Precision subclassification of type 2 diabetes: a systematic review.

BACKGROUND: Heterogeneity in type 2 diabetes presentation and progression suggests that precision medicine interventions could improve clinical outcomes. We undertook a systematic review to determine whether strategies to subclassify type 2 diabetes were associated with high quality evidence, reproducible results and improved outcomes for patients. METHODS: We searched PubMed and Embase for publications that used 'simple subclassification' approaches using simple categorisation of clinical characteristics, or 'complex subclassification' approaches which used machine learning or 'omics approaches in people with established type 2 diabetes. We excluded other diabetes subtypes and those predicting incident type 2 diabetes. We assessed quality, reproducibility and clinical relevance of extracted full-text articles and qualitatively synthesised a summary of subclassification approaches. RESULTS: Here we show data from 51 studies that demonstrate many simple stratification approaches, but none have been replicated and many are not associated with meaningful clinical outcomes. Complex stratification was reviewed in 62 studies and produced reproducible subtypes of type 2 diabetes that are associated with outcomes. Both approaches require a higher grade of evidence but support the premise that type 2 diabetes can be subclassified into clinically meaningful subtypes. CONCLUSION: Critical next steps toward clinical implementation are to test whether subtypes exist in more diverse ancestries and whether tailoring interventions to subtypes will improve outcomes.

In people with type 2 diabetes there may be differences in the way people present, including for example, their symptoms, body weight or how much insulin they make. We looked at recent publications describing research in this area to see whether it is possible to separate people with type 2 diabetes into different subgroups and, if so, whether these groupings were useful for patients. We found that it is possible to group people with type 2 diabetes into different subgroups and being in one subgroup can be more strongly linked to the likelihood of developing complications over others. This might mean that in the future we can treat people in different subgroups differently in ways that improves their treatment and their health but it requires further study.

Second international consensus report on gaps and opportunities for the clinical translation of precision diabetes medicine.

Precision medicine is part of the logical evolution of contemporary evidence-based medicine that seeks to reduce errors and optimize outcomes when making medical decisions and health recommendations. Diabetes affects hundreds of millions of people worldwide, many of whom will develop life-threatening complications and die prematurely. Precision medicine can potentially address this enormous problem by accounting for heterogeneity in the etiology, clinical presentation and pathogenesis of common forms of diabetes and risks of complications. This second international consensus report on precision diabetes medicine summarizes the findings from a systematic evidence review across the key pillars of precision medicine (prevention, diagnosis, treatment, prognosis) in four recognized forms of diabetes (monogenic, gestational, type 1, type 2). These reviews address key questions about the translation of precision medicine research into practice. Although not complete, owing to the vast literature on this topic, they revealed opportunities for the immediate or near-term clinical implementation of precision diabetes medicine; furthermore, we expose important gaps in knowledge, focusing on the need to obtain new clinically relevant evidence. Gaps include the need for common standards for clinical readiness, including consideration of cost-effectiveness, health equity, predictive accuracy, liability and accessibility. Key milestones are outlined for the broad clinical implementation of precision diabetes medicine.

Associations between diet quality and NT-proBNP in U.S. adults, NHANES 1999-2004.

Objective: N-terminal pro-brain-type natriuretic peptide (NT-proBNP) is a marker of cardiac wall stress and is a predictor of cardiovascular disease. Higher diet quality is associated with lower risk of cardiovascular disease. The association between diet quality and subclinical cardiovascular disease assessed by NT-proBNP is uncharacterized. We investigated the associations between diet quality, using Healthy Eating Index-2015 (HEI-2015), and NT-proBNP from the National Health and Nutrition Examination Survey (NHANES) 1999-2004. Methods: We included 9,782 adults from NHANES 1999-2004 without self-reported cardiovascular disease. The HEI-2015 ranges from 0 to 100, with higher scores indicating better diet quality. The HEI-2015 was categorized into sex-specific quintiles. Regression models were used to quantify associations between the overall HEI-2015 score and its 13 components with log-transformed NT-proBNP. The beta coefficients were converted to percent differences. Results: Among 9,782 participants, mean age was 45 years, 48% were men, and 72% were non-Hispanic White adults. After adjusting for sociodemographic characteristics, lifestyle factors, and medical history, those in the highest vs. lowest HEI-2015 quintile had an 8.5% (95% CI: -14.6% to -2.0%) lower NT-proBNP level. There was a dose-response association between HEI-2015 and NT-proBNP (P value for trend = 0.01). Each 1-unit higher in sodium and added sugars score indicating lower intake was associated with lower NT-proBNP by 7.7% (95% CI: -12.8% to -2.2%) and 6.5% (95% CI: -12.0% to -0.7%), respectively. Conclusion: Higher diet quality, especially lower intakes of sodium and added sugars, was associated with lower serum levels of NT-proBNP.

Systematic review of precision subclassification of type 2 diabetes.

Heterogeneity in type 2 diabetes presentation, progression and treatment has the potential for precision medicine interventions that can enhance care and outcomes for affected individuals. We undertook a systematic review to ascertain whether strategies to subclassify type 2 diabetes are associated with improved clinical outcomes, show reproducibility and have high quality evidence. We reviewed publications that deployed 'simple subclassification' using clinical features, biomarkers, imaging or other routinely available parameters or 'complex subclassification' approaches that used machine learning and/or genomic data. We found that simple stratification approaches, for example, stratification based on age, body mass index or lipid profiles, had been widely used, but no strategy had been replicated and many lacked association with meaningful outcomes. Complex stratification using clustering of simple clinical data with and without genetic data did show reproducible subtypes of diabetes that had been associated with outcomes such as cardiovascular disease and/or mortality. Both approaches require a higher grade of evidence but support the premise that type 2 diabetes can be subclassified into meaningful groups. More studies are needed to test these subclassifications in more diverse ancestries and prove that they are amenable to interventions.

Inverse Associations between Measures of Adiposity and Glycated Albumin in US Adults, NHANES 1999-2004.

BACKGROUND: Glycated albumin (GA) is a short-term measure of glycemic control. Several studies have demonstrated an inverse association between body mass index (BMI) and GA, which may affect its performance as a biomarker of hyperglycemia. We investigated cross-sectional associations between GA and multiple measures of adiposity, and compared its performance as a glycemic biomarker by obesity status, in a nationally representative sample of US adults. METHODS: We measured GA in adults from the 1999-2004 National Health and Nutrition Examination Survey. Separately in adults with and without diabetes, we assessed associations of GA with adiposity measures (BMI, waist circumference, trunk fat, total body fat, and fat mass index) in sex-stratified multivariable regression models. We compared sensitivity and specificity of GA to identify elevated hemoglobin A1c (HbA1c), by obesity status. RESULTS: In covariate-adjusted regression models, all adiposity measures were inversely associated with GA in adults without diabetes (ß=-0.48 to -0.22%-point GA per 1 SD adiposity measure; n = 9750) and with diabetes (ß=-1.73 to -0.92%-point GA per SD). Comparing adults with vs without obesity, GA exhibited lower sensitivity (43% vs 54%) with equivalent specificity (99%) to detect undiagnosed diabetes (HbA1c ≥ 6.5%). Among adults with diagnosed diabetes (n = 1085), GA performed well to identify above-target glycemia (HbA1c ≥ 7.0%), with high specificity (>80%) overall but lower sensitivity in those with vs without obesity (81% vs 93%). CONCLUSIONS: Inverse associations between GA and adiposity were present in people with and without diabetes. GA is highly specific but may not be sufficiently sensitive for diabetes screening in adults with obesity.

Performance of glycated albumin as a biomarker of hyperglycemia in pregnancy: Results from the National Health and Nutrition Examination Survey 1999-2004.

AIM: We sought to evaluate the performance of glycated albumin (GA) as a measure of hyperglycemia in pregnant women. METHODS: We used data from 555 pregnant women aged 20-40 years who participated in NHANES 1999-2004 and did not report a pre-pregnancy diagnosis of diabetes. We used Pearson's correlations and evaluated the area under the curve (AUC) for GA to detect elevated concentrations of random glucose, HbA1c, or fasting glucose (subset). We compared results to 1607 nonpregnant women aged 20-40 without diabetes. RESULTS: In pregnant women, 1.9 % had HbA1c ≥ 39 mmol/mol (≥5.7 %), 9.1 % had random glucose ≥ 5.3 mmol/L (≥95 mg/dL), and 10.7 % had fasting glucose ≥ 5.3 mmol/L. In pregnancy, GA was poorly correlated with HbA1c (r = 0.08) and random glucose (r = 0.17). BMI was positively associated with HbA1c (r = 0.33) and random glucose (r = 0.25) but was inversely associated with GA (r = -0.27). GA had poor discrimination for detecting hyperglycemia in pregnant women, defined as HbA1c ≥ 39 mmol/mol (AUC = 0.634) or random glucose ≥ 5.3 mmol/L (AUC = 0.628). Similar patterns were observed among nonpregnant women. CONCLUSIONS: GA is not a sensitive test to screen for hyperglycemia in pregnancy. GA was inversely associated with adiposity in pregnant women without diabetes. Pregnancy-related weight gain may complicate interpretation of repeated GA measurements.

Obesity and Chronic Kidney Disease in US Adults With Type 1 and Type 2 Diabetes Mellitus.

OBJECTIVE: Obesity is a global public health challenge and strongly associated with type 2 diabetes (T2D), but its burden and effects are not well understood in people with type 1 diabetes (T1D). Particularly, the link between obesity and chronic kidney disease (CKD) in T1D is poorly characterized. RESEARCH DESIGN AND METHODS: We included all T1D and, for comparison, T2D in the Geisinger Health System from 2004 to 2018. We evaluated trends in obesity (body mass index ≥ 30 kg/m2), low estimated glomerular filtration rate (eGFR) (≤60 mL/min/1.73m2), and albuminuria (urine albumin-to-creatinine ratio ≥ 30 mg/g). We used multivariable logistic regression to evaluate the independent association of obesity with CKD in 2018. RESULTS: People with T1D were younger than T2D (median age 39 vs 62 years). Obesity increased in T1D over time (32.6% in 2004 to 36.8% in 2018), while obesity in T2D was stable at ~60%. The crude prevalence of low eGFR was higher in T2D than in T1D in all years (eg, 30.6% vs 16.1% in 2018), but after adjusting for age differences, prevalence was higher in T1D than T2D in all years (eg, 16.2% vs 9.3% in 2018). Obesity was associated with increased odds of low eGFR in T1D [adjusted odds ratio (AOR) = 1.52, 95% CI 1.12-2.08] and T2D (AOR = 1.29, 95% CI 1.23-1.35). CONCLUSIONS: Obesity is increasing in people with T1D and is associated with increased risk of CKD. After accounting for age, the burden of CKD in T1D exceeded the burden in T2D, suggesting the need for increased vigilance and assessment of kidney-protective medications in T1D.

The performance of glycated albumin as a biomarker of hyperglycemia and cardiometabolic risk in children and adolescents in the United States.

OBJECTIVE: Diabetes and prediabetes are growing concerns among US youth. Fasting glucose (FG) and HbA1c are standard diabetes screening tests, but HbA1c may be unreliable in some settings and fasting is burdensome in children. Glycated albumin (GA) is a non-fasting test that was recently cleared for clinical use in the United States, but studies in youth without diabetes are limited. RESEARCH DESIGN AND METHODS: We conducted a cross-sectional analysis in 6826 youth without diabetes aged 8-19 years in the 1999-2004 National Health and Nutrition Examination Survey. We evaluated the associations of GA with HbA1c, FG, and cardiometabolic risk factors. RESULTS: GA was poorly correlated with HbA1c (ρ = 0.074) and FG (ρ = -0.047) and was negatively associated with body mass index (BMI) and cardiometabolic risk factors. Compared to youth in the highest tertile of GA (≥13.5%), those in the lowest GA tertile (<12.4%) had a higher prevalence of obesity (29.9% vs. 7.6%), low high-density lipoprotein cholesterol (29.7% vs. 16.5%), and hypertensive blood pressure (4.0% vs. 2.7%). These inverse associations persisted after adjustment for age, sex, race/ethnicity, serum albumin, and C-reactive protein. CONCLUSIONS: GA was poorly correlated with traditional markers of hyperglycemia in youth without diabetes. Counterintuitively, there was a negative association between GA and BMI. Among youth without diabetes, GA does not identify youth at high cardiometabolic risk, and it does not appear to be an appropriate biomarker for screening of hyperglycemia.

Screening and Diagnosis of Prediabetes and Diabetes in US Children and Adolescents.

BACKGROUND: The optimal approach to screening and diagnosis of prediabetes and diabetes in youth is uncertain. METHODS: We conducted a cross-sectional analysis of 14 119 youth aged 10 to 19 years in the 1999-2016 NHANES. First, we examined the performance of American Diabetes Association risk-based screening criteria. Second, we evaluated the performance of current clinical definitions of prediabetes and diabetes based on hemoglobin A1c (HbA1c), fasting plasma glucose (FPG), either HbA1c or FPG, or both HbA1c and FPG (confirmatory definition) to identify youth at high cardiometabolic risk. RESULTS: Overall, 25.5% of US youth (10.6 million in 2016) were eligible for screening. Sensitivity and specificity of the screening criteria for detecting any hyperglycemia were low for both HbA1c ≥5.7% (sensitivity = 55.5%, specificity = 76.3%) and FPG ≥100 mg/dL (sensitivity = 35.8%, specificity = 77.1%). Confirmed undiagnosed diabetes (HbA1c ≥6.5% and FPG ≥126 mg/dL) was rare, <0.5% of youth. Most (>85%) cases of diabetes were diagnosed. Associations with cardiometabolic risk were consistently stronger and more specific for HbA1c-defined hyperglycemia (specificity = 98.6%; sensitivity = 4.0%) than FPG-defined hyperglycemia (specificity = 90.1%; sensitivity = 19.4%). CONCLUSIONS: One-quarter of US youth are eligible for screening for diabetes and prediabetes; however, few will test positive, especially for diabetes. Most cases of diabetes in US youth are diagnosed. Regardless of screening eligibility, we found that HbA1c is a specific and useful nonfasting test to identify high-risk youth who could benefit from lifestyle interventions to prevent diabetes and cardiovascular risk in adulthood.

Recommendations to the Society for Epidemiologic Research for Further Promoting Diversity and Inclusion at the Annual Meeting and Beyond.

Increasing diverse engagement in the Society for Epidemiologic Research (SER) will positively impact the field of epidemiology. As the largest and longest-running epidemiologic society in North America, SER has long been a pioneer in promoting diversity and inclusion. A recent survey of SER members, however, showed there is still room for improving diversity, inclusion, representation, and participation in the Society. In this commentary, as members of both the SER and the Johns Hopkins Bloomberg School of Public Health Department of Epidemiology's Inclusion, Diversity, Equity, Anti-Racism, and Science (Epi IDEAS) Working Group, we recommend 4 goals for the SER Annual Meeting and beyond: 1) convene epidemiologic researchers with diverse backgrounds and ideas; 2) promote an inclusive environment at the SER Annual Meeting; 3) develop, compile, and disseminate best practices to honor diversity in epidemiologic research; and 4) increase prioritization of health disparities research and methods. We also suggest strategies for achieving these goals so that SER can better include, support, and elevate members from historically disadvantaged groups. While our recommendations are tailored specifically to SER, the greater epidemiologic and academic communities could benefit from adopting these goals and strategies within their professional societies and conferences.

Congenital Heart Surgery Outcomes in Turner Syndrome: The Society of Thoracic Surgeons Database Analysis.

BACKGROUND: Turner syndrome (TS) is a genetic syndrome characterized by monosomy X (45,XO) in phenotypic females and is commonly associated with congenital heart disease. We sought to describe the distribution, mortality, and morbidity of congenital heart surgery in TS and compare outcomes to individuals without genetic syndromes. METHODS: The Society of Thoracic Surgeons Congenital Heart Surgery Database was used to evaluate index cardiovascular operations performed from 2000 to 2017 in pediatric patients (aged 0-18 years) with and without TS. Analyses were stratified by the most common operations, including coarctation repair, aortic arch repair, partial anomalous pulmonary venous return repair, Norwood, superior cavopulmonary anastomosis (Glenn), and Fontan. RESULTS: Included were 780 operations in TS and 62,659 operations in controls. The most common TS operations were coarctation repair in 274 (35%), aortic arch repair in 116 (15%), and Norwood in 59 (8%). Compared with controls, TS patients had lower weight-for-age Z-scores across all operations (P < .01 for all); however, operative mortality rates did not differ significantly. The chylothorax rate was higher in TS after coarctation repair (8.8% vs 2.8%, P < .001) and Norwood (22% vs 8.1%, P < .001). The median (interquartile range) postoperative length of stay was longer in TS for coarctation repair (6.5 [5.0-15.5] days vs 5.0 [4.0-9.0] days, P < .001), aortic arch repair (15.0 [8.0-27.5] days vs 11.0 [7.0-21.0] days, P = .004), and Glenn (9.0 [6.0-16.0] days vs 6.0 [5.0-11.0] days, P = .013). CONCLUSIONS: Turner syndrome patients most commonly underwent operations for left-sided obstructive lesions. Despite increased morbidity for select operations, TS was not associated with increased operative mortality.

Postoperative Transcatheter Interventions in Children Undergoing Congenital Heart Surgery.

Background Postoperative transcatheter interventions (TCIs) are performed after congenital heart surgery to treat residual or recurrent anatomic lesions. We used the Society of Thoracic Surgeons Congenital Heart Surgery Database to evaluate rates of postoperative TCIs, center variability, and to determine whether center approaches to postoperative TCI might be associated with outcomes. Methods and Results Patients <18 years undergoing an index operation (2010-2016) were included. We determined predischarge postoperative TCI rates and used multivariable modeling, adjusting for patient factors and case complexity, to evaluate the association between center risk-adjusted postoperative TCI rates and risk-adjusted outcomes (operative mortality, post-TCI mortality, and failure-to-rescue). Postoperative TCI was performed after 2615/105 742 (2.5%) index operations and after 1443/25 416 (5.7%) highest complexity operations (STAT [Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery Mortality Score] Mortality Category 4 and 5). Median (interquartile range) age of patients undergoing TCI was 2.7 (0.2-8.0) months with 43% performed in neonates. There was a wide center variability across the 107 included centers with risk-adjusted rates of postoperative TCI ranging from 0.0% to 8.0% overall and 0.0% to 20.7% for STAT 4 and 5 cases. Postoperative TCI was associated with higher risk-adjusted odds of operative mortality (odds ratio, 4.06; 95% CI, 3.60-4.58). Centers with higher postoperative TCI rates had higher overall operative mortality ( R2=0.23; P=0.02) but did not have higher post-TCI mortality ( P=0.10). There was no correlation between center TCI rates and failure-to-rescue ( P=0.19). Conclusions Patients undergoing postoperative TCI represent a high-risk cohort. Wide center variability suggests the potential for improving outcomes, but further study is necessary to better understand optimal approaches.

A Study of Practice Behavior for Endotracheal Intubation Site for Children With Congenital Heart Disease Undergoing Surgery: Impact of Endotracheal Intubation Site on Perioperative Outcomes-An Analysis of the Society of Thoracic Surgeons Congenital Cardiac Anesthesia Society Database.

BACKGROUND: In adults undergoing cardiopulmonary bypass surgery, oral intubation is typically preferred over nasal intubation due to reduced risk of sinusitis and infection. In children, nasal intubation is more common and sometimes preferred due to perceived benefits of less postoperative sedation and a lower risk for accidental extubation. This study sought to describe the practice of nasal intubation in the pediatric population undergoing cardiopulmonary bypass surgery and assess the risks/benefits of a nasal route against an oral one. METHODS: Patients <18 years of age in the Society of Thoracic Surgeons Congenital Heart Surgery Database between January 2010 and December 2015 were included. Patients with a preoperative endotracheal tube, tracheostomy, or known airway anomalies were excluded. Multivariable modeling was used to assess the association between route of tracheal intubation and a composite measure of infection risk (wound infection, mediastinitis, septicemia, pneumonia, and endocarditis). Covariates were included to adjust for important patient characteristics (eg, weight, age, comorbidities), case complexity, and center effects. Secondary outcomes included length of intubation, hospital length of stay, and airway complications including accidental extubations. We also performed a subanalysis in children <12 months of age in high-volume centers (>100 cases/y) examining how infection risk may change with age at the time of surgery. RESULTS: Nasal intubation was used in 41% of operations in neonates, 38% in infants, 15% in school-aged children, and 2% in adolescents. Nasal intubation appeared protective for accidental extubation only in neonates (P = .02). Multivariable analysis in infants and neonates showed that the nasal route of intubation was not associated with the infection composite (relative risk [RR], 0.84; 95% CI, 0.59-1.18) or a shorter length of stay (RR, 0.992; 95% CI, 0.947-1.039), but was associated with a shorter intubation length (RR, 0.929; 95% CI, 0.869-0.992). Restricting to high-volume centers showed a significant interaction between age and intubation route with a risk change for infection occurring between approximately 6-12 months of age (P = .003). CONCLUSIONS: While older children undergoing nasal intubation trend similar to the adult population with an increased risk of infection, nasal intubation in neonates and infants does not appear to carry a similar risk. Nasal intubation in neonates and infants may also be associated with a shorter intubation length but not a shorter length of stay. Prospective studies are required to better understand these complex associations.

Prenatal Diagnosis Influences Preoperative Status in Neonates with Congenital Heart Disease: An Analysis of the Society of Thoracic Surgeons Congenital Heart Surgery Database.

The early postnatal course for a newborn with critical congenital heart disease (CHD) can be negatively impacted if diagnosis is delayed. Despite this, there continues to be inconsistent evidence regarding potential benefits associated with prenatal diagnosis (PND) in neonates who undergo cardiac surgery. The objective of this study was to better define the impact of a PND on pre-operative morbidity by utilizing a large clinical database. Neonates (< 30 days) undergoing heart surgery from 2010 to 2014 and entered in the Society of Thoracic Surgeons Congenital Heart Surgery Database (STS-CHSD) were included. Multivariable logistic regression was used to evaluate the association between PND and a composite measure including nine major pre-operative risk factors. Co-variates were included to adjust for important patient characteristics (e.g., weight-for-age z-score, genetic syndromes, prematurity), case complexity, and center effects. Centers and patients with excess missing data for relevant co-variates were excluded. Included were 12,899 neonates undergoing surgery at 112 centers. Major pre-operative risk factors were present in 34% overall. By univariate analysis, PND was associated with a lower overall prevalence of major pre-operative risk factors. After adjusting for potential confounders, major pre-operative risk factors were less prevalent among neonates with PND compared to neonates without PND (adjusted OR 0.62, 95% CI 0.57-0.68, p < 0.001). A sensitivity analysis excluding neonates with genetic syndromes, non-cardiac anatomic abnormalities, and prematurity demonstrated similar findings (adjusted OR 0.55, 95% CI 0.49-0.61, p < 0.0001). Among neonates with CHD, prenatal diagnosis is associated with significantly lower rates of pre-operative risk factors for cardiac surgery. Further studies are needed to define association of these pre-operative benefits of a PND with longer term clinical outcomes.

Using a society database to evaluate a patient safety collaborative: the Cardiovascular Surgical Translational Study.

AIM: To assess the utility of using external databases for quality improvement (QI) evaluations in the context of an innovative QI collaborative aimed to reduce three infections and improve patient safety across the cardiac surgery service line. METHODS: We compared changes in each outcome between 15 intervention hospitals (infection reduction protocols plus safety culture intervention) and 52 propensity score-matched hospitals (feedback only). RESULTS: Improvement trends in several outcomes among the intervention hospitals were not statistically different from those in comparison hospitals. CONCLUSION: Using external databases such as those of professional societies may permit comparative effectiveness assessment by providing concurrent comparison groups, additional outcome measures and longer follow-up. This can better inform evaluation of continuous QI in healthcare organizations.

Single- Versus Multicenter Surgeons' Risk-Adjusted Coronary Artery Bypass Graft Procedural Outcomes.

BACKGROUND: Since 2010, 460+ hospital mergers have occurred in the United States, rerouting historical coronary artery bypass graft (CABG) referral patterns. The goals of this study were: (1) to compare risk-adjusted CABG outcomes between single-center versus multicenter surgeons; and (2) for multicenter surgeons, to evaluate the risk-adjusted outcomes between their home (primary) versus satellite (secondary) hospitals. METHODS: Using The Society of Thoracic Surgeons Adult Cardiac Surgery Database, nonemergent, first-time CABG procedures (n = 543,403) performed in the US between 2011 and 2014 were extracted across 1,120 centers and for 2,676 surgeons. Surgeons were classified as multicenter if they performed operations at two separate hospitals for ≥ 2 consecutive quarters; their home hospital was identified as their highest volume center. Observed-to-expected outcome ratios were reported using approved multivariable risk models for 30-day operative mortality and major morbidity. RESULTS: Of 2,676 cardiac surgeons, 668 (25.0%) operated at multiple centers. The observed-to-expected mortality ratios were 1.06 (95% confidence interval [CI], 1.01 to 1.12) and 0.97 (95% CI, 0.94 to 1.00) for multi- and single-center surgeons (p < 0.001). For multicenter surgeons, the observed-to-expected mortality ratios were 1.17 (95% CI, 1.09 to 1.27) versus 1.01 (95% CI, 0.96 to 1.07), p < 0.001, for their satellite versus home facilities, respectively. CONCLUSIONS: Single-center surgeons performing CABG had lower risk-adjusted outcome rates compared with multicenter surgeons, who performed better at their home versus satellite hospitals. To improve future quality of care, surgeons, health care networks, and health policy makers should now more closely scrutinize their single versus multicenter performance.