Association Between Physician Teamwork and Health System Outcomes After Coronary Artery Bypass Grafting

Association between clinician team segregation, receipt of cardiovascular care and outcomes in valvular heart diseases

AIMS

Racial disparities exist in clinical outcomes for valvular heart disease (VHD). It is unknown whether clinician segregation contributes to these disparities. Among an adequately insured population, we evaluated the relationship between clinician segregation in a hospital and receipt of care by a cardiologist according to patient race. We also evaluated the association between clinician segregation, race and care by a cardiologist on 30-day readmission and 1-year survival.

METHODS AND RESULTS

Using Optum's Clinformatics® Data Mart Database (CDM, US commercial and Medicare beneficiaries) from 2010 to 2018, we identified patients with a primary diagnosis of VHD. Hospitals were categorized into low, medium and high segregation groups (SG), according to clinician segregation index (SI). SI can range from 0-1 (0: the ratio of Black to White patients is the same for all clinicians; 1: each clinician treats only Black or only White patients). Outcomes were analysed using generalized linear mixed effect models. Among 8649 patients [median age 75 (67-82), 45.4% female, 16.1% Black, 83.9% White], odds of care from a cardiologist did not vary across race for all SGs [Low SG adjusted odds ratio (aOR): 0.79 (95% CI: 0.58-1.08), P = 0.14; Medium SG aOR: 0.86 (95% CI: 0.60-1.25), P = 0.43; High SG aOR: 1.07 (95% CI: 0.68-1.69), P = 0.76]. Among those that received care from a cardiologist, there was no difference in the 30-day readmission between Black and White patients across SGs [Low SG aOR: 1.05 (95% CI: 0.83-1.31), P = 0.70; Medium SG aOR: 1.22 (95% CI: 0.92-1.61), P = 0.17; High SG aOR: 0.81 (95% CI: 0.57-1.17), P = 0.27]. Among patients that did not receive care from a cardiologist, Black patients in low SG had higher odds of 30-day readmission compared to White patients [aOR: 2.74 (95%CI:1.38-5.43), P < 0.01]. Odds of 1-year survival were similar across race for all SG irrespective of receipt of care from a cardiologist [seen by a cardiologist: Low SG aOR: 1.13 (95% CI: 0.86-1.48), P = 0.38; Medium SG aOR: 0.83 (95% CI: 0.59-1.17), P = 0.29; High SG aOR: 1.01 (95% CI: 0.66-1.52), P = 0.98; not seen by a cardiologist: Low SG aOR: 0.56 (95% CI: 0.23-1.34), P = 0.19; Medium SG aOR: 0.81 (95% CI: 0.28-2.37), P = 0.70; High SG aOR: 0.63 (95% CI: 0.23-1.74), P = 0.37].

CONCLUSIONS

Among an insured population, race was not associated with care by a cardiologist for VHD or survival. Black patients not seen by cardiologists had higher odds of 30-day readmission in low clinician SG.

Physician patient sharing relationships within insurance plan networks

OBJECTIVE

To quantify shared patient relationships between primary care physicians (PCPs) and cardiologists and oncologists and the degree to which those relationships were captured within insurance networks.

DATA SOURCES

Secondary analysis of Vericred data on physician networks, CareSet data on physicians' shared Medicare patients, and insurance plan attributes from Health Insurance Compare. Data validation exercises used data from Physician Compare and IQVIA.

STUDY DESIGN

Cross-sectional study of the PCP-to-specialist in-network shared patient percentage (primary outcome). We also categorized networks by insurance market segment (Medicare Advantage [MA], Medicaid managed care, small-group or individually purchased), insurance plan type, and network breadth.

DATA EXTRACTION

We analyzed data on 219,982 PCPs, 29,400 cardiologists, and 22,745 oncologists who, in 2021, accepted MA (n = 941 networks), Medicaid managed care (n = 293), and individually-purchased (n = 332) and small-group (n = 501) plans.

PRINCIPAL FINDINGS

Networks captured, on average, 64.6% of PCP-cardiology shared patient ties, and 61.8% of PCP-oncologist ties. Less than half of in-network ties (44.5% and 38.9%, respectively) were among physicians with a common organizational affiliation. After adjustment for network breadth, we found no evidence of differences in the shared patient percentage across insurance market segments or networks of different types (p-value >0.05 for all comparisons). An exception was among national versus local and regional networks, where we found that national plans captured fewer shared patient ties, particularly among the narrowest networks (58.4% for national networksvs. 64.7% for local and regional networks for PCP-cardiology).

CONCLUSIONS

Given recent trends toward narrower networks, our findings underscore the importance of incorporating additional and nuanced measures of network composition to aid plan selection (for patients) and to guide regulatory oversight.

Infections following left ventricular assist device implantation and 1-year health-related quality of life

BACKGROUND

Left ventricular assist device (LVAD) implantation leads to substantial and sustained improvement in health-related quality of life (HRQOL) among patients. Infection following device implantation remains an important and frequent complication and adversely affects patient-reported HRQOL.

METHODS

Patients in The Society of Thoracic Surgeons' Interagency Registry for Mechanically Assisted Circulatory Support receiving a primary LVAD between April 2012 to October 2016 were included. The primary exposure was one-year post-implant infection, characterized by: (1) any infection; (2) total number of infections and (3) type (LVAD-specific, LVAD-related, non-LVAD). The association between infection and the primary composite adverse outcome (defined as EuroQoL Visual Analog Scale< 65, too sick to complete the survey, or death at 1-year) was estimated using inverse probability weighting and Cox regression.

RESULTS

The study cohort included 11,618 patients from 161 medical centers with 4,768 (41.0%) patients developing an infection, and 2,282 (19.6%) patients having> 1 infection during the follow up period. The adjusted odds ratio for the primary composite adverse outcome was 1.22 (95% CI, 1.19-1.24, p < 0.001) for each additional infection. Each additional infection was associated with a 3.49% greater probability of the primary composite outcome and was associated with worse performance across multiple dimensions of HRQOL as assessed by the EQ-5D for patients who survived to 1 year.

CONCLUSIONS

For patients undergoing LVAD implantation, each additional infection within the first post-implantation year was associated with an incremental negative effect on survival free of impaired HRQOL.

Characteristics of Facilities With Early and Rapid Ustekinumab Adoption for Patients With Inflammatory Bowel Disease

INTRODUCTION

To examine which facility characteristics, including teamwork, are associated with early or rapid inflammatory bowel disease-related ustekinumab adoption.

METHODS

We examined the association between ustekinumab adoption and the characteristics of 130 Veterans Affairs facilities.

RESULTS

Mean ustekinumab adoption increased by 3.9% from 2016 to 2018 and was higher in urban compared with rural facilities (β = 0.03, P = 0.033) and among facilities with more teamwork (β = 0.11, P = 0.041). Compared with nonearly adopters, early adopters were more likely be high-volume facilities (46% vs 19%, P = 0.001).

DISCUSSION

Facility variation in medication adoption provides an opportunity for improving inflammatory bowel disease care through targeted dissemination strategies to improve medication uptake.

Care fragmentation predicts 90-day durable ventricular assist device outcomes

OBJECTIVES

To examine whether fragmentation of care is associated with worse in-hospital and 90-day outcomes following durable ventricular assist device (VAD) implant.

STUDY DESIGN

Cohort study.

METHODS

This study was conducted using Medicare claims linked to the Society of Thoracic Surgeons (STS) Interagency Registry for Mechanically Assisted Circulatory Support (Intermacs) among patients undergoing VAD implant between July 2009 and April 2017. Medicare data were used to measure fragmentation of the multidisciplinary care delivery network for the treating hospital, based on providers' history of shared patients within the previous year. STS Intermacs data were used for risk adjustment and outcomes ascertainment. Hospitals were sorted into terciles based on the degree of network fragmentation, measured as the mean number of links separating providers in the network. Multivariable regression was used to associate network fragmentation with 90-day death or infection risk.

RESULTS

The cohort included 5159 patients who underwent VAD implant, with 11.2% dying and 27.6% experiencing an infection within 90 days after implant. After adjustment, a 1-unit increase in network fragmentation was associated with an increase of 0.179 in the probability of in-hospital infection and an increase of 0.183 in the probability of 90-day infection (both P < .05). Similar results were observed in models of the numbers of in-hospital and 90-day infections. Network fragmentation was predictive of the probability of 90-day mortality, although this relationship was not significant after adjustment.

CONCLUSIONS

Care delivery network fragmentation is associated with higher in-hospital and 90-day infection rates following durable VAD implant. These networks may serve as novel targets for enhancing outcomes for patients undergoing VAD implant.

Collaboration Between Physicians from Different Medical Specialties in Hospital Settings: A Systematic Review

Health care today is characterized by an increasing number of patients with comorbidities for whom interphysician collaboration seems very important. We reviewed the literature to understand what factors affect interphysician collaboration, determine how interphysician collaboration is measured, and determine its effects. We systematically searched six major databases. Based on 63 articles, we identified five categories that influence interphysician collaboration: personal factors, professional factors, preconditions and tools, organizational elements, and contextual characteristics. We identified a diverse set of mostly unvalidated tools for measuring interphysician collaboration that focus on information being transferred and understood, frequency of interaction and tone of the relationship, and value judgements about quality or satisfaction. We found that interphysician collaboration increased clinical outcomes as well as patient and staff satisfaction, while error rates and length of stay were reduced. The results should, however, be interpreted with caution, as most of the studies provide a low level of evidence.

Association Between Care Fragmentation and Total Spending After Durable Left Ventricular Device Implant: A Mediation Analysis of Health Care-Associated Infections Within a National Medicare-Society of Thoracic Surgeons Intermacs Linked Dataset

BACKGROUND

Care fragmentation is associated with higher rates of infection after durable left ventricular assist device (LVAD) implant. Less is known about the relationship between care fragmentation and total spending, and whether this relationship is mediated by infections.

METHODS

Total payments were captured from admission to 180 days post-discharge. Drawing on network theory, a measure of care fragmentation was developed based on the number of shared patients among providers (ie, anesthesiologists, cardiac surgeons, cardiologists, critical care specialists, nurse practitioners, physician assistants) caring for 4,987 Medicare beneficiaries undergoing LVAD implantation between July 2009 - April 2017. Care fragmentation was measured using average path length, which describes how efficiently information flows among network members; longer path length indicates greater fragmentation. Terciles based on the level of care fragmentation and multivariable regression were used to analyze the relationship between care fragmentation and LVAD payments and mediation analysis was used to evaluate the role of post-implant infections.

RESULTS

The patient cohort was 81% male, 73% white, 11% Intermacs Profile 1 with mean (SD) age of 63.1 years (11.1). The mean (SD) level of care fragmentation in provider networks was 1.7 (0.2) and mean (SD) payment from admission to 180 days post-discharge was $246,905 ($109,872). Mean (SD) total payments at the lower, middle, and upper terciles of care fragmentation were $250,135 ($111,924), $243,288 ($109,376), and $247,290 ($108,241), respectively. In mediation analysis, the indirect effect of care fragmentation on total payments, through infections, was positive and statistically significant (β=16032.5, p=0.008).

CONCLUSIONS

Greater care fragmentation in the delivery of care surrounding durable LVAD implantation is associated with a higher incidence of infections, and consequently, higher payments for Medicare beneficiaries. Interventions to reduce care fragmentation may reduce the incidence of infections and in turn enhance the value of care for patients undergoing durable LVAD implantation.

Association of Physician Referrals with Timely Cancer Care Using Tumor Registry and Claims Data

More Americans are being screened for and more are surviving colorectal cancer due to advanced treatments and better quality of care; however, these benefits are not equitably distributed among diverse or older populations. Differential care delivery outcomes are driven by multiple factors, including access to timely treatment that comes from high-quality care coordination. Providers help ensure such coordinated care, which includes timely referrals to specialists. Variation in referrals between providers can also result in differences in treatment plans and outcomes. Patients who are more often referred between the same diagnosing and treating providers may benefit from more timely care compared to those who are not. Our objective is to examine patterns of referral, or patient-sharing networks (PSNs), and our outcome, treatment delay of 30-days (yes/no). We hypothesize that if a patient is in a PSN they will have lower odds of a 30-day treatment initiation delay. Our observational population-based analysis using the National Cancer Institute (NCI)-linked tumor registry and Medicare claims database includes records for 27,689 patients diagnosed with colorectal cancer from 2001 to 2013, and treated with either chemotherapy, radiotherapy, or surgery. We modeled the adjusted odds of a delay and found 17.04% of patients experienced a 30-day delay in initial treatment. Factors that increased odds of a delay were lack of membership in a PSN (adjusted odds ratio [AOR]: 2.20; 95% confidence interval [CI]: 1.71-2.84), racial/ethnic minority status, and having multiple comorbidities. Provider characteristics significantly associated with greater odds of a delay were if dyads were not in the same facility (AOR: 1.95; 95% CI: 1.81-2.10), if providers were different genders, most notably male (diagnosing) and female (treating) [AOR: 1.23; 95% CI: 1.08-1.40, p = 0.0015]. PSNs appear to be associated with reduced of a care delay. The associations observed in our study address the demand for developing multilevel interventions to improve the delivery and coordination of high-quality of care for older cancer patients.

Assessing the Association Between Network-based Provider Communities and Patient Mortality in the Medicare Population with Multiple Chronic Conditions

Understanding the complexity of care delivery and care coordination for patients with multiple chronic conditions is challenging. Network analysis can model the relationship between providers and patients to find factors associated with patient mortality. We constructed a network by connecting the providers through shared patients, which was then partitioned into tightly connected communities using a community detection algorithm. After adjusting for patient characteristics, the odds ratio of death for one standard deviation increase in degree centrality ratio between primary care providers (PCPs) and non-PCPs was 0.95 (0.92-0.98). Our result suggest that the centrality of PCPs may be a modifiable factor for improving care delivery. We demonstrated that network analysis can be used to find higher order features associated with health outcomes in addition to patient-level features.

Physician Network Connections Associated With Faster De-Adoption of Dronedarone for Permanent Atrial Fibrillation

BACKGROUND

Physicians' professional networks are an important source of new medical information and have been shown to influence the adoption of new treatments, but it is unknown how physician networks impact the de-adoption of harmful practices.

METHODS

We analyzed changes in physicians' use of dronedarone after the PALLAS trial (Palbociclib Collaborative Adjuvant Study; November 2011) showed that dronedarone increased the risk of death from cardiovascular events among patients with permanent atrial fibrillation. Deidentified administrative claims from the OptumLabs Data Warehouse were combined with physicians' demographic information from the Doximity database and publicly available data on physicians' patient-sharing relationships compiled by the Centers for Medicare and Medicaid Services. We used a linear probability model with an interrupted linear time trend specification to model the impact of the PALLAS trial on physicians' dronedarone usage between 2009 and 2014.

RESULTS

Before the PALLAS trial, the use of dronedarone was increasing by 0.22 percentage points per quarter (95% CI, 0.19-0.25) in our Medicare Advantage sample (N=343 429 patient-quarter observations) and 0.63 percentage points per quarter (95% CI, 0.52-0.75) in our commercially insured sample (N=44 402 patient-quarter observations). After the PALLAS trial and subsequent United States Food and Drug Administration black box warning, physicians in the Medicare Advantage sample with an above-median number of network connections to other physicians decreased their quarterly usage of dronedarone by 0.12 percentage points more per quarter (95% CI, -0.20 to -0.04; P=0.031) than physicians with equal to or below the median number of network connections. Similar patterns existed in the commercially insured sample (P=0.0318).

CONCLUSIONS

After controlling for a wide range of patient, physician, and geographic characteristics, physicians with a greater number of network connections were faster de-adopters of dronedarone for patients with permanent atrial fibrillation after the PALLAS trial and subsequent United States Food and Drug Administration black box warning detailed the harmfulness of dronedarone for these patients. Policies for improving physicians' responsiveness to new medical information should consider utilizing the influence of these important professional network relationships.

Investigation of patient-sharing networks using a Bayesian network model selection approach for congruence class models

A Bayesian approach to conduct network model selection is presented for a general class of network models referred to as the congruence class models (CCMs). CCMs form a broad class that includes as special cases several common network models, such as the Erdős-Rényi-Gilbert model, stochastic block model, and many exponential random graph models. Due to the range of models that can be specified as CCMs, our proposed method is better able to select models consistent with generative mechanisms associated with observed networks than are current approaches. In addition, our approach allows for incorporation of prior information. We illustrate the use of this approach to select among several different proposed mechanisms for the structure of patient-sharing networks; such networks have been found to be associated with the cost and quality of medical care. We found evidence in support of heterogeneity in sociality but not selective mixing by provider type or degree.

Provider Care Team Segregation and Operative Mortality Following Coronary Artery Bypass Grafting

BACKGROUND

Studies have shown that Black patients die more frequently following coronary artery bypass grafting than their White counterparts for reasons not fully explained by disease severity or comorbidity. To examine whether provider care team segregation within hospitals contributes to this inequity, we analyzed national Medicare data.

METHODS

Using national Medicare data, we identified beneficiaries who underwent coronary artery bypass grafting at hospitals where this procedure was performed on at least 10 Black and 10 White patients between 2008 and 2014 (n=12 646). After determining the providers who participated in their perioperative care, we examined the extent to which Black and White patients were cared for by unique networks of provider care teams within the same hospital. We then evaluated whether a lack of overlap in composition of the provider care teams treating Black versus White patients (ie, high segregation) was associated with higher 90-day operative mortality among Black patients.

RESULTS

The median level of provider care team segregation was high (0.89) but varied across hospitals (interquartile range, 0.85-0.90). On multivariable analysis, after controlling for patient-, hospital-, and community-level differences, mortality rates for White patients were comparable at hospitals with high and low levels of provider care segregation (5.4% [95% CI, 4.7%-6.1%] versus 5.8% [95% CI, 4.7%-7.0%], respectively; P=0.601), while Black patients treated at high-segregation hospitals had significantly higher mortality than those treated at low-segregation hospitals (8.3% [95% CI, 5.4%-12.4%] versus 3.3% [95% CI, 2.0%-5.4%], respectively; P=0.017). The difference in mortality rates for Black and White patients treated at low-segregation hospitals was nonsignificant (-2.5%; P=0.098).

CONCLUSIONS

Black patients who undergo coronary artery bypass grafting at a hospital with a higher level of provider care team segregation die more frequently after surgery than Black patients treated at a hospital with a lower level.

Patient-sharing relationship between Chinese medicine doctors and other physicians: costs and outcomes of breast cancer survivorship care

PURPOSE

Breast cancer survivors represent a unique group of patients who need complex and continuous care after their cancer treatment. These patients often see several providers in various specialties. This study aimed to analyze how traditional Chinese medicine (TCM) integration within care networks of patients with breast cancer might be related to health care costs and patient outcomes under the National Health Insurance program in Taiwan.

METHODS

We enrolled all patients who underwent definitive mastectomy for newly diagnosed breast cancer between 2007 and 2015. We analyzed the presence of TCM physicians and the patient-sharing relationship between TCM physicians and other physicians during the first year after mastectomy. The outcomes included all-cause mortality, avoidable hospitalization, and medical expenditures.

RESULTS

There were 68,987 patients with breast cancer, with a median age of 53 years. After propensity score matching, patients whose TCM doctors had the highest connectedness with other physicians had the lowest odds of avoidable hospitalization (adjusted odds ratio 0.86; 95% confidence interval [CI], 0.78-0.96) and lowest hazard of mortality (adjusted hazard ratio, 0.82; 95% CI, 0.72-0.93), followed by those with TCM doctors with medium connectedness, then low connectedness, and lastly those patients with no TCM doctor in their care network.

CONCLUSIONS

A dose-response pattern was observed regarding the relationship between TCM doctor's connectedness with other physicians within a patient's care network and patient outcomes.

IMPLICATIONS FOR CANCER SURVIVORS

The findings demonstrated that stronger connectedness between TCM and other physicians could help improve the health outcomes of breast cancer survivors.

Administrative Claims Measure for Profiling Hospital Performance Based on 90-Day All-Cause Mortality Following Coronary Artery Bypass Graft Surgery

BACKGROUND

Coronary artery bypass graft (CABG) surgery is a focus of bundled and alternate payment models that capture outcomes up to 90 days postsurgery. While clinical registry risk models perform well, measures encompassing mortality beyond 30 days do not currently exist. We aimed to develop a risk-adjusted hospital-level 90-day all-cause mortality measure intended for assessing hospital performance in payment models of CABG surgery using administrative data.

METHODS

Building upon Centers for Medicare and Medicaid Services hospital-level 30-day all-cause CABG mortality measure specifications, we extended the mortality timeframe to 90 days after surgery and developed a new hierarchical logistic regression model to calculate hospital risk-standardized 90-day all-cause mortality rates for patients hospitalized for isolated CABG. The model was derived from Medicare claims data for a 3-year cohort between July 2014 to June 2017. The data set was randomly split into 50:50 development and validation samples. The model performance was evaluated with C statistics, overfitting indices, and calibration plot. The empirical validity of the measure result at the hospital level was evaluated against the Society of Thoracic Surgeons composite star rating.

RESULTS

Among 137 819 CABG procedures performed in 1183 hospitals, the unadjusted mortality rate within 30 and 90 days were 3.1% and 4.7%, respectively. The final model included 27 variables. Hospital-level 90-day risk-standardized mortality rates ranged between 2.04% and 11.26%, with a median of 4.67%. C statistics in the development and validation samples were 0.766 and 0.772, respectively. We identified a strong positive correlation between 30- and 90-day risk-standardized mortality rates, with a regression slope of 1.09. Risk-standardized mortality rates also showed a stepwise trend of lower 90-day mortality with higher Society of Thoracic Surgeons composite star ratings.

CONCLUSIONS

We present a measure of hospital-level 90-day risk-standardized mortality rates following isolated CABG. This measure complements Centers for Medicare and Medicaid Services' existing 30-day CABG mortality measure by providing greater insight into the postacute recovery period. It offers a balancing measure to ensure efforts to reduce costs associated with CABG recovery and rehabilitation do not result in unintended consequences.

How Specialist Aftercare Impacts Long-Term Readmission Risks in Elderly Patients With Metabolic, Cardiac, and Chronic Obstructive Pulmonary Diseases: Cohort Study Using Administrative Data

BACKGROUND

The health state of elderly patients is typically characterized by multiple co-occurring diseases requiring the involvement of several types of health care providers.

OBJECTIVE

We aimed to quantify the benefit for multimorbid patients from seeking specialist care in terms of long-term readmission risks.

METHODS

From an administrative database, we identified 225,238 elderly patients with 97 different diagnosis (ICD-10 codes) from hospital stays and contact with 13 medical specialties. For each diagnosis associated with the first hospital stay, we used multiple logistic regression analysis to quantify the sex-specific and age-adjusted long-term all-cause readmission risk (hospitalizations occurring between 3 months and 3 years after the first admission) and how specialist contact impacts these risks.

RESULTS

Men have a higher readmission risk than women (mean difference over all first diagnoses 1.9%, P<.001), but similar reduction in readmission risk after receiving specialist care. Specialist care can reduce readmission risk by almost 50%. We found the greatest reductions in risk when the first hospital stay was associated with diagnoses corresponding to complex chronic diseases such as acute myocardial infarction (57.6% reduction in readmission risk, SE 7.6% for men [m]; 55.9% reduction, SE 9.8% for women [w]), diabetic and other retinopathies (m: 62.3%, SE 8.0; w: 60.1%, SE 8.4%), chronic obstructive pulmonary disease (m: 63.9%, SE 7.8%; w: 58.1%, SE 7.5%), disorders of lipoprotein metabolism (m: 64.7%, SE 3.7%; w: 63.8%, SE 4.0%), and chronic ischemic heart diseases (m: 63.6%, SE 3.1%; w: 65.4%, SE 3.0%).

CONCLUSIONS

Specialist care can greatly reduce long-term readmission risk for patients with chronic and multimorbid diseases. Further research is needed to identify the specific reasons for these findings and to understand the detected sex-specific differences.

The association between patient sharing network structure and healthcare costs

STUDY QUESTION

While physician relationships (measured through shared patients) are associated with clinical and utilization outcomes, the extent to which this is driven by local or global network characteristics is not well established. The objective of this research is to examine the association between local and global network statistics with total medical spending and utilization.

DATA SOURCE

Data used are the 2011 Massachusetts All Payer Claims Database.

STUDY DESIGN

The association between network statistics and total medical spending and utilization (using standardized prices) is estimated using multivariate regression analysis controlling for patient demographics and health status.

DATA COLLECTION

We limit the sample to continuously enrolled commercially insured patients in Massachusetts in 2011.

PRINCIPAL FINDINGS

Mean patient age was 45 years, and 56.3% of patients were female. 73.4% were covered by a health maintenance organization. Average number of visits was 5.43, with average total medical spending of $4,911 and total medical utilization of $4,252. Spending was lower for patients treated by physicians with higher degree (p<0.001), eigenvector centrality (p<0.001), clustering coefficient (p<0.001), and measures reflecting the normalized degree (p<0.001) and eigenvector centrality (p<0.001) of specialists connected to a patient's PCP. Spending was higher for patients treated by physicians with higher normalized degree, which accounts for physician specialty and patient panel size (p<0.001). Results were similar for utilization outcomes, although magnitudes differed indicating patients may see different priced physicians.

CONCLUSIONS

Generally, higher values of network statistics reflecting local connectivity adjusted for physician characteristics are associated with increased costs and utilization, while higher values of network statistics reflecting global connectivity are associated with decreased costs and utilization. As changes in the financing and delivery system advance through policy changes and healthcare consolidation, future research should examine mechanisms through which this structure impacts outcomes and potential policy responses to determine ways to reduce costs while maintaining quality and coordination of care.

WHAT THIS STUDY ADDS

It is unknown whether local and global measures of physician network connectivity associated with spending and utilization for commercially insured patients?In this social network analysis, we found generally higher values of network statistics reflecting local connectivity are associated with increased costs and utilization, while higher values of network statistics reflecting global connectivity are associated with decreased costs and utilization.Understanding how to influence local and global physician network characteristics may be important for reducing costs while maintaining quality.

Outcome of Percutaneous Coronary Intervention in Relation to the Institutional Volume of Coronary Artery Bypass Surgery

BACKGROUND

Percutaneous coronary intervention (PCI) is performed in a wide range of institutions. We sought to assess the relationship between coronary artery bypass grafting (CABG) volume relative to PCI volume and clinical outcome using nationally representative PCI and CABG registries in Japan.

METHODS

This was a collaborative, registry-based cohort study enrolling patients undergoing percutaneous coronary intervention in 2013-2014 using Japanese nationwide registry (J-PCI) with follow up until discharge. The absolute volume of CABG for each hospital was calculated using additional data from Japan CardioVascular Surgery Database (JCVSD). Patients undergoing their first PCI registered in the registry (N = 220,934), at 943 facilities were studied. Main outcomes were in-hospital mortality, and incidence of composite of in-hospital death and postprocedural complications.

RESULTS

Among the 220,934 patients, 162,411 were men, with a mean age of 69.7 (SD 11.6) years. Patients underwent PCI at hospitals with varying CABG volume: The overall in-hospital mortality and composite event rate for PCI patients was 0.9% and 2.4%, respectively. CABG volume was associated with the in-hospital mortality of PCI at facilities performing less than 200 PCIs per year, but not at facilities performing 200 or more. Similarly, in-hospital mortality or complication was associated with PCI volume <200 only if no CABG is done at the facility. The result remained largely consistent in subgroup of patients presenting with acute coronary syndrome or even after excluding these institutions with extremely low number of PCI (<50 cases/year) or CABG (<15 cases / year).

CONCLUSIONS

In a nationwide registry-based analysis, the surgical volume was associated with patients' clinical outcome after PCI, when limited number of PCIs were performed at the facility.

Understanding and Addressing Variation in Health Care-Associated Infections After Durable Ventricular Assist Device Therapy: Protocol for a Mixed Methods Study

BACKGROUND

Durable ventricular assist device (VAD) therapy is reserved for patients with advanced heart failure who have a poor estimated 1-year survival. However, despite highly protocolized management processes, patients are at a unique risk for developing a health care-associated infection (HAI). Few studies have examined optimal strategies for HAI prevention after durable VAD implantation, despite variability in rates across centers and their impact on short- and long-term outcomes.

OBJECTIVE

The objective of this study is to develop recommendations for preventing the most significant HAIs after durable VAD implantation. The study has 3 specific aims: (1) identify determinants of center-level variability in HAI rates, (2) develop comprehensive understanding of barriers and facilitators for achieving low center-level HAI rates, and (3) develop and disseminate a best practices toolkit for preventing HAIs that accommodates various center contexts.

METHODS

This is a sequential mixed methods study starting with a cross-sectional assessment of current practices. To address aim 1, we will conduct (1) a systematic review of HAI prevention studies and (2) in-depth quantitative analyses using administrative claims, in-depth clinical data, and organizational surveys of VAD centers. For aim 2, we will apply a mixed methods patient tracer assessment framework to conduct semistructured interviews, field observations, and document analysis informed by findings from aim 1 at 5 high-performing (ie, low HAIs) and 5 low-performing (ie, high HAI) centers, which will be examined using a mixed methods case series analysis. For aim 3, we will build upon the findings from the previous aims to develop and field test an HAI preventive toolkit, acquire stakeholder input at an annual cardiac surgical conference, disseminate the final version to VAD centers nationwide, and conduct follow-up surveys to assess the toolkit's adoption.

RESULTS

The project was funded by the Agency for Healthcare Research and Quality in 2018 and enrollment for the overall project is ongoing. Data analysis is currently under way and the first results are expected to be submitted for publication in 2019.

CONCLUSIONS

This mixed methods study seeks to quantitatively assess the determinants of HAIs across clinical centers and qualitatively identify the context-specific facilitators and barriers for attaining low HAI rates. The mixed data findings will be used to develop and disseminate a stakeholder-acceptable toolkit of evidence-based HAI prevention recommendations that will accommodate the specific contexts and needs of VAD centers.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/14701.

Evaluation of Physician Network-Based Measures of Care Coordination Using Medicare Patient-Reported Experience Measures

BACKGROUND

There is significant promise in analyzing physician patient-sharing networks to indirectly measure care coordination, yet it is unknown whether these measures reflect patients' perceptions of care coordination.

OBJECTIVE

To evaluate the associations between network-based measures of care coordination and patient-reported experience measures.

DESIGN

We analyzed patient-sharing physician networks within group practices using data made available by the Centers for Medicare and Medicaid Services.

SUBJECTS

Medicare beneficiaries who provided responses to the Consumer Assessment of Healthcare Providers and Systems (CAHPS) Survey in 2016 (data aggregated by physician group practice made available through the Physician Compare 2016 Group Public Reporting).

MAIN MEASURES

The outcomes of interest were patient-reported experience measures reflecting aspects of care coordination (CAHPS). The predictor variables of interests were physician group practice density (the number of physician pairs who share patients adjusting for the total number of physician pairs) and clustering (the extent to which sets of three physicians share patients).

KEY RESULTS

Four hundred seventy-six groups had patient-reported measures available. Patients' perception of "Clinicians working together for your care" was significantly positively associated with both physician group practice density (Est (95 % CI) = 5.07(0.83, 9.33), p = 0.02) and clustering (Est (95 % CI) = 3.73(1.01, 6.44), p = 0.007). Physician group practice clustering was also significantly positively associated with "Getting timely care, appointments, and information" (Est (95 % CI) = 4.63(0.21, 9.06), p = 0.04).

CONCLUSIONS

This work suggests that network-based measures of care coordination are associated with some patient-reported experience measures. Evaluating and intervening on patient-sharing networks may provide novel strategies for initiatives aimed at improving quality of care and the patient experience.

Association of Informal Clinical Integration of Physicians With Cardiac Surgery Payments

Importance

To reduce inefficiency and waste associated with care fragmentation, many current programs target greater clinical integration among physicians. However, these programs have led to only modest Medicare spending reductions. Most programs focus on formal integration, which often bears little resemblance to actual physician interaction patterns.

Objectives

To examine how physician interaction patterns vary between health systems and to assess whether variation in informal integration is associated with care delivery payments.

Design, Setting, and Participants

National Medicare data from January 1, 2008, through December 31, 2011, identified 253 545 Medicare beneficiaries (aged ≥66 years) from 1186 health systems where Medicare beneficiaries underwent coronary artery bypass grafting (CABG) procedures. Interactions were mapped between all physicians who treated these patients-including primary care physicians and surgical and medical specialists-within a health system during their surgical episode. The level of informal integration was measured in these networks of interacting physicians. Multivariate regression models were fitted to evaluate associations between payments for each surgical episode made on a beneficiary's behalf and the level of informal integration in the health system where the patient was treated.

Exposures

The informal integration level of a health system.

Main Outcomes and Measures

Price-standardized total surgical episode and component payments.

Results

The total 253 545 study participants included 175 520 men (69.2%; mean [SD] age, 74.51 [5.75] years) and 78 024 women (34.3%; 75.67 [5.91] years). One beneficiary of the 253 545 participants did not have sex information. The low level of informal clinical integration included 84 598 patients (33.4%; mean [SD] age, 75.00 [5.93] years); medium level, 84 442 (33.30%; 74.94 [5.87] years); and high level, 84 505 (33.34%; 74.66 [5.72] years) (P < .001). Informal integration levels varied across health systems. After adjusting for patient, health-system, and community factors, higher levels of informal integration were associated with significantly lower total episode and component payments (β coefficients for informal integration were -365.87 [95% CI, -451.08 to -280.67] for total episode payments, -182.63 [-239.80 to -125.46] for index hospitalization, -43.13 [-55.53 to -30.72] for physician services, -74.48 [-103.45 to -45.51] for hospital readmissions, and -62.04 [-88.00 to -36.07] for postacute care; P < .001 for each association). When beneficiaries were treated in health systems with higher informal integration, the greatest savings of lower estimated payments were from hospital readmissions (13.0%) and postacute care services (5.8%).

Conclusions and Relevance

Informal integration is associated with lower spending. Although most programs that seek to promote clinical integration are focused on health systems' formal structures, policy makers may also want to address informal integration.

Informal Clinical Integration in Medicare Accountable Care Organizations and Mortality Following Coronary Artery Bypass Graft Surgery

BACKGROUND

Accountable care organizations' (ACOs') focus on formal clinical integration to improve outcomes overlooks actual patterns of provider interactions around shared patients.

OBJECTIVE

To determine whether such informal clinical integration relates to a health system's performance in an ACO.

RESEARCH DESIGN

We analyzed national Medicare data (2008-2014), identifying beneficiaries who underwent coronary artery bypass grafting (CABG). After determining which physicians delivered care to them, we aggregated across episodes to construct physician networks for each health system. We used network analysis to measure each system's level of informal clinical integration (defined by cross-specialty ties). We fit regression models to examine the association between a health system's CABG mortality rate and ACO participation, conditional on informal clinical integration.

SUBJECTS

Beneficiaries age 66 and older undergoing CABG.

MEASURES

Ninety-day CABG mortality.

RESULTS

Over the study period, 3385 beneficiaries were treated in 161 ACO-participating health systems. The remaining 49,854 were treated in 875 nonparticipating systems or one of the 161 ACO-participating systems before the ACO start date. ACO systems with higher levels of informal clinical integration had lower CABG mortality rates than nonparticipating ones (2.8% versus 5.5%; P<0.01); however, there was no difference based on ACO participation for health systems with lower to relatively moderate informal clinical integration. Regression results corroborate this finding (coefficient for interaction between ACO participation and informal clinical integration level is -0.25; P=0.01).

CONCLUSIONS

Formal clinical integration through ACO participation may be insufficient to improve outcomes. Health systems with higher informal clinical integration may benefit more from ACO participation.

Comparison of physician networks constructed from thresholded ties versus shared clinical episodes

OBJECTIVE

To compare standard methods for constructing physician networks from patient-physician encounter data with a new method based on clinical episodes of care.

DATA SOURCE

We used data on 100% of traditional Medicare beneficiaries from 51 nationally representative geographical regions for the years 2005-2010.

STUDY DESIGN

We constructed networks of physicians based on their shared patients. In the fixed-threshold networks and adaptive-threshold networks, we included data on all patient-physician encounters to form the physician-physician ties, and then subsequently thresholded some proportion of the strongest ties. In contrast, in the episode-based approach, only those patient-physician encounters that occurred within shared clinical episodes treating specific conditions contributed towards physician-physician ties.

DATA COLLECTION/EXTRACTION METHODS

We extracted clinical episodes in the Medicare data and investigated structural properties of the patient-sharing networks of physicians, temporal dynamics of their ties, and temporal stability of network communities across the two approaches.

PRINCIPAL FINDINGS

The episode-based networks accentuated ties between primary care physicians (PCPs) and medical specialists, had ties that were more likely to reappear in the future, and appeared to have more fluid community structure.

CONCLUSIONS

Constructing physician networks around shared episodes of care is a clinically sound alternative to previous approaches to network construction that does not require arbitrary decisions about thresholding. The resulting networks capture somewhat different aspects of patient-physician encounters.

A scoping review of patient-sharing network studies using administrative data

There is a robust literature examining social networks and health, which draws on the network traditions in sociology and statistics. However, the application of social network approaches to understand the organization of health care is less well understood. The objective of this work was to examine approaches to conceptualizing, measuring, and analyzing provider patient-sharing networks. These networks are constructed using administrative data in which pairs of physicians are considered connected if they both deliver care to the same patient. A scoping review of English language peer-reviewed articles in PubMed and Embase was conducted from inception to June 2017. Two reviewers evaluated article eligibility based upon inclusion criteria and abstracted relevant data into a database. The literature search identified 10,855 titles, of which 63 full-text articles were examined. Nine additional papers identified by reviewing article references and authors were examined. Of the 49 papers that met criteria for study inclusion, 39 used a cross-sectional study design, 6 used a cohort design, and 4 were longitudinal. We found that studies most commonly theorized that networks reflected aspects of collaboration or coordination. Less commonly, studies drew on the strength of weak ties or diffusion of innovation frameworks. A total of 180 social network measures were used to describe the networks of individual providers, provider pairs and triads, the network as a whole, and patients. The literature on patient-sharing relationships between providers is marked by a diversity of measures and approaches. We highlight key considerations in network identification including the definition of network ties, setting geographic boundaries, and identifying clusters of providers, and discuss gaps for future study.

Physician peer group characteristics and timeliness of breast cancer surgery

PURPOSE

Little is known about how the structure of interdisciplinary groups of physicians affects the timeliness of breast cancer surgery their patients receive. We used social network methods to examine variation in surgical delay across physician peer groups and the association of this delay with group characteristics.

METHODS

We used linked Surveillance, Epidemiology, and End Results-Medicare data to construct physician peer groups based on shared breast cancer patients. We used hierarchical generalized linear models to examine the association of three group characteristics, patient racial composition, provider density (the ratio of potential vs. actual connections between physicians), and provider transitivity (clustering of providers within groups), with delayed surgery.

RESULTS

The study sample included 8338 women with breast cancer in 157 physician peer groups. Surgical delay varied widely across physician peer groups (interquartile range 28.2-50.0%). For every 10% increase in the percentage of black patients in a peer group, there was a 41% increase in the odds of delayed surgery for women in that peer group regardless of a patient's own race [odds ratio (OR) 1.41, 95% confidence interval (CI) 1.15-1.73]. Women in physician peer groups with the highest provider density were less likely to receive delayed surgery than those in physician peer groups with the lowest provider density (OR 0.65, 95% CI 0.44-0.98). We did not find an association between provider transitivity and delayed surgery.

CONCLUSIONS

The likelihood of surgical delay varied substantially across physician peer groups and was associated with provider density and patient racial composition.

Linkage of Medicare Records to the Interagency Registry of Mechanically Assisted Circulatory Support

BACKGROUND

The Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) is a United States registry for adults receiving durable United States Food and Drug Administration-approved mechanical circulatory support devices (MCSDs). We merged INTERMACS records with Medicare claims to investigate the uncertainty of penetrance of Medicare beneficiaries within INTERMACS.

METHODS

INTERMACS records and Medicare claims (January 1, 2008, through December 31, 2013) from the Centers for Medicare and Medicaid (CMS) were linked using a deterministic matching methodology.

RESULTS

There was annual growth of CMS and INTERMACS centers performing durable MCSD implants among adults from 2008 through 2013 (54% and 87% increase, respectively). The number of CMS centers outnumbered INTERMACS centers throughout all years, with the 68% to 88% of CMS centers being represented in INTERMACS. Although annual patient volume was greatest for INTERMACS, the absolute number of patients significantly increased annually across both data sets from 2008 through 2013 (149% increase in CMS; 268% increase in INTERMACS). As a proportion of all INTERMACS registrants, Medicare beneficiary representation grew from 30% in 2008 to a high of 48% in 2010 and remained stable thereafter. Representation within INTERMACS of MCSDs implanted in Medicare beneficiaries more than doubled, from 36% in 2008 to 77% in 2013.

CONCLUSIONS

Using a merged data set of MCSDs implanted between 2008 and 2013, we report that the vast majority of CMS centers and Medicare beneficiaries receiving MCSDs are increasingly captured in INTERMACS. Accordingly, contemporary studies in INTERMACS are relevant and generalizable to the Medicare population.

Return to the workforce following coronary artery bypass grafting: A Danish nationwide cohort study

BACKGROUND

Returning to the workforce after coronary artery bypass grafting (CABG) holds important socioeconomic consequences not only for patients, but the society as well. Yet data on this issue are limited. We examined return to the workforce and associated factors in patients of working age undergoing CABG.

METHODS AND RESULTS

Using Danish nationwide administrative registries, we identified 6031 patients of working age (18-60years) undergoing isolated CABG (1998-2011) who were part of the workforce 30days prior to admission and alive at discharge. One year after discharge for CABG, 4827 (80.0%) patients had returned to the workforce, 614 (10.2%) were on paid sick leave, 267 (4.4%) received disability pension, 250 (4.1%) were on early retirement, 57 (0.9%) had died, and 16 (0.3%) had emigrated. Factors associated with return to the workforce were identified using multivariable logistic regression. Younger age (18-45 versus 56-60years; odds ratio, 1.89; 95% confidence interval, 1.48-2.42), male sex (1.51, 1.24-1.84), and higher level of education (higher educational level versus basic school; 1.53, 1.05-2.23) and income (highest quartile versus lowest; 3.01, 2.42-3.75) were associated with return to the workforce. Urgency of surgery (emergency versus elective; 0.65, 0.49-0.88), cardiovascular comorbidity, a history of chronic kidney disease (0.49, 0.29-0.84) and liver disease (0.47, 0.28-0.80), as well as additional hospital admissions within the first year post-discharge (>2 versus none; 0.25, 0.19-0.32) were associated with a lower likelihood of returning to the workforce.

CONCLUSION

One year after discharge for CABG, four out of five patients were part of the workforce and mortality was low. Younger age, male sex, higher socioeconomic status, and absence of major comorbidities were associated with return to the workforce.