Association Between Surgeon and Hospital Volume in Coronary Artery Bypass Graft Surgery Outcomes: A Population-Based Study

Association of Hospital Volume and Outcomes Following Off-Pump Coronary Artery Bypass Grafting

BACKGROUND

Off-pump coronary artery bypass grafting (OPCAB) has been used to mitigate the negative systemic effects of cardiopulmonary bypass. Recent consortium and single-institution studies suggest an association between operator experience and long-term survival. We thus aimed to ascertain the relationship between institutional OPCAB volume and outcomes using a contemporary nationwide all-payer database.

METHODS

Adult admissions for elective isolated OPCAB were identified from the 2016-2019 Nationwide Readmissions Database. The primary outcome was major adverse events (MAE), defined as a composite of mortality, reoperation, prolonged mechanical ventilation, acute kidney injury requiring dialysis, or perioperative stroke during the index hospitalisation. Secondary outcomes included temporal trends, postoperative length of stay (pLOS), hospitalisation costs, non-home discharge, and 30-day readmission rate. High-volume hospitals (HVH) were defined to have annual caseloads >35 based on cubic spline analysis.

RESULTS

Of an estimated 41,154 patients, 59.9% were treated at HVH. The proportion of coronary artery bypass grafting operations that were OPCAB significantly decreased from 21.1% in 2016 to 18.3% in 2019. After adjustment, HVH status was associated with lower adjusted odds of MAE (adjusted odds ratio [AOR] 0.78, 95% confidence interval [CI] 0.70-0.88), compared to others. HVH were also associated with shorter pLOS (β -0.10, 95% -0.13, -0.07), reduced costs (β -US$4,900, - US$6,300, - US$3,600), non-home discharge (AOR 0.54, 95% CI 0.45-0.64), and 30-day readmission (AOR 0.86, 95% CI 0.77-0.96).

CONCLUSIONS

Our results suggest that OPCAB requires a distinct set of surgical expertise and institutional aptitude. As a result, centralisation of care to centres of excellence should be considered.

Do older surgeons have safer hands? A retrospective cohort study

Background

For complex surgical procedures a volume-outcome relationship can often be demonstrated implicating multiple factors at a unit and surgeon specific level. This study aims to investigate this phenomenon in lung transplantation over a 30-year period with particular reference to surgeon age and experience, cumulative unit activity and time/day of transplant.

Methods

Prospective databases identified adult patients undergoing isolated lung transplantation at a single UK centre between June 1987 and October 2017. Mortality data was acquired from NHS Spine. Individual surgeon demographics were obtained from the General Medical Council. Student t-test, Pearson’s Chi-squared, Logistic Regression, and Kaplan–Meier Survival analyses were performed using Analyse-it package for MicrosoftExcel and STATA/IC.

Results

954 transplants (55.9% male, age 44.4 ± 13.8 years, 67.9% bilateral lung) were performed, with a median survival to follow-up of 4.37 years. There was no difference in survival by recipient gender (p = 0.661), between individual surgeons (p = 0.224), or between weekday/weekend procedures (p = 0.327).

Increasing centre experience with lung transplantation (OR1.001, 95%CI: 1.000–1.001, p = 0.03) and successive calendar years (OR1.028, 95%CI: 1.005–1.052, p = 0.017) was associated with improved 5-year survival.

Advancing surgeon age at the time of transplant (mean, 48.8 ± 6.6 years) was associated with improved 30-day survival (OR1.062, 95%CI: 1.019 to1.106, p = 0.003), which persisted 5 years post-transplant (OR1.043, 95%CI: 1.014–1.073, p = 0.003).

Individual surgeon experience, measured by the number of previous lung transplants performed, showed a trend towards improved outcomes at 30 days (p = 0.0413) with no difference in 5-year survival (p = 0.192).

Conclusions

Our study demonstrates a relationship between unit volume, increasing surgeon age and survival after lung transplantation. A transplant volume: outcome relationship was not seen for individual surgeons.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13019-022-01943-2.

Advocacy and Legislation for Regionalization Practices in the Treatment of Cardiogenic Shock: The Time Is Now

Cardiogenic shock is a complex hemodynamic state that, despite improvements in care, often remains challenging to treat and confers a high mortality rate. Timely application of advanced strategies, including advanced hemodynamic management and mechanical circulatory support, is of the utmost importance for this critically ill patient population. Based on data and historic experiences with similar life-threatening conditions, a national system in the US of regionalized, structured care for patients with cardiogenic shock has the potential to improve outcomes and save lives. To enact this, national and state leaders, as well as federal regulatory bodies, physician thought leaders, industry representatives, and national organizations, must collaborate and advocate for a clear, structured cardiac shock center network with a tiered model for delivery of care for the sickest population of cardiac patients.

Factors affecting mortality after coronary bypass surgery: a scoping review

OBJECTIVES

Previous research reports numerous factors of post-operative mortality in patients undergoing isolated coronary artery bypass graft surgery. However, this evidence has not been mapped to the conceptual framework of care improvement. Without such mapping, interventions designed to improve care quality remain unfounded.

METHODS

We identified reported factors of in-hospital mortality post isolated coronary artery bypass graft surgery in adults over the age of 19, published in English between January 1, 2000 and December 31, 2019, indexed in PubMed, CINAHL, and EMBASE. We grouped factors and their underlying mechanism for association with in-hospital mortality according to the augmented Donabedian framework for quality of care.

RESULTS

We selected 52 factors reported in 83 articles and mapped them by case-mix, structure, process, and intermediary outcomes. The most reported factors were related to case-mix (characteristics of patients, their disease, and their preoperative health status) (37 articles, 27 factors). Factors related to care processes (27 articles, 12 factors) and structures (11 articles, 6 factors) were reported less frequently; most proposed mechanisms for their mortality effects.

CONCLUSIONS

Few papers reported on factors of in-hospital mortality related to structures and processes of care, where intervention for care quality improvement is possible. Therefore, there is limited evidence to support quality improvement efforts that will reduce variation in mortality after coronary artery bypass graft surgery.

How to build a successful hypertrophic cardiomyopathy team and ensure training the next generation of myectomy surgeons

Transaortic extended septal myectomy is the most reliable method for septal reduction for symptomatic patients with obstructive hypertrophic cardiomyopathy. In addition, surgical management of nonobstructive hypertrophic cardiomyopathy is possible for selected patients with diastolic heart failure and small left ventricular end-diastolic cavity dimensions. These procedures, however, are performed infrequently in many centers, and trainees may not be exposed to the preoperative evaluation and intraoperative management of patients with hypertrophic cardiomyopathy. In this paper, we review what we believe are the central features for creating a successful program for septal myectomy and detail our strategies to optimize instruction in these techniques for residents and fellows.

Fragmentation of practice: The adverse effect of surgeons moving around

BACKGROUND

Whether surgical team familiarity is associated with improved postoperative outcomes remains unknown. We sought to characterize the impact of fragmented surgical practice on the likelihood that a patient would experience a textbook outcome, which is a validated patient-centric composite outcome representing an "ideal" postoperative outcome.

METHOD

Medicare beneficiaries aged 65 and older who underwent elective inpatient abdominal aortic aneurysm repair, coronary artery bypass graft, cholecystectomy, colectomy, or lung resection were identified. Rate of fragmented practice was calculated based on the total number of surgical procedures of interest performed over the study period (2013-2017) divided by the number of different hospitals in which the surgeon operated. Surgeons were categorized into "low," "average," "above average," or "high" rate of fragmented practice categories using an unsupervised machine learning technique known k-medians cluster analysis.

RESULTS

Among 546,422 Medicare beneficiaries who underwent an elective surgical procedure of interest (coronary artery bypass graft: n = 156,384, 28.6%; lung resection: n = 83,164, 15.2%; abdominal aortic aneurysm: n = 112,578, 20.6%; cholecystectomy: n = 42,955, 7.9%; colectomy: n = 151,341, 27.7%), median patient age was 74 years (interquartile range: 69-80), and most patients were male (n = 319,153, 58.4%). Machine learning identified 3 cutoffs to categorize rate of fragmented practice: 2.8%, 5.6%, and 10.6%. Overall, the majority of surgical procedures were performed by surgeons with a low rate of fragmented practice (n = 382,504, 70.0%); other surgical procedures were performed by surgeons with average (n = 109,141, 20.0%), above average (n = 44,249, 8.1%), or high (n = 10,528, 1.9%) rate of fragmented practice. On multivariable analyses, after controlling for patient demographics, individual surgeon volume, procedure type, and a random effect for hospital, patients who underwent a surgical procedure by a high versus low rate of fragmented practice surgeon had lower odds to achieve a postoperative textbook outcome (odds ratio 0.71, 95% confidence interval 0.77-0.84). Patients who underwent a procedure by a high rate of fragmented practice surgeon also had increased odds of a perioperative complication (odds ratio 1.30, 95% confidence interval: 1.23-1.37), extended length of stay (odds ratio 1.17, 95% confidence interval: 1.11-1.24), 90-day readmission (odds ratio 1.17, 95% confidence interval: 1.11-1.23), and 90-day mortality (odds ratio 1.29, 95% confidence interval: 1.17-1.42) (all P < .05).

CONCLUSION

Patients undergoing a surgical procedure by a surgeon with a high rate of fragmented practice had lower odds of achieving an optimal postoperative textbook outcome. Surgical team familiarity, measured by a surgeon rate of fragmented practice, may represent a modifiable mechanism to improve surgical outcomes.

Hospital Case Volume, Health Care Providers, and Mortality in Patients Undergoing Coronary Artery Bypass Grafting: a Nationwide Cohort Study in South Korea

Our South Korean population-based cohort study showed that a higher annual hospital case volume was associated with a lower 90-day mortality after isolated coronary artery bypass grafting (CABG). Additionally, a higher overall specialty physician volume was independently associated with a lower 90-day mortality. We reported cut-off values of ≥65 and ≥18 for the annual case volume of CABG and the total number of overall specialty doctors per 100 hospital beds, respectively, for achieving better outcomes after CABG.

Background and Objectives

Surgical quality is evaluated by measuring the annual hospital case volume; a higher case volume is associated with better survival after various surgeries. We aimed to investigate if the annual hospital case volume and the health care providers were associated with a 90-day mortality after coronary artery bypass grafting (CABG).

Methods

For this population-based cohort study, we used data from a National Health Insurance Service database in South Korea. We included all adult patients diagnosed with ischemic heart disease who underwent isolated CABG between January 2012 and December 2017. Data on the annual surgical volume for CABG in each hospital where the patients received CABG and the total number of health care providers (including physicians [trainees and specialists] from all department of the hospitals, nurses, and pharmacists) were collected.

Results

The final analysis included 15,790 adult patients; of these, 1,039 (6.6%) died within 90 days. The annual CABG volume was divided into 4 groups (Q1: ≤33, Q2: 34–86, Q3: 87–223, and Q4: ≥224). Multivariable Cox regression analysis revealed that the 90-day mortality rates in the Q4, Q3, Q2 groups were 75%, 32%, and 31% lower than that in the Q1 group, respectively. Additionally, an increase in the ratio of the total number of specialist physicians to 100 hospital beds was associated with a 4% decrease in the 90-day mortality after CABG.

Conclusion

Both, a higher annual hospital case volume and overall specialist physician volume were associated with better 90-day mortality rates after isolated CABG.

Center-level CABG and valve operative outcomes and volume-outcome relationships in New York State

BACKGROUND

We analyzed center-level outcome correlations between valve surgery and coronary artery bypass graft (CABG) in New York (NY) State and how volume-outcome effect differ between case types.

METHODS

We used the 2014-2016 NY cardiac surgery outcomes report. Center-level observed to-expected (observed-to-expected ratio [O/E]) ratio for operative mortality provided risk-adjusted operative outcomes for isolated CABG and valve operations. Correlation coefficient characterized the concordance in center-level outcomes in CABG and valve. Discordant outcomes were defined as having O/E ratio greater than 2 in one operation type with O/E ratio ≤1 in another. Linearized slope of volume-outcome effect in case types offered insights into centers with discordant performances between procedures.

RESULTS

Among 37 NY centers, annual center volumes were 220 ± 120 cases for CABG and 190 ± 178 cases for valve operations. Modest center-level correlation between CABG and valve O/E ratio was shown (R²  = 0.31). Two centers had discordant performance between valve and CABG (O/E ≤ 1 for CABG while O/E > 2 for valve procedures). No centers had CABG O/E ratio greater than 2 while valve O/E ratio ≤1. Linearized slope describing volume-outcome effects showed stronger effect in valve operations compared to CABG: O/E ratio declined 0.1 units per 100 CABG volume increase, while O/E ratio declined 0.33 units per 100 valve volume increase.

CONCLUSION

In NY hospitals, favorable valve outcomes may indicate good CABG outcomes but good CABG outcomes may not ensure valve outcomes. Outcome variation in valve operation could be related to stronger volume-outcome effect in valve operations relative to CABG. Valve operations may benefit from regionalization.

Impact of Mitral Valve Repair Case Volume on Postoperative Mortality - A Nationwide Korean Cohort Study

BACKGROUND

Although mitral valve repair is recommended over replacement due to better outcomes, repair rates vary significantly among centers. This study examined the effect of institutional mitral valve repair volume on postoperative mortality.

METHODS AND RESULTS

All cases of adult mitral valve repair performed in Korea between 2009 and 2016 were analyzed. The association between case volume and 1-year mortality was analyzed after categorizing centers according to the number of mitral valve repairs performed as low-, medium-, or high-volume centers (<20, 20-40, and >40 cases/year, respectively). The effect of case volume on cumulative all-cause mortality was also assessed. In all, 6,041 mitral valve repairs were performed in 86 centers. The 1-year mortality in low-, medium-, and high-volume centers was 10.1%, 8.7%, and 4.7%, respectively. Low- and medium-volume centers had increased risk of 1-year mortality compared with high-volume centers, with odds ratios of 2.80 (95% confidence interval [CI] 2.15-3.64; P<0.001) and 2.66 (95% CI 1.94-3.64; P<0.001), respectively. The risk of cumulative all-cause mortality was also worse in low- and medium-volume centers, with hazard ratios of 1.96 (95% CI 1.68-2.29; P<0.001) and 1.77 (95% CI 1.47-2.12; P<0.001), respectively.

CONCLUSIONS

Lower institutional case volume was associated with higher mortality after mitral valve repair. A minimum volume standard may be required for hospitals performing mitral valve repair to guarantee adequate outcome.

A Nationwide Study Assessing Preventable Hospitalization Rate on Mortality After Major Cardiovascular Surgery

Despite the use of various factors to measure hospital quality, most measures have not resulted in long-term improvements in patient outcomes. This study's purpose is to determine the effect of a previously unassessed measure of quality of care-a hospital's preventable hospitalization rate-on 30-day mortality at both the hospital and individual levels after three major cardiovascular surgery procedures. This is a population-based study using Taiwan's National Health Insurance database. We retrieved data from 2001 to 2014 for patients who had undergone abdominal aortic aneurysm (AAA) repair, coronary artery bypass graft, or aortic valve replacement (AVR). Preventable hospitalizations are hospitalizations for 11 chronic conditions that are considered preventable with effective primary care. The outcome was 30-day surgical mortality. Our dataset contained 65,863 patients who had undergone surgery for one of the three cardiovascular procedures. Preventable hospitalization rate was significantly associated with higher hospital mortality rates for all procedures. At the patient level, the adjusted odds of mortality after AAA repair were increased 55% (P < 0.01) for every 2% increase in the preventable hospitalization rate. For coronary artery bypass graft, preventable hospitalization was not a significant predictor of mortality, but rather patient factors and surgeon factors were significant. For AVR, the adjusted odds of mortality were increased 7% (P < 0.01) for every 1% increase in preventable hospitalization rate. High preventable hospitalization rate may serve as a hospital quality measure that could signal increased odds of mortality for selected cardiovascular procedures, especially for higher risk-lower volume procedures such as AAA repair and AVR.

Predicting 90-Day Mortality in Locoregionally Advanced Head and Neck Squamous Cell Carcinoma after Curative Surgery

Purpose: To propose a risk classification scheme for locoregionally advanced (Stages III and IV) head and neck squamous cell carcinoma (LA-HNSCC) by using the Wu comorbidity score (WCS) to quantify the risk of curative surgeries, including tumor resection and radical neck dissection. Methods: This study included 55,080 patients with LA-HNSCC receiving curative surgery between 2006 and 2015 who were identified from the Taiwan Cancer Registry database; the patients were classified into two groups, mortality (n = 1287, mortality rate = 2.34%) and survival (n = 53,793, survival rate = 97.66%), according to the event of mortality within 90 days of surgery. Significant risk factors for mortality were identified using a stepwise multivariate Cox proportional hazards model. The WCS was calculated using the relative risk of each risk factor. The accuracy of the WCS was assessed using mortality rates in different risk strata. Results: Fifteen comorbidities significantly increased mortality risk after curative surgery. The patients were divided into low-risk (WCS, 0–6; 90-day mortality rate, 0–1.57%), intermediate-risk (7–11; 2.71–9.99%), high-risk (12–16; 17.30–20.00%), and very-high-risk (17–18 and >18; 46.15–50.00%) strata. The 90-day survival rates were 98.97, 95.85, 81.20, and 53.13% in the low-, intermediate-, high-, and very-high-risk patients, respectively (log-rank p < 0.0001). The five-year overall survival rates after surgery were 70.86, 48.62, 22.99, and 18.75% in the low-, intermediate-, high-, and very-high-risk patients, respectively (log-rank p < 0.0001). Conclusion: The WCS is an accurate tool for assessing curative-surgery-related 90-day mortality risk and overall survival in patients with LA-HNSCC.

Contemporary Management of Cardiogenic Shock: A Scientific Statement From the American Heart Association

Cardiogenic shock is a high-acuity, potentially complex, and hemodynamically diverse state of end-organ hypoperfusion that is frequently associated with multisystem organ failure. Despite improving survival in recent years, patient morbidity and mortality remain high, and there are few evidence-based therapeutic interventions known to clearly improve patient outcomes. This scientific statement on cardiogenic shock summarizes the epidemiology, pathophysiology, causes, and outcomes of cardiogenic shock; reviews contemporary best medical, surgical, mechanical circulatory support, and palliative care practices; advocates for the development of regionalized systems of care; and outlines future research priorities.

Early mortality following percutaneous coronary intervention and cardiac surgery: Correlations within providers and operators

BACKGROUND

It is not clear whether correlations exist within hospitals or operators among risk-adjusted mortality rates (RAMRs) for the most common cardiac interventions and how much of variations in outcomes are residually explained by providers and physicians. We examined these aspects by using recent national data on percutaneous coronary intervention (PCI) and cardiac surgery.

METHODS

Publically available data from New York State aggregated at hospital and operator level were downloaded by Department of Health website for in-hospital/30-day mortality after PCI, coronary artery bypass graft (CABG) and valve surgery. Correlations between RAMRs were evaluated by using Spearman's coefficient (rho). The proportion of mortality variation attributed to hospitals and operators was estimated.

RESULTS

During the period 2008-2013, 390 cardiologists from 63 hospitals and 163 surgeons from 41 centres were evaluated. The RAMRs during 2008-2010 correlated with the RAMRs during 2011-2013 for valve surgery within providers (rho=0.55;p<0.001) and within interventionists for PCI (rho=0.21;p<0.001), isolated CABG (rho=0.25;p=0.009), and any valve surgery or CABG procedure (rho=0.49;p<0.001). The most recent hospital's RAMRs (year 2012 and 2013) significantly correlated in PCI (rho=0.40;p=0.002) but not in CABG (rho=0.13;p=0.413). <2% of mortality variations was attributed to providers and 2-3% to difference between operators.

CONCLUSIONS

A correlation exists at provider and operator level in RAMRs for PCI and cardiac surgery procedures performed in New York State. Beyond patient's risk profile, that is the strongest predictor of early mortality after a cardiac procedure, hospitals and operators have a small but statistically significant contribution to variation in post-operative outcome.

Percutaneous Coronary Intervention: Relationship Between Procedural Volume and Outcomes

Percutaneous coronary intervention (PCI) is an integral treatment modality for acute coronary syndromes (ACS) as well as chronic stable coronary artery disease (CAD) not responsive to optimal medical therapy. This coupled with studies on the feasibility and safety of performing PCI in centers without on-site surgical backup led to widespread growth of PCI centers. However, this has been accompanied by a recent steep decline in the volume of PCIs at both the operator and hospital level, which raises concerns regarding minimal procedural volumes required to maintain necessary skills and favorable clinical outcomes. The 2011 ACC/AHA/SCAI competency statement required PCI be performed by operators with a minimal procedural volume of >75 PCIs annually at high-volume centers with >400 PCIs per year, a number which was relaxed in the 2013 ACC/AHA/SCAI update to >50 PCIs/operator/year in hospitals with >200 PCIs annually to coincide with reduction in national PCI volume. Recent data suggests that many hospitals do not meet these thresholds. We review data on the importance of volume as a vital quality metric at both an operator and hospital level in determining procedural outcomes following PCI.

The effectiveness of a pay for performance program on diabetes care in Taiwan: A nationwide population-based longitudinal study

Over the past two decades, studies have widely examined the effectiveness of pay-for-performance (P4P) programs by conducting biochemical tests and assessing complications; however, the reported effectiveness of such programs among participants selected through purposeful sampling is controversial. Therefore, the objective of the current study was to analyze the effectiveness of a P4P program on patients' prognoses, including hospitalization for chronic diabetic complications, and all-cause mortality during specific follow-up years by using a nationwide population-based database in Taiwan. Based on 125,315 newly diagnosed type 2 diabetes patient cohort during 2002-2006, two control sets were designed by propensity-score-matching strategy according to participation of P4P program and followed up to 2012. The results indicated that full participants demonstrated the lowest risks of developing complications and all-cause mortality compared with nonparticipants. These findings confirm the long-term effect of P4P programs on full participants and reveal that this effect is not due to confounding variables. The results indicate the importance of performance management and adherence to interventions for patients with chronic diseases in a long-term observation. Comprehensive and continuous care is suggested to improve patient prognosis and quality of care.

Influence of experience and the surgical learning curve on long-term patient outcomes in cardiac surgery

OBJECTIVE

We hypothesized that increased postgraduate surgical experience correlates with improved operative efficiency and long-term survival in standard cardiac surgery procedures.

METHODS

Utilizing a prospectively collected retrospective database, we identified patients who underwent isolated coronary artery bypass grafting (CABG) (n = 3726), aortic valve replacement (AVR) (n = 1626), mitral valve repair (n = 731), mitral valve replacement (MVR) (n = 324), and MVR + AVR (n = 184) from January 2002 through June 2012. After adjusting for patient risk and surgeon variability, we evaluated the influence of surgeon experience on cardiopulmonary bypass and crossclamp times, and long-term survival.

RESULTS

Mean surgeon experience after fellowship graduation was 16.0 ± 11.7 years (range, 1.0-35.2 years). After adjusting for patient risk and surgeon-level fixed effects, learning curve analyses demonstrated improvements in cardiopulmonary bypass and crossclamp times with increased surgeon experience. There was marginal improvement in the predictability (R(2) value) of cardiopulmonary bypass and crossclamp time for CABG with the addition of surgeon experience; however, all other procedures had marked increases in the R(2) following addition of surgeon experience. Cox proportional hazard models revealed that increased surgeon experience was associated with improved long-term survival in AVR (hazard ratio [HR], 0.85; P < .0001), mitral valve repair (HR, 0.73; P < .0001), and MVR + AVR (HR, 0.95; P = .006) but not in CABG (HR, 0.80; P = .15), and a trend toward significance in MVR (HR, 0.87; P = .09).

CONCLUSIONS

In cardiac surgery, not including CABG, surgeon experience is an important determinant of operative efficiency and of long-term survival.

Association Between Physician Caseload and Patient Outcome for Sepsis Treatment

Objective.

The purpose of this study was to investigate whether physicians with larger sepsis caseloads provide better outcomes, defined as lower in-hospital mortality rates, for patients with sepsis.

Design.

Retrospective cross-sectional study.

Method.

This study used pooled data from the 2002-2004 Taiwan National Health Insurance Research Database. A total of 48,336 patients hospitalized with a principal diagnosis of septicemia were selected and assigned to 1 of 4 caseload groups on the basis of their treating physician's sepsis caseload during the 3 years reflected in the pooled data (low caseload, less than 39 cases; medium caseload, 39–88 cases; high caseload, 89–176 cases; and very high caseload, more than 176 cases). Generalized estimating equation models were used for analysis.

Results.

Receipt of treatment from physicians in the very high, high, and medium caseload groups decreased patients' odds of inhospital mortality by 49% (95% confidence interval [CI], 0.41-0.67; P < .001 ), 40% (95% CI, 0.53-0.68; P < .001 ), and 18% (95% CI, 0.73-0.92; P < .001), respectively, compared with the odds for patients treated by low-caseload physicians. These findings persisted after partitioning out systematic physician-specific and hospital-specific variation and isolating the effects of most hospital, physician, and patient confounders.

Conclusion.

Patients treated by physicians who had a larger sepsis caseload had a substantially lower in-hospital mortality rate than did patients treated by physicians in the other caseload groups, and the difference was statistically significant. This result supports the “practice makes perfect” hypothesis.

Cardiovascular events in patients with atherothrombotic disease: a population-based longitudinal study in Taiwan

Background

Atherothrombotic diseases including cerebrovascular disease (CVD), coronary artery disease (CAD), and peripheral arterial disease (PAD), contribute to the major causes of death in the world. Although several studies showed the association between polyvascular disease and poor cardiovascular (CV) outcomes in Asian population, there was no large-scale study to validate this relationship in this population.

Methods and Results

This retrospective cohort study included patients with a diagnosis of CVD, CAD, or PAD from the database contained in the Taiwan National Health Insurance Bureau during 2001–2004. A total of 19954 patients were enrolled in this study. The atherothrombotic disease score was defined according to the number of atherothrombotic disease. The study endpoints included acute coronary syndrome (ACS), all strokes, vascular procedures, in hospital mortality, and so on. The event rate of ischemic stroke (18.2%) was higher than that of acute myocardial infarction (5.7%) in our patients (P = 0.0006). In the multivariate Cox regression analyses, the adjusted hazard ratios (HRs) of each increment of atherothrombotic disease score in predicting ACS, all strokes, vascular procedures, and in hospital mortality were 1.41, 1.66, 1.30, and 1.14, respectively (P≦0.0169).

Conclusions

This large population-based longitudinal study in patients with atherothrombotic disease demonstrated the risk of subsequent ischemic stroke was higher than that of subsequent AMI. In addition, the subsequent adverse CV events including ACS, all stroke, vascular procedures, and in hospital mortality were progressively increased as the increase of atherothrombotic disease score.

Volume-outcome relation for acute appendicitis: evidence from a nationwide population-based study

Background

Although procedures like appendectomy have been studied extensively, the relative importance of each surgeon's surgical volume-to-ruptured appendicitis has not been explored. The purpose of this study was to investigate the rate of ruptured appendicitis by surgeon-volume groups as a measure of quality of care for appendicitis by using a nationwide population-based dataset.

Methods

We identified 65,339 first-time hospitalizations with a discharge diagnosis of acute appendicitis (International Classification of Disease, Ninth Revision, Clinical Modification (ICD-9-CM) codes 540, 540.0, 540.1 and 540.9) between January 2007 and December 2009. We used “whether or not a patient had a perforated appendicitis” as the outcome measure. A conditional (fixed-effect) logistic regression model was performed to explore the odds of perforated appendicitis among surgeon case volume groups.

Results

Patients treated by low-volume surgeons had significantly higher morbidity rates than those treated by high-volume (28.1% vs. 26.15, p<0.001) and very-high-volume surgeons (28.1% vs. 21.4%, p<0.001). After adjusting for surgeon practice location, and teaching status of practice hospital, and patient age, gender, and Charlson Comorbidity Index, and hospital acute appendicitis volume, patients treated by low-volume surgeons had significantly higher rates of perforated appendicitis than those treated by medium-volume surgeons (OR = 1.09, p<0.001), high-volume surgeons (OR = 1.16, p<0.001), or very-high-volume surgeons (OR = 1.54, p<0.001).

Conclusion

Our study suggested that surgeon volume is an important factor with regard to the rate of ruptured appendicitis.

In-hospital mortality and three-year survival after repaired acute type A aortic dissection

Background. The results of acute type A dissection (AAD) surgery in the Netherlands are largely unknown, as was recently stated in a report by the Health Council of the Netherlands. In order to gain more insight into the Dutch situation we investigated predictors of in-hospital mortality of surgically treated AAD patients and assessed threeyear survival.Methods. 104 consecutive patients undergoing surgery for AAD in a 16-year period (1990-2006) were evaluated. Preoperative and intraoperative variables were analysed to identify predictors of early mortality.Results. Preoperative malperfusion (limb ischaemia or mesenteric ischaemia) was present in 15.4%, shock in 18.3%, and 6.7% were operated under cardiac massage. Marfan syndrome was present in four patients and four patients had a bicuspid aortic valve. In-hospital mortality was 22.1%. Seven patients died intraoperatively; other causes of inhospital mortality were major brain damage in ten patients, multiple organ failure in three patients, low cardiac output in two patients and sudden cardiac death in one patient. Multivariate logistic regression revealed preoperative malperfusion (p=0.004) to be the only independent predictor of in-hospital mortality. Three-year survival was 68.8+/-4.7% (including hospital mortality). Hospital survivors had a three-year survival of 88.3+/-3.9%.Conclusion. In-hospital mortality of our patients (22.1%) is comparable with the results of larger case series published in the literature. Prognosis after successful surgical treatment is relatively good with a three-year survival of 88.3% in our series. (Neth Heart J 2009;17:226-31.).

How valid is the quantity and quality relationship in CABG surgery? A review of the literature

Numerous analyses have identified an inverse relationship between case volume in coronary artery bypass graft (CABG) surgery and mortality, and have led some to call for the consideration of minimum-volume standards for open-heart surgery programs. These findings, however, have been questioned by studies that demonstrate a weak or absent association, and by the availability of risk-adjusted mortality data. There is also growing evidence that clinical care processes have greater impact on mortality than sheer numbers alone. Policy decisions that may address this issue in the future need to consider the impact of mandating referrals away from low-volume programs, including the negative financial and programmatic effect on hospitals and both the clinical and social ramifications for patients and families, particularly in rural regions of the country.

Case volume, quality of care, and care efficiency in coronary artery bypass surgery

BACKGROUND

How case volume and quality of care relate to hospital costs or length of stay (LOS) are important questions as we seek to improve the value of health care.

METHODS

We conducted an observational study of patients 18 years or older who underwent coronary artery bypass grafting surgery in a network of US hospitals. Case volumes were estimated using our data set. Quality was assessed by whether recommended medications and services were not received in ideal patients, as well as the overall number of measures missed. We used multivariable hierarchical models to estimate the effects of case volume and quality on hospital cost and LOS.

RESULTS

The majority of hospitals (51%) and physicians (78%) were lowest-volume providers, and only 18% of patients received all quality of care measures. Median LOS was 7 days (interquartile range [IQR], 6-11 days), and median costs were $25 140 (IQR, $19 677-$33 121). In analyses adjusted for patient and site characteristics, lowest-volume hospitals had 19.8% higher costs (95% CI, 3.9%-38.0% higher); adjusting for care quality did not eliminate differences in costs. Low surgeon volume was also associated with higher costs, though less strongly (3.1% higher costs [95% CI, 0.6%-5.6% higher]). Individual quality measures had inconsistent associations with costs or LOS, but patients who had no quality measures missed had much shorter LOS and lower costs than those who missed even one.

CONCLUSION

Avoiding lowest-volume hospitals and maximizing quality are separate approaches to improving health care efficiency through reducing costs of coronary bypass surgery.

Physician quality and health care for the poor and uninsured

Adverse health outcomes for uninsured patients have been attributed to their health status and to the quality of treatment received. A question about treatment that remains unexplored is whether physicians treating the uninsured are more likely to have characteristics indicative of lower quality than physicians treating insured patients. Using education, training, experience, and board certification to measure physician quality, we find that uninsured and Medicaid patients are treated by lower-quality physicians both because of the hospitals these patients attend and because of sorting within hospitals. The effects are statistically significant, but small.

Association of increasing surgeon age with decreasing in-hospital mortality after coronary artery bypass graft surgery

BACKGROUND

The aim of this study was to investigate the relation between surgeon age and in-hospital mortality for patients who underwent a coronary artery bypass graft (CABG) using a nationwide population-based data set.

METHODS

This study used data from the 2004 Taiwan National Health Insurance Research Database. The study sample comprised 3766 patients hospitalized for CABG surgery and was divided into three equal-sized surgeon age groups: <40, 40 to 45, and >45 years. A conditional (fixed-effect) logistic regression was performed to examine the relation between surgeon age and in-hospital mortality after adjusting for surgeon CABG caseload and characteristics of patients and surgeons as well as the clustering effect among surgeons.

RESULTS

Patients who underwent CABG performed by surgeons in the <40 years age group had significantly higher in-hospital mortality rates (5.4%) than those operated on by surgeons in the 40- to 45-year age group (3.5%) and surgeons in the >45-year age group (2.6%). Regression shows that the adjusted odds ratio of in-hospital mortality for patients operated on by surgeons in the <40-year age group was 1.47 (p < 0.05) times that for surgeons in the 40- to 45-year age group and 1.82 (p < 0.05) times that for surgeons in the >45-year age group.

CONCLUSION

We conclude that older surgeons are more likely to achieve better clinical performance with CABG surgery because of their greater clinical experience.

Surgeon volume is predictive of 5-year survival in patients with hepatocellular carcinoma after resection: a population-based study

BACKGROUND AND AIM

No study has examined associations between physician volume or hospital volume and survival in patients with liver malignancies in the hepatitis B virus-endemic areas such as Taiwan. This study was to examine the effect of hospital and surgeon volume on 5-year survival and to determine whether hospital or surgeon volume is the stronger predictor in patients with hepatocellular carcinoma after hepatic resection in Taiwan.

METHODS

Using the 1997-1999 Taiwan National Health Insurance Research Database and the 1997-2004 Cause of Death Data File, we identified 2,799 patients who underwent hepatic resection and 1,836 deaths during the 5-year follow-up period. The Cox proportional hazard regressions were performed to adjust for patient demographics, comorbidity, physician, and hospital characteristics when assessing the association of hospital and surgeon volume with 5-year survival.

RESULTS

When we examined the effect of physician and hospital volumes separately, both physician and hospital volumes significantly predicted 5-year survival after adjusting for characteristics of patient, surgeon, and hospital. However, after we adjusted for characteristics of physician and hospital, only physician volume remained a significant predictor of the 5-year survival.

CONCLUSIONS

Physician volume is a stronger predictor of 5-year survival in hepatocellular carcinoma patients receiving hepatic resection.

Surveillance, control, and prevention of surgical site infections in breast cancer surgery: a 5-year experience

BACKGROUND

We analyzed variations in surgical site infections (SSIs) during 5 years of a prospective surveillance program and investigated possible contributors to SSIs in a cohort of patients who underwent surgery for breast cancer.

METHODS

All breast surgeries performed between January 2001 and December 2005 were registered. Patients were followed-up by direct observation for at least 30 days under standardized conditions. The main outcome studied was SSI. A case-control analysis was conducted to identify SSI-associated risk factors and to evaluate SSI variations by means of a control chart.

RESULTS

During the study period, a total of 2338 breast cancer surgeries were recorded, and 441 SSIs (18.9%) were diagnosed. SSI frequency varied across the 5-year period, with a sharp decline seen after the introduction of preventive policies. After 2002, 3 out-of-confidence limits of SSIs were observed, 2 related to the use of evacuation systems and 1 associated with a group of rotating residents. Concomitant preoperative chemoradiation (odds ratio [OR]=3.47; 95% confidence interval [CI]=2.51 to 4.80), hematoma (OR=3.05; 95% CI=1.70 to 5.52), age > or = 58 years (OR=1.83; 95% CI=1.27 to 2.65), body mass index > or = 30.8 (OR=1.58; 95% CI=1.14 to 2.18), and duration of surgery > or = 160 minutes (OR=1.73; 95% CI=1.20 to 2.50) were found to be SSI-associated risk factors.

CONCLUSIONS

After 5 years of a continuous prospective surveillance program, we were able to decrease the rate of SSIs in patients undergoing breast cancer surgery (from 33.3% in 2000 to 18.9% in 2005), identify SSI-associated risk factors, and improve the quality of care delivered to these patients.

Association between urologists' caseload volume and in-hospital mortality for transurethral resection of prostate: a nationwide population-based study

OBJECTIVES

To examine the relationship between the urologist case volume for transurethral resection of the prostate (TURP) and in-hospital mortality using a Taiwan nationwide population-based data set.

METHODS

This study used data from the 2003 Taiwan National Health Insurance Research Database. The sample of 9539 patients who had undergone TURP was divided into three urologist caseload volume groups: fewer than 27 cases annually (low volume), 27-55 cases annually (medium volume), and more than 55 cases annually (high volume). Multivariate logistic regression analysis using generalized estimating equations was conducted to assess the adjusted association of urologist TURP caseload volume and patient in-hospital mortality to account for the urologist, patient, and hospital characteristics and the clustered nature of the study sample.

RESULTS

The in-hospital mortality rate decreased with an increasing TURP caseload volume. The in-hospital mortality rate was 2.37%, 1.97%, and 1.16% for patients treated in the low, medium, and high-volume urologist group, respectively. After adjusting for others factors, the likelihood of in-hospital mortality for patients treated by urologists with a low and medium TURP caseload volume was 1.835 (95% confidence interval 1.198-2.812, P < .01) and 1.606 (95% confidence interval 1.052-2.452, P < .05) respectively, compared with that for patients treated at high-volume hospitals.

CONCLUSIONS

The results of our study have shown that, after adjusting for patient, urologist, and hospital characteristics, high-volume urologists are associated with superior treatment outcomes for patients undergoing TURP.

Physician's case volume of intensive care unit pneumonia admissions and in-hospital mortality

RATIONALE

Although several studies have investigated volume-outcome relationships for surgical procedures, there has been no such study of intensive care unit (ICU) patients admitted for pneumonia.

OBJECTIVES

This study examines associations between in-hospital mortality of ICU-admitted pneumonia patients and their attending physician's case volume.

METHODS

We used 2002-2004 claims data from Taiwan's National Health Insurance for all 87,479 adult ICU admissions for pneumonia. Patients were assigned to one of four groups, on the basis of their physician's ICU pneumonia case volume (low volume, <36 cases; medium volume, 37-114 cases; high volume, 118-314 cases; and very high volume, > or =315 cases). Generalized estimating equations (conditional on hospital, and unconditional) were used, adjusting for physician demographics and specialty, hospital characteristics, patient characteristics (including clinical severity and comorbidities), and physician-level random effect (clustering effect) to assess whether physicians' case volume predicts in-hospital mortality.

MEASUREMENTS AND MAIN RESULTS

In-hospital mortality systematically declined with increasing physician case volume: 14.7, 14.3, 11.4, and 8.1% from low-volume to very-high-volume groups. Adjusted unconditional odds of mortality among low-volume physicians' patients were 2.04 times those of very-high-volume physicians, 1.35 times that of high-volume physicians, and 1.09 times those of medium-volume physicians (all P < 0.001). The relationship is sustained when the odds are estimated conditional on hospital, when initial 5-day mortality is separated from 30-day mortality, and when pulmonologists' and critical care specialists' patients are studied separately.

CONCLUSIONS

Physician volume significantly predicts inpatient mortality among ICU patients with pneumonia. Detailed study of clinical approaches, decision algorithms, and treatment plans of high-volume physicians is recommended to identify possible mediating factors in this phenomenon.

The Relationship between Hospital Case Volume and Outcome from Carotid Endartectomy in England from 2000 to 2005

OBJECTIVES

To assess the outcome of carotid endarterectomy in England with respect to the hospital case-volume.

METHODS

Data were from English Hospital Episode Statistics (2000-2005). Admissions were classified as elective or emergency. Risk-adjusted data were analysed through modelling of death rate, complication rate and length of admission with regard to the year of procedure and annual hospital volume of surgery. Hospitals with elevated death rates were identified and the evidence quantified that they had outlying mortality rates.

RESULTS

There were 280,081 diagnoses of extra-cranial atherosclerotic arterial disease in which 18,248 CEA were performed. The mean mortality rates were 1.04% for elective and 3.16% for emergency CEA. A volume-related improvement in mortality (p=0.047) was seen for elective CEA. Length of stay decreased as annual volume increased for elective and emergency CEA (p<0.001). 20% of the operations were performed in 67.1% of the hospitals, each of which performed fewer than 10 CEA per annum. A number of hospitals had elevated death rates.

CONCLUSIONS

Volume-related improvements in outcome were demonstrated for elective CEA. Minimum volume-criteria of 35 CEA per annum should be established in England. Hospitals performing low annual volumes of surgery should consider arrangements to network services.

Is the volume-outcome relationship sustained in psychiatric care?

BACKGROUND

Although much prior research has found a consistently positive volume-outcome relationship, there is scanty documentation on this issue in mental healthcare. This study examines the association between a hospitals' psychiatric inpatient volume and 30-day readmission rates.

METHODS

Using administrative data from Taiwan's National Health Insurance Research Database for 2003, the likelihood of 30-day readmission is examined relative to the hospital's volume of voluntary psychiatric admissions and total bed-days.

RESULTS

As hospital volume increases, so too does the 30-day readmission rates for patients with schizophrenia, bipolar disorder and major depressive disorders.

CONCLUSIONS

The positive volume-outcome relationship in patients suffering from psychiatric disorders suggests a different scenario from the 'practice makes perfect' phenomenon that may underlie the inverse volume-outcome relationship found among most physical disorders, both surgical and medical.