Real-World Effectiveness of Preventive Pharmacological Therapy in Patients With Urolithiasis: A Retrospective Cohort Study.

RATIONALE & OBJECTIVE: Data supporting the efficacy of preventive pharmacological therapy (PPT) to reduce urolithiasis recurrence are based on clinical trials with composite outcomes that incorporate imaging findings and have uncertain clinical significance. This study evaluated whether the use of PPT leads to fewer symptomatic stone events. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: Medicare enrollees with urolithiasis who completed 24-hour urine collections that revealed hypercalciuria, hypocitraturia, low urine pH, or hyperuricosuria. EXPOSURE: PPT (thiazide diuretics for hypercalciuria, alkali for hypocitraturia or low urine pH, or uric acid lowering drugs for hyperuricosuria) categorized as (1) adherent to guideline-concordant PPT, (2) nonadherent to guideline-concordant PPT, or (3) untreated. OUTCOME: Symptomatic stone event occurrence (emergency department [ED] visit or hospitalization for urolithiasis or stone-directed surgery). ANALYTICAL APPROACH: Cox proportional hazards regression. RESULTS: Among 13,942 patients, 31.0% were prescribed PPT. Compared with no treatment, concordant/adherent PPT use was associated with a significantly lower hazard of symptomatic stone events for patients with hypercalciuria (HR, 0.736 [95% CI, 0.593-0.915]) and low urine pH (HR, 0.804 [95% CI, 0.650-0.996]) but not for patients with hypocitraturia or hyperuricosuria. These associations were largely driven by significantly lower rates of ED visits after initiating PPT among the concordant/adherent group versus untreated patients. Patients with hypercalciuria had adjusted 2-year predicted probabilities of a visit of 3.8% [95% CI, 2.5%-5.2%%] and 6.9% [95% CI, 6.0%-7.7%] for the concordant/adherent PPT and no-treatment groups, respectively. Among patients with low urine pH, these probabilities were 4.3% (95% CI, 2.9%-5.7%) and 7.3% (95% CI, 6.5%-8.0%) for the concordant/adherent PPT and no-treatment groups, respectively. LIMITATIONS: Potential bias from the possibility that patients prescribed PPT had more severe disease than untreated patients. CONCLUSIONS: Patients with urolithiasis and hypercalciuria who were adherent to treatment with thiazide diuretics as well as those with low urine pH adherent to prescribed alkali therapy had fewer symptomatic stone events than untreated patients. PLAIN-LANGUAGE SUMMARY: Despite multiple clinical trials demonstrating the efficacy of thiazide diuretics and alkali for secondary prevention of kidney stones, they are infrequently prescribed due in part to a lack of data about their effectiveness in real-world settings. We analyzed medical claims from older adults with kidney stones for whom urine chemistry data were available. We found that patients who took prescribed thiazide diuretics for elevated urine calcium levels or alkali for low urinary pH were less likely to experience symptomatic stone recurrences than untreated patients. This benefit was expressed as lower rates of emergency department visits after initiating therapy. Our findings should inform the prescription of and adherence to treatment with thiazide diuretics and alkali for the prevention of recurrent kidney stones.

Improving the Quality of Upper Urinary Tract Stone Surgery: External Validation of a Statewide Collaborative's Efforts to Reduce Emergency Department Visits After Ureteroscopy.

PURPOSE: The ROCKS (Reducing Operative Complications from Kidney Stones) program in MUSIC (Michigan Urological Surgery Improvement Collaborative) was created to optimize ureteroscopy outcomes. Through data collection, distribution of reports, patient education, and standardization of medication, post-ureteroscopy emergency department visits in Michigan have declined. It is unclear whether this is because of statewide quality efforts or due to national trends. We therefore sought to understand emergency department visit rates in Michigan compared to a national data set. MATERIALS AND METHODS: We compared the MUSIC ROCKS clinical registry in Michigan against a national cohort, Optum's de-identified Clinformatics Data Mart, from 2016-2021 (excluding Michigan). We identified patients who underwent ureteroscopy and the proportion who had a postoperative emergency department visit within 30 days. Emergency department rates were modeled over time, adjusting for age, gender, comorbidity, and ureteral stenting. RESULTS: We identified 24,688 patients in MUSIC ROCKS and 99,340 in the Clinformatics Data Mart database who underwent ureteroscopy. The risk-adjusted emergency department visit rate in MUSIC ROCKS significantly declined over the study period (10.5% in 2016 to 6.9% in 2021, P < 0.001) while the mean emergency department visit rate in the Clinformatics Data Mart cohort was 9.9% and did not change over time (9.6% in 2016 to 10% in 2021). Comparing emergency department visits between the cohorts, the MUSIC ROCKS rate significantly declined relative to the Clinformatics Data Mart (P < 0.001) over the study period. CONCLUSIONS: Postoperative emergency department visit rates in Michigan have declined significantly after ureteroscopy since the establishment of MUSIC ROCKS. This decline outpaced national rates, providing evidence that systematic quality initiatives can improve urological care.

Association of Hospital Participation in Bundled Payments for Care Improvement Advanced With Medicare Spending and Hospital Incentive Payments.

Importance: Bundled Payments for Care Improvement Advanced (BPCI-A) is a Centers for Medicare & Medicaid Services (CMS) initiative that aims to produce financial savings by incentivizing decreases in clinical spending. Incentives consist of financial bonuses from CMS to hospitals or penalties paid by hospitals to CMS. Objective: To investigate the association of hospital participation in BPCI-A with spending, and to characterize hospitals receiving financial bonuses vs penalties. Design, Setting, and Participants: Difference-in-differences and cross-sectional analyses of 4 754 139 patient episodes using 2013-2019 US Medicare claims at 694 participating and 2852 nonparticipating hospitals merged with hospital and market characteristics. Exposures: BPCI-A model years 1 and 2 (October 1, 2018, through December 31, 2019). Main Outcomes and Measures: Hospitals' per-episode spending, CMS gross and net spending, and the incentive allocated to each hospital. Results: The study identified 694 participating hospitals. The analysis observed a -$175 change in mean per-episode spending (95% CI, -$378 to $28) and an aggregate spending change of -$75.1 million (95% CI, -$162.1 million to $12.0 million) across the 428 670 episodes in BPCI-A model years 1 and 2. However, CMS disbursed $354.3 million (95% CI, $212.0 million to $496.0 million) more in bonuses than it received in penalties. Hospital participation in BPCI-A was associated with a net loss to CMS of $279.2 million (95% CI, $135.0 million to $423.0 million). Hospitals in the lowest quartile of Medicaid days received a mean penalty of $0.41 million; (95% CI, $0.09 million to $0.72 million), while those in the highest quartile received a mean bonus of $1.57 million; (95% CI, $1.09 million to $2.08 million). Similar patterns were observed for hospitals across increasing quartiles of Disproportionate Share Hospital percentage and of patients from racial and ethnic minority groups. Conclusions and Relevance: Among US hospitals measured between 2013 and 2019, participation in BPCI-A was significantly associated with an increase in net CMS spending. Bonuses accrued disproportionately to hospitals providing care for marginalized communities.

Dispersion in the hospital network of shared patients is associated with less efficient care.

BACKGROUND: There is growing recognition that health care providers are embedded in networks formed by the movement of patients between providers. However, the structure of such networks and its impact on health care are poorly understood. PURPOSE: We examined the level of dispersion of patient-sharing networks across U.S. hospitals and its association with three measures of care delivered by hospitals that were likely to relate to coordination. METHODOLOGY/APPROACH: We used data derived from 2016 Medicare Fee-for-Service claims to measure the volume of patients that hospitals treated in common. We then calculated a measure of dispersion for each hospital based on how those patients were concentrated in outside hospitals. Using this measure, we created multivariate regression models to estimate the relationship between network dispersion, Medicare spending per beneficiary, readmission rates, and emergency department (ED) throughput rates. RESULTS: In multivariate analysis, we found that hospitals with more dispersed networks (those with many low-volume patient-sharing relationships) had higher spending but not greater readmission rates or slower ED throughput. Among hospitals with fewer resources, greater dispersion related to greater readmission rates and slower ED throughput. Holding an individual hospital's dispersion constant, the level of dispersion of other hospitals in the hospital's network was also related to these outcomes. CONCLUSION: Dispersed interhospital networks pose a challenge to coordination for patients who are treated at multiple hospitals. These findings indicate that the patient-sharing network structure may be an overlooked factor that shapes how health care organizations deliver care. PRACTICE IMPLICATIONS: Hospital leaders and hospital-based clinicians should consider how the structure of relationships with other hospitals influences the coordination of patient care. Effective management of this broad network may lead to important strategic partnerships.

Variation in Provider Connectedness Associates With Outcomes of Inflammatory Bowel Diseases in an Analysis of Data From a National Health System.

BACKGROUND & AIMS: Inflammatory bowel diseases (IBD) often require multidisciplinary care with tight coordination among providers. Provider connectedness, a measure of the relationship among providers, is an important aspect of care coordination that has been linked to higher quality care. We aimed to assess variation in provider connectedness among medical centers, and to understand the association between this established measure of care coordination and outcomes of patients with IBD. METHODS: We conducted a national cohort study of 32,949 IBD patients with IBD from 2005 to 2014. We used network analysis to examine provider connectedness, defined using network properties that measure the strength of the collaborative relationship, team cohesiveness, and between-facility collaborations. We used multilevel modeling to examine variations in provider connectedness and association with patient outcomes. RESULTS: There was wide variation in provider connectedness among facilities in complexity, rural designation, and volume of patients with IBD. In a multivariable model, patients followed in a facility with team cohesiveness (odds ratio, 0.38; 95% CI, 0.16-0.88) and where providers often collaborated with providers outside their facility (odds ratio, 0.48; 95% CI, 0.31-0.75) were less likely to have clinically active disease, defined by a composite of outpatient flare, inpatient flare, and IBD-related surgery. CONCLUSIONS: A national study found evidence for heterogeneity in patient-sharing among IBD care teams. Patients with IBD seen at health centers with higher provider connectedness appear to have better outcomes. Understanding provider connectedness is a step toward designing network-based interventions to improve coordination and quality of care.

Ureteral Stent Placement following Ureteroscopy Increases Emergency Department Visits in a Statewide Surgical Collaborative.

PURPOSE: Ureteral stents are commonly placed after ureteroscopy. Although studies indicate that stents are associated with patient discomfort, their impact on downstream health services use is unclear. We examined patterns of stent utilization in Michigan and their association with unplanned health care encounters. MATERIALS AND METHODS: We used the Michigan Urological Surgery Improvement Collaborative's Reducing Operative Complications from Kidney Stones (MUSIC ROCKS) clinical registry to identify ureteroscopy cases between 2016 and 2019. Factors associated with stent placement were examined using bivariate and multivariable statistics. Using multivariable logistic regression, we evaluated whether stent placement was associated with emergency department visits and hospitalizations within 30 days. RESULTS: We identified 9,662 ureteroscopies and a stent was placed in 7,025 (73%) of these. Frequency of stent use across the 137 urologists varied (11%-100%, p <0.001) and was not associated with total case volume. Factors associated with stent use included age and stone size. Pre-stented cases and renal stones had a decreased odds of stent placement. On multivariable analysis after adjusting for risk factors, stent placement was associated with a 1.25 higher odds of emergency department visit (OR 1.25, 95% CI 1.01-1.54, p=0.043) but not hospitalization (OR 1.28, 95% CI 0.94-1.76, p=0.12). In a single high volume practice, 0.5% of cases that omitted a stent required urgent stenting postoperatively. CONCLUSIONS: There is substantial variation in the use of stents in Michigan, irrespective of case volume. Stent placement significantly increased the odds of an emergency department visit after surgery. Importantly, stent omission rarely required subsequent urgent stent placement.

Trends in Procedures to Initiate Renal Replacement Therapy among People Living with Spina Bifida.

PURPOSE: Given the increasing prevalence of chronic kidney disease in people with spina bifida, we sought to determine if this is associated with an increase in end stage kidney disease. We examined population based data to measure the frequency of procedures to establish renal replacement therapy-a marker for end stage kidney disease-among patients with spina bifida. MATERIALS AND METHODS: We used the Healthcare Cost and Utilization Project State Inpatient Database and State Ambulatory Surgery and Services Database from Florida, Kentucky, Maryland and New York (2000 to 2014), which include encounter level data. With a diagnosis code based algorithm we identified all procedural encounters made by patients with spina bifida. We determined the percentage of these encounters that were for facilitating renal replacement therapy (ie arteriovenous anastomosis, renal transplantation). We assessed for changes over time in this percentage with the Cochran-Armitage trend test. Bivariate analysis was performed using chi-square test. RESULTS: Of all procedures performed on patients with spina bifida over this time the proportion of procedures performed to establish renal replacement therapy significantly decreased in both the inpatient and outpatient settings (p=0.042 and p <0.001, respectively). People with spina bifida undergoing procedures to establish renal replacement therapy were, on average, young adults (mean age 34.5 and 36.0 years) with a high prevalence hypertension (75.8% of inpatients, 68.6% of outpatients). CONCLUSIONS: The frequency of surgeries to initiate renal replacement therapy among people with spina bifida undergoing procedures is low and is not increasing. This highlights the importance of consistent care throughout adolescence and young adulthood, and hypertension screening.

Ureteroscopy in Patients Taking Anticoagulant or Antiplatelet Therapy: Practice Patterns and Outcomes in a Surgical Collaborative.

PURPOSE: AUA guidelines recommend ureteroscopy as first line therapy for patients on anticoagulant or antiplatelet therapy and advocate using a ureteral access sheath. We examined practice patterns and unplanned health care use for these patients in Michigan. MATERIALS AND METHODS: Using the Michigan Urological Surgery Improvement Collaborative (MUSIC) clinical registry we identified ureteroscopy cases from 2016 to 2019. We assessed outcomes and adherence to guidelines based on therapy at time of ureteroscopy: 1) anticoagulant: continuous warfarin or novel oral agent therapy; 2) antiplatelet: continuous clopidogrel or aspirin therapy; 3) control: not on anticoagulant/antiplatelet therapy. We fit multivariate models to assess anticoagulant or antiplatelet therapy association with emergency department visits, hospitalization and ureteral access sheath use. RESULTS: In total, 9,982 ureteroscopies were performed across 31 practices with 3.1% and 7.8% on anticoagulant and antiplatelet therapy, respectively. There were practice (0% to 21%) and surgeon (0% to 35%) variations in performing ureteroscopy on patients on anticoagulant/antiplatelet therapy regardless of volume. After adjusting for risk factors, anticoagulant or antiplatelet therapy was not associated with emergency department visits. Hospitalization rates in anticoagulant, antiplatelet and control groups were 4.3%, 5.5% and 3.2%, respectively, and significantly increased with antiplatelet therapy (OR 1.48, 95% CI 1.02-2.14). Practice-level ureteral access sheath use varied (23% to 100%) and was not associated with anticoagulant/antiplatelet therapy. Limitations include inability to risk stratify between type/dosage of anticoagulant/antiplatelet therapy. CONCLUSIONS: We found practice-level and surgeon-level variation in performing ureteroscopy while on anticoagulant/antiplatelet therapy. Ureteroscopy on anticoagulant is safe. However, antiplatelet therapy increases the risk of hospitalization. Despite guideline recommendations, ureteral access sheath use is not associated with anticoagulant/antiplatelet therapy.

Wood smoke particle exposure in mice reduces the severity of influenza infection.

Elevated ambient temperatures and extreme weather events have increased the incidence of wildfires world-wide resulting in increased wood smoke particle (WSP). Epidemiologic data suggests that WSP exposure associates with exacerbations of respiratory diseases, and with increased respiratory viral infections. To assess the impact of WSP exposure on host response to viral pneumonia, we performed WSP exposures in rodents followed by infection with mouse adapted influenza (HINI-PR8). C57BL/6 male mice aged 6-8 weeks were challenged with WSP or PBS by oropharyngeal aspiration in acute (single dose) or sub-acute exposures (day 1, 3, 5, 7 and 10). Additional groups underwent sub-acute exposure followed by infection by influenza or heat-inactivated (HI) virus. Following exposures/infection, bronchoalveolar lavage (BAL) was performed to assess for total cell counts/differentials, total protein, protein carbonyls and hyaluronan. Lung tissue was assessed for viral counts by real time PCR. When compared to PBS, acute WSP exposure associated with an increase in airspace macrophages. Alternatively, sub-acute exposure resulted in a dose dependent increase in airspace neutrophils. Sub-acute WSP exposure followed by influenza infection was associated with improved respiratory viral outcomes including reduced weight loss and increased blood oxygen saturation, and decreased protein carbonyls and viral titers. Flow cytometry demonstrated dynamic changes in pulmonary macrophage and T cell subsets based on challenge with WSP and influenza. This data suggests that sub-acute WSP exposure can improve host response to acute influenza infection.

Case series of acute appendicitis association with SARS-CoV-2 infection.

BACKGROUND: Describe the indications for surgical interventions in asymptomatic patients with SARS-CoV-2. We are unaware of previous reports of an association between SARS-CoV-2 and acute appendicitis. METHODS: We performed a single institution retrospective review of SARS-CoV-2 pre-procedure testing and indications for surgical intervention. Statistical comparisons were performed using Chi Square analysis or two-tailed Student T test. RESULTS: We report a high prevalence of SARS-CoV-2 in both all testing and pre-procedure testing during the enrollment period. We observe a high prevalence of acute appendicitis among patients identified to be SARS-CoV-2 positive during pre-procedure testing and without recognized symptoms of COVID19. CONCLUSION: We report a previously unrecognized association between SARS-CoV-2 and acute appendicitis.

Understanding the Costs Associated With Surgical Care Delivery in the Medicare Population.

BACKGROUND: Surgical care has been largely untargeted by Medicare payment reforms because episode costs associated with its delivery are not currently well understood. OBJECTIVE: To quantify the costs of inpatient and outpatient surgery in the Medicare population. METHODS: We analyzed claims data from a 20% national sample of Medicare beneficiaries (2008-2014). For a given study year, we identified all inpatient and outpatient procedures and constructed claims windows around them to define surgical episodes. After summing payments for services rendered during each episode, we totaled all inpatient and outpatient episode payments by surgical specialty. For inpatient episodes, we determined component payments related to the index hospitalization, readmissions, physician services, and postacute care. For outpatient episodes, we differentiated by the site of care (hospital outpatient department versus physician office versus ambulatory surgery center). We used linear regression to evaluate temporal trends in inpatient and outpatient surgical spending. Finally, we estimated the contribution of surgical care to overall Medicare expenditures. RESULTS: Total Medicare payments for surgical care are substantial, representing 51% of Program spending in 2014. They declined modestly over the study period, from $133.1 billion in 2008 to $124.9 billion in 2014 (-6.2%, P = 0.085 for the temporal trend). While spending on inpatient surgery contributed the most to total surgical payments (69.4% in 2014), it declined over the study period, driven by decreases in index hospitalization (-16.7%, P = 0.002) and readmissions payments (-27.0%, P = 0.003). In contrast, spending on outpatient surgery increased by $8.5 billion (28.7%, P < 0.001). This increase was realized across all sites of care (hospital outpatient department: 36.6%, P < 0.001; physician office: 22.1%, P < 0.001; ambulatory surgery center: 36.6%, P < 0.001). Ophthalmology and hand surgery witnessed the greatest growth in surgical spending over the study period. CONCLUSIONS AND RELEVANCE: Surgical care accounts for half of all Medicare spending. Our findings not only highlight the magnitude of spending on surgery, but also the areas of greatest growth, which could be targeted by future payment reforms.

Low-Value Care and Clinician Engagement in a Large Medicare Shared Savings Program ACO: a Survey of Frontline Clinicians.

BACKGROUND: Although the Medicare Shared Savings Program (MSSP) created new incentives for organizations to improve healthcare value, Accountable Care Organizations (ACOs) have achieved only modest reductions in the use of low-value care. OBJECTIVE: To assess ACO engagement of clinicians and whether engagement was associated with clinicians' reported difficulty implementing recommendations against low-value care. DESIGN: Cross-sectional survey of ACO clinicians in 2018. PARTICIPANTS: 1289 clinicians in the Physician Organization of Michigan ACO, including generalist physicians (18%), internal medicine specialists (16%), surgeons (10%), other physician specialists (27%), and advanced practice providers (29%). Response rate was 34%. MAIN MEASURES: Primary exposures included clinicians' participation in ACO decision-making, awareness of ACO incentives, perceived influence on practice, and perceived quality improvement. Our primary outcome was clinicians' reported difficulty implementing recommendations against low-value care. RESULTS: Few clinicians participated in the decision to join the ACO (3%). Few clinicians were aware of ACO incentives, including knowing the ACO was accountable for both spending and quality (23%), successfully lowered spending (9%), or faced upside risk only (3%). Few agreed (moderately or strongly) the ACO changed compensation (20%), practice (19%), or feedback (15%) or that it improved care coordination (17%) or inappropriate care (13%). Clinicians reported they had difficulty following recommendations against low-value care 18% of the time; clinicians reported patients had difficulty accepting recommendations 36% of the time. Increased ACO awareness (1 standard deviation [SD]) was associated with decreased difficulty (- 2.3 percentage points) implementing recommendations (95% confidence interval [CI] - 3.8, - 0.7), as was perceived quality improvement (1 SD increase, - 2.1 percentage points, 95% CI, - 3.4, - 0.8). Participation in ACO decision-making and perceived influence on practice were not associated with recommendation implementation. CONCLUSIONS: Clinicians participating in a large Medicare ACO were broadly unaware of and unengaged with ACO objectives and activities. Whether low clinician engagement limits ACO efforts to reduce low-value care warrants further longitudinal study.

Mechanisms of decision-making in preoperative assessment for older adult prostate cancer patients-A qualitative study.

BACKGROUND AND OBJECTIVE: Little research exists which investigates the contextual factors and hidden influences that inform surgeons and surgical teams decision-making in preoperative assessment when deciding whether to or not to operate on older adult prostate cancer patients living with aging-associated functional declines and illnesses. The aim of this study is to identify and examine the underlying mechanisms that uniquely shape preoperative surgical decision-making strategies concerning older adult prostate cancer patients. METHODS: Qualitative methodologies were used that paired ethnographic field observations with semistructured interviews for data collection. An inductive thematic analysis approach was used to identify, analyze, and describe patterns in the data. RESULTS: Factors underlining surgical decision-making originated from the context of two categories: (1) clinical and surgery-specific factors; and (2) non-patient factors. Thematic subcategories included personal experiences, methods of assessment during medical encounters, anticipation of outcomes, perceptions of preoperative assessment instruments for frailty and multimorbidity, routines and workflow patterns, microcultures, and indirect observation and second-hand knowledge. CONCLUSION: Surgeon's personal experiences has a significant impact on the decision-making processes during preoperative assessments. However, non-patient factors such as institutional microcultures passively and actively influence decision-making process during preoperative assessment.

Infection-related hospitalization following ureteroscopic stone treatment: results from a surgical collaborative.

BACKGROUND: Unplanned hospitalization following ureteroscopy (URS) for urinary stone disease is associated with patient morbidity and increased healthcare costs. To this effect, AUA guidelines recommend at least a urinalysis in patients prior to URS. We examined risk factors for infection-related hospitalization following URS for urinary stones in a surgical collaborative. METHODS: Reducing Operative Complications from Kidney Stones (ROCKS) is a quality improvement (QI) initiative from the Michigan Urological Surgery Improvement Collaborative (MUSIC) consisting of academic and community practices in the State of Michigan. Trained abstractors prospectively record standardized data elements from the health record in a web-based registry including patient characteristics, surgical details and complications. Using the ROCKS registry, we identified all patients undergoing primary URS for urinary stones between June 2016 and October 2017, and determined the proportion hospitalized within 30 days with an infection-related complication. These patients underwent chart review to obtain clinical data related to the hospitalization. Multivariable logistic regression analysis was performed to determine risk factors for hospitalization. RESULTS: 1817 URS procedures from 11 practices were analyzed. 43 (2.4%) patients were hospitalized with an infection-related complication, and the mortality rate was 0.2%. Median time to admission and length of stay was 4 and 3 days, respectively. Nine (20.9%) patients did not have a pre-procedure urinalysis or urine culture, which was not different in the non-hospitalized cohort (20.5%). In hospitalized patients, pathogens included gram-negative (61.5%), gram-positive (19.2%), yeast (15.4%), and mixed (3.8%) organisms. Significant factors associated with infection-related hospitalization included higher Charlson comorbidity index, history of recurrent UTI, stone size, intra-operative complication, and procedures where fragments were left in-situ. CONCLUSIONS: One in 40 patients are hospitalized with an infection-related complication following URS. Awareness of risk factors may allow for individualized counselling and management to reduce these events. Approximately 20% of patients did not have a pre-operative urine analysis or culture, and these findings demonstrate the need for further study to improve urine testing and compliance.

Performance in the Medicare Shared Savings Program After Accounting for Nonrandom Exit: An Instrumental Variable Analysis.

Background: Accountable care organizations (ACOs) in the Medicare Shared Savings Program (MSSP) are associated with modest savings. However, prior research may overstate this effect if high-cost clinicians exit ACOs. Objective: To evaluate the effect of the MSSP on spending and quality while accounting for clinicians' nonrandom exit. Design: Similar to prior MSSP analyses, this study compared MSSP ACO participants versus control beneficiaries using adjusted longitudinal models that accounted for secular trends, market factors, and beneficiary characteristics. To further account for selection effects, the share of nearby clinicians in the MSSP was used as an instrumental variable. Hip fracture served as a falsification outcome. The authors also tested for compositional changes among MSSP participants. Setting: Fee-for-service Medicare, 2008 through 2014. Patients: A 20% sample (97 204 192 beneficiary-quarters). Measurements: Total spending, 4 quality indicators, and hospitalization for hip fracture. Results: In adjusted longitudinal models, the MSSP was associated with spending reductions (change, -$118 [95% CI, -$151 to -$85] per beneficiary-quarter) and improvements in all 4 quality indicators. In instrumental variable models, the MSSP was not associated with spending (change, $5 [CI, -$51 to $62] per beneficiary-quarter) or quality. In falsification tests, the MSSP was associated with hip fracture in the adjusted model (-0.24 hospitalizations for hip fracture [CI, -0.32 to -0.16 hospitalizations] per 1000 beneficiary-quarters) but not in the instrumental variable model (0.05 hospitalizations [CI, -0.10 to 0.20 hospitalizations] per 1000 beneficiary-quarters). Compositional changes were driven by high-cost clinicians exiting ACOs: High-cost clinicians (99th percentile) had a 30.4% chance of exiting the MSSP, compared with a 13.8% chance among median-cost clinicians (50th percentile). Limitation: The study used an observational design and administrative data. Conclusion: After adjustment for clinicians' nonrandom exit, the MSSP was not associated with improvements in spending or quality. Selection effects-including exit of high-cost clinicians-may drive estimates of savings in the MSSP. Primary Funding Source: Horowitz Foundation for Social Policy, Agency for Healthcare Research and Quality, and National Institute on Aging.

Making 'Chemical Cocktails' - Evolution of Urban Geochemical Processes across the Periodic Table of Elements.

Urbanization contributes to the formation of novel elemental combinations and signatures in terrestrial and aquatic watersheds, also known as 'chemical cocktails.' The composition of chemical cocktails evolves across space and time due to: (1) elevated concentrations from anthropogenic sources, (2) accelerated weathering and corrosion of the built environment, (3) increased drainage density and intensification of urban water conveyance systems, and (4) enhanced rates of geochemical transformations due to changes in temperature, ionic strength, pH, and redox potentials. Characterizing chemical cocktails and underlying geochemical processes is necessary for: (1) tracking pollution sources using complex chemical mixtures instead of individual elements or compounds; (2) developing new strategies for co-managing groups of contaminants; (3) identifying proxies for predicting transport of chemical mixtures using continuous sensor data; and (4) determining whether interactive effects of chemical cocktails produce ecosystem-scale impacts greater than the sum of individual chemical stressors. First, we discuss some unique urban geochemical processes which form chemical cocktails, such as urban soil formation, human-accelerated weathering, urban acidification-alkalinization, and freshwater salinization syndrome. Second, we review and synthesize global patterns in concentrations of major ions, carbon and nutrients, and trace elements in urban streams across different world regions and make comparisons with reference conditions. In addition to our global analysis, we highlight examples from some watersheds in the Baltimore-Washington DC region, which show increased transport of major ions, trace metals, and nutrients across streams draining a well-defined land-use gradient. Urbanization increased the concentrations of multiple major and trace elements in streams draining human-dominated watersheds compared to reference conditions. Chemical cocktails of major and trace elements were formed over diurnal cycles coinciding with changes in streamflow, dissolved oxygen, pH, and other variables measured by high-frequency sensors. Some chemical cocktails of major and trace elements were also significantly related to specific conductance (p<0.05), which can be measured by sensors. Concentrations of major and trace elements increased, peaked, or decreased longitudinally along streams as watershed urbanization increased, which is consistent with distinct shifts in chemical mixtures upstream and downstream of other major cities in the world. Our global analysis of urban streams shows that concentrations of multiple elements along the Periodic Table significantly increase when compared with reference conditions. Furthermore, similar biogeochemical patterns and processes can be grouped among distinct mixtures of elements of major ions, dissolved organic matter, nutrients, and trace elements as chemical cocktails. Chemical cocktails form in urban waters over diurnal cycles, decades, and throughout drainage basins. We conclude our global review and synthesis by proposing strategies for monitoring and managing chemical cocktails using source control, ecosystem restoration, and green infrastructure. We discuss future research directions applying the watershed chemical cocktail approach to diagnose and manage environmental problems. Ultimately, a chemical cocktail approach targeting sources, transport, and transformations of different and distinct elemental combinations is necessary to more holistically monitor and manage the emerging impacts of chemical mixtures in the world's fresh waters.

Association Between Hospital Participation in Medicare Shared Savings Program Accountable Care Organizations and Readmission Following Major Surgery.

OBJECTIVE: To evaluate the effect of Medicare Shared Savings Program accountable care organizations (ACOs) on hospital readmission after common surgical procedures. SUMMARY BACKGROUND DATA: Hospital readmissions following surgery lead to worse patient outcomes and wasteful spending. ACOs, and their associated hospitals, have strong incentives to reduce readmissions from 2 distinct Centers for Medicare and Medicaid Services policies. METHODS: We performed a retrospective cohort study using a 20% national Medicare sample to identify beneficiaries undergoing 1 of 7 common surgical procedures-abdominal aortic aneurysm repair, colectomy, cystectomy, prostatectomy, lung resection, total knee arthroplasty, and total hip arthroplasty-between 2010 and 2014. The primary outcome was 30-day risk-adjusted readmission rate. We performed difference-in-differences analyses using multilevel logistic regression models to quantify the effect of hospital ACO affiliation on readmissions following these procedures. RESULTS: Patients underwent a procedure at one of 2974 hospitals, of which 389 were ACO affiliated. The 30-day risk-adjusted readmission rate decreased from 8.4% (95% CI, 8.1-8.7%) to 7.0% (95% CI, 6.7-7.3%) for ACO affiliated hospitals (P < 0.001) and from 7.9% (95% CI, 7.8-8.0%) to 7.1% (95% CI, 6.9-7.2%) for non-ACO hospitals (P < 0.001). The difference-in-differences of the 2 trends demonstrated an additional 0.52% (95% CI, 0.97-0.078%) absolute reduction in readmissions at ACO hospitals (P = 0.021), which would translate to 4410 hospitalizations avoided. CONCLUSION: Readmissions following common procedures decreased significantly from 2010 to 2014. Hospital affiliation with Shared Savings ACOs was associated with significant additional reductions in readmissions. This emphasis on readmission reduction is 1 mechanism through which ACOs improve value in a surgical population.

Impact of the Image Gently® Campaign on Computerized Tomography Use for Evaluation of Pediatric Nephrolithiasis.

PURPOSE: The Image Gently® campaign was launched by several radiological societies in 2007 to promote safe imaging in children. A goal of the campaign was to reduce ionizing radiation exposure in children. Given the recurrent nature of kidney stones, affected children are at risk for unnecessary ionizing radiation exposure from computerized tomography. We sought to determine whether the Image Gently campaign led to a decrease in the use of computerized tomography for evaluating children with nephrolithiasis. We hypothesized that the campaign was the primary cause of a reduction in the use of computerized tomography. MATERIALS AND METHODS: We analyzed medical claims data from 2001 to 2015 identifying children with nephrolithiasis covered by the same commercial insurance provider. Using a difference in differences design, we estimated changes in computerized tomography use after the campaign started among patients less than 18 years old compared to a control group age 18 years or older with nephrolithiasis. RESULTS: We identified 12,734 children and 787,720 adults diagnosed with nephrolithiasis. Before 2007 quarterly rates of computerized tomography use during a stone episode (per 1,000 patients) were increasing at a parallel rate in children and adults (5.1 in children vs 7.2 in adults, p = 0.123). After the Image Gently campaign started the use of computerized tomography decreased in both groups but at a slightly higher rate in adults (difference in differences 2.96, 95% CI 0.00 to 5.91, p = 0.050). CONCLUSIONS: Although there has been a reduction in the use of computerized tomography among children with nephrolithiasis, given a similar trend seen in adults this change cannot be primarily attributed to the Image Gently campaign.

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.

Physician Participation in Medicare Accountable Care Organizations and Spillovers in Commercial Spending.

IMPORTANCE: The benefits of public payment policy may extend to private populations through "spillover" effects. If cost-saving efforts in Medicare also reduce costs among commercially insured patients, Medicare payment systems could be a versatile policy tool in future reform efforts. OBJECTIVES: To determine whether physicians who participated in a Medicare Accountable Care Organization (ACO) reduced spending among their commercial patients. DESIGN: This was a retrospective, longitudinal study which was conducted using Blue Cross Blue Shield of Michigan (BCBSM) claims data from 2010 to 2015. We compared patients seen by physicians who participated in a Medicare ACO to patients whose physicians were not part of an ACO. We used a difference-in-differences (DIDs) design to test whether physician participation in an ACO was associated with reduced spending among their commercially insured patients. We also tested for heterogeneous effects: we assessed whether spillovers were larger among patients with clinical conditions (acute myocardial infarction, pneumonia, congestive heart failure) that have previously been targeted by Medicare payment programs. SETTING: This was a population-based study of commercially insured patients in Michigan. PARTICIPANTS: Patients who experienced a significant clinical episode (eg, labor and delivery, acute myocardial infarction) between 2010 and 2015. EXPOSURE: Our patient-level exposure is treatment by a Medicare ACO-affiliated physician. MAIN OUTCOMES AND MEASURES: Medical spending of 0-90 days and 91-365 days after a clinical episode. RESULTS: Patients in the exposure group (n=54,750) and in the control group (n=137,883) were similar in demographic characteristics of age, sex, and type of clinical episodes. Adjusted mean 90-day spending in the preexposure period was $21,292 among the exposure group and $21,157 among the comparison group; these means declined to $21,250 and $20,995 in the postperiod, yielding a DIDs estimate of $119 [95% confidence interval (CI), -$170 to $408]. Adjusted means for 91-365 days spending in the preperiod were $4258 among the exposure group and $4251 among the comparison group; these means rose to $4338 and $4421 in the postperiod, yielding a DIDs estimate of -$90 (95% CI, -$312 to $132). We also separately examined patients with conditions that have been targeted by other Medicare payment programs. Among these patients, 90-day spending did not differ between exposure and comparison groups (DIDs, -$223; 95% CI, -$2037 to $1591), although 91-365 days spending decreased among the exposure group with marginal statistical significance (DIDs, -$1160; 95% CI, -$2459 to $140). CONCLUSIONS AND RELEVANCE: Physicians who participated in Medicare ACOs did not reduce spending among most of their commercially insured patients. Medicare policy is unlikely to confer significant spillover benefits to the commercially insured population.