Volume Quintiles Research Articles

Case Volume-Outcomes Associations Among Patients With Severe Sepsis Who Underwent Interhospital Transfer.

Case volume-outcome associations bolster arguments to regionalize severe sepsis care, an approach that may necessitate interhospital patient transfers. Although transferred patients may most closely reflect care processes involved with regionalization, associations between sepsis case volume and outcomes among transferred patients are unclear. We investigated case volume-outcome associations among patients with severe sepsis transferred from another hospital. Serial cross-sectional study using the Nationwide Inpatient Sample. United States nonfederal hospitals, years 2003-2011. One hundred forty-one thousand seven hundred seven patients (weighted national estimate of 717,732) with severe sepsis transferred from another acute care hospital. None. We examined associations between quintiles of annual hospital severe sepsis case volume for the receiving hospital and in-hospital mortality among transferred patients with severe sepsis. Secondary outcomes included hospital length of stay and total charges. Transferred patients accounted for 13.2% of hospitalized severe sepsis cases. In-hospital mortality was 33.2%, with median length of stay 11 days (interquartile range, 5-22), and median total charge $70,722 (interquartile range, $30,591-$159,013). Patients transferred to highest volume hospitals had higher predicted mortality risk, greater number of acutely dysfunctional organs, and lower adjusted in-hospital mortality when compared with the lowest-volume hospitals (odds ratio, 0.80; 95% CI, 0.67-0.90). In stratified analysis (p < 0.001 for interaction of case volume by organ failure), mortality benefit associated with case volume was limited to patients with single organ dysfunction (n = 48,607, 34.3% of transfers) (odds ratio, 0.66; 95% CI, 0.55-0.80). Treatment at highest volume hospitals was significantly associated with shorter adjusted length of stay (incidence rate ratio, 0.86; 95% CI, 0.75-0.98) but not costs (% charge difference, 95% CI: [-]18.8, [-]37.9 to [+]0.3). Hospital mortality was lowest among patients with severe sepsis who were transferred to high-volume hospitals; however, case volume benefits for transferred patients may be limited to patients with lower illness severity.

Hospitals with higher volumes of emergency general surgery patients achieve lower mortality rates: A case for establishing designated centers for emergency general surgery.

Higher volume has been associated with lower mortality for several surgical diseases. It is not known if this relationship exists in the management of Emergency General Surgery (EGS). Our hypothesis was that EGS patients treated at hospitals with higher EGS volume experienced lower mortality rates than those treated at low-volume hospitals. This was a retrospective analysis of 2010 National Inpatient Sample data, maintained by the Agency for Healthcare Quality and Research as a representative national sample of inpatients. Patients with EGS diseases were identified using American Association for the Surgery of Trauma definitions using ICD-9 codes (2,640,725 patients from 943 hospitals). Multivariable hierarchical logistic regression model was used to estimate the risk-standardized mortality rate (RSMR) for each hospital, adjusted for patient (age, sex, race, ethnicity, insurance type, socioeconomic status, comorbidities) and hospital (region, location, bed size, teaching status, ownership) characteristics. A cubic spline regression model with 4 knots was used to identify the volume associated with low mortality rates. The volume of EGS patients treated was inversely associated with hospital mortality rate. RSMR in hospitals in the highest quintile of volume (median, 7424 patients) was 1.62% (95% CI: 1.61-1.64%); at hospitals in the lowest quintile of volume (median, 68 patients), it was 6.1% (95% CI: 6.0-6.2%) (p < 0.0001). Mortality rate stabilized at an annual volume of 688 (95% CI: 554-753) patients. The mortality rate in hospitals that treated fewer than 688 patients was 5.0% (95% CI: 4.8-5.1%), compared to 1.99% (95% CI: 1.96-2.01%) at those that treated 688 or more patients (p < 0.0001). EGS patients treated at hospitals with a higher volume of EGS patients experienced lower mortality rates, with a possible threshold of 688 patients per year. A regionalized system of EGS care where complex patients are treated at large-volume centers may improve patient outcomes. Therapeutic study, level III.

The effect of surgeon and hospital volume on mortality after open and endovascular repair of abdominal aortic aneurysms

BackgroundHigher hospital and surgeon volumes are independently associated with improved mortality after open repair of abdominal aortic aneurysms (AAAs) in the era before endovascular AAA repair (EVAR). The effects of both surgeon and hospital volume on mortality after EVAR and open repair in the current era are less well defined. MethodsWe studied Medicare beneficiaries who underwent elective AAA repair from 2001 to 2008. Volume was measured by procedure type during the 1-year period preceding each procedure and was further categorized into quintiles of volume for surgeon and hospital. Multilevel logistic regression models were used to evaluate the effect of surgeon volume, accounting for hospital volume, on mortality after adjusting for patient demographic and comorbid conditions as well as the analogous effect of hospital volume adjusting for surgeon volume. The multilevel models included random effects for surgeon and hospital to account for the clustering of multiple patients within the same surgeon and within the same hospital. ResultsWe studied 122,495 patients who underwent AAA repair (open: 45,451; EVAR: 77,044). After EVAR, perioperative mortality did not differ by surgeon volume (quintile 1 [0-6 EVARs]: 1.8%; quintile 5 [28-151 EVARs]: 1.6%; P = .29), but decreased with greater hospital volume (quintile 1 [0-9 EVARs]: 1.9%; quintile 5 [49-198 EVARs]: 1.4%; P < .01). After open repair, perioperative mortality decreased with both higher surgeon volume (quintile 1 [0-3 open repairs]: 6.4%; quintile 5 [14-62 open repairs]: 3.8%; P < .01) and hospital volume (quintile 1 [0-5 open repairs]: 6.3%; quintile 5 [14-62 open repairs]: 3.8%; P < .01). After adjustment for other predictors, surgeon volume was not associated with perioperative mortality after EVAR (odds ratio [OR], 0.9; 95% confidence interval [CI], 0.7-1.1); however, hospital volume was associated with higher perioperative mortality (quintile 1: OR, 1.5; 95% CI, 1.2-1.9; quintile 2: OR, 1.3; 95% CI, 1.02-1.6; and quintile 3: OR, 1.2; 95% CI, 1.01-1.5, compared with 5). After open repair, higher surgeon volume was also associated with lower mortality (quintile 1: OR, 1.5; 95% CI, 1.3-1.8; quintile 2: OR, 1.3; 95% CI, 1.1-1.6; and quintile 3: OR, 1.2; 95% CI, 1.1-1.4, compared with 5). Risk of mortality also was higher for patients treated at lower-volume hospitals (quintile 1: OR, 1.3; 95% CI, 1.1-1.5; quintile 2: OR, 1.3; 95% CI, 1.1-1.5; and quintile 3: OR, 1.2; 95% CI, 1.1-1.4, compared with 5). ConclusionsAfter EVAR, hospital volume is minimally associated with perioperative mortality, with no such association for surgeon volume. After open AAA repair, surgeon and hospital volume are both strongly associated with mortality. These findings suggest that open surgery should be concentrated in hospitals and surgeons with high volume.

Risk of Peripartum Hysterectomy and Center Hysterectomy and Delivery Volume.

To characterize where women at risk for and undergoing peripartum hysterectomy delivered in terms of obstetric volume and procedural experience. We used data from the Perspective database to retrospectively evaluate trends in peripartum hysterectomy and deliveries at high risk of peripartum hysterectomy based on placenta previa and prior cesarean delivery delivered from 2006 through 2014. Hospitals were categorized two separate ways for the analysis: 1) into five roughly equal quintiles based on annualized delivery volume and 2) by the mean number of hysterectomies performed annually over the study period. Four thousand eight hundred eleven hysterectomies occurred among 5,388,486 deliveries in 500 hospitals over the study period. The peripartum hysterectomy rate increased from 81.4 per 100,000 deliveries in 2006 to 98.4 in 2014. The prevalence rate of placenta previa in the setting of previous cesarean delivery also increased over the study period. Between 2006-2008 and 2012-2014, peripartum hysterectomy decreased in the lowest delivery volume quintile and increased in the highest delivery volume quintile (-14.9/100,000 deliveries, 95% confidence interval [CI] -25.6 to -4.2 and +35.4/100,000 deliveries, 95% CI 20.3-50.5, respectively). Similarly, hospitals performing high rates of hysterectomies saw the largest increase over the study period. With peripartum hysterectomy rates increasing in the population, hospitals with high delivery volumes and high rates of hysterectomies saw the largest increases in peripartum hysterectomy rates. These trends support that improved referral practices and uptake of evidence-based recommendations may be occurring.

High lung cancer surgical procedure volume is associated with shorter length of stay and lower risks of re-admission and death: National cohort analysis in England

It is debated whether treating cancer patients in high-volume surgical centres can lead to improvement in outcomes, such as shorter length of hospital stay, decreased frequency and severity of post-operative complications, decreased re-admission, and decreased mortality.The dataset for this analysis was based on cancer registration and hospital discharge data and comprised information on 15,738 non-small-cell lung cancer patients resident and diagnosed in England in 2006–2010 and treated by surgical resection. The number of lung cancer resections was computed for each hospital in each calendar year, and patients were assigned to a hospital volume quintile on the basis of the volume of their hospital.Hospitals with large lung cancer surgical resection volumes were less restrictive in their selection of patients for surgical management and provided a higher resection rate to their geographical population. Higher volume hospitals had shorter length of stay and the odds of re-admission were 15% lower in the highest hospital volume quintile compared with the lowest quintile. Mortality risks were 1% after 30 d and 3% after 90 d. Patients from hospitals in the highest volume quintile had about half the odds of death within 30 d than patients from the lowest quintile.Variations in outcomes were generally small, but in the same direction, with consistently better outcomes in the larger hospitals. This gives support to the ongoing trend towards centralisation of clinical services, but service re-organisation needs to take account of not only the size of hospitals but also referral routes and patient access.

WE‐DE‐207B‐11: Implementation of Size‐Specific 3D Beam Modulation Filters On a Dedicated Breast CT Platform Using Breast Immobilization

Purpose:To implement a 3D beam modulation filter (3D‐BMF) in dedicated breast CT (bCT) and develop a method for conforming the patient's breast to a pre‐defined shape, optimizing the effects of the filter. This work expands on previous work reporting the methodology for designing a 3D‐BMF that can spare unnecessary dose and improve signal equalization at the detector by preferentially filtering the beam in the thinner anterior and peripheral breast regions.Methods:Effective diameter profiles were measured for 219 segmented bCT images, grouped into volume quintiles, and averaged within each group to represent the range of breast sizes found clinically. These profiles were then used to generate five size‐specific computational phantoms and fabricate five size‐specific UHMW phantoms. Each computational phantom was utilized for designing a size‐specific 3D‐BMF using previously reported methods. Glandular dose values and projection images were simulated in MCNP6 with and without the 3DBMF using the system specifications of our prototype bCT scanner “Doheny”. Lastly, thermoplastic was molded around each of the five phantom sizes and used to produce a series of breast immobilizers for use in conforming the patient's breast during bCT acquisition.Results:After incorporating the 3D‐BMF, MC simulations estimated an 80% average reduction in the detector dynamic range requirements across all phantom sizes. The glandular dose was reduced on average 57% after normalizing by the number of quanta reaching the detector under the thickest region of the breast.Conclusion:A series of bCT‐derived breast phantoms were used to design size‐specific 3D‐BMFs and breast immobilizers that can be used on the bCT platform to conform the patient's breast and therefore optimally exploit the benefits of the 3D‐BMF. Current efforts are focused on fabricating several prototype 3D‐BMFs and performing phantom scans on Doheny for MC simulation validation and image quality analysis.Research reported in this paper was supported in part by the National Cancer Institute of the National Institutes of Health under award R01CA181081. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institue of Health.

Contemporaneous and asymmetric volume-return relationship: cross-product evidence from an emerging market

This paper demonstrates that both Taiwan’s exchange-traded funds (ETFs) and equities exhibit an asymmetric volume-return relationship in which the ETF display a mixed, negative or positive, asymmetry and the equity exhibits primarily a positive asymmetry. The positive asymmetry in equities and its decline with the progressive elimination of the short-sale restriction on equities support the costly short-sale hypothesis, which considers a costly short-sale restriction or asymmetric transaction costs on long and short trading to be the source of the asymmetry. The part of a less positive asymmetry in ETFs also consists with what the costly short-sale hypothesis predicts. The later information models that consider asymmetrically-informed traders or the heterogeneity of traders to be the source of the asymmetry explain the negative asymmetry in ETFs and the upward trend in the magnitude of volume-return correlation with the grow of volume quintiles. An important conclusion is that not a single hypothesis can be a universal explanation for the asymmetric volume-return relationship. Which hypothesis may explain the volume-return asymmetry depends largely on whether the short-sale restriction is present

Abstract 12010: Penalizing Hospitals for Excess Heart Failure Readmissions: Probability of Hospital Misclassification Error

Introduction: The Centers for Medicare &amp; Medicaid Services (CMS) adjust hospital payments for heart failure (HF) admissions if the estimate of risk-standardized excess readmission ratio (ERR) is above 1. The 2012 Inpatient Prospective Payment Systems Final Rule does not take into account the uncertainty of ERR measurement raising concerns about possible consequences. Hypothesis: Ignoring the uncertainty of ERR measurement results in significant probability of hospital misclassification error (HME) in HF, the most costly of applicable conditions. Methods: For a cohort of 1,085,568 Medicare fee-for-service patients undergoing 1,494,993 HF admissions in 4,930 U. S. hospitals between July 1, 2005 and June 30, 2008, we reproduced ERR distributions for individual hospitals using hierarchical logistic regression model and bootstrap method employed by CMS to obtain confidence intervals of ERR. Based on ERR distributions, we calculated probability of HME for each hospital and stratified results by hospital volume. Results: Mean probability of HME due to ignoring the uncertainty of ERR measurement is 28.2% (95% CI: 27.7%, 28.6%). Probability of HME varies with hospital volume: 41.5, 33.9, 26.9, 21.5, 16.7% in the 1st-5th volume quintiles (p&lt;.001). In the subset of 2,381 hospitals with ERR above 1 (subject to payment adjustment per existing regulations), the falsely penalized rate was 27.5% (95% CI: 26.7%, 28.3%). In the subset of 2,549 hospitals with point estimate ≤ 1 (not subject to payment adjustment), the probability of not penalizing a poorly performing hospital was 28.8% (95% CI: 28.2%, 29.4%). (Possible maximum of probability of HME is 50% equivalent to no discrimination). Conclusions: Ignoring uncertainty of ERR measurement leads to errors in imposing financial penalties on hospitals associated with heart failure readmissions: good performers are penalized and poor performers escape penalties with estimated probability ~30%. Furthermore, disparity exists among hospitals with different volume: probability of erroneous adjustment of payment is inversely related to hospital volume.

The Impact of Hospital and Surgeon Volume on In-Hospital Mortality of Ventricular Assist Device Recipients

BackgroundThe use of left ventricular assist devices (LVADs) in the United States has increased since the Food and Drug Administration approved the 1st device in 1994. Despite a rapid increase in the number of LVADs implanted per year, there are substantial variations in procedure volume among hospitals and surgeons. This study evaluated the association between hospital and surgeon volumes of LVAD procedures and in-hospital mortality. Methods and ResultsWe conducted a retrospective cross-sectional analysis of all patient discharges after an LVAD implantation from University HealthSystem Consortium (UHC) academic medical center members from January 2007 through June 2012. With the use of International Classification of Diseases–9th Edition, Clinical Modification, procedure code 37.66, we identified 7714 patients who received an LVAD from 581 surgeons across 88 hospitals. The primary outcome was all-cause in-hospital mortality. Annual hospital and surgeon LVAD procedure volumes were evaluated as both continuous variables and quintiles. Hierarchical binary logistic regression models were fitted to test the association of in-hospital mortality with hospital and surgeon volume, controlling for hospital and patient characteristics. Hospital volume was not associated with lower in-hospital mortality. Highest annual surgeon volume quintile was a significant predictor of lower in-hospital mortality (odds ratio 1.69; P < .001); this model had the highest predictive accuracy, with area under the receiver operating characteristic curve of 0.79. ConclusionsSurgeons' LVAD procedure volume, not annual hospital procedure volume, was associated with in-hospital mortality.

Impact of Provider Characteristics on Outcomes of Carotid Endarterectomy for Asymptomatic Carotid Stenosis in New York State

Background The purpose of this study is to explore the impact of surgeon characteristics (including annual volume, specialty, and years in practice) on outcomes of carotid endarterectomy (CEA) for asymptomatic carotid atherosclerosis in New York State. Methods The New York Statewide Planning and Cooperation System database was utilized to identify patients undergoing CEA from 2004 to 2011. Provider characteristics were determined by linkage to the New York Office of Professions and National Provider Identification databases. Provider-level factors were characterized by defining 5 quintiles of equal size for each factor. Hierarchical logistic regression models were created to evaluate the impact of provider characteristics on outcome. Results In total, 36,495 patients underwent CEA for asymptomatic disease performed by vascular (75.7%), general (16.1%), cardiac (6%), and neuro (2.1%) surgeons. Outcomes of interest included in-hospital mortality (0.26%), stroke (0.45%), and the composite end point of mortality, stroke, or cardiac complication (2.2%). Unadjusted outcomes improved with increasing surgeon annual CEA volume. Mid-career surgeons had lower mortality and stroke rates than early or late-career surgeons. Odds of mortality were increased when surgery was performed by the lowest volume providers (quintile 1; 0–11 CEA/year) (odds ratio [OR] 2.62, 95% confidence interval [CI] 1.3–5.28) or a nonspecialty trained (general) surgeon (OR 1.64, 95% 1.01–2.67). After adjustment for all patient-level factors, provider volume remained an independent predictor of outcome, with significantly increased odds of mortality for volume quintile 1 (OR 2.57, 95% CI 1.27–5.23) and quintile 2 (12–22 CEA/year) (0.30%; OR 2.07, 95% CI 1–4.27) surgeons. Conclusions Adverse events after CEA for asymptomatic disease are comparatively rare. However, surgeon characteristics impact outcome, with the best results offered by high-volume, mid-career, specialty-trained surgeons. Efforts to define the optimal treatment of asymptomatic carotid atherosclerosis must account for the impact of surgeon characteristics on patient outcomes.

Volume-dependent effect of supervised exercise training on fatty liver and visceral adiposity index in subjects with type 2 diabetes The Italian Diabetes Exercise Study (IDES)

AimsThis study evaluated the effect of supervised exercise training on liver enzymes and two surrogate measures of non-alcoholic fatty liver disease (NAFLD) in subjects with type 2 diabetes. MethodsSedentary patients from 22 outpatient diabetes clinics were randomized by center, age and treatment to twice-a-week supervised aerobic and resistance training plus structured exercise counseling (exercise group, EXE; n=303) versus counseling alone (control group, CON; n=303) for 12 months. EXE participants were further randomized to low-to-moderate (n=142) or moderate-to-high (n=161) intensity training of equal energy cost. Baseline and end-of-study levels of liver enzymes, fatty liver index (FLI) and visceral adiposity index (VAI) were obtained. ResultsEnzyme levels did not change, whereas FLI and VAI decreased significantly in EXE, but not CON participants. Physical activity (PA) volume was an independent predictor of both FLI and VAI reductions, the extent of which increased from the 1st to the 4th quintile of PA volume and baseline to end-of-study changes in fitness parameters. Differences in the effect of LI versus HI training were negligible. ConclusionsData from this large cohort of subjects with type 2 diabetes indicate that FLI and VAI decrease with supervised training in a volume-dependent manner.

Association between hospital procedure volume and early complications after pacemaker implantation: results from a large, unselected, contemporary cohort of the German nationwide obligatory external quality assurance programme.

Several studies demonstrated an inverse relationship between cardioverter-defibrillator implantation volume and complication rates, suggesting better outcomes for higher volume centres. However, the association of institutional procedural volume with patient outcomes for permanent pacemaker (PPM) implantation remains less known, especially in decentralized implantation systems. We performed retrospective examination of data on patients undergoing PPM from the German obligatory quality assurance programme (2007-12) to evaluate the relationship of hospital PPM volume (categorized into quintiles of their mean annual volume) with risk-adjusted in-hospital surgical complications (composite of pneumothorax, haemothorax, pericardial effusion, or pocket haematoma, all requiring intervention, or device infection) and pacemaker lead dislocation. Overall 430 416 PPM implantations were documented in 1226 hospitals. Systems included dual (72.8%) and single (25.8%) chamber PPM and cardiac resynchronization therapy (CRT) devices (1.1%). Complications included surgical (0.92%), and ventricular (0.99%), and atrial (1.22%) lead dislocation. Despite an increase in relatively complex procedures (dual chamber, CRT), there was a significant decrease in the procedural and fluoroscopy times and complications from lowest to highest implantation volume quintiles (P for trend <0.0001). The greatest difference was observed between the lowest (1-50 implantations/year-reference group) and the second-lowest (51-90 implantations/year) quintile: surgical complications [odds ratio (OR) 0.69; confidence interval (CI) 0.60-0.78], atrial lead dislocations (OR 0.69; CI 0.59-0.80), and ventricular lead dislocations (OR 0.73; CI 0.63-0.84). Hospital annual PPM volume was directly related to indication-based implantation of relatively more complex PPM and yet inversely with procedural times and rates of early surgical complications and lead dislocations. Thus, our data suggest better performance and lower complications with increasing procedural volume.

The relationship between trauma center volume and in-hospital outcomes

BackgroundIncreases in hospital volume are positively associated with improved surgical outcomes. However, in the trauma setting, studies have reported conflicting findings in regard to volume's effect on in-hospital mortality. This study investigates whether complications, failure-to-rescue (FTR), and mortality are influenced by trauma centers' average annual volume. MethodsWe performed a retrospective cohort study that analyzed patient records included in the National Trauma Data Bank from years 2008–2010. We calculated risk-adjusted complication, FTR, and mortality rates for centers treating different volumes of patients. We also performed multilevel logistic regression modeling to examine the probability that patients treated at trauma centers with higher annual volumes would experience complication, FTR, and mortality while controlling for injury severity, type of injury, mechanism of trauma, age, gender, race, number of comorbidities, head injury, hypotension, and hospital clustering. Hospital characteristics including designation level, academic status, nonprofit status, safety-net status, and region were incorporated into the model. ResultsRisk-adjusted complication, FTR, and mortality rates differed significantly across hospital volume quintiles. Regression analyses indicated that higher hospital volumes were significantly associated with a decreased likelihood of mortality for individual patient but not for complication or FTR. ConclusionsOur findings suggest that higher trauma center volume is associated with improved mortality outcomes. However, the relationship between volume and FTR is more complex. Future research should address the question of determining optimal volume levels that lead to high provider experience, efficient resource usage, and low unintended consequences or outcomes.

The Complex Association of Metabolic Syndrome and Its Components with Computed Tomography–Determined Emphysema Index

Recent reports have suggested the association between emphysema and cardiovascular disease (CVD); however, there are few reports regarding association of emphysema severity with metabolic syndrome and its components representing CVD risk factors. A retrospective cross-sectional study was performed in 2814 adult male subjects over age 40 who visited the Health Promotion Center in Samsung Medical Center for a health checkup program. We classified patients according to the quintiles of forced expiratory volume in 1 sec (FEV1) and emphysema index (EI). FEV1 percentage predicted values (% pred) was inversely associated with prevalence of metabolic syndrome and most of its components, such as abdominal obesity, hypertension, fasting hyperglycemia, and low high-density lipoprotein cholesterol. Although there was no association between prevalence of metabolic syndrome and EI, hypertension was positively associated with EI (P<0.001) and high triglycerides (TGs) were inversely associated with EI (P=0.021). These associations persisted after adjustment of other variables (P<0.001 in hypertension and P=0.039 in high TGs). The computed tomography-determined EI has a complex association with components of metabolic syndrome that is associated with increased prevalence of hypertension but decreased prevalence of high TGs, whereas FEV1 (% pred) has an inverse association with metabolic syndrome and most of its components with consistent direction.

The volume-quality relationship in antibiotic prescribing: when more isn't better.

For many surgeries and high-risk medical conditions, higher volume providers provide higher quality care. The impact of volume on more common medical conditions such as acute respiratory infections (ARIs) has not been examined. Using electronic health record data for adult ambulatory ARI visits, we divided primary care physicians into ARI volume quintiles. We fitted a linear regression model of antibiotic prescribing rates across quintiles to assess for a significant difference in trend. Higher ARI volume physicians had lower quality across a number of domains, including higher antibiotic prescribing rates, higher broad-spectrum antibiotic prescribing, and lower guideline concordance. Physicians with a higher volume of cases manage ARI very differently and are more likely to prescribe antibiotics. When they prescribe an antibiotic for a diagnosis for which an antibiotic may be indicated, they are less likely to prescribe guideline-concordant antibiotics. Given that high-volume physicians account for the bulk of ARI visits, efforts targeting this group are likely to yield important population effects in improving quality.

Site Volume Is Associated With Achievement of Complete Eradication of Intestinal Metaplasia (CEIM) in Radiofrequency Ablation (RFA)

Introduction: The predictors of successful outcomes following RFA are poorly understood. We sought to describe the association between site volume of RFA cases and the rates of CEIM. Methods: The U.S. RFA registry is a national study of patients with BE treated with RFA at 148 institutions (113 community, 35 academic). We divided sites into quintiles based on case volume, such that sites in the lowest quintile enrolled ≤7 patients, while sites in the highest quintile enrolled ≥56 patients in the registry. We then estimated adjusted and unadjusted rate differences (aRD and uRD) for achieving CEIM using generalized linear models. Results: In total, 5,444 patients were enrolled. CEIM was strongly associated with site volume, with higher rates occurring in larger centers (Table 1). The difference per quintile of center size attenuated, but persisted, after adjustment for pre-treatment histologic grade, academic vs. community site, race/ethnicity, BE segment length, age, and order treated (aRD=2.6% per quintile increase [1.3-3.8%], uRD=4.2% [3.1-5.4%]). Comparing the 1st to the 5th quintile of patient volume, for every 7 subjects treated, an additional patient would achieve CEIM in the 5th quintile. Additionally, patients treated in centers where narrow band imaging was not used had lower rates of eradication (aRD=-0.054 [-0.095, -0.014]).Table 1: Characteristics of 5,444 Patients at 148 RFA Sites by Quintile of Number of Patients EnrolledConclusion: Higher volume centers had better rates of CEIM than smaller ones. Adjustment for patient characteristics does not eliminate this difference. Disclosure - Dr. Shaheen has received research funding from GI Solutions, a subsidiary of Covidien. This research was supported by an industry grant from This research was funded by GI Solutions, a subsidiary of Covidien.Figure 1

Hospital Volume and Operative Mortality in the Modern Era

To determine whether the relationship between hospital volume and mortality has changed over time. It is generally accepted that hospital volume is associated with mortality in high-risk procedures. However, as surgical safety has improved over the last decade, recent evidence has suggested that the inverse relationship has diminished or been eliminated. Using national Medicare claims data from 2000 through 2009, we examined mortality among 3,282,127 patients who underwent 1 of 8 gastrointestinal, cardiac, or vascular procedures. Hospitals were stratified into quintiles of operative volume. Using multivariable logistic regression models to adjust for patient characteristics, we examined the relationship between hospital volume and mortality, and assessed for changes over time. We performed sensitivity analyses using hierarchical logistic regression modeling with hospital-level random effects to confirm our results. Throughout the 10-year period, a significant inverse relationship was observed in all procedures. In 5 of the 8 procedures studied, the strength of the volume-outcome relationship increased over time. In esophagectomy, for example, the adjusted odds ratio of mortality in very low volume hospitals compared to very high volume hospitals increased from 2.25 [95% confidence interval (CI): 1.57-3.23] in 2000-2001 to 3.68 (95% CI: 2.66-5.11) in 2008-2009. Only pancreatectomy showed a notable decrease in strength of the relationship over time, from 5.83 (95% CI: 3.64-9.36) in 2000-2001, to 3.08 (95% CI: 2.07-4.57) in 2008-2009. For all procedures examined, higher volume hospitals had significantly lower mortality rates than lower volume hospitals. Despite recent improvements in surgical safety, the strong inverse relationship between hospital volume and mortality persists in the modern era.

Understanding the Volume-Outcome Effect in Cardiovascular Surgery

To effectively guide interventions aimed at reducing mortality in low-volume hospitals, the underlying mechanisms of the volume-outcome relationship must be further explored. Reducing mortality after major postoperative complications may represent one point along the continuum of patient care that could significantly affect overall hospital mortality. To determine whether increased mortality at low-volume hospitals performing cardiovascular surgery is a function of higher postoperative complication rates or of less successful rescue from complications. We used patient-level data from 119434 Medicare fee-for-service beneficiaries aged 65 to 99 years undergoing coronary artery bypass grafting, aortic valve repair, or abdominal aortic aneurysm repair between January 1, 2005, and December 31, 2006. For each operation, we first divided hospitals into quintiles of procedural volume. We then assessed hospital risk-adjusted rates of mortality, major complications, and failure to rescue (ie, case fatality among patients with complications) within each volume quintile. Hospital procedural volume. Hospital rates of risk-adjusted mortality, major complications, and failure to rescue. For each operation, hospital volume was more strongly related to failure-to-rescue rates than to complication rates. For example, patients undergoing aortic valve replacement at very low-volume hospitals (lowest quintile) were 12% more likely to have a major complication than those at very high-volume hospitals (highest quintile) but were 57% more likely to die if a complication occurred. High-volume and low-volume hospitals performing cardiovascular surgery have similar complication rates but disparate failure-to-rescue rates. While preventing complications is important, hospitals should also consider interventions aimed at quickly recognizing and managing complications once they occur.

Abstract W MP100: Hospital SAH Volume Associated With Better Outcomes

Objective: The net impact of hospital care on outcomes in subarachnoid hemorrhage (SAH) has not been well established. We hypothesized that increased experience and technical expertise at high volume hospitals would lead to better outcomes. Methods: We performed a serial cross-sectional retrospective study using the Nationwide Inpatient Sample from 2002-2010. All adult (&gt;18 years) discharges with a primary diagnosis of SAH (ICD-9-CM 435) from 2002-2010 were included and records with trauma or AVM were excluded. Survey-weighted descriptive statistics were used to estimate temporal trends. Multi-level logistic regression was used to estimate volume-outcome associations for two outcomes: inpatient mortality and discharge home. Models were adjusted for demographics, year, transfer status, insurance status, all individual Charlson comorbidities, intubation, and APR-DRG mortality. Analyses were repeated by excluding records where aggressive care was not pursued _ no intubation, no procedures and in-hospital death within 48 hours. Results: A total of 66,818 discharges were included in the weighted sample, including 19, 356 who received clipping or coiling. Inpatient mortality declined from 32.2% (30.1%- 33.9%) to 22.2% (20.8%-23.6%) from 2002 to 2010 while discharges to home increased from 28.5% (27.0-30.03%) to 40.8% (39.1%-42.4%). Hospitals in the highest volume quintile (greater than 63 discharges per year) had an unadjusted inpatient mortality of 22.7% (95% CI 22.0%-23.2%) compared to 41.5% (39.0%-43.7%) in quintile 3 (11-21 discharges per year) compared to 51.9% (47.0 -55.7%) in quintile 1 (less than 6 discharges per year). Similar trends were observed when excluding cases where aggressive care was not pursued. The proportion of patients discharged home also increased with hospital volume: 39.3 %( 38.0-39.9%) in quintile 5 vs. 23.2% (21.0%-25.1%) in quintile 3 vs. 16.7% (13.0%-19.7%) in quintile 1. Conclusion: Inpatient SAH mortality has decreased over time while the likelihood of discharge home has increased. High volume hospitals have more favorable outcomes than low volume hospitals and the magnitude of this effect is substantial. SAH volume should be accounted for in developing SAH systems of care.

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Introduction: Others have demonstrated modest inverse relationships between PICU patient volume and severity-adjusted mortality rates (1,2). We previously were unable to demonstrate a clear relationship between overall PICU volume and severity-adjusted mortality (3). Methods: The VPS database (VPS, LLC) was queried for all patients discharged from September 2009 through March 2012 with valid pediatric index of mortality 2 (PIM2) and PRISM3 scores. Anonymized data received included ICU mortality, PIM2 and PRISM3 score. Average PICU volume/quarter (VOL) was calculated as total discharges divided by the number of valid quarters (VPS sites submit data quarterly) per PICU. VOL was then divided by 100 (VOL-100) to assess the impact per 100 discharges per quarter. The population was divided into quintiles based on VOL-100. Several multiple logistic regression models were performed to assess the impact of VOL-100 on severity-adjusted mortality for the entire sample and within each quintile (reported as odds ratios (OR with 95% CI's). This study received a waiver as non-human research from the IRB at CHLA. Results: From 113 PICU's, 194,400 patients were studied, with an overall ICU mortality rate of 2.6%. VOL ranged from 32 to 881; the mean VOL was 269. There was a trend towards lower mortality rates as VOL-100 increased; OR.0.98 (0.97, 1.00; p = 0.08). However, the OR for VOL-100 was 1.06 (1.04, 1.08) when adjusted with PIM2 and 1.03 (1.00, 1.06) with PRISM3. In the quintile analysis, there was an increased risk of mortality per unit of VOL-100 within the lowest volume quintile; unadjusted OR 1.76 (1.48, 2.08), that remained significant after adjustment with either PIM2 (OR 1.62; 1.34, 1.95) or PRISM3 (OR 1.29; 1.04, 1.61). In the highest volume quintile, VOL-100 was associated with reduced mortality; unadjusted OR 0.88 (0.81, 0.95) that was not significant once adjusted with either PIM2 (OR 0.98; 0.89, 1.08) or PRISM3 (OR 0.92; 0.82, 1.02). Conclusions: In this preliminary analysis, the relationship between PICU volume and mortality appears to vary with unit size. In the smallest volume units, mortality increases with volume, even after severity-of-illness adjustment. There does not appear to be a relationship between volume and outcome in the highest volume units after adjusting for severity of illness. 1. Tilford et al. Pediatrics 2000; 106:289-294. 2. Marcin et al. Pediatr Crit Care Med 2005; 6:136-141. 3. Markovitz et al. Crit Care Med 2009; 37(12):A356