Investigating the impact of suboptimal prescription of preoperative antiplatelets and statins on race and ethnicity-related disparities in major limb amputation

BACKGROUND

Non-Hispanic Black and Hispanic patients with symptomatic PAD may receive different treatments than White patients with symptomatic PAD. The delivery of guideline-directed medical treatment may be a modifiable upstream driver of race and ethnicity-related disparities in outcomes such as limb amputation. The purpose of our study was to investigate the prescription of preoperative antiplatelets and statins in producing disparities in the risk of amputation following revascularization for symptomatic peripheral artery disease (PAD).

METHODS

We used data from the Vascular Quality Initiative, a vascular procedure-based registry in the United States (2011-2018). We estimated the probability of preoperative antiplatelet and statin prescriptions and 1-year incidence of amputation. We then estimated the amputation risk difference between race/ethnicity groups that could be eliminated under a hypothetical intervention.

RESULTS

Across 100,579 revascularizations, the 1-year amputation risk was 2.5% (2.4%, 2.6%) in White patients, 5.3% (4.9%, 5.6%) in Black patients, and 5.3% (4.7%, 5.9%) in Hispanic patients. Black (57.5%) and Hispanic patients (58.7%) were only slightly less likely than White patients (60.9%) to receive antiplatelet and statin therapy. However, the effect of antiplatelets and statins was greater in Black and Hispanic patients such that, had all patients received these medications, the estimated risk difference comparing Black to White patients would have reduced by 8.9% (-2.9%, 21.9%) and the risk difference comparing Hispanic to White patients would have been reduced by 17.6% (-0.7%, 38.6%).

CONCLUSION

Even though guideline-directed care appeared evenly distributed by race/ethnicity, increasing access to such care may decrease health care disparities in major limb amputation.

Prevalence of and Risk Factors for Peripheral Artery Disease in Rural South Africa: A Cross-Sectional Analysis of the HAALSI Cohort

BACKGROUND

The burden of peripheral artery disease (PAD) is increasing in low- and middle-income countries. Existing literature from sub-Saharan Africa is limited and lacks population-representative estimates. We estimated the burden and risk factor profile of PAD for a rural South African population.

METHODS AND RESULTS

We used data from 1883 participants from a rural, low-income cohort of South African adults aged 40 to 69 years with available ankle-brachial index measurements. We defined clinical PAD as ankle-brachial index ≤0.90 or >1.40, and borderline PAD as ankle-brachial index >0.90 and ≤1.00. We compared the distribution of sociodemographic variables, biomarkers, and comorbidities across PAD classifications. To identify associated factors, we calculated unadjusted and age-sex-adjusted prevalence ratios (PRs) with log-binomial models. Overall, 6.6% (95% CI, 5.6-7.7) of the sample met the diagnostic criteria for clinical PAD, while 44.7% (95% CI, 42.4-47.0) met the diagnostic criteria for borderline PAD. Age (PR: 1.9 [95% CI, 1.2-3.1] for ages 50-59 years compared with 40-49 years; PR: 2.5 [95% CI, 1.5-4.0] for ages 60-69 years compared with 40-49 years); diagnosed hypertension (PR: 1.53 [95% CI, 1.08-2.17]); and C-reactive protein (PR: 1.08 [95% CI, 1.03-1.12]) were associated with increased prevalence of clinical PAD. All other examined factors were not significantly associated with clinical PAD.

CONCLUSIONS

We found high PAD prevalence for younger age groups compared with previous research and a lack of statistical evidence for the influence of traditional risk factors for this rural, low-income population. Future research should focus on identifying the underlying risk factors for PAD in this setting. South African policymakers and clinicians should consider expanded screening for early PAD detection in rural areas.

Sex differences in outcomes of exercise therapy for patients with intermittent claudication: A scoping review

Exercise therapy is first-line treatment for intermittent claudication due to peripheral artery disease. We sought to synthesize the literature on sex differences in response to exercise therapy for the treatment of intermittent claudication due to peripheral artery disease. A scoping review was performed (1997 to 2023) using Ovid MEDLINE, CINAHL (Cumulative Index to Nursing and Allied Health Literature), Embase, SPORTDiscus, and Web of Science. Articles were included if they were a scientific report of any measures of health-related quality of life or walking performance after an intervention that included a structured walking program. Of the 13 studies, 11 included measures of walking distance; 7 included measures of walking time, 5 included measures of walking speed, and 4 included quality of life measures. Overall, exercise therapy resulted in significant improvements across most measures of walking performance for both men and females. When comparing magnitudes of outcome improvement by sex, results of walking-based measures were contradictory; some studies noted no difference and others found superior outcomes for men. Results of quality of life-based measures were also contradictory, with some finding no difference and others reporting substantially more improvement for females. Both men and females experienced considerable improvement in walking performance and quality of life with exercise therapy. Evidence regarding the differential effect of exercise therapy on outcomes by sex for intermittent claudication is limited and contradictory. Further efforts should be directed at using standardized interventions and metrics for measuring the outcomes that match the indications for intervention in these patients to better understand the expected benefits and any variance according to sex.

Efficacy of Messenger RNA-1273 Against Severe Acute Respiratory Syndrome Coronavirus 2 Acquisition in Young Adults From March to December 2021

Background

The efficacy of messenger RNA (mRNA)-1273 against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is not well defined, particularly among young adults.

Methods

Adults aged 18-29 years with no known history of SARS-CoV-2 infection or prior vaccination for coronavirus disease 2019 (COVID-19) were recruited from 44 US sites from 24 March to 13 September 2021 and randomized 1:1 to immediate vaccination (receipt of 2 doses of mRNA-1273 vaccine at months 0 and 1) or the standard of care (receipt of COVID-19 vaccine). Randomized participants were followed up for SARS-CoV-2 infection measured by nasal swab testing and symptomatic COVID-19 measured by nasal swab testing plus symptom assessment and assessed for the primary efficacy outcome. A vaccine-declined observational group was also recruited from 16 June to 8 November 2021 and followed up for SARS-CoV-2 infection as specified for the randomized participants.

Results

The study enrolled 1149 in the randomized arms and 311 in the vaccine-declined group and collected >122 000 nasal swab samples. Based on randomized participants, the efficacy of 2 doses of mRNA-1273 vaccine against SARS-CoV-2 infection was 52.6% (95% confidence interval, -14.1% to 80.3%), with the majority of infections due to the Delta variant. Vaccine efficacy against symptomatic COVID-19 was 71.0% (95% confidence interval, -9.5% to 92.3%). Precision was limited owing to curtailed study enrollment and off-study vaccination censoring. The incidence of SARS-CoV-2 infection in the vaccine-declined group was 1.8 times higher than in the standard-of-care group.

Conclusions

mRNA-1273 vaccination reduced the incidence of SARS-CoV-2 infection from March to September 2021, but vaccination was only one factor influencing risk.

Clinical Trials Registration

NCT04811664.

Disparities in healthcare utilization by insurance status among patients with symptomatic peripheral artery disease

BACKGROUND

Peripheral artery disease (PAD) is a common circulatory disorder associated with increased hospitalizations and significant health care-related expenditures. Among patients with PAD, insurance status is an important determinant of health care utilization, treatment of disease, and treatment outcomes. However, little is known about PAD-costs differences across different insurance providers. In this study we examined possible disparities in length of stay and total charge of inpatient hospitalizations among patients with PAD by insurance type.

METHODS

We conducted a cross-sectional analysis of length of stay and total charge by insurance provider for all hospitalizations for individuals with PAD in South Carolina (2010-2018). Cross-classified multilevel modeling was applied to account for the non-nested hierarchical structure of the data, with county and hospital included as random effects. Analyses were adjusted for patient age, race/ethnicity, county, year of admission, admission type, all-patient refined diagnostic groups, and Charlson comorbidity index.

RESULTS

Among 385,018 hospitalizations for individuals with PAD in South Carolina, the median length of stay was 4 days (IQR: 5) and the median total charge of hospitalization was $43,232 (IQR: $52,405). Length of stay and total charge varied significantly by insurance provider. Medicare patients had increased length of stay (IRR = 1.08, 95 CI%: 1.07, 1.09) and higher total charges (β: 0.012, 95% CI: 0.007, 0.178) than patients with private insurance. Medicaid patients also had increased length of stay (IRR = 1.26, 95% CI: 1.24,1.28) but had lower total charges (β: -0.022, 95% CI: -0.003. -0.015) than patients with private insurance.

CONCLUSIONS

Insurance status was associated with inpatient length of stay and total charges in patients with PAD. It is essential that Medicare and Medicaid individuals with PAD receive proper management and care of their PAD, particularly in the primary care settings, to prevent hospitalizations and reduce the excess burden on these patients.

Abstract P370: Implicit Bias Among Vascular Surgeons

Objective: Implicit bias is an unconscious bias that may influence behavior, cognitive processes and decision-making. In clinical settings, implicit bias present in clinicians may influence the treatment that people receive and may be a root cause of health disparities. Our study measured implicit bias among vascular surgeons who participate in the management of individuals with peripheral artery disease (PAD).

Methods: Our sampling frame included all vascular surgeons that contribute to the Vascular Quality Initiative (VQI) registry. We invited these individuals to take the race implicit association test (IAT) used to measure level of unconscious bias. The IAT asks participants to classify items presented on a computer by quickly pressing computer keys. The underpinning of the IAT is that people will match a representative group (images of African American or European American faces) to an attribute (good and bad words, such as excellent and angry) more quickly if there is already an implicit connection. Based on the differences in reaction time from several trials, participants are classified as having a no preference between African American and European Americans or a preference for one or the other. The level of preference can be slight, moderate, or strong. We stratified implicit findings by physician race/ethnicity.

Results: Among 2765 vascular surgeons that participate in the VQI, 338 (12%) completed the IAT. Most participants (70%) showed an automatic preference for European Americans over African Americans, with more than half of participants (51%) showing a moderate or strong automatic preference. Of 195 participants who identified as Non-Hispanic White, 25% showed a slight automatic preference for European Americans, 41% showed a moderate automatic preference, and 34% showed a strong automatic preference. Of 16 participants who identified as Non-Hispanic Black, 38% showed an automatic preference for European Americans over African Americans and 31% showed an automatic preference for African Americans. We also found that participants were often unaware of their biases: More than two-thirds (n=64) of the 94 participants who disagreed with a statement asking if they are biased (“I am biased”) had an automatic preference upon testing.

Conclusions: Implicit bias was found among vascular surgeons. The next step in our research will focus on the ability of implicit bias scores to predict a surgeon’s actual delivery of guideline care. Pending our findings, training and clinical support tools offer techniques to mitigate the impact of implicit biases on PAD-related health care.

Predicting COVID-19 Infected Individuals in a Defined Population from Wastewater RNA Data

Wastewater surveillance of SARS-CoV-2 RNA has become an important tool for tracking the presence of the virus and serving as an early indicator for the onset of rapid transmission. Nevertheless, wastewater data are still not commonly used to predict the number of infected individuals in a sewershed. The main objective of this study was to calibrate a susceptible-exposed-infectious-recovered (SEIR) model using RNA copy rates in sewage (i.e., gene copies per liter times flow rate) and the number of SARS-CoV-2 saliva-test-positive infected individuals in a university student population that was subject to repeated weekly testing during the Spring 2021 semester. A strong correlation was observed between the RNA copy rates and the number of infected individuals. The parameter in the SEIR model that had the largest impact on calibration was the maximum shedding rate, resulting in a mean value of 7.72 log10 genome copies per gram of feces. Regressing the saliva-test-positive infected individuals on predictions from the SEIR model based on the RNA copy rates yielded a slope of 0.87 (SE=0.11), which is statistically consistent with a 1:1 relationship between the two. These findings demonstrate that wastewater surveillance of SARS-CoV-2 can be used to estimate the number of infected individuals in a sewershed.

Surgical site infection after open lower extremity revascularization associated with doubled rate of major limb amputation

OBJECTIVE

Surgical site infection (SSI) after open lower extremity revascularization is a relatively common complication associated with increased hospital stays, graft infection, and in severe cases, graft loss. Although the short-term effects of SSI can be significant, it has not been considered a complication that increases major limb amputation. The purpose of this study was to determine the association of SSI with outcomes in patients undergoing surgical revascularization for peripheral arterial disease.

METHODS

We analyzed nationwide Vascular Quality Initiative (VQI) data from the infrainguinal bypass module from 2003 to 2017. The cohort included adults who underwent open lower extremity bypass for symptomatic peripheral arterial disease and had at least one follow-up record. Weighted Kaplan-Meier curves and Cox proportional hazards regression were used to assess the association between SSI and 1-year mortality and major limb amputation. Inverse-probability of treatment weights were used to account for differences in demographics and patient characteristics and allow for 'adjusted' Kaplan-Meier curves.

RESULTS

The analysis included 21,639 patients, and 1155 (5%) had a reported SSI within 30 days of surgery. Patients with SSI were more likely be obese (41% vs 30%), but there were no other clinically relevant differences between demographics, comorbidities, and bypass details. After weighting, patients with SSI were almost twice as likely to undergo major amputation by 6 months (hazard ratio, 1.84; 95% confidence interval, 1.07-3.17). The association with SSI and increased amputation rates persisted at 1 year. The association of SSI on amputation was no different based on preoperative Rutherford class (P = .91). The association between SSI and 1-year mortality rate was not statistically significant (hazard ratio, 1.15; 95% confidence interval, 0.91-1.46).

CONCLUSIONS

SSI is more common in obese patients, and patients who develop an SSI are observed to have a significantly increased rate of limb amputation after open lower extremity revascularization.

Implementation of a Rural Community Diagnostic Testing Strategy for SARS-CoV-2 in Upstate South Carolina

By developing a partnership amongst a public university lab, local city government officials and community healthcare providers, we established a drive-through COVID-19 testing site aiming to improve access to SARS-CoV-2 testing in rural Upstate South Carolina. We collected information on symptoms and known exposures of individuals seeking testing to determine the number of pre- or asymptomatic individuals. We completed 71,102 SARS-CoV-2 tests in the community between December 2020-December 2021 and reported 91.49% of results within 24 h. We successfully identified 5,244 positive tests; 73.36% of these tests originated from individuals who did not report symptoms. Finally, we identified high transmission levels during two major surges and compared test positivity rates of the local and regional communities. Importantly, the local community had significantly lower test positivity rates than the regional community throughout 2021 (p < 0.001). While both communities reached peak case load and test positivity near the same time, the local community returned to moderate transmission as indicated by positivity 4 weeks before the regional community. Our university lab facilitated easy testing with fast turnaround times, which encouraged voluntary testing and helped identify a large number of non-symptomatic cases. Finding the balance of simplicity, accessibility, and community trust was vital to the success of our widespread community testing program for SARS-CoV-2.

Non-Hispanic Black and Hispanic Patients Have Worse Outcomes Than White Patients Within Similar Stages of Peripheral Artery Disease

Background Racial and ethnic disparities in outcomes following lower limb revascularization for peripheral artery disease have been ascribed to disease severity at presentation for surgery. Methods and Results We calculated 1-year risk of major adverse limb events (MALEs), major amputation, and death for patients undergoing elective revascularization for claudication or chronic limb-threatening ischemia in the Vascular Quality Initiative data (2011-2018). We report hazard ratios according to race and ethnicity using Cox (death) or Fine and Gray subdistribution hazards models (MALE and major amputation, treating death as a competing event), adjusted for patient, treatment, and anatomic factors associated with disease severity. Among 88 599 patients (age, 69 years; 37% women), 1-year risk of MALE (major amputation and death) was 12.8% (95% CI, 12.5-13.0) in 67 651 White patients, 16.5% (95% CI, 5.8-7.8) in 15 442 Black patients, and 17.2% (95% CI, 5.6-6.9) in 5506 Hispanic patients. Compared with White patients, we observed an increased hazard of poor limb outcomes among Black (MALE: 1.17; 95% CI, 1.12-1.22; amputation: 1.52; 95% CI, 1.39-1.65) and Hispanic (MALE: 1.22; 95% CI, 1.14-1.31; amputation: 1.45; 95% CI, 1.28-1.64) patients. However, Black and Hispanic patients had a hazard of death of 0.85 (95% CI, 0.79-0.91) and 0.71 (95% CI, 0.63-0.79) times the hazard among White patients, respectively. Worse limb outcomes were observed among Black and Hispanic patients across subcohorts of claudication and chronic limb-threatening ischemia. Conclusions Black and Hispanic patients undergoing infrainguinal revascularization for chronic limb-threatening ischemia and claudication had worse limb outcomes compared with White patients, even with similar disease severity at presentation. Additional investigation aimed at eliminating disparate limb outcomes is needed.

The association between socioeconomic distress communities index and amputation among patients with peripheral artery disease

Background

Socioeconomic factors have been shown to be associated with amputation in peripheral artery disease (PAD); however, analyses have normally focused on insurance status, race, or median income. We sought to determine whether community-level socioeconomic distress was associated with major amputation and if that association differed by race.

Materials and methods

Community-level socioeconomic distress was measured using the distressed communities index (DCI). The DCI is a zip code level compositive socioeconomic score (0-100) that accounts for unemployment, education level, poverty rate, median income, business growth, and housing vacancies. A distressed community was defined as a zip code with DCI of 40 or greater. We calculated one-year risk of major amputation by DCI score for individuals with peripheral artery disease in South Carolina, 2012-2017. Treating death as competing event, we reported Fine and Gray subdistribution hazards ratios (sdHR), adjusted for patient demographic and clinical comorbidities associated with amputation. Further analyses were completed to identify potential differences in outcomes within strata of race and DCI.

Results

Among 82,848 individuals with peripheral artery disease, the one-year incidence of amputation was 3.5% (95% CI: 3.3%, 3.6%) and was significantly greater in distressed communities than non-distressed communities (3.9%; 95% CI: 3.8%, 4.1% vs. 2.4%; 95% CI: 2.2%, 2.6%). After controlling for death and adjusting for covariates, we found an increased hazard of amputation among individuals in a distressed community (sdHR: 1.25; 95% CI: 1.14, 1.37), which persisted across racial strata. However, regardless of DCI score, Black individuals had the highest incidence of amputation.

Conclusion

Socioeconomic status is independently predictive of limb amputation after controlling for demographic characteristics and clinical comorbidities. Race continues to be an important risk factor, with Black individuals having higher incidence of amputation, even in non-distressed communities, than White individuals had in distressed communities.

Geographic Disparities in Readmissions for Peripheral Artery Disease in South Carolina

Readmissions constitute a major health care burden among peripheral artery disease (PAD) patients. This study aimed to 1) estimate the zip code tabulation area (ZCTA)-level prevalence of readmission among PAD patients and characterize the effect of covariates on readmissions; and (2) identify hotspots of PAD based on estimated prevalence of readmission. Thirty-day readmissions among PAD patients were identified from the South Carolina Revenue and Fiscal Affairs Office All Payers Database (2010-2018). Bayesian spatial hierarchical modeling was conducted to identify areas of high risk, while controlling for confounders. We mapped the estimated readmission rates and identified hotspots using local Getis Ord (G*) statistics. Of the 232,731 individuals admitted to a hospital or outpatient surgery facility with PAD diagnosis, 30,366 (13.1%) experienced an unplanned readmission to a hospital within 30 days. Fitted readmission rates ranged from 35.3 per 1000 patients to 370.7 per 1000 patients and the risk of having a readmission was significantly associated with the percentage of patients who are 65 and older (0.992, 95%CI: 0.985-0.999), have Medicare insurance (1.013, 1.005-1.020), and have hypertension (1.014, 1.005-1.023). Geographic analysis found significant variation in readmission rates across the state and identified priority areas for targeted interventions to reduce readmissions.

Ankle-Brachial Index and Subsequent Risk of Severe Ischemic Leg Outcomes: The ARIC Study

Background Ankle-brachial index (ABI) is used to identify lower-extremity peripheral artery disease (PAD). However, its association with severe ischemic leg outcomes (eg, amputation) has not been investigated in the general population. Methods and Results Among 13 735 ARIC (Atherosclerosis Risk in Communities) study participants without clinical manifestations of PAD (mean age, 54 [SD, 5.8] years; 44.4% men; and 73.6% White) at baseline (1987-1989), we quantified the prospective association between ABI and subsequent severe ischemic leg outcomes, critical limb ischemia (PAD with rest pain or tissue loss) and ischemic leg amputation (PAD requiring amputation) according to discharge diagnosis. Over a median follow-up of ≈28 years, there were 221 and 129 events of critical limb ischemia and ischemic leg amputation, respectively. After adjusting for demographics, ABI ≤0.90 versus 1.11 to 1.20 had a ≈4-fold higher risk of critical limb ischemia and ischemic leg amputation (hazard ratios, 3.85 [95% CI, 2.09-7.11] and 4.39 [95% CI, 2.08-9.27]). The magnitude of the association was modestly attenuated after multivariable adjustment (hazard ratios, 2.44 [95% CI, 1.29-4.61] and 2.72 [95% CI, 1.25-5.91], respectively). ABI 0.91 to 1.00 and 1.01 to 1.10 were also associated with these severe leg outcomes, with hazard ratios ranging from 1.7 to 2.0 after accounting for potential clinical and demographic confounders. The associations were largely consistent across various subgroups. Conclusions In a middle-aged community-based cohort, lower ABI was independently and robustly associated with increased risk of severe ischemic leg outcomes. Our results further support ABI ≤0.90 as a threshold diagnosing PAD and also suggest the importance of recognizing the prognostic value of ABI 0.91 to 1.10 for limb prognosis.

Ankle-brachial index and subsequent risk of incident and recurrent cardiovascular events in older adults: The Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND AND AIMS

The ankle-brachial index (ABI) is a diagnostic test for screening and detecting peripheral artery disease (PAD), as well as a risk enhancer in the AHA/ACC guidelines on the primary prevention of atherosclerotic cardiovascular disease (ASCVD). However, our understanding of the association between ABI and cardiovascular risk in contemporary older populations is limited. Additionally, the prognostic value of ABI among individuals with prior ASCVD is not well understood.

METHODS

Among 5,003 older adults at ARIC visit 5 (2011-2013) (4,160 without prior ASCVD [median age 74 years, 38% male], and 843 with ASCVD [median age 76 years, 65% male]), we quantified the association between ABI and the risk of heart failure (HF), and composite coronary heart disease and stroke (CHD/stroke) using multivariable Cox regression models.

RESULTS

Over a median follow-up of 5.5 years, we observed 400 CHD/stroke events and 338 HF cases (242 and 199 cases in those without prior ASCVD, respectively). In participants without a history of ASCVD, a low ABI ≤0.9 (relative to ABI 1.11-1.20) was associated with both CHD/stroke and HF (adjusted hazard ratios 2.40 [95% CI: 1.55-3.71] and 2.23 [1.40-3.56], respectively). In those with prior ASCVD, low ABI was not significantly associated with CHD/stroke, but was with HF (7.12 [2.47-20.50]). The ABI categories of 0.9-1.2 and > 1.3 were also independently associated with increased HF risk. Beyond traditional risk factors, ABI significantly improved the risk discrimination of CHD/stroke in those without ASCVD and HF, regardless of baseline ASCVD.

CONCLUSIONS

Low ABI was associated with CHD/stroke in those without prior ASCVD and higher risk of HF regardless of baseline ASCVD status. These results support ABI as a risk enhancer for guiding primary cardiovascular prevention and suggest its potential value in HF risk assessment for older adults.

Healthy volunteers in US phase I clinical trials: Sociodemographic characteristics and participation over time

BACKGROUND

Increasing the diversity of research participants is an important focus of clinical trials. However, little is known regarding who enrolls as healthy volunteers in Phase I clinical trials, which test the safety and tolerability of investigational new drugs. Despite the risk, healthy volunteers can derive no medical benefit from their participation, and they are financially compensated for enrolling.

OBJECTIVE

This study's purpose is to describe sociodemographic characteristics and clinical trial participation histories of healthy people who enroll in US Phase I trials.

METHODS

The HealthyVOICES Project (HVP) is a longitudinal study of healthy individuals who have enrolled in Phase I trials. We describe self-reported sociodemographic information and Phase I trial history from HVP recruitment (May-December 2013) through the project's end three years later (December 2016). Trial experiences are presented as medians and quartiles.

RESULTS

The HVP included 178 participants. Nearly three-fourths of participants were male, and two-thirds were classified as racial and ethnic minorities. We found that some groups of participants were more likely to have completed a greater number of clinical trials over a longer timeframe than others. Those groups included participants who were male, Black, Hispanic, 30-39-years-old, unemployed, had received vocational training in a trade, or had annual household incomes of less than $25,000. Additionally, the greater the number of clinical trials participants had completed, the more likely they were to continue screening for new trials over the course of three years. Participants who pursued clinical trials as a full-time job participated in the greatest number of trials and were the most likely to continuing screening over time.

IMPLICATIONS

Participation as a healthy volunteer in US Phase I trials is driven by social inequalities. Disadvantaged groups tend to participate in a greater number of clinical trials and participate longer than more privileged groups.

The impact of phased university reopenings on mitigating the spread of COVID-19: a modeling study

BACKGROUND

Several American universities have experienced COVID-19 outbreaks, risking the health of their students, employees, and local communities. Such large outbreaks have drained university resources and forced several institutions to shift to remote learning and send students home, further contributing to community disease spread. Many of these outbreaks can be attributed to the large numbers of active infections returning to campus, alongside high-density social events that typically take place at the semester start. In the absence of effective mitigation measures (e.g., high-frequency testing), a phased return of students to campus is a practical intervention to minimize the student population size and density early in the semester, reduce outbreaks, preserve institutional resources, and ultimately help mitigate disease spread in communities.

METHODS

We develop dynamic compartmental SARS-CoV-2 transmission models to assess the impact of a phased reopening, in conjunction with pre-arrival testing, on minimizing on-campus outbreaks and preserving university resources (measured by isolation bed capacity). We assumed an on-campus population of N = 7500, 40% of infected students require isolation, 10 day isolation period, pre-arrival testing removes 90% of incoming infections, and that phased reopening returns one-third of the student population to campus each month. We vary the disease reproductive number (R_t) between 1.5 and 3.5 to represent the effectiveness of alternative mitigation strategies throughout the semester.

RESULTS

Compared to pre-arrival testing only or neither intervention, phased reopening with pre-arrival testing reduced peak active infections by 3 and 22% (R_t = 1.5), 22 and 29% (R_t = 2.5), 41 and 45% (R_t = 3.5), and 54 and 58% (improving R_t), respectively. Required isolation bed capacity decreased between 20 and 57% for values of R_t ≥ 2.5.

CONCLUSION

Unless highly effective mitigation measures are in place, a reopening with pre-arrival testing substantially reduces peak number of active infections throughout the semester and preserves university resources compared to the simultaneous return of all students to campus. Phased reopenings allow institutions to ensure sufficient resources are in place, improve disease mitigation strategies, or if needed, preemptively move online before the return of additional students to campus, thus preventing unnecessary harm to students, institutional faculty and staff, and local communities.

Precision Medicine Enables More TNM-Like Staging in Patients With Chronic Limb Threatening Ischemia

Introduction: In cancer, there are survival-based staging systems and tailored, stage-based treatments. There is little personalized treatment in vascular disease. The 2019 Global Vascular Guidelines on the Management of CLTI proposed successful treatment hinges upon Patient risk, Limb severity, and ANatomic complexity (PLAN). We sought to confirm a three axis approach and define how increasing severity affects mortality, not just limb loss.

Methods: Patients revascularized for incident CLTI at our institution from 2013 to 2017 were included. Outcomes were mortality, limb loss, the composite endpoint of amputation-free survival. Using Bayesian machine learning, specifically supervised topic modeling, clusters of patient features associated with mortality were formed after controlling for revascularization type. Patients were assigned to the cluster they belonged to with highest probability; clusters were characterized by analyzing the characteristics of patients within them. Patient outcomes were used to order the clusters into stages with increasing mortality.

Results: We defined three distinct clusters as the basis for patient- and limb-centered stages. Across stages, rates of 1-year mortality were 7.6, 13.8, 18.9% and rates of amputation-free survival were 84.8, 79.3, and 63.2%. Stage one had patients with rest pain and previous revascularization who were less likely to have wounds, diabetes, and renal disease. Stage two had doubled mortality, likely related to diabetes prevalence. Stage three is characterized by high rates of complicated comorbidities, particularly end stage renal disease, and significantly higher rate of limb loss (22.6 vs. 8% in stages one and two).

Conclusion: Using precision medicine, we have demonstrated clustering of CLTI patients that can be used toward a robust staging system. We provide empiric evidence for PLAN and detail about how changes in each variable affect survival and amputation-free survival.

Disparities in Peripheral Artery Disease Hospitalizations Identified Among Understudied Race-Ethnicity Groups

Background: To assess racial/ethnic differences in disease severity, hospital outcomes, length of stay and healthcare costs among hospitalized patients with peripheral artery disease (PAD).

Methods: This study used data from the National Inpatient Sample (NIS) to explore the racial/ethnic disparities in PAD-related hospitalizations including presence of PAD with chronic limb threatened ischemia (CLI), amputation, in-hospital mortality, length of hospital stays and estimated medical costs. Race-ethnicity groups included non-Hispanic White, Black, Hispanic, Asian or Pacific Islander, Native American, and others (multiple races). Regression analyses adjusted for age, gender, Charlson Comorbidity Index, primary payer, patient location, bed size of the admission hospital, geographic region of the hospital, and rural/urban location of the hospital.

Results: A total of 341,480 PAD hospitalizations were identified. Compared with non-Hispanic Whites, Native Americans had the highest odds of PAD with CLI (OR = 1.77, 95% CI: 1.61, 1.95); Black (OR = 1.71, 95% CI: 1.66, 1.76) and Hispanic (OR = 1.36, 95% CI: 1.31,1.41) patients had higher odds of amputation; Asian or Pacific Islanders had a higher mortality (OR = 1.20, 95% CI: 1.01,1.43), whereas Black (OR = 0.81, 95% CI: 0.76, 0.87) patients has a lower mortality; Asian or Pacific Islanders incurred higher overall inpatient costs (Margin = 30093.01, 95% CI: 28827.55, 31358.48) and most prolonged length of stay (IRR = 0.14, 95% CI: 0.09, 0.18).

Conclusions: Our study identified elevated odds of amputation among Hispanic patients hospitalized with PAD as well as higher hospital mortality and medical expenses among Asian or Pacific Islander PAD inpatients. These two demographic groups were previously thought to have a lower risk for PAD and represent important populations for further investigation.

Risk of peripheral artery disease according to race and sex: The Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND AND AIMS

Previous community-based studies have demonstrated sex and race-based disparities in the risk of cardiovascular disease. We sought to examine the association of sex and race with incident peripheral artery disease (PAD-) and critical limb ischemia (CLI-) related hospitalizations.

METHODS

In 13,451 Black and White ARIC participants without prevalent PAD at baseline (1987-89), we estimated the cumulative incidence of PAD- and CLI-related hospitalization over a median follow-up of 26 years. We quantified hazard ratios (HRs) using Cox models across four sex- and race-groups. PAD and CLI were defined by hospitalization discharge codes.

RESULTS

The cumulative incidence of PAD-related hospitalization was higher in males than females in Whites (5.1% vs. 2.7%; p<0.001) but not in Blacks (5.7% vs. 5.0%; p=0.39). The cumulative incidence of CLI-related hospitalization differed significantly by race more than sex, occurring in 3.1% Black males, 3.1% Black females, 1.4% White males, and 0.8% White females (p<0.001). After risk factor adjustment, the risk of incident PAD-related hospitalization was similar for White males vs. White females [HR 1.14, 95%CI 0.90-1.45], and slightly higher for Black males [HR 1.26, 95%CI 0.92-1.72] and Black females [HR 1.39, 95%CI 1.03-1.87] compared to White females. The adjusted risk of incident CLI-related hospitalization was similar for White males vs. White females [HR 1.15, 95%CI 0.75-1.76], and significantly higher for Black males [HR 1.96, 95%CI 1.22-3.16] and Black females [HR 2.06, 95%CI 1.31-3.24] compared to White females.

CONCLUSIONS

These data suggest that there are both sex- and race-specific patterns of PAD-related hospitalization that lead to differences in clinical disease risk and presentation.

Surveillance-based informative testing for detection and containment of SARS-CoV-2 outbreaks on a public university campus: an observational and modelling study

Background

Despite severe outbreaks of COVID-19 among colleges and universities across the USA during the Fall 2020 semester, the majority of institutions did not routinely test students. While high-frequency repeated testing is considered the most effective strategy for disease mitigation, most institutions do not have the necessary infrastructure or funding for implementation. Therefore, alternative strategies for testing the student population are needed. Our study detailed the implementation and results of testing strategies to mitigate SARS-CoV-2 spread on a university campus, and we aimed to assess the relative effectiveness of the different testing strategies.

Methods

For this retrospective cohort study, we included 6273 on-campus students arriving to a large public university in the rural USA (Clemson, SC, USA) for in-person instruction in the Fall 2020 semester (Sept 21 to Nov 25). Individuals arriving after Sept 23, those who tested positive for SARS-CoV-2 before Aug 19, and student athletes and band members were not included in this study. We implemented two testing strategies to mitigate SARS-CoV-2 spread during this period: a novel surveillance-based informative testing (SBIT) strategy, consisting of random surveillance testing to identify outbreaks in residence hall buildings or floors and target them for follow-up testing (Sept 23 to Oct 5); followed by a repeated weekly surveillance testing (Oct 6 to Nov 22). Relative changes in estimated weekly prevalence were examined. We developed SARS-CoV-2 transmission models to compare the relative effectiveness of weekly testing (900 daily surveillance tests), SBIT (450 daily surveillance tests), random surveillance testing (450 daily surveillance tests), and voluntary testing (0 daily surveillance tests) on disease mitigation. Model parameters were based on our empirical surveillance data in conjunction with published sources.

Findings

SBIT was implemented from Sept 23 to Oct 5, and identified outbreaks in eight residence hall buildings and 45 residence hall floors. Targeted testing of residence halls was 2·03 times more likely to detect a positive case than random testing (95% CI 1·67–2·46). Weekly prevalence was reduced from a peak of 8·7% to 5·6% during this 2-week period, a relative reduction of 36% (95% CI 27–44). Prevalence continued to decrease after implementation of weekly testing, reaching 0·8% at the end of in-person instruction (week 9). SARS-CoV-2 transmission models concluded that, in the absence of SBIT (ie, voluntary testing only), the total number of COVID-19 cases would have increased by 154% throughout the semester. Compared with SBIT, random surveillance testing alone would have resulted in a 24% increase in COVID-19 cases. Implementation of weekly testing at the start of the semester would have resulted in 36% fewer COVID-19 cases throughout the semester compared with SBIT, but it would require twice the number of daily tests.

Interpretation

It is imperative that institutions rigorously test students during the 2021 academic year. When high-frequency testing (eg, weekly) is not possible, SBIT is an effective strategy to mitigate disease spread among the student population that can be feasibly implemented across colleges and universities.

Funding

Clemson University, USA.

Fibrosis and Inflammatory Markers and Long-Term Risk of Peripheral Artery Disease: The ARIC Study

OBJECTIVE

Inflammatory markers, such as hs-CRP (high-sensitivity C-reactive protein), have been reported to be related to peripheral artery disease (PAD). Galectin-3, a biomarker of fibrosis, has been linked to vascular remodeling and atherogenesis. However, its prospective association with incident PAD is unknown; as is the influence of inflammation on the association between galectin-3 and PAD. Approach and Results: In 9851 Atherosclerosis Risk in Communities Study participants free of PAD at baseline (1996-1998), we quantified the association of galactin-3 and hs-CRP with incident PAD (hospitalizations with PAD diagnosis [International Classification of Diseases-Ninth Revision: 440.2-440.4] or leg revascularization [eg, International Classification of Diseases-Ninth Revision: 38.18]) as well as its severe form, critical limb ischemia (PAD cases with resting pain, ulcer, gangrene, or leg amputation) using Cox models. Over a median follow-up of 17.4 years, there were 316 cases of PAD including 119 critical limb ischemia cases. Log-transformed galectin-3 was associated with incident PAD (adjusted hazard ratio, 1.17 [1.05-1.31] per 1 SD increment) and critical limb ischemia (1.25 [1.05-1.49] per 1 SD increment). The association was slightly attenuated after further adjusting for hs-CRP (1.14 [1.02-1.27] and 1.22 [1.02-1.45], respectively). Log-transformed hs-CRP demonstrated robust associations with PAD and critical limb ischemia even after adjusting for galectin-3 (adjusted hazard ratio per 1 SD increment 1.34 [1.18-1.52] and 1.34 [1.09-1.65], respectively). The addition of galectin-3 and hs-CRP to traditional atherosclerotic predictors (C statistic of the base model 0.843 [0.815-0.871]) improved the risk prediction of PAD (ΔC statistics, 0.011 [0.002-0.020]).

CONCLUSIONS

Galectin-3 and hs-CRP were independently associated with incident PAD in the general population, supporting the involvement of fibrosis and inflammation in the pathophysiology of PAD.

Poor glycemic control is associated with significant increase in major limb amputation and adverse events in the 30-day postoperative period after infrainguinal bypass

OBJECTIVE

Understanding modifiable risk factors to improve surgical outcomes is increasingly important in value-based health care. There is an established association between peripheral artery disease (PAD), diabetes, and limb loss, but less is known about expected outcomes after revascularization relative to the degree of glycemic control. The purpose of this study was to determine the association between hemoglobin A_1c (HbA_1c) management in diabetics and surgical outcomes after open infrainguinal bypass.

METHODS

The Vascular Quality Initiative infrainguinal bypass module was used to identify adult patients (≥18 years) with a history of diabetes who underwent bypass for PAD between 2011 and 2018. Exclusion criteria included missing or illogical HbA_1c values and if the indication for the limb treated was not PAD. Patients were categorized by preoperative HbA_1c levels as low severity/controlled (<7.0%), high severity (7.0%-10.0%), and very high severity (>10.0%). Primary outcomes were 30-day incidence of major adverse cardiac events (MACEs), major adverse limb events (MALEs), ipsilateral amputation, and 1-year all-cause mortality. Thirty-day outcomes were calculated using multivariable regression to compute odds ratios; hazard ratios were calculated for all-cause mortality. All analyses were adjusted for demographics, comorbidities, and clinical characteristics.

RESULTS

The final sample included 30,813 operations (27,988 unique patients): 17,517 (57%) nondiabetic patients, 5194 patients with low-severity/controlled diabetes, and 8102 (26%) patients with poorly controlled diabetes, including 5531 (70%) treated with insulin. There were 6439 (21%) patients with high-severity HbA_1c values and 1663 (5%) patients with very-high-severity HbA_1c values. Those with a very high HbA_1c level were more likely to be nonwhite, insulin dependent, and active smokers. Compared with nondiabetics, patients with very-high-severity HbA_1c had an 81% increase in MACEs and 31% increase in MALEs, whereas patients with high-severity HbA_1c only had a 49% increase in MACEs and a 12% increase in MALEs. Each one-step increase in severity category (eg, low to high to very high) was associated with an average 29% increase in the odds of MACEs and an 8% increase in the odds of MALEs.

CONCLUSIONS

Uncontrolled diabetes with an HbA_1c value >10.0% was associated with significantly worse 30-day surgical outcomes. Patients with incrementally better glycemic control (HbA_1c level of 7.0%-10.0%) did not suffer the same rate of complications, suggesting that preoperative attempts at improving diabetes management even slightly could lead to improved surgical outcomes in open infrainguinal bypass patients.

Physical Activity and Subsequent Risk of Hospitalization With Peripheral Artery Disease and Critical Limb Ischemia in the ARIC Study

Background

Whether physical activity is a determinant of peripheral artery disease (PAD) remains unclear. We therefore assessed the association of physical activity (amount and intensity) with subsequent risk of hospitalization with PAD and its severe form, critical limb ischemia, in the ARIC (Atherosclerosis Risk in Communities) study.

Methods and Results

We included 12 513 participants free of cardiovascular disease at baseline (1987–1989), with a mean age of 53.9 years, 55.3% women, and 25.0% black. Physical activity was assessed using a modified Baecke questionnaire and categorized into poor (no moderate [3 to <6 metabolic equivalents] or vigorous [≥6 metabolic equivalents] exercise), intermediate (1–74 min/wk vigorous or 1–149 min/wk moderate plus vigorous exercise), and recommended (≥75 min/wk vigorous or ≥150 min/wk moderate plus vigorous exercise). We also modeled moderate and vigorous exercise individually. All analyses applied Cox regression models. Intermediate and recommended exercise were seen in 24.7% and 38.1%, respectively. During a median follow‐up of 25.4 years, 434 incident hospitalizations with PAD (166 critical limb ischemia) were documented. Recommended versus poor activity was associated with a lower demographically adjusted PAD risk (hazard ratio, 0.68; 95% CI, 0.54–0.85) but attenuated after accounting for lifestyle factors (hazard ratio, 0.84; 95% CI, 0.66–1.05). When analyzing moderate and vigorous exercise separately, vigorous exercise was robustly related to lower risk of hospitalization with PAD, and critical limb ischemia in particular (hazard ratio, 0.72; 95% CI, 0.54–0.97 per 200 metabolic equivalents*min/wk increment in the most extended model).

Conclusions

Higher amount and intensity of physical activity were related to lower risks of hospitalization with PAD and critical limb ischemia, further highlighting the importance of engaging in physical activity for vascular health.

Cigarette Smoking, Smoking Cessation, and Long-Term Risk of 3 Major Atherosclerotic Diseases

BACKGROUND

Public statements about the effect of smoking on cardiovascular disease are predominantly based on investigations of coronary heart disease (CHD) and stroke, although smoking is recognized as a strong risk factor for peripheral artery disease (PAD). No study has comprehensively compared the long-term association of cigarette smoking and its cessation with the incidence of 3 major atherosclerotic diseases (PAD, CHD, and stroke).

OBJECTIVES

The aim of this study was to quantify the long-term association of cigarette smoking and its cessation with the incidence of the 3 outcomes.

METHODS

A total of 13,355 participants aged 45 to 64 years in the ARIC (Atherosclerosis Risk In Communities) study without PAD, CHD, or stroke at baseline (1987 to 1989) were included. The associations of smoking parameters (pack-years, duration, intensity, and cessation) with incident PAD were quantified and contrasted with CHD and stroke using Cox models.

RESULTS

Over a median follow-up of 26 years, there were 492 PAD cases, 1,798 CHD cases, and 1,106 stroke cases. A dose-response relationship was identified between pack-years of smoking and 3 outcomes, with the strongest results for PAD. The pattern was consistent when investigating duration and intensity separately. A longer period of smoking cessation was consistently related to lower risk of PAD, CHD, and stroke, but a significantly elevated risk persisted up to 30 years following smoking cessation for PAD and up to 20 years for CHD.

CONCLUSIONS

All smoking measures showed significant associations with 3 major atherosclerotic diseases, with the strongest effect size for incident PAD. The risk due to smoking lasted up to 30 years for PAD and 20 years for CHD. Our results further highlight the importance of smoking prevention and early smoking cessation, and indicate the need for public statements to take PAD into account when acknowledging the impact of smoking on overall cardiovascular health.

Cigarette smoking intensity informs outcomes after open revascularization for peripheral artery disease

OBJECTIVE

Cigarette smoking is the leading risk factor for peripheral artery disease (PAD). Existing literature often defines smoking history in broad categories of current, former, and never smokers, which may not sufficiently identify patients at the highest risk for poor outcomes. The purpose of this study was to examine the use of more informative categorization of smoking and to determine the association with important revascularization outcomes.

METHODS

We conducted a retrospective review of all patients undergoing open lower extremity revascularization for symptomatic PAD, defined as claudication (Rutherford 3) or critical limb ischemia (Rutherford 4-6), during a 5-year period (2013-2017). Smoking history, demographics, and comorbidities were abstracted from electronic health records from seven hospitals within our health care system. Smoking history was defined by intensity (packs/day), duration (years), pack-year history, and cessation time. Outcomes included major adverse limb events (MALEs), death, limb loss, and amputation-free survival. Cox proportional hazards models were used to calculate hazard ratios and 95% confidence intervals (CIs) for each parameter adjusted for patients' demographics and comorbidities. Cumulative incidence is reported for outcomes at 30, 180, and 365 days of follow-up.

RESULTS

We identified 693 patients undergoing open lower extremity revascularization for PAD (66% critical limb ischemia; 46% diabetes). The 1-year cumulative incidence of MALEs was 29.9% (95% CI, 26.4-33.9), whereas the 1-year incidence of death was 9.8% (95% CI, 7.5-12.7). The broad classification of current and former smokers identified no statistically significant differences in any measured outcomes. Patients who smoked more than one pack/day had 1.48 (95% CI, 1.01-2.16) times increase in risk of MALEs at 1 year compared with patients who smoked one or fewer packs/day. Patients who smoked more than one pack/day also had the highest 1-year amputation incidence (12.7%). Each of the four parameters was associated with increased risk of poor outcomes, although small sample size limited the precision of our estimates.

CONCLUSIONS

We found that smoking intensity is particularly informative of outcomes of patients undergoing open lower extremity revascularization for symptomatic PAD. These findings lay the groundwork for future research on relevant smoking history parameters and benefits of smoking reduction and cessation for clinicians to discuss with patients and to better understand and inform patients of intervention risks and expected outcomes.

Outcomes and complications after fenestrated-branched endovascular aortic repair

OBJECTIVE

To report the outcomes of patients enrolled in a physician-sponsored investigational device exemption trial for endovascular treatment of complex thoracoabdominal aortic aneurysms with fenestrated and/or branched devices.

METHODS

This study represents a retrospective analysis of a prospectively maintained database of patients enrolled in a physician-sponsored investigational device exemption trial for endovascular treatment of complex thoracoabdominal aneurysms between July 2012 and July 2017. Subjects included high-risk patients for open repair and patients with unsuitable anatomy for either standard endovascular aneurysm repair or Zenith (Cook Medical, Bloomington, Ind) fenestrated device. Aneurysm classification was based upon Crawford classification. We included the pararenal and paravisceral aneurysms in the type IV aneurysm group, because the repair of these aneurysms usually involved treatment of all four visceral branches. The endografts implanted were custom manufactured devices or off-the-shelf devices based on the Cook Zenith platform. Variables analyzed included preoperative demographics and comorbidities, anatomic aneurysmal characteristics, procedural details, and perioperative complications.

RESULTS

One -hundred fifty patients with a mean age of 71 ± 7.9 years were treated; 69% were male. Tobacco use (93%) and hypertension (91%) were the most common risk factors. Fifty-seven patients (38%) had a history of previous aortic repair. The mean aneurysm diameter was 62 ± 12 mm and 14 (9%) aneurysms were associated with chronic dissection. A total of 573 visceral vessels were incorporated (celiac artery/superior mesenteric artery [287 vessels], renal arteries [275 vessels], and 11 additional vessels) and 539 were stented. The celiac artery/superior mesenteric artery received a fenestrated design in 76.1% of cases. Branch designs were used in the renal artery in 13.2%, with the remainder treated with fenestrations. Spinal cord drainage was used in 51% of patients (76/150). The mean operative time, fluoroscopy time, and estimated blood loss were 283 ± 89 minutes, 83 ± 38 minutes, and 417 ± 404 mL, respectively. There were five patients (3.3%) with intraoperative complications, resulting in one intraoperative death. The early mortality was 2.7% (4/150). Major complications included respiratory failure in 7% (10/150), stroke and myocardial infarction in 0.7% each (1/150), and paraplegia in 2.7% (4/150). Acute kidney injury occurred in 4.7% of patients (7/150), two of whom required temporary dialysis. Thirty-nine percent of patients experienced at least one complication. Early branch vessel patency was 99.8% (525/526). Survival, primary, and primary-assisted branch patency at 2 years of follow-up were 79%, 97%, and 99%, respectively.

CONCLUSIONS

Endovascular repair of complex aneurysms is safe and effective when performed in a high-volume center experienced in aortic disease management. Branch vessels patency and the low incidence of paraplegia and mortality support expanded use to treat most complex thoracoabdominal aortic aneurysms.

The role of selective stenting for superior mesenteric artery scallops during fenestrated endovascular aneurysm repair

OBJECTIVE

Stenting of small fenestrations of the Zenith fenestrated endograft (ZFEN; Cook Medical, Bloomington, Ind) is necessary during fenestrated endovascular aneurysm repair (FEVAR) of complex abdominal aortic aneurysms to avoid malalignment. However, stenting of superior mesenteric artery (SMA) scallops of ZFEN devices is optional according to the instructions for use. The objective of this study was to assess the early and midterm outcomes of selective use of stents in SMA scallops of ZFEN during FEVAR procedures.

METHODS

This study is a single-institution retrospective review of prospectively enrolled patients treated at the University of North Carolina at Chapel Hill between July 2010 and August 2014. Only patients with SMA scallops were included for analysis. We compared results between patients grouped as stented or unstented SMA scallops. The scallops were stented when one or more of the following criteria were present: misalignment of scallop determined by balloon testing intraoperatively; configuration consisting of an SMA scallop and a single renal fenestration or stent; and pre-existing stenosis in the vessel adjacent to the graft scallop. The study was approved by the local Institutional Review Board. Primary outcomes addressed were mortality, vessel patency, early and late complications, and reintervention rates. Baseline characteristics of the patients and procedure data were also described.

RESULTS

During the 48-month study period, 61 patients were treated for complex abdominal aortic aneurysms at the University of North Carolina with a mean age of 73 years, and 74.3% of patients were male. Thirty-nine of 61 patients (63.9%) had a device design with an SMA scallop and were included for analysis. Eleven of 39 patients (28%) had the SMA primarily stented and 28 (72%) were unstented. There was only one death (2.5%) during the 30-day postoperative period, with 100% technical success and branch patency. In the unstented group, there were three SMA complications during follow-up, two requiring reintervention; however, there were no associated deaths. Among the stented group, there was one branch-related complication that occurred during the procedure but no stent stenosis or occlusion during the long-term follow-up. During the mean follow-up period of 21.7 months, no SMA stent thrombosis occurred. There was no statistical difference in outcomes between groups.

CONCLUSIONS

Single-wide SMA scallops of ZFEN during FEVAR procedures may be selectively stented using specific criteria and rigorous follow-up, without compromising the safety and efficacy of the SMA.

Frequency of Care and Mortality Following an Incident Diagnosis of Peripheral Artery Disease in the Inpatient or Outpatient Setting: The ARIC (Atherosclerosis Risk in Communities) Study

Background

Available health services data for individuals with peripheral artery disease (PAD) are often from studies of those eligible for or undergoing intervention. Knowledge of the frequency of care and mortality following an initial PAD diagnosis by setting (outpatient versus inpatient) is limited and represents an opportunity to provide new benchmark information.

Methods and Results

The purpose of this study was to characterize the frequency of care and mortality following an incident PAD diagnosis in the outpatient or inpatient setting using data from the ARIC (Atherosclerosis Risk in Communities) study cohort linked with Centers for Medicare and Medicaid Services fee‐for‐service claims data (2002–2012). Direct standardization was used to estimate age‐standardized rates of encounters and mortality. PAD was defined by billing code in any claim position. We observed 1086 incident PAD cases (873 outpatient, 213 inpatient). At 1 year after diagnosis, participants diagnosed in the outpatient setting had 2.15 (95% confidence interval [CI], 2.10–2.21) PAD‐related outpatient encounters per person‐year, and 6.4% (95% CI, 4.8–8.1) had a PAD‐related hospitalization. Conversely, participants diagnosed in the inpatient setting had 1.02 (95% CI, 0.94–1.10) PAD‐related outpatient encounters per person‐year, and 14.2% (95% CI, 9.3–18.7) had a PAD‐related rehospitalization. One‐year mortality was 7.1% (95% CI, 5.4–8.7) and 16.0% (95% CI, 11.0–21.1) among those diagnosed in outpatient and inpatient settings, respectively.

Conclusions

This study provides important data estimating frequency of care and mortality by the setting of initial PAD diagnosis. Individuals with PAD are frequent users of health care, and those diagnosed in the inpatient setting have high rates of rehospitalization and mortality.

Incidence of venous leg ulcer healing and recurrence after treatment with endovenous laser ablation

BACKGROUND

The Effect of Surgery and Compression on Healing and Recurrence (ESCHAR) trial previously reported that patients with venous leg ulcers treated with saphenous stripping experienced a significantly reduced incidence of ulcer recurrence compared with patients treated with compression therapy. Most patients with leg ulcers and saphenous insufficiency are currently treated with endovenous thermal ablation (EVTA), but little information is available on the long-term results after EVTA in Clinical, Etiology, Anatomy, and Pathophysiology (CEAP) clinical class 5 (C5) and class 6 (C6) patients.

METHODS

We retrospectively reviewed all CEAP C5 or C6 patients treated with EVTA to define the incidence of ulcer healing and recurrence. Patients with active ulcers were managed weekly in a comprehensive wound center until healed. After healing, patients were treated with compression stockings and returned at 6-month intervals for follow-up. Time to healing and time to ulcer recurrence were determined by Kaplan-Meier survival analysis. Risk factors were assessed to determine their association with ulcer recurrence.

RESULTS

EVTA of the great saphenous vein (n = 146), small saphenous vein (n = 20), or both (n = 7) was performed on 173 limbs with active (n = 72) or healed (n = 101) ulcers. Deep venous insufficiency was present in 54 cases (31.2%). Concomitant phlebectomy was performed in 59 limbs (34%). Median follow-up time was 25.2 months after EVTA. Venous ulcers healed after EVTA in 57% of cases at 3 months, 74% at 6 months, and 78% at 12 months. Ulcers recurred in 9% of patients at 1 year after EVTA, 20% at 2 years, and 29% at 3 years of follow-up. Ulcers recurred significantly more often in patients with deep venous insufficiency and in patients who did not undergo phlebectomy of associated varicose veins at the time of EVTA.

CONCLUSIONS

Ulcers recurred in a minority of CEAP clinical C5 and C6 patients after EVTA of the saphenous veins. Ulcer recurrence was less frequent in patients without concomitant deep venous reflux and in those treated with phlebectomy of varicose veins at the time of EVTA. We suggest consideration of phlebectomy at the time of EVTA for patients with C5 and C6 venous insufficiency, particularly in those with isolated superficial venous insufficiency.

Peripheral Artery Disease Prevalence and Incidence Estimated From Both Outpatient and Inpatient Settings Among Medicare Fee-for-Service Beneficiaries in the Atherosclerosis Risk in Communities (ARIC) Study

Background

Outpatient ascertainment of peripheral artery disease (PAD) is rarely considered in the measurement of PAD clinical burden; therefore, the clinical burden of PAD likely has been underestimated while contributing to a decreased awareness of PAD in comparison to other circulatory system disorders.

Methods and Results

The purpose of this study was to estimate the age‐standardized annual period prevalence and incidence of PAD in the outpatient and inpatient settings using data from the Atherosclerosis Risk in Communities (ARIC) study linked with Centers for Medicare and Medicaid Services claims. The majority (>70%) of all PAD encounters occurred in the outpatient setting. The weighted mean age‐standardized prevalence and incidence of outpatient PAD was 11.8% (95% CI 11.5–12.1) and 22.4 per 1000 person‐years (95% CI 20.8–24.0), respectively. Black patients had higher weighted mean age‐standardized prevalence (15.6%; 95% CI 14.6–16.4) compared with white patients (11.4%; 95% CI 11.1–11.7). Black women had the highest weighted mean age‐standardized prevalence (16.9%; 95% CI 16.0–17.8). Black patients also had a higher incidence rate of PAD (31.3 per 1000 person‐years; 95% CI 27.3–35.4) compared with white patients (25.4 per 1000 person‐years; 95% CI 23.5–27.3). PAD prevalence and incidence did not differ by sex alone.

Conclusions

This study provides comprehensive estimates of PAD in the inpatient and outpatient settings where the majority of PAD burden was found. PAD is an important circulatory system disorder similar in prevalence to stroke and coronary heart disease.

Is Incidental Renal Arteriography Justified in a Population of Patients with Symptomatic Peripheral Arterial Disease?

Renal artery stenosis is a consequence of generalized atherosclerosis and many specialists perform routine selective renal angiography to detect and treat renal artery stenosis. The incidence of clinically important renal artery stenosis is not well defined in patients with symptomatic peripheral arterial disease. The purpose of this study was to better delineate the incidence of and the risk factors associated with renal artery stenosis, renovascular hypertension, and ischemic nephropathy incidentally discovered during angiography for symptomatic peripheral arterial disease. Two hundred consecutive patients undergoing angiographic evaluation of symptomatic lower extremity peripheral arterial disease were studied retrospectively. Angiograms were reviewed for the presence of renal artery stenosis (defined as ≥ 25% diameter reduction in either renal artery) and findings were then correlated to the clinical diagnosis of renovascular hypertension (> 50% renal artery stenosis and ≥ 3-drug resistive hypertension) and ischemic nephropathy (defined as > 50% bilateral renal artery stenosis, 3-drug hypertension, and creatinine ≥ 1.5). Angiographic findings were also correlated with risk factors to determine if a relationship correlated to the presence of and degree of renal artery stenosis. Data were analyzed using the Student's t test, Chi-square model, and multiple logistic regression analysis. The overall incidence of any degree of renal artery stenosis in this study population was 26% (52 patients). Only 24 (12%) patients had an incidental finding of ≥ 50% stenosis in either renal artery. Six (3%) of these patients were found to have associated renovascular hypertension. Additionally, 9 (4.5%) patients had coexistent renal insufficiency and significant renal artery stenosis; five with end-stage renal disease on chronic hemodialysis. Only one patient with end-stage renal disease had poorly controlled 3-drug hypertension. Thus definitive ischemic nephropathy was present in only one (0.5%) patient. Statistically significant risk factors associated with the presence of renal artery stenosis include hypertension ( P < .001), coronary disease ( P = .024), female gender ( P = .010), diabetes ( P = .039), aorto-iliac disease ( P = .031), multiple levels of peripheral arterial disease ( P < .001), and age over 60 ( P < .001). While the incidence of renal artery stenosis in patients being evaluated for symptomatic peripheral arterial disease is similar to that reported in the cardiology literature, the incidence of renovascular hypertension and ischemic nephropathy is exceedingly low (3% and 0.5%, respectively)—findings similar to data reported in the general hypertensive population. These data suggest that incidental selective renal angiography is not justified in patients with symptomatic peripheral arterial disease.

Characteristics and outcomes of patients with acute decompensated heart failure developing after hospital admission

There are limited data on acute decompensated heart failure (ADHF) that develops after hospital admission. This study sought to compare patient characteristics, co-morbidities, mortality, and length of stay by timing of ADHF onset. The surveillance component of the Atherosclerosis Risk in Communities study (2005 to 2011) sampled, abstracted, and adjudicated hospitalizations with select International Classification of Disease, Ninth Revision, Clinical Modification discharge codes from 4 United States communities among those aged ≥55 years. We included 5,602 validated ADHF hospitalizations further classified as preadmission or postadmission onset. Vital status was assessed up to 1 year since admission. We estimated multivariate-adjusted associations of in-hospital mortality and 28- and 365-day case fatalities with timing of ADHF onset (postadmission vs preadmission). All analyses were weighted to account for the stratified sampling design. Of 25,862 weighted ADHF hospitalizations, 7% had postadmission onset of ADHF. Patients with postadmission ADHF were more likely to be older, white, and women. The most common primary discharge diagnosis codes for those with postadmission ADHF included diseases of the circulatory or digestive systems or infectious diseases. Short-term mortality among postadmission ADHF was almost 3 times that of preadmission ADHF (in-hospital mortality: odds ratio 2.7, 95% confidence interval 1.9 to 3.9; 28-day case fatality: odds ratio 2.6, 95% confidence interval 1.8 to 3.7). The average hospital stay was almost twice as long among postadmission as preadmission ADHF (9.6 vs 5.0 days). In conclusion, postadmission onset of ADHF is characterized by differences in co-morbidities and worse short-term prognosis, and opportunities for reducing postadmission ADHF occurrence and associated risks need to be studied.

Peering into the pharmaceutical "pipeline": investigational drugs, clinical trials, and industry priorities

In spite of a growing literature on pharmaceuticalization, little is known about the pharmaceutical industry's investments in research and development (R&D). Information about the drugs being developed can provide important context for existing case studies detailing the expanding--and often problematic--role of pharmaceuticals in society. To access the pharmaceutical industry's pipeline, we constructed a database of drugs for which pharmaceutical companies reported initiating clinical trials over a five-year period (July 2006-June 2011), capturing 2477 different drugs in 4182 clinical trials. Comparing drugs in the pipeline that target diseases in high-income and low-income countries, we found that the number of drugs for diseases prevalent in high-income countries was 3.46 times higher than drugs for diseases prevalent in low-income countries. We also found that the plurality of drugs in the pipeline was being developed to treat cancers (26.2%). Interpreting our findings through the lens of pharmaceuticalization, we illustrate how investigating the entire drug development pipeline provides important information about patterns of pharmaceuticalization that are invisible when only marketed drugs are considered.

A Novel Core Competencies-Based Academic Medicine Curriculum: Description and Preliminary Results

BACKGROUND

Physicians practice health care in a rapidly changing system that requires more than the delivery of safe and effective care. Modern physicians must also acquire skills beyond direct patient care. Residency programs must, therefore, prepare physicians to meet these demands by providing appropriate education and training.

METHODS

We designed, implemented and assessed an academic medicine curriculum in the first post-graduate year. This curriculum provides comprehensive exposure to necessary non-patient contact related physician skills. Topics centered around four domains: critical appraisal of literature of literature, quality improvement, professional development, and teaching. Each of these domains is linked to the six core competencies established by the Accreditation Council for Graduate Medical Education's (ACGME). Instruction includes small-group learning sessions with additional time for self-directed online modules and a faculty-mentored quality improvement research project that is presented at a graduation symposium. All residents completed a survey evaluation of the curriculum before and after the course via open-ended questions and Likert responses (0-5). We assessed improvement in resident confidence with each curricular domain using mean Likert score change and 95% confidence intervals (CI).

RESULTS

Residents improved at all curricular domains measured. The most significant mean changes included confidence in: poster presentations (2.7; 95% CI: 1.9-3.5), plan-do-check-act cycle (2.5; 95% CI: 2.1-2.9), quality improvement projects (2.4; 95% CI: 1.9-2.9), and abstract presentation (2.3; 95% CI: 1.6-3.0).

CONCLUSIONS

We found that the academic medicine rotation (AMR) is feasible in a large academic setting. Furthermore, the AMR allows early exposure to and improvement in essential non-patient contact related physician skills required by the ACGME core competencies and assessed through the milestones.

Tracking the pharmaceutical pipeline: clinical trials and global disease burden

Aggregate data about pharmaceutical research and development (R&D) tend to examine Phase III trials. Hence, there are few published data about investigational drugs in earlier phases of clinical development that might fail. It is also unclear how well R&D corresponds to disease burden. We track the pharmaceutical pipeline using data from industry publications that provide otherwise unreported information about industry-sponsored clinical trials. The sample includes 2,477 unique drug entities in 4,182 clinical trials. The majority of drugs targeted neoplasms (26.20%), neurological diseases/diseases of the sense organs (13.48%), infectious and parasitic diseases (10.5%), and endocrine, metabolic, nutrition, and immunity disorders (9.45%). Less than 6% of drugs targeted diseases of the circulatory system, which represent the most prevalent causes of global mortality. Detailing the pharmaceutical pipeline, our findings suggest that pharmaceutical development does not adequately address global disease burden. Future research on the under-reported details of Phase I and II clinical trials is needed to understand how the industry operates and how its resource-allocation matches global health concerns.