Including socioeconomic status reduces readmission penalties to safety-net hospitals.

OBJECTIVE: Medicare's Hospital Readmissions Reduction Program (HRRP) financially penalizes "excessive" postoperative readmissions. Concerned with creating a double standard for institutions treating a high percentage of economically vulnerable patients, Medicare elected to exclude socioeconomic status (SES) from its risk-adjustment model. However, recent evidence suggests that safety-net hospitals (SNHs) caring for many low-SES patients are disproportionately penalized under the HRRP. We sought to simulate the impact of including SES-sensitive models on HRRP penalties for hospitals performing lower extremity revascularization (LER). METHODS: This is a retrospective, cross-sectional analysis of national data on Medicare patients undergoing open or endovascular LER procedures between 2007 and 2009. We used hierarchical logistic regression to generate hospital risk-standardized 30-day readmission rates under Medicare's current model (adjusting for age, sex, comorbidities, and procedure type) compared with models that also adjust for SES. We estimated the likelihood of a penalty and penalty size for SNHs compared with non-SNHs under the current Medicare model and these SES-sensitive models. RESULTS: Our study population comprised 1708 hospitals performing 284,724 LER operations with an overall unadjusted readmission rate of 14.4% (standard deviation: 5.3%). Compared with the Centers for Medicare and Medicaid Services model, adjusting for SES would not change the proportion of SNHs penalized for excess readmissions (55.1% vs 53.4%, P = .101) but would reduce penalty amounts for 38% of SNHs compared with only 17% of non-SNHs, P < .001. CONCLUSIONS: For LER, changing national Medicare policy to including SES in readmission risk-adjustment models would reduce penalty amounts to SNHs, especially for those that are also teaching institutions. Making further strides toward reducing the national disparity between SNHs and non-SHNs on readmissions, performance measures require strategies beyond simply altering the risk-adjustment model to include SES.

Understanding and finding opportunities for inclusive mentorship and sponsorships in vascular surgery.

Deliberate efforts are needed to address the lack of diversity in the vascular surgery workforce and to correct the current scarcity of diversity in vascular surgery leadership. Effective mentorship and sponsorship are crucial for success in academic surgery. In the present report, we have explained the importance of mentorship and sponsorship relationships for surgeons historically underrepresented in medicine, discussed the unique challenges faced by them in academic surgery, and provided a practical framework for fostering intentional and thoughtful mentor and sponsor relationships to nurture their careers.

Biodiversity as insurance: from concept to measurement and application.

Biological insurance theory predicts that, in a variable environment, aggregate ecosystem properties will vary less in more diverse communities because declines in the performance or abundance of some species or phenotypes will be offset, at least partly, by smoother declines or increases in others. During the past two decades, ecology has accumulated strong evidence for the stabilising effect of biodiversity on ecosystem functioning. As biological insurance is reaching the stage of a mature theory, it is critical to revisit and clarify its conceptual foundations to guide future developments, applications and measurements. In this review, we first clarify the connections between the insurance and portfolio concepts that have been used in ecology and the economic concepts that inspired them. Doing so points to gaps and mismatches between ecology and economics that could be filled profitably by new theoretical developments and new management applications. Second, we discuss some fundamental issues in biological insurance theory that have remained unnoticed so far and that emerge from some of its recent applications. In particular, we draw a clear distinction between the two effects embedded in biological insurance theory, i.e. the effects of biodiversity on the mean and variability of ecosystem properties. This distinction allows explicit consideration of trade-offs between the mean and stability of ecosystem processes and services. We also review applications of biological insurance theory in ecosystem management. Finally, we provide a synthetic conceptual framework that unifies the various approaches across disciplines, and we suggest new ways in which biological insurance theory could be extended to address new issues in ecology and ecosystem management. Exciting future challenges include linking the effects of biodiversity on ecosystem functioning and stability, incorporating multiple functions and feedbacks, developing new approaches to partition biodiversity effects across scales, extending biological insurance theory to complex interaction networks, and developing new applications to biodiversity and ecosystem management.

Emergency Department Utilization and Readmissions Following Major Surgery: A Retrospective Study of Medicare Data.

BACKGROUND: Reliable strategies for reducing postoperative readmissions remain elusive. As the emergency department (ED) is a frequent source of post-operative admissions, we investigated whether hospitals with high readmission rates also have high rates of post-discharge ED visits and high rates of readmission once an ED visit occurs. METHODS: We conducted a retrospective analysis of 1,947,621 Medicare beneficiaries undergoing 1 of 5 common procedures in 2,894 hospitals between 2008 and 2011. We stratified hospitals into quintiles based on risk-standardized, 30-day post-discharge readmission rates (RSRR) and then compared rates of post-discharge ED visits, proportion readmitted from the ED, and readmissions within 7 days of ED discharge across these quintiles. RESULTS: RSRR varied widely across extremes of hospital quintiles (3.9% to 17.5%). Hospitals with either very low or very high RSRR had modest differences in rates of ED visits (12.4% versus 14.6%). In contrast, the proportion readmitted from the ED was nearly 3 times greater in Hospitals with very high RSRR compared with those with very low RSRR (12% versus 32.2%). These findings were consistent across all procedures. Importantly, hospitals with a low proportion readmitted from the ED did not exhibit an increased rate of readmission within 7 days of ED discharge. CONCLUSIONS: Although hospitals experience similar rates of ED visits following major surgery, some EDs and their affiliated surgeons and health system may deliver care preventing readmissions without an increased short-term risk of readmission following ED discharge. Reducing 30-day readmissions requires greater attention to the coordination of care delivered in the ED.

Managing central venous access during a health care crisis.

OBJECTIVE: During the COVID-19 pandemic, central venous access line teams were implemented at many hospitals throughout the world to provide access for critically ill patients. The objective of this study was to describe the structure, practice patterns, and outcomes of these vascular access teams during the COVID-19 pandemic. METHODS: We conducted a cross-sectional, self-reported study of central venous access line teams in hospitals afflicted with the COVID-19 pandemic. To participate in the study, hospitals were required to meet one of the following criteria: development of a formal plan for a central venous access line team during the pandemic; implementation of a central venous access line team during the pandemic; placement of central venous access by a designated practice group during the pandemic as part of routine clinical practice; or management of an iatrogenic complication related to central venous access in a patient with COVID-19. RESULTS: Participants from 60 hospitals in 13 countries contributed data to the study. Central venous line teams were most commonly composed of vascular surgery and general surgery attending physicians and trainees. Twenty sites had 2657 lines placed by their central venous access line team or designated practice group. During that time, there were 11 (0.4%) iatrogenic complications associated with central venous access procedures performed by the line team or group at those 20 sites. Triple lumen catheters, Cordis (Santa Clara, Calif) catheters, and nontunneled hemodialysis catheters were the most common types of central venous lines placed by the teams. Eight (14%) sites reported experience in placing central venous lines in prone, ventilated patients with COVID-19. A dedicated line cart was used by 35 (59%) of the hospitals. Less than 50% (24 [41%]) of the participating sites reported managing thrombosed central lines in COVID-19 patients. Twenty-three of the sites managed 48 iatrogenic complications in patients with COVID-19 (including complications caused by providers outside of the line team or designated practice group). CONCLUSIONS: Implementation of a dedicated central venous access line team during a pandemic or other health care crisis is a way by which physicians trained in central venous access can contribute their expertise to a stressed health care system. A line team composed of physicians with vascular skill sets provides relief to resource-constrained intensive care unit, ward, and emergency medicine teams with a low rate of iatrogenic complications relative to historical reports. We recommend that a plan for central venous access line team implementation be in place for future health care crises.

Examining variation in Medicare payments and drivers of cost for carotid endarterectomy.

BACKGROUND: There is a growing interest in providing high quality and low-cost care to Americans. A pursuit exists to measure not only how well hospitals are performing but also at what cost. We examined the variation in costs associated with carotid endarterectomy (CEA), to determine which components contribute to the variation and what drives increased payments. MATERIALS AND METHODS: Patients undergoing CEA between 2009 and 2012 were identified in the Medicare provider and analysis review database. Hospital quintiles of cost were generated and variation examined. Multivariable logistic regression was performed to identify independent predictors of high-payment hospitals for both asymptomatic and symptomatic patients undergoing CEA. RESULTS: A total of 264,018 CEAs were performed between 2009 and 2012; 250,317 were performed in asymptomatic patients in 2302 hospitals and 13,701 in symptomatic patients in 1851 hospitals. Higher payment hospitals had a higher percentage of nonwhite patients and comorbidity burden. The largest contributors to variation in overall payments were diagnosis-related groups, postdischarge, and readmission payments. After accounting for clustering at the hospital level, independent predictors of high-payment hospitals for all patients were postoperative stroke, length of stay, and readmission ,whereas in the symptomatic group, additional drivers included yearly volume and serious complications. CONCLUSIONS: CEA Medicare payments vary nationwide with diagnosis-related group, readmission, and postdischarge payments being the largest contributors to overall payment variation. In addition, stroke, length of stay, and readmission were the only independent predictors of high payment for all patients undergoing CEA.

A National Study Evaluating Hospital Volume and Inpatient Mortality after Open Abdominal Aortic Aneurysm Repair in Vulnerable Populations.

BACKGROUND: There is a large body of evidence documenting better outcomes for abdominal aortic aneurysm (AAA) repairs performed in high-volume centers. However, it remains unknown if the strength of this volume-outcome relationship is moderated by race or socioeconomic status (SES). METHODS: This is a cross-sectional retrospective cohort study evaluating 60,618 Medicare fee-for-service beneficiaries undergoing open AAA repair across 1,649 hospitals between 2005 and 2009. We selected, a priori, black race and low SES as vulnerable populations based on previous reports showing each is independently associated with higher mortality. Next, we divided hospitals into quintiles of procedural volume and used logistic regression to compare risk-adjusted rates of inpatient mortality across volume quintiles for the overall study population and separately by race (black versus nonblack) and SES (low, middle, and high). RESULTS: Overall, patients treated in the lowest-volume hospitals (LVHs) had higher risk-adjusted inpatient mortality rates than patients treated in the highest-volume hospitals (HVHs) (15.3% vs. 10.6%, P < 0.001). Higher mortality was associated with black versus nonblack race (12.9% vs. 11.7%, P < 0.001) and low SES versus high SES (12.2% vs. 11.6% P < 0.001). While nonblack patients treated in LVHs had higher odds of mortality (versus HVHs, adjusted odds ratio (aOR) 1.83 [1.59-2.11]), this volume-outcome effect was greater for black patients (aOR 2.60 [1.63-4.16]). In contrast, high and low SES patients experienced similar differences in mortality when treated in LVHs (aOR 1.79 [1.49-2.12]; aOR 1.72 [1.28-2.30], respectively). CONCLUSIONS: While a volume-outcome effect was observed in all patients, black patients appeared to derive a disproportionate benefit from undergoing open AAA repair in HVHs. The mechanism underlying these disparate outcomes remains unclear but warrants further evaluation of contributing hospital and patient factors.

Indication for Lower Extremity Revascularization and Hospital Profiling of Readmissions.

BACKGROUND: Surgical readmissions are common, costly, and the focus of national quality improvement efforts. Given the relatively high readmission rates among vascular patients, pay-for-performance initiatives such as Medicare's Hospital Readmissions Reduction Program (HRRP) have targeted vascular surgery for increased scrutiny in the near future. Yet, the extent to which institutional case mix influences hospital profiling remains unexplored. We sought to evaluate whether higher readmission rates in vascular surgery are a reflection of worse performance or of treating sicker patients. METHODS: This retrospective observational cohort study of the national Medicare population includes 479,047 beneficiaries undergoing lower extremity revascularization (LER) in 1,701 hospitals from 2005 to 2009. We employed hierarchical logistic regression to mimic Center for Medicare and Medicaid Services methodology accounting for age, gender, preexisting comorbidities, and differences in hospital operative volume. We estimated 30-day risk-standardized readmission rates (RSRR) for each hospital when including (1) all LER patients; (2) claudicants; or (3) high-risk patients (rest pain, ulceration, or tissue loss). We stratified hospitals into quintiles based on overall RSRR for all LERs and examined differences in RSRR for claudicants and high-risk patients between and within quintiles. Next, we evaluated differences in case mix (the proportion of claudicants and high-risk patients treated) across quintiles. Finally, we simulated differences in the receipt of penalties before and after adjusting for hospital case mix. RESULTS: Readmission rates varied widely by indication: 7.3% (claudicants) vs. 19.5% (high risk). Even after adjusting for patient demographics, length of stay, and discharge destination, high-risk patients were significantly more likely to be readmitted (odds ratio 1.76, 95% confidence interval 1.71-1.81). The Best hospitals (top quintile) under the HRRP treated a much lower proportion of high-risk patients compared with the Worst hospitals (bottom quintile) (20% vs. 56%, P < 0.001). In the absence of case-mix adjustment, we observed a stepwise increase in the proportion of hospitals penalized as the proportion of high-risk patients treated increased (35-60%, P < 0.001). However, after case-mix adjustment, there were no differences between quintiles in the proportion of hospitalized penalized (50-46%, P = 0.30). CONCLUSION: Our findings suggest that the differences in readmission rates following LER are largely driven by hospital case mix rather than true differences in quality.

Effect of Index Hospitalization Costs on Readmission Among Patients Undergoing Major Abdominal Surgery.

IMPORTANCE: Reduction of postoperative readmissions has been identified as an opportunity for containment of health care costs. To date, the effect of index hospitalization costs on subsequent readmissions, however, has not been examined. OBJECTIVES: To identify the effect of index admission costs on readmission rates and to quantify any potential variation in costs and readmission attributable to the patient, procedure, and surgeon. DESIGN, SETTING, AND PARTICIPANTS: Retrospective analysis of the medical records of 4114 patients who underwent a colorectal, pancreatic, or hepatic resection from January 1, 2009, to December 31, 2013, at a tertiary care hospital. Readmission was defined as a second hospitalization within 30 days of discharge from the index hospitalization. Final follow-up was completed on April 24, 2014, and data were analyzed from July 1 to August 1, 2015. MAIN OUTCOMES AND MEASURES: Total inpatient costs of the index hospitalization and readmission rates. RESULTS: Among 4114 patients who met inclusion criteria (2122 women [51.6%] and 1992 men [48.4%]; median [interquartile range (IQR)] age, 59 [49-69] years), 1760 (42.8%) underwent colorectal resection; 1660 (40.4%), pancreatic resection; and 694 (16.9%), hepatic resection. Seven hundred seven patients were readmitted within 30 days (unadjusted readmission rate, 17.2%), including 328 patients (18.6%) for colorectal procedures, 309 patients (18.6%) for pancreatic procedures, and 70 patients (10.1%) for hepatic procedures (P < .001). The median cost of surgery during the index hospitalization was $24 992 and varied by procedure (colorectal, $22 186; pancreatic, $29 175; hepatic, $22 757; P < .001). The median index length of stay was 7 (IQR, 5-11) days and was higher among patients who were eventually readmitted (8 [IQR, 6-13] vs 7 [IQR, 5-11] days; P < .001). Readmitted patients had a higher incidence of perioperative morbidity during the index hospitalization (169 of 707 [23.9%] vs 662 of 3407 [19.4%]; P = .007). On adjusted analysis, an independent association with a higher risk for readmission was found for African American patients (odds ratio [OR], 1.45; 95% CI, 1.17-1.81), those undergoing pancreatic (OR, 1.99; 95% CI, 1.50-2.63) or colorectal (OR, 1.93; 95% CI, 1.46-2.55) resection, and patients with an observed-to-expected index length of stay of greater than 1 (OR, 1.26; 95% CI, 1.05-1.54) (P ≤ .001 for all). Total index hospitalization costs were higher among patients who were readmitted ($21 312 vs $24 321; P < .001). Further, among patients without a complication during the index hospitalization, total costs remained higher among patients who were eventually readmitted ($26 799 vs $22 462; P < .001). At the surgeon level, readmission rates varied among surgeons performing the same procedure (0%-33% among colorectal surgeons, 13%-38%% among pancreatic surgeons, and 8%-33% among hepatic surgeons; P < .001). Similarly, substantial variation in index hospitalization costs was also observed among surgeons performing the same procedure (coefficient of variation, 118.4% for colorectal, 89.0% for pancreatic, and 85.0% for hepatic). CONCLUSIONS AND RELEVANCE: Thirty-day readmission rates among patients undergoing major abdominal surgery vary significantly. Higher index hospitalization costs did not translate into lower readmission rates.

Hospital Ownership of a Postacute Care Facility Influences Discharge Destinations After Emergent Surgery.

OBJECTIVE: The aim of the study was to identify hospital characteristics associated with variation in patient disposition after emergent surgery. SUMMARY BACKGROUND DATA: Colon resections in elderly patients are often done in emergent settings. Although these operations are known to be riskier, there are limited data regarding postoperative discharge destination. METHODS: We evaluated Medicare beneficiaries who underwent emergent colectomy between 2008 and 2010. Using hierarchical logistic regression, we estimated patient and hospital-level risk-adjusted rates of nonhome discharges. Hospitals were stratified into quintiles based on their nonhome discharge rates. Generalized linear models were used to identify hospital structural characteristics associated with nonhome discharges (comparing discharge to skilled nursing facilities vs home with/without home health services). RESULTS: Of the 122,604 patients surviving to discharge after emergent colectomy at 3012 hospitals, 46.7% were discharged to a nonhome destination. There was a wide variation in risk and reliability-adjusted nonhome discharge rates across hospitals (15% to 80%). Patients at hospitals in the highest quintile of nonhome discharge rates were more likely to have longer hospitalizations (15.1 vs 13.2; P < 0.001) and more complications (43.2% vs 34%; P < 0.001). On multivariable analysis, only hospital ownership of a skilled nursing facility (P < 0.001), teaching status (P = 0.025), and low nurse-to-patient ratios (P = 0.002) were associated with nonhome discharges. CONCLUSIONS: Nearly half of Medicare beneficiaries are discharged to a nonhome destination after emergent colectomy. Hospital ownership of a skilled nursing facility and low nurse-to-patient ratios are highly associated with nonhome discharges. This may signify the underlying financial incentives to preferentially utilize postacute care facilities under the traditional fee-for-service payment model.

Evaluating hospital quality for vascular surgery.

Increasingly, there is a wealth of data available to aid patients in determining where to seek care for quality vascular disease. At times, these data may be difficult for the public to comprehend. Hospital rating organizations, frequently motivated by profit, are marketing directly to consumers with increasingly granular data. In this report, we examine the most popular ratings for hospitals that perform vascular surgical procedures and describe the methodology of each rating system, as well as the validity of the data underscoring these ratings. Understanding how hospital quality is being evaluated and what outcomes measures are being collated allows vascular surgeons to take appropriate actions to ensure the validity of their own hospital ratings.

Predicting the outcome of competition when fitness inequality is variable.

Traditional niche theory predicts that when species compete for one limiting resource in simple ecological settings the more fit competitor should exclude the less fit competitor. Since the advent of neutral theory ecologists have increasingly become interested both in how the magnitude of fitness inequality between competitors and stochasticity may affect this prediction. We used numerical simulations to investigate the outcome of two-species resource competition along gradients of fitness inequality (inequality in R*) and initial population size in the presence of demographic stochasticity. We found that the deterministic prediction of more fit competitors excluding less fit competitors was often unobserved when fitness inequalities were low or stochasticity was strong, and unexpected outcomes such as dominance by the less fit competitor, long-term co-persistence of both competitors or the extinction of both competitors could be common. By examining the interaction between fitness inequality and stochasticity our results mark the range of parameter space in which the predictions of niche theory break down most severely, and suggest that questions about whether competitive dynamics are driven by neutral or niche processes may be locally contingent.

Time-to-readmission and Mortality After High-risk Surgery.

OBJECTIVES: To determine if mortality varies by time-to-readmission (TTR). BACKGROUND: Although readmissions reduction is a national health care priority, little progress has been made toward understanding why only some readmissions lead to adverse outcomes. METHODS: In this retrospective cross-sectional cohort analysis, we used 2005-2009 Medicare data on beneficiaries undergoing colectomy, lung resection, or coronary artery bypass grafting (n = 1,033,255) to created 5 TTR groups: no 30-day readmission (n = 897,510), less than 6 days (n = 44,361), 6 to 10 days (n = 31,018), 11 to 15 days (n = 20,797), 16 to 20 days (n = 15,483), or more than 21 days (n = 24,086). Our analyses evaluated TTR groups for differences in risk-adjusted mortality (30, 60, and 90 days) and complications during the index admission. RESULTS: Increasing TTR was associated with a stepwise decline in mortality. For example, 90-day mortality rates in patients readmitted between 1 and 5 days, 6 and 10 days, and 11 and 15 days were 12.6%, 11.4%, and 10.4%, respectively (P < 0.001). Compared to nonreadmitted patients, the adjusted odds ratios (and 95% confidence intervals) were 4.88 (4.72-5.05), 4.20 (4.03-4.37), and 3.81 (3.63-3.99), respectively. Similar patterns were observed for 30- and 60-day mortality. There were no sizable differences in complication rates for patients readmitted within 5 days versus after 21 days (24.8% vs 26.2%, P < 0.001). CONCLUSIONS: Surgical readmissions within 10 days of discharge are disproportionately common and associated with increased mortality independent of index complications. These findings suggest 10-day readmissions should be specially targeted by quality improvement efforts.

Medicare's Hospital Readmissions Reduction Program in Surgery May Disproportionately Affect Minority-serving Hospitals.

OBJECTIVE: To project readmission penalties for hospitals performing cardiac surgery and examine how these penalties will affect minority-serving hospitals. BACKGROUND: The Hospital Readmissions Reduction Program will potentially expand penalties for higher-than-predicted readmission rates to cardiac procedures in the near future. The impact of these penalties on minority-serving hospitals is unknown. METHODS: We examined national Medicare beneficiaries undergoing coronary artery bypass grafting in 2008 to 2010 (N = 255,250 patients, 1186 hospitals). Using hierarchical logistic regression, we calculated hospital observed-to-expected readmission ratios. Hospital penalties were projected according to the Hospital Readmissions Reduction Program formula using only coronary artery bypass grafting readmissions with a 3% maximum penalty of total Medicare revenue. Hospitals were classified into quintiles according to proportion of black patients treated. Minority-serving hospitals were defined as hospitals in the top quintile whereas non-minority-serving hospitals were those in the bottom quintile. Projected readmission penalties were compared across quintiles. RESULTS: Forty-seven percent of hospitals (559 of 1186) were projected to be assessed a penalty. Twenty-eight percent of hospitals (330 of 1186) would be penalized less than 1% of total Medicare revenue whereas 5% of hospitals (55 of 1186) would receive the maximum 3% penalty. Minority-serving hospitals were almost twice as likely to be penalized than non-minority-serving hospitals (61% vs 32%) and were projected almost triple the reductions in reimbursement ($112 million vs $41 million). CONCLUSIONS: Minority-serving hospitals would disproportionately bear the burden of readmission penalties if expanded to include cardiac surgery. Given these hospitals' narrow profit margins, readmission penalties may have a profound impact on these hospitals' ability to care for disadvantaged patients.

Using same-hospital readmission rates to estimate all-hospital readmission rates.

BACKGROUND: Since October of 2012, Medicare's Hospital Readmissions Reduction Program has fined 2,200 hospitals a total of $500 million. Although the program penalizes readmission to any hospital, many institutions can only track readmissions to their own hospitals. We sought to determine the extent to which same-hospital readmission rates can be used to estimate all-hospital readmission rates after major surgery. STUDY DESIGN: We evaluated 3,940 hospitals treating 741,656 Medicare fee-for-service beneficiaries undergoing CABG, hip fracture repair, or colectomy between 2006 and 2008. We used hierarchical logistic regression to calculate risk- and reliability-adjusted rates of 30-day readmission to the same hospital and to any hospital. We next evaluated the correlation between same-hospital and all-hospital rates. To analyze the impact on hospital profiling, we compared rankings based on same-hospital rates with those based on all-hospital rates. RESULTS: The mean risk- and reliability-adjusted all-hospital readmission rate was 13.2% (SD 1.5%) and mean same-hospital readmission rate was 8.4% (SD 1.1%). Depending on the operation, between 57% (colectomy) and 63% (CABG) of hospitals were reclassified when profiling was based on same-hospital readmission rates instead of on all-hospital readmission rates. This was particularly pronounced in the middle 3 quintiles, where 66% to 73% of hospitals were reclassified. CONCLUSIONS: In evaluating hospital profiling under Medicare's Hospital Readmissions Reduction Program, same-hospital rates provide unstable estimates of all-hospital readmission rates. To better anticipate penalties, hospitals require novel approaches for accurately tracking the totality of their postoperative readmissions.

Reliability of hospital readmission rates in vascular surgery.

OBJECTIVE: The Center for Medicare and Medicaid Services recently began assessing financial penalties to hospitals with high readmission rates for a narrow set of medical conditions. Because these penalties will be extended to surgical conditions in the near future, we sought to determine whether readmissions are a reliable predictor of hospital performance with vascular surgery. METHODS: We examined 4 years of national Medicare claims data from 1576 hospitals on beneficiaries undergoing three common vascular procedures: open or endovascular abdominal aortic aneurysm repair (n = 81,520) or lower extremity arterial bypass (n = 57,190). First, we divided our population into two groups on the basis of operative date (2005-2006 and 2007-2008) and generated hospital risk- and reliability-adjusted readmission rates for each time period. We evaluated reliability through the use of the "test-retest" method; highly reliable measures will show little variation in rates over time. Specifically, we evaluated the year-to-year reliability of readmissions by calculating Spearman rank correlation and weighted κ tests for readmission rates between the two time periods. RESULTS: The Spearman coefficient between 2005-2006 readmissions rankings and 2007-2008 readmissions rankings was 0.57 (P < .001) and weighted κ was 0.42 (P < .001), indicating a moderate correlation. However, only 32% of the variation in hospital readmission rates in 2007-2008 was explained by readmissions during the 2 prior years. There were major reclassifications of hospital rankings between years, with 63% of hospitals migrating among performance quintiles between 2005-2006 and 2007-2008. CONCLUSIONS: Risk-adjusted readmission rates for vascular surgery vary substantially year to year; this implies that much of the observed variation in readmission rates is either random or caused by unmeasured factors and not caused by changes in hospital quality that may be captured by administrative data.

A cross-national analysis of how economic inequality predicts biodiversity loss.

We used socioeconomic models that included economic inequality to predict biodiversity loss, measured as the proportion of threatened plant and vertebrate species, across 50 countries. Our main goal was to evaluate whether economic inequality, measured as the Gini index of income distribution, improved the explanatory power of our statistical models. We compared four models that included the following: only population density, economic footprint (i.e., the size of the economy relative to the country area), economic footprint and income inequality (Gini index), and an index of environmental governance. We also tested the environmental Kuznets curve hypothesis, but it was not supported by the data. Statistical comparisons of the models revealed that the model including both economic footprint and inequality was the best predictor of threatened species. It significantly outperformed population density alone and the environmental governance model according to the Akaike information criterion. Inequality was a significant predictor of biodiversity loss and significantly improved the fit of our models. These results confirm that socioeconomic inequality is an important factor to consider when predicting rates of anthropogenic biodiversity loss.

Combined residency training in emergency medicine and internal medicine: an update on career outcomes and job satisfaction.

OBJECTIVES: This study was designed to provide an update on the career outcomes and experiences of graduates of combined emergency medicine-internal medicine (EM-IM) residency programs. METHODS: The graduates of the American Board of Emergency Medicine (ABEM) and American Board of Internal Medicine (ABIM)-accredited EM-IM residencies from 1998 to 2008 were contacted and asked to complete a survey concerning demographics, board certification, fellowships completed, practice setting, academic affiliation, and perceptions about EM-IM training and careers. RESULTS: There were 127 respondents of a possible 163 total graduates for a response rate of 78%. Seventy graduates (55%) practice EM only, 47 graduates (37%) practice both EM and IM, and nine graduates (7%) practice IM or an IM subspecialty only. Thirty-one graduates (24%) pursued formal fellowship training in either EM or IM. Graduates spend the majority of their time practicing clinical EM in an urban (72%) and academic (60%) environment. Eighty-seven graduates (69%) spend at least 10% of their time in an academic setting. Most graduates (64%) believe it practical to practice both EM and IM. A total of 112 graduates (88%) would complete EM-IM training again. CONCLUSIONS: Dual training in EM-IM affords a great deal of career opportunities, particularly in academics and clinical practice, in a number of environments. Graduates hold their training in high esteem and would do it again if given the opportunity.

Source-sink dynamics shape the evolution of antibiotic resistance and its pleiotropic fitness cost.

Understanding the conditions that favour the evolution and maintenance of antibiotic resistance is the central goal of epidemiology. A crucial feature explaining the adaptation to harsh, or 'sink', environments is the supply of beneficial mutations via migration from a 'source' population. Given that antibiotic resistance is frequently associated with antagonistic pleiotropic fitness costs, increased migration rate is predicted not only to increase the rate of resistance evolution but also to increase the probability of fixation of resistance mutations with minimal fitness costs. Here we report in vitro experiments using the nosocomial pathogenic bacterium Pseudomonas aeruginosa that support these predictions: increasing rate of migration into environments containing antibiotics increased the rate of resistance evolution and decreased the associated costs of resistance. Consistent with previous theoretical work, we found that resistance evolution arose more rapidly in the presence of a single antibiotic than two. Evolution of resistance was also more rapid when bacteria were subjected to sequential exposure with two antibiotics (cycling therapy) compared with simultaneous exposure (bi-therapy). Furthermore, pleiotropic fitness costs of resistance to two antibiotics were higher than for one antibiotic, and were also higher under bi-therapy than cycling therapy, although the cost of resistance depended on the order of the antibiotics through time. These results may be relevant to the clinical setting where immigration is known to be important between chemotherapeutically treated patients, and demonstrate the importance of ecological and evolutionary dynamics in the control of antibiotic resistance.

Economic inequality predicts biodiversity loss.

Human activity is causing high rates of biodiversity loss. Yet, surprisingly little is known about the extent to which socioeconomic factors exacerbate or ameliorate our impacts on biological diversity. One such factor, economic inequality, has been shown to affect public health, and has been linked to environmental problems in general. We tested how strongly economic inequality is related to biodiversity loss in particular. We found that among countries, and among US states, the number of species that are threatened or declining increases substantially with the Gini ratio of income inequality. At both levels of analysis, the connection between income inequality and biodiversity loss persists after controlling for biophysical conditions, human population size, and per capita GDP or income. Future research should explore potential mechanisms behind this equality-biodiversity relationship. Our results suggest that economic reforms would go hand in hand with, if not serving as a prerequisite for, effective conservation.