients with multimorbidity should discuss with their surgeon the optimal location of their care.

How to direct patients to high-volume hospitals: exploring the influencing drivers

BackgroundDuring the last decade, planning concentration policies have been applied in healthcare systems. Among them, attention has been given to guiding patients towards high-volume hospitals that perform better, acccording to the volume-outcome association. This paper analyses which factors drive patients to choose big or small hospitals (with respect to the international standards of volumes of activity).MethodsWe examined colon cancer surgeries performed in Piedmont (Italy) between 2004 and 2018. We categorised the patient choice of the hospital as big/small, and we used this outcome as main dependent variable of descriptive statistics, tests and logistic regression models. As independent variables, we included (i) patient characteristics, (ii) characteristics of the closest big hospital (which should be perceived as the most immediate to be chosen), and (iii) territorial characteristics (i.e., characteristics of the set of hospitals among which the patient can choose). We also considered interactions among variables to examine which factors influence all or a subset of patients.ResultsOur results confirm that patient personal characteristics (such as age) and hospital characteristics (such as distance) play a primary role in the patient decision process. The findings seem to support the importance of closing small hospitals when they are close to big hospitals, although differences emerge between rural and urban areas. Other interesting insights are provided by examining the interactions between factors, e.g., patients affected by comorbidities are more responsive to hospital quality even though they are distant.ConclusionsReorganising healthcare services to concentrate them in high-volume hospitals emerged as a crucial issue more than forty years ago. Evidence suggests that concentration strategies guarantee better clinical performance. However, in healthcare systems in which patients are free to choose where to be treated, understanding patients’ behaviour and what drives them towards the most effective choice is of paramount importance. Our study builds on previous research that has already analysed factors influencing patients’ choices, and takes a step further to enlighten which factors drive patients to choose between a small or a big hospital (in terms of volume). The results could be used by decision makers to design the best concentration strategy.

A novel approach to determine the optimal annual case volume for cardiovascular interventions in need of centralization

Abstract Background There is an incentive to centralize specialized health care, which particularly applies to high-risk surgical and trans-catheter cardiovascular procedures. In health care policy, annual hospital case volume is the main criterion to define expertise and determine centralization. Purpose We propose a novel methodology to evaluate the volume-outcome relation for high-risk and infrequent cardiovascular procedures, by use of a meta-analytical approach, and aim to determine a specific annual case volume threshold, using surgery for acute type A aortic dissection (ATAAD) as an example. Methods This study was designed as a systematic review and meta-analysis (PROSPERO; registration number CRD42022345024). We included studies reporting on (i) consecutive ATAAD patients, (ii) years of inclusion and (iii) early mortality. The primary outcome was early mortality in relation to annual hospital case volume. Secondary outcome was long-term survival. Data were presented and compared in volume quartiles (Q's, Q1 1-12, Q2 12-17, Q3 17-28, and Q4 28-241 cases/year). Restricted cubic spline analysis was used to demonstrate the volume-outcome relation. Derived from optimization statistics, we introduce the concept of the 'elbow-method' to determine the optimal annual case volume (see Figure 1). For long-term survival, individual patient data derived from Kaplan-Meier curves were integrated. For clinical interpretation, numbers needed to treat (NNT) were calculated. Results 125 studies from 125 unique centers were included (25 countries, 5 continents, see Figure 1), comprising 33 027 patients. A significant between-quartile difference for early mortality was observed (10.5% [Q4] vs. 16.8% [Q1], p&amp;lt;0.001, I2=72%), which persisted after correction for age, sex, and dissection type (p&amp;lt;0.001). Furthermore, a significant non-linear volume-outcome association was observed as well (p&amp;lt;0.001, Figure 1). The optimal annual case volume after which results did not improve any further, was determined at 41 cases/year (95% CI 39-45, relative risk reduction 37.1%, NNT 16.1, compared to 10 cases/year, Figure 1). Even more pronounced between-quartile survival differences were observed for long-term survival (43 studies, n=11 704, 10-year survival Q4 69% vs Q1 56%, p&amp;lt;0.001, HR=0.87, 95%CI=0.84-0.90, p&amp;lt;0.001, NNT 6.7, Figure 2). This notable long-term survival difference persisted after correction for age, sex, and dissection type (Figure 2). Conclusions High volume centers exhibit superior results in surgery for ATAAD, compared to lower volume centers. Using a novel approach, the optimal annual hospital ATAAD case volume threshold was statistically determined at 41 cases/year, with a high degree of certainty. Despite its acute character, rerouting of patients and centralization of ATAAD care in high-volume centers may lead to improved outcomes. This novel method has the potential to be applied to various other cardiovascular procedures requiring centralization.Figure 1Early mortalityFigure 2Long-term survival

Association between hospital volume and outcomes in invasive ovarian cancer in Belgium: A population-based study

ObjectivesTo study the association between hospital volume and outcomes in patients with invasive epithelial ovarian cancer (EOC). MethodsThis study included 3988 patients diagnosed with invasive EOC between 2014 and 2018, selected from the population-based database of the Belgian Cancer Registry (BCR), and coupled with health insurance and vital status data. The associations between hospital volume and observed survival since diagnosis were assessed with Cox proportional hazard models, while volume associations with 30-day post-operative mortality and complicated recovery were evaluated using logistic regression models. ResultsTreatment for EOC was very dispersed with half of the 100 centres treating fewer than six patients per year. The median survival of patients treated in centres with the highest-volume quartile was 2.5 years longer than in those with the lowest-volume quartile (4.2 years versus 1.7 years). When taking the case-mix of hospitals into account, patients treated in the lowest volume centres had a 47% higher hazard to die than patients treated in the highest volume centres (HR: 1.47, 95% CI: 1.11–1.93, p = 0.006) over the first five years after incidence. A similar association was found when focussing on the surgical volume of the hospitals and considering only operated patients with invasive EOC. Lastly, the 30-day post-operative mortality decreased significantly with increasing surgical volume. ConclusionsThe large dispersion of care and expertise within Belgium and the volume-outcome associations observed in this study support the implementation of the concentration of care for patients with invasive EOC in reference centres.

Role of intraoperative processes of care during major upper gastrointestinal oncological resection in postoperative outcomes: a scoping review protocol

IntroductionOptimal delivery and organisation of care is critical for surgical outcomes and healthcare systems efficiency. Anaesthesia volumes have been recently associated with improved postoperative recovery outcomes; however, the mechanism is...

Systematic Review and Meta-analysis of the Association Between Radiation Therapy Treatment Volume and Patient Outcomes

Evidence of a volume-outcome association in cancer surgery has shaped the centralization of cancer services; however, it is unknown whether a similar association exists for radiation therapy.The objective of this study was to determine the association between radiation therapy treatment volume and patient outcomes. This systematic review and meta-analysis included studies that compared outcomes of patients who underwent definitive radiation therapy at high-volume radiation therapy facilities (HVRFs) versus low-volume facilities (LVRFs). The systematic review used Ovid MEDLINE and Embase. For the meta-analysis, a random effects model was used. Absolute effects and hazard ratios (HRs) were used to compare patient outcomes. The search identified 20 studies assessing the association between radiation therapy volume and patient outcomes. Seven of the studies looked at head and neck cancers (HNCs). The remaining studies covered cervical (4), prostate (4), bladder (3), lung (2), anal (2), esophageal (1), brain (2), liver (1), and pancreatic cancer (1). The meta-analysis demonstrated that HVRFs were associated with a lower chance of death compared with LVRFs (pooled HR, 0.90; 95% CI, 0.87- 0.94). HNCs had the strongest evidence of a volume-outcome association for both nasopharyngeal cancer (pooled HR, 0.74; 95% CI, 0.62-0.89) and nonnasopharyngeal HNC subsites (pooled HR, 0.80; 95% CI, 0.75-0.84), followed by prostate cancer (pooled HR, 0.92; 95% CI, 0.86-0.98). The remaining cancer types showed weak evidence of an association. The results also demonstrate that some centers defined as HVRFs are undertaking very few procedures per annum (<5 radiation therapy cases per year). An association between radiation therapy treatment volume and patient outcomes exists for most cancer types. Centralization of radiation therapy services should be considered for cancer types with the strongest volume-outcome association, but the effect on equitable access to services needs to be explicitly considered.

Association between hospital surgical case volume and postoperative mortality in patients undergoing gastrectomy for gastric cancer: a systematic review and meta-analysis.

Postoperative mortality is an important indicator for evaluating surgical safety. Postoperative mortality is influenced by hospital volume; however, this association is not fully understood. This study aimed to investigate the volume-outcome association between the hospital surgical case volume for gastrectomies per year (hospital volume) and the risk of postoperative mortality in patients undergoing a gastrectomy for gastric cancer. Studies assessing the association between hospital volume and the postoperative mortality in patients who underwent gastrectomy for gastric cancer were searched for eligibility. Odds ratios were pooled for the highest versus lowest categories of hospital volume using a random-effects model. The volume-outcome association between hospital volume and the risk of postoperative mortality was analyzed. The study protocol was registered with Prospective Register of Systematic Reviews (PROSPERO). Thirty studies including 586993 participants were included. The risk of postgastrectomy mortality in patients with gastric cancer was 35% lower in hospitals with higher surgical case volumes than in their lower-volume counterparts (odds ratio: 0.65; 95% CI: 0.56-0.76; P <0.001). This relationship was consistent and robust in most subgroup analyses. Volume-outcome analysis found that the postgastrectomy mortality rate remained stable or was reduced after the hospital volume reached a plateau of 100 gastrectomy cases per year. The current findings suggest that a higher-volume hospital can reduce the risk of postgastrectomy mortality in patients with gastric cancer, and that greater than or equal to 100 gastrectomies for gastric cancer per year may be defined as a high hospital surgical case volume.

The influence of procedural volume on the outcome of endoscopic submucosal dissection for gastric neoplasm: A nationwide population-based study.

285 Background: Endoscopic submucosal dissection (ESD) is a well-established treatment modality for gastric neoplasms. The aim of this study was to investigate the effect of procedural volume on the outcome of endoscopic submucosal dissection (ESD) for gastric cancer or adenoma. Methods: Patients who underwent ESD for gastric cancer or adenoma from November 2011 to December 2017 were identified using the Korean National Health Insurance Service database. Operational definitions to identify target population and post-procedural complications were created by combining the diagnosis and procedure codes, and validated using individual hospital medical record data. The outcomes were the occurrence of post-procedural complications (bleeding, perforation, pneumonia, and 30-day mortality) and additional resection within 180 days after the initial ESD procedure. Hospital volume was categorized into four groups based on the mean annual number of procedures: very high-, high-, low-, very low-volume hospitals (VHVH, HVH, LVH, VLVH). The outcome of ESD was compared in relation to hospital volume. Results: There were 95,411 procedures in 89,780 patients during the study period. There were 5,607 composite events, which included 5,098 bleeding, 601 perforation, and 712 pneumonia cases, respectively. Additional resection within 180days occurred in 7,900 cases. There were significant differences in ESD-related adverse outcomes among the four hospital volume categories. Multiple logistic regression revealed that VHVH, HVH, and LVH were associated with significantly lower relative risk of composite outcome, when compared to VLVH. Similar tendencies were also shown in terms of bleeding, perforation, and pneumonia. This volume-outcome association was not evident in additional resection. Conclusions: Hospital volume was closely associated with adverse clinical outcome in patients with ESD for gastric cancer or adenoma. The outcomes of gastric ESD should be closely and systemically monitored to ensure the safety of patients. [Table: see text]

ASO Visual Abstract:Impact of Mediatingand ConfoundingVariables ontheVolume-OutcomeAssociationin theTreatment ofPancreaticCancer.

ASO Visual Abstract:Impact of Mediatingand ConfoundingVariables ontheVolume-OutcomeAssociationin theTreatment ofPancreaticCancer.

A Population-Based Study Using Belgian Cancer Registry Data Supports Centralization of Esophageal Cancer Surgery in Belgium.

Esophageal cancer surgery outcomes benefit from higher hospital volumes. Despite the evidence, organization of national health care often is complex and depends on various factors. The volume-outcome results of this population-based study supported national health policy measures regarding concentration of esophageal resections in Belgium. The Belgian Cancer Registry (BCR) database was linked to administrative data on cancer treatment. All Belgian patients with newly diagnosed esophageal cancer in 2008-2018 undergoing resection were allocated to the hospital at which surgery was performed. The study assessed hospital volume association with 90-day mortality and 5-year overall survival, classifying average annual hospital volume of resections as low (LV, <6), medium (MV, 6-19), or high (HV, ≥20) and as a continuous covariate in the regression models. The study included 4156 patients who had surgery in 79hospitals (2 HV hospitals [37% of all surgeries], 12 MV hospitals [30% of all surgeries], and 65 LV hospitals [33% of all surgeries]). Adjusted 90-day mortality in HV hospitals was lower than in LV hospitals (odds ratio [OR], 0.37; 95% CI, 0.21-0.65; p = 0.001). Case-mix adjusted 5-year survival was superior in HV versus LV (hazard ratio [HR], 0.43; 95% CI, 0.31-0.60; p < 0.001). The continuous model demonstrated a lower 90-day mortality (OR, 0.40; 95% CI, 0.23-0.71; p = 0.002) and a superior 5-year survival (HR, 0.45; 95% CI, 0.33-0.63; p < 0.001) in hospitals with volumes of 40 or more resections annually. Population-based data from the BCR confirmed a strong volume-outcome association for esophageal resections. Improved 5-year survival in centers with annual volumes of 20 or more resections was driven mainly by the achievement of superior 90-day mortality. These findings supported centralization of esophageal resections in Belgium.

Impact of Mediating and Confounding Variables on the Volume-Outcome Association in the Treatment of Pancreatic Cancer.

High-volume centers (HVC), academic centers (AC), and longer travel distances (TD) have been associated with improved outcomes for patients undergoing surgery for pancreatic adenocarcinoma (PAC). Effects of mediating variables on these associations remain undefined. The purpose of this study is to examine the direct effects of hospital volume, facility type, and travel distance on overall survival (OS) in patients undergoing surgery for PAC and characterize the indirect effects of patient-, disease-, and treatment-related mediating variables. Using the National Cancer Database, patients with non-metastatic PAC who underwent resection were stratified by annual hospital volume (< 11, 11-19, and ≥ 20cases/year), facility type (AC versus non-AC), and TD (≥ 40 versus < 40 miles). Associations with survival were evaluated using multiple regression models. Effects of mediating variables were assessed using mediation analysis. In total, 19,636 patients were included. Treatment at HVC or AC was associated with lower risk of death [hazard ratio (HR) 0.90, confidence interval (CI) 0.88-0.92; HR 0.89, CI 0.86-0.91, respectively]. TD did not impact OS. Patient-, disease-, and treatment-related variables explained 25.5% and 41.8% of the survival benefit attained from treatment at HVC and AC, reducing the survival benefit directly attributable to each variable to 4.9% and 6.4%, respectively. Treatment of PAC at HVC and AC was associated with improved OS, but the magnitude of this benefit was less when mediating variables were considered. From a healthcare utilization and cost-resource perspective, further research is needed to identify patients who would benefit most from selective referral to HVC or AC.

Lack of volume-outcome association in ECMO bridge to heart transplantation.

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is increasingly used as a bridge to cardiac transplantation. As the 2018United Network for Organ Sharing(UNOS) heart allocation policy change elevated waitlist status for patients receiving mechanical circulatory support (MCS), we aimed to determine if a center's annual heart transplant volume was associated with ECMO-support duration and posttransplant outcomes. Adults heart transplant candidates between January 1, 2011, and December 31, 2021, were isolated in the UNOS database. VA-ECMO use was identified at the time of listing for transplant. Average annual transplant volume was calculated by the center, with stratification as high (≥20 cardiac transplants, high volume center [HVC]) or low (<20 cardiac transplants, low volume center [LVC]) volume centers. Results are reported as mean(interquartile range) or n(%). In total, 543 patients at HVCs and 275 at LVCs were listed for transplant supported with VA-ECMO. Those listed at HVCs were more likely to be supported by intra-aortic balloon pump (103[19%] vs. 32[11.6%], p = .008) and inotropes (267[49.2%] vs. 106[38.5%], p = .004) at time of listing. Patients at HVCs received ECMO support for 6[4-9] days, compared to 8[4-15] days at low-volume centers (p = .030), and but were cannulated a similar time before listing (2[1-5] vs. 3[1-7] days, p = .517). There were no differences in rates of transplant (p = .2126), waitlist mortality (p = .8645), delisting due to clinical deterioration (p = .8419), or recovery (p = .1773) between groups. Among transplanted patients, there were no differences in support duration (6[4-8] vs. 6[4-10], p = .187), or time from registration to transplant (5[2-20] vs. 7[3-22] days, p = .560). Posttransplant survival did not vary (p = .293). LVCs can successfully bridge patients to transplant with VA-ECMO and achieve comparable outcomes to HVCs.

SP9.1.2 Investigating the association between trust case volume and perioperative outcomes in colorectal cancer surgery

Abstract Background Whilst current colorectal cancer care pathways operate by referral to local hospitals, there has been a recent drive to centralise cancer services to improve patient outcomes. Centralisation will inevitably increase trust case volume and the existing literature is inconclusive regarding a possible volume-outcome association. This study aims to investigate the association between case volume and unplanned readmission or unplanned return to theatre (URTT) rates in patients undergoing colorectal surgery across England and Wales. Methods A retrospective analysis was conducted of 14028 patients across 135 trusts using the 2020 NBOCA dataset. Primary outcome measures were 30-day unplanned readmission and 30-day URTT rates. Trusts were dichotomised into low or high-volume sites. Statistical analysis used Spearman's ρ correlation, Mann-Whitney U and Student T-test. Results 11.2% (2.30–24.5) and 8.31% (0.00–23.3) of 14028 patients underwent an unplanned readmission and URTT respectively. There was no significant correlation between the number of cases and 30-day unplanned readmission (r=0.0628, 95%CI: -0.112–0.234, p=0.469), with no significant difference between low and high-volume trusts (p=0.432). Similarly, no significant correlation was found between the number of cases and 30-day URTT rate (r=-0.0848, 95%CI: -0.255–0.0904, p=0.328), with no significant difference between low and high-volume trusts (p=0.285). Conclusions No association was discovered between volume and unplanned readmission or URTT in this cohort. Increasing volume among trusts who demonstrate favourable outcomes, rather than indiscriminately increasing volume may be beneficial. This study increases our understanding of volume-outcome relationships, however further prospective studies at a national level into other outcomes should be conducted to rule out centralisation.

Association of High-Volume Centers With Survival Outcomes Among Patients With Nontraumatic Out-of-Hospital Cardiac Arrest

Although high volume of cases of out-of-hospital cardiac arrest (OHCA) is a key feature of cardiac arrest centers, which have proven survival benefit, the role of center volume as an independent variable associated with improved outcomes is unclear. To assess the association of high-volume centers with survival and neurological outcomes in nontraumatic OHCA. Medline, Embase, and the Cochrane Central Register of Controlled Trials were searched from inception to October 11, 2021, for studies including adult patients with nontraumatic OHCA who were treated at high-volume vs non-high-volume centers. Randomized clinical trials, nonrandomized studies of interventions, prospective cohort studies, and retrospective cohort studies were selected that met the following criteria: (1) adult patients with OHCA of nontraumatic etiology, (2) comparison of high-volume with low-volume centers, (3) report of a volume-outcome association, and (4) report of outcomes of interest. At least 2 authors independently reviewed each article, blinded to each other's decision. Data abstraction and quality assessment were independently conducted by 2 authors. Meta-analyses were performed for adjusted odds ratios (aORs) and crude ORs using a random-effects model. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline. Survival and good neurological outcomes according to the Cerebral Performance Categories Scale at hospital discharge or 30 days. A total of 16 studies involving 82 769 patients were included. Five studies defined high volume as 40 or more cases of OHCA per year; 3 studies defined high volume as greater than 100 cases of OHCA per year. All other studies differed in definitions. Survival to discharge or 30 days improved with treatment at high-volume centers, regardless of whether aORs (1.28 [95% CI, 1.00-1.64]) or crude ORs (1.43 [95% CI, 1.09-1.87]) were pooled. There was no association between center volume and good neurological outcomes at 30 days or hospital discharge in patients with OHCA (aOR, 0.96 [95% CI, 0.77-1.20]). In this meta-analysis and systematic review, care at high-volume centers was associated with improved survival outcomes, even after adjustment for potential confounders, but was not associated with improved neurological outcomes for patients with nontraumatic OHCA. More studies evaluating the relative importance of center volume compared with other variables (eg, the availability of treatment modalities) associated with survival outcomes in patients with OHCA are required.

Hospital case-volume and mortality after lung cancer surgery: A population-based retrospective cohort study

ObjectivesRecent advances in lung cancer treatment warrants reassessment of the volume-outcome association in lung cancer surgery. This study reassessed the relationship between surgical case-volume and both in-hospital and long-term mortality after lung cancer surgery using a current database to reflect recent advances. Materials and methodsUsing the database of the National Health Insurance Service in Korea, data of all adult patients who underwent lung cancer surgery in Korea between 2005 and 2019 were obtained. Hospitals were categorized by the annual number of lung cancer surgeries. Risk-adjusted in-hospital and 1, 3, 5-year mortality after surgery were assessed. ResultsA total of 84,194 lung cancer surgeries were performed in 163 centers during the study period. High-volume centers were defined as > 200 cases/year, medium-volume centers as 60–200 cases/year, and low-volume centers as < 60 cases/year. After adjustment, in-hospital mortality was significantly lower in high-volume centers (1.03%) compared to medium-volume centers (2.06%, adjusted odds ratio [OR], 1.43; 95% confidence interval [CI], 1.23–1.65; P < 0.001), and low-volume centers (3.08%, OR, 1.32; 95% CI, 1.16–1.51; P < 0.001). Long-term mortality was also significantly lower in high-volume centers compared to the other groups. ConclusionHigh-volume centers showed lower in-hospital and long-term mortality compared to centers with less case-volume.

Volume-Outcome Associations for Parathyroid Surgery in England

Previous studies have suggested an association between surgical volume and patient outcomes for parathyroid surgery. However, most previous studies are relatively small and the literature is dominated by studies form the US, which might not be readily generalizable to other settings. To investigate volume-outcome associations for parathyroid surgery in England. Cohort study that included all National Health Service hospital trusts in England with secondary analysis of administrative data using International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10). Participants included all adult, elective hospital admissions for parathyroid surgery without a diagnosis of multiple endocrine neoplasia, parathyroid cancer, or kidney disease over a 5-year period (April 2014-March 2019 inclusive). The number of procedures conducted in the year prior to the index procedure by each surgeon and each hospital trust. Repeat parathyroid surgery within 1 year of the index procedure. This study included data for 17 494 participants who underwent parathyroidectomies conducted across 125 hospital trusts. The median (IQR) age of patients was 62 (53-71) years, and 13 826 were female (79.0%). Across the period, the number of surgeons conducting parathyroid surgery changed little (280 in 2014-2015 and 2018-2019), although the number of procedures conducted rose from 3331 to 3848 per annum. Repeat parathyroid surgery at 1 year was significantly associated with surgeon volume (odds ratio [OR], 0.99; 95% CI, 0.98-0.99), but not trust volume, in the previous 12 months. Extended length of stay (OR, 0.98; 95% CI, 0.98-0.99), hypoparathyroidism/calcium disorder (OR, 1.0; 95% CI, 0.99-1.0), and postprocedural complications (OR, 0.99; 95% CI, 0.99-1.0) were also associated with lower surgeon volume. In this cohort study, higher surgeon annual volume was associated with decreased rates of repeat parathyroid surgery. A minimum volume threshold of 20 procedures per annum should improve patient outcomes, although possible negative effects on access to services should be monitored.