Diabetes, its duration, and the long-term risk of abdominal aortic aneurysm: The Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND AND AIMS

We aimed at comprehensively evaluate the independent association of diabetes and its duration with incident abdominal aortic aneurysm (AAA) and aortic diameter.

METHODS AND RESULTS

We prospectively studied incident AAA according to baseline glycemic status (diabetes, prediabetes, normal glycemia) in 13,116 ARIC participants (1990-1992) and the time-varying exposure of duration post incident diabetes in 11,675 participants (1987-1989) using Cox models. Additionally, we cross-sectionally explored ultrasound-based abdominal aortic diameter by glycemic status and cumulative duration of diabetes in 4710 participants (2011-2013) using linear regression models. Over ~20 years of follow-up, diabetes (vs. normal glycemia) at baseline was independently associated with lower AAA risk (489 cases) (hazard ratio: 0.71 [95%CI 0.51-0.99]), especially after 10 years (hazard ratio: 0.58 [0.38-0.87]). Prediabetes did not demonstrate an independent association. The inverse association was more evident with longer duration of diabetes (p for trend = 0.045), with 30-50% lower risk in eight years after diabetes diagnosis. The cross-sectional analysis demonstrated smaller aortic diameters with longer duration of diabetes (e.g., -0.76 mm [-1.24, -0.28] in diabetes with 8-12 years) compared to non-diabetes, whereas prediabetes consistently showed nominally greater diameter.

CONCLUSIONS

Diabetes, especially with longer duration, but not prediabetes, was independently associated with lower risk of AAA and smaller aortic diameter. Our findings suggest that long lasting clinical hyperglycemia plays an important role in the reduced AAA risk, and the reduced aortic diameter may be a structural mechanism behind this paradoxical association.

Heat-capacity measurements under uniaxial pressure using a piezo-driven device

We report the development of a technique to measure heat capacity at large uniaxial pressure using a piezoelectric-driven device generating compressive and tensile strain in the sample. Our setup is optimized for temperatures ranging from 8 K down to millikelvin. Using an AC heat-capacity technique, we are able to achieve an extremely high resolution and to probe a homogeneously strained part of the sample. We demonstrate the capabilities of our setup on the unconventional superconductor Sr₂RuO₄. By replacing thermometer and adjusting the remaining setup accordingly, the temperature regime of the experiment can be adapted to other temperature ranges of interest.

Glycemic control and diabetic foot ulcer outcomes: A systematic review and meta-analysis of observational studies

OBJECTIVE

To evaluate the association between glycemic control (hemoglobin A1C, fasting glucose, and random glucose) and the outcomes of wound healing and lower extremity amputation (LEA) among patients with diabetic foot ulcers (DFUs).

RESEARCH DESIGN AND METHODS

Medline, EMBASE, Cochrane Library, and Scopus were searched for observational studies published up to March 2019. Five independent reviewers assessed in duplicate the eligibility of each study based on predefined eligibility criteria and two independent reviewers assessed risk of bias. Ameta-analysis was performed to calculate a pooled odds ratio (OR) or hazard ratio (HR) using random effects for glycemic measures in relation to the outcomes of wound healing and LEA. Subgroup analyses were conducted to explore potential source of heterogeneity between studies. The study protocol is registered with PROSPERO (CRD42018096842).

RESULTS

Of 4572 study records screened, 60 observational studies met the study eligibility criteria of which 47 studies had appropriate data for inclusion in one or more meta-analyses(n = 12,604 DFUs). For cohort studies comparing A1C >7.0 to 7.5% vs. lower A1C levels, the pooled OR for LEA was 2.04 (95% CI, 0.91, 4.57) and for studies comparing A1C ≥ 8% vs. <8%, the pooled OR for LEA was 4.80 (95% CI 2.83, 8.13). For cohort studies comparing fasting glucose ≥126 vs. <126 mg/dl, the pooled OR for LEA was 1.46 (95% CI, 1.02, 2.09). There was no association with A1C category and wound healing (OR or HR). There was high risk of bias with respect to comparability of cohorts as many studies did not adjust for potential confounders in the association between glycemic control and DFU outcomes.

CONCLUSIONS

Our findings suggest that A1C levels ≥8% and fasting glucose levels ≥126 mg/dl are associated with increased likelihood of LEA in patients with DFUs. A purposively designed prospective study is needed to better understand the mechanisms underlying the association between hyperglycemia and LEA.

Impact of Geographic Socioeconomic Disadvantage on Minor Amputation Outcomes in Patients With Diabetes

BACKGROUND

Socioeconomic disadvantage is a known contributor to adverse events and higher admission rates in the diabetic population. However, its impact on outcomes after lower extremity amputation is unclear. We aimed to assess the association of geographic socioeconomic disadvantage with short- and long-term outcomes after minor amputation in patients with diabetes.

MATERIALS AND METHODS

Geographic socioeconomic disadvantage was determined using the area deprivation index (ADI). All patients from the Maryland Health Services Cost Review Commission database (2012-2019) who underwent minor amputation with a concurrent diagnosis of diabetes were included and stratified by the ADI quartile. Associations of the ADI quartile with 30-day readmission and 1-year reamputation were evaluated using Kaplan-Meier survival analyses and multivariable logistic regression models adjusting for baseline differences.

RESULTS

A total of 7415 patients with diabetes underwent minor amputation (70.1% male, 38.7% black race), including 28.1% ADI1 (least deprived), 42.8% ADI2, 22.9% ADI3, and 6.2% ADI4 (most deprived). After adjusting for demographic and clinical factors, the odds of 30-day readmission were greater in the intermediate ADI groups than those in the ADI1 group, but not among the most deprived. Adjusted odds of 1-year reamputation were greater among ADI4 than those among ADI1. Kaplan-Meier analysis confirmed a greater likelihood of reamputation with an increasing ADI quartile over a 1-year period (P < 0.001).

CONCLUSIONS

Geographic socioeconomic disadvantage is independently associated with both short- and long-term outcomes after minor diabetic amputations in Maryland. A targeted approach addressing the health care needs of deprived regions may be beneficial in optimizing postoperative care in this vulnerable population.

Deep Learning and Multivariable Models Select EVAR Patients for Short-Stay Discharge

OBJECTIVES

We sought to develop a prediction score with data from the Vascular Quality Initiative (VQI) EVAR in efforts to assist endovascular specialists in deciding whether or not a patient is appropriate for short-stay discharge.

BACKGROUND

Small series describe short-stay discharge following elective EVAR. Our study aims to quantify characteristics associated with this decision.

METHODS

The VQI EVAR and NSQIP datasets were queried. Patients who underwent elective EVAR recorded in VQI, between 1/2010-5/2017 were split 2:1 into test and analytic cohorts via random number assignment. Cross-reference with the Medicare claims database confirmed all-cause mortality data. Bootstrap sampling was employed in model. Deep learning algorithms independently evaluated each dataset as a sensitivity test.

RESULTS

Univariate outcomes, including 30-day survival, were statistically worse in the DD group when compared to the SD group (all P < 0.05). A prediction score, SD-EVAR, derived from the VQI EVAR dataset including pre- and intra-op variables that discriminate between SD and DD was externally validated in NSQIP (Pearson correlation coefficient = 0.79, P < 0.001); deep learning analysis concurred. This score suggests 66% of EVAR patients may be appropriate for short-stay discharge. A free smart phone app calculating short-stay discharge potential is available through QxMD Calculate https://qxcalc.app.link/vqidis.

CONCLUSIONS

Selecting patients for short-stay discharge after EVAR is possible without increasing harm. The majority of infrarenal AAA patients treated with EVAR in the United States fit a risk profile consistent with short-stay discharge, representing a significant cost-savings potential to the healthcare system.

Contemporary Trends in Physician Utilization Rates of CEA and CAS for Asymptomatic Carotid Stenosis among Medicare Beneficiaries

BACKGROUND

Carotid revascularization for asymptomatic carotid artery stenosis (ACAS) has become increasingly controversial in the past few decades as the best medical therapy has improved. The aim of this study was to assess and define contemporary trends in the rate of carotid revascularization procedures for ACAS in the United States and to characterize outlier physicians performing a higher rate of asymptomatic revascularization compared to their peers.

METHODS

We used 100% Medicare fee-for-service claims to identify all patients who were newly diagnosed with ACAS between 01/2011-06/2018. Patients with symptomatic carotid artery stenosis, those with prior carotid revascularization, and surgeons who performed ≤10 CEAs during the study period were excluded. We used a hierarchical multivariable logistic regression model to evaluate patient and physician characteristics associated with undergoing a carotid endarterectomy or carotid artery stent procedure within 3 months after the initial diagnosis of ACAS. We also assessed temporal trends in carotid revascularization rates over time using the Cochran-Armitage Trend Test.

RESULTS

Overall, 795,512 patients (median age 73.9 years, 50.9% male, 87.6% white) had a first-time diagnosis of ACAS during the study period, of which 23,481 (3.0%) underwent carotid revascularization within 3 months. There was a significant decline in overall carotid artery revascularization rates over time (2011: 3.2% vs. 2018: 2.1%; P < 0.001). The median and mean physician-specific carotid revascularization rates were 2.0% (IQR 0.0%-6.3%) and 4.7% ± 7.1%, respectively. Three-hundred and fifty physicians (5.2%) had carotid revascularization rates ≥19%, which was more than 2 standard deviations above the mean. After adjusting for patient-level characteristics, physician-level variables associated with carotid revascularization for newly diagnosed ACAS included male sex (adjusted OR 1.59, 95% CI 1.35-1.89), more years in practice (≥31 vs. <10 years, aOR 1.64, 95% CI 1.32-2.04), rural practice location (aOR 1.34, 95% CI 1.18-1.52), Southern region practice location (versus Northeast, aOR 1.54, 95% CI 1.39-1.69), and lower volume of ACAS patients (lower versus upper tertile, aOR 2.62, 95% CI 2.39-2.89). Cardiothoracic surgeons had a 1.52-fold higher odds of carotid revascularization compared to vascular surgeons (95% CI 1.36-1.68), whereas cardiologists and radiologists had lower intervention rates (both, P < 0.05).

CONCLUSIONS

The current early revascularization rate for newly diagnosed ACAS is <5% among proceduralists in the United States, and has been decreasing steadily since 2014. There are particular physician-level characteristics that are associated with higher rates of carotid revascularization that cannot be fully contextualized without high-level contemporary outcomes data to guide decision making in ACAS.

Using Uniaxial Stress to Probe the Relationship between Competing Superconducting States in a Cuprate with Spin-stripe Order

We report muon spin rotation and magnetic susceptibility experiments on in-plane stress effects on the static spin-stripe order and superconductivity in the cuprate system La_{2-x}Ba_{x}CuO_{4} with x=0.115. An extremely low uniaxial stress of ∼0.1  GPa induces a substantial decrease in the magnetic volume fraction and a dramatic rise in the onset of 3D superconductivity, from ∼10 to 32 K; however, the onset of at-least-2D superconductivity is much less sensitive to stress. These results show not only that large-volume-fraction spin-stripe order is anticorrelated with 3D superconducting coherence but also that these states are energetically very finely balanced. Moreover, the onset temperatures of 3D superconductivity and spin-stripe order are very similar in the large stress regime. These results strongly suggest a similar pairing mechanism for spin-stripe order and the spatially modulated 2D and uniform 3D superconducting orders, imposing an important constraint on theoretical models.

Regional Market Competition is Associated with Aneurysm Diameter at the Time of EVAR

BACKGROUND

Local market competition has been previously associated with more aggressive surgical decision-making. For example, more local competition for organs is associated with acceptance of lower quality kidney offers in transplant surgery. We hypothesized that market competition would be associated with the size of an abdominal aortic aneurysm (AAA) at the time of elective endovascular aneurysm repair (EVAR).

METHODS

We included all elective EVARs reported in the Vascular Quality Initiative database (2012-2018). Small AAAs were defined as a maximum diameter <5.5 cm in men or <5.0 cm in women. We calculated the Herfindahl-Hirschman Index (HHI), a measure of physician market concentration (higher HHI = less market competition), for each US census region. Multilevel regression was used to examine the association between the size of AAA at EVAR and HHI, clustering by region.

RESULTS

Of 37,914 EVARs performed, 15,379 (40.6%) were for small AAAs. There was significant variation in proportion of EVARs performed for small AAAs across regions (P < 0.001). The South had both the highest proportion of EVARs for small AAAs (44.2%) as well as the highest market competition (HHI 50), whereas the West had the lowest proportion of EVARs for small AAAs (35.0%) and the lowest market competition (HHI 107). Adjusting for patient characteristics, each 10 unit increase in HHI was associated with a 0.1 mm larger maximum AAA diameter at the time of EVAR (95% CI 0.04-0.24 mm, P = 0.005).

CONCLUSIONS

Physician market concentration is independently associated with AAA diameter at time of elective EVAR. These data suggest that physician decision-making for EVAR is impacted by market competition.

Assessment of Use of Arteriovenous Graft vs Arteriovenous Fistula for First-time Permanent Hemodialysis Access

Importance

Initial hemodialysis access with arteriovenous fistula (AVF) is associated with superior clinical outcomes compared with arteriovenous graft (AVG) and should be the procedure of choice whenever possible. To address the national underuse of AVF in the United States, the Centers for Medicare & Medicaid has established an AVF goal of 66% or greater in 2009.

Objective

To explore contemporary practice patterns and physician characteristics associated with high AVG use compared with AVF use.

Design, Setting, and Participants

This review of 100% Medicare Carrier claims between January 1, 2016, and December 31, 2017, includes both inpatient and outpatient Medicare claims data. All patients undergoing initial permanent hemodialysis access placement with an AVF or AVG were included. All surgeons performing more than 10 hemodialysis access procedures during the study period were analyzed.

Exposures

Placement of an AVF or AVG for initial permanent hemodialysis access.

Main Outcomes and Measures

A surgeon-level AVG (vs AVF) use rate was calculated for all included surgeons. Hierarchical logistic regression modeling was used to identify patient-level and surgeon-level factors associated with AVG use.

Results

A total of 85 320 patients (median age, 70 [range, 18-103] years; 47 370 men [55.5%]) underwent first-time hemodialysis access placement, of whom 66 489 (77.9%) had an AVF and 18 831 (22.1%) had an AVG. Among the 2397 surgeons who performed more than 10 procedures per year, the median surgeon level AVG use rate was 18.2% (range, 0.0%-96.4%). However, 498 surgeons (20.8%) had an AVG use rate greater than 34%. After accounting for patient characteristics, surgeon factors that were independently associated with AVG use included more than 30 years of clinical practice (vs 21-30 years; odds ratio, 0.85 [95% CI, 0.75-0.96]), metropolitan setting (odds ratio, 1.25 [95% CI, 1.02-1.54]), and vascular surgery specialty (vs general surgery; odds ratio, 0.77 [95% CI, 0.69-0.86]). Surgeons in the Northeast region had the lowest rate of AVG use (vs the South; odds ratio, 0.83 [95% CI, 0.73-0.96]). First-time hemodialysis access benchmarking reports for individual surgeons were created for potential distribution.

Conclusions and Relevance

In this study, one-fifth of surgeons had an AVG use rate above the recommended best practices guideline of 34%. Although some of these differences may be explained by patient referral practices, sharing benchmarked performance data with surgeons could be an actionable step in achieving more high-value care in hemodialysis access surgery.

Cost Awareness of Common Supplies Is Severely Impaired Among All Members of the Surgical Team

BACKGROUND

Increased health care spending concerns have generated interest in reducing operating room (OR) costs, but the cost awareness of the surgical team selecting intraoperative supplies remains unclear. This work characterizes knowledge of supply cost among surgeons and OR staff in a large academic hospital and seeks to examine the role of experience and training with regards to cost insight.

METHODS

This work is a cross-sectional study of surgeons, trainees, nurses, and surgical technicians (n = 372) across all surgical specialties at a large academic hospital. Participants completed a survey reporting frequency of use and estimated cost for 11 common surgical supplies as well as opinions on access to cost information in the OR. Cost estimation error was expressed as the ratio of estimated-to-actual cost, and groups were compared with one-way analysis of variance and chi-squared testing. Spearman correlation (ρ) was used to describe the relationship between monotonic variables.

RESULTS

Overestimation error was universal and ranged widely (3.80-49.79). There was no significant difference in estimation accuracy when stratified by role or years of experience. Less expensive items had higher rates of estimation error than more expensive items (P < 0.001), and a moderately strong relationship was found between decreased item cost and increased estimation error (ρ: 0.49). The overwhelming majority (91%) of respondents expressed a desire to learn more about supply pricing.

CONCLUSIONS

Price knowledge of common supplies is globally impaired for entire surgical team but coexists with a strong desire to augment cost awareness. Improved access to cost information has a high potential to inform surgical decision-making and decrease OR waste.

Sex does not have an impact on perioperative transfemoral carotid artery stenting outcomes among octogenarians

OBJECTIVE

Transfemoral carotid artery stenting (CAS) has been validated as an acceptable alternative to carotid endarterectomy in patients at high risk for open surgery. There are variable sex- and age-based differences in transfemoral CAS outcomes of published randomized controlled trials. The aim of our study was to evaluate sex-based differences in perioperative outcomes after transfemoral CAS performed in octogenarians.

METHODS

The National Surgical Quality Improvement Program targeted vascular module was queried for all patients ≥80 years of age who underwent transfemoral CAS between 2011 and 2017. Symptomatic status was defined as a history of prior ipsilateral stroke, transient ischemic attack, or amaurosis fugax. The primary outcome was a composite outcome of perioperative (30-day) stroke or death. Outcomes were compared for male vs female patients and stratified by symptomatic status using univariate and multivariable logistic regression analyses adjusting for emergent status, symptomatic status, comorbidities, and use of an embolic protection device.

RESULTS

Overall, there were 143 patients ≥80 years of age who underwent transfemoral CAS during the study period, including 95 men (66.4%) and 48 women (33.6%). Race (white, 88.0% vs 85.4%), symptomatic status (30.9% vs 29.2%), and degree of stenosis (severe, 71.6% vs 62.5%) were not significantly different for men vs women (P ≥ .27). Periprocedural stroke/death occurred in six men (6.4%) vs two women (4.2%; P = .59) and did not significantly differ when stratified according to symptomatic (6.9% vs 7.1%; P = .98) and asymptomatic (6.2% vs 2.9%; P = .49) status. Based on multivariable analysis, independent factors associated with the composite end point included emergent vs elective status (adjusted odds ratio OR [aOR], 20.3; 95% confidence interval [CI], 2.25-183) and failure to use an embolic protection device (aOR, 2.86; 95% CI, 1.59-50.0). Sex was not significantly associated with the primary outcome after risk adjustment (aOR, 0.81; 95% CI, 0.28-3.28).

CONCLUSIONS

We found no sex-based differences in risk of perioperative stroke/death among patients ≥80 years of age undergoing transfemoral CAS. Our study validates previous studies showing a high rate of perioperative complications after transfemoral CAS in octogenarians and suggests that the decision to use this technology in older patients should be determined by patients' anatomic and medical risk factors irrespective of sex.

Race and socioeconomic differences associated with endovascular peripheral vascular interventions for newly diagnosed claudication

BACKGROUND

Despite guidelines cautioning against the use of endovascular peripheral vascular interventions (PVI) for claudication, more than 1.3 million PVI procedures are performed annually in the United States. We aimed to describe national rates of PVI for claudication, and identify patient and county-level risk factors associated with a high rate of PVI.

METHODS

We used the Medicare claims database to identify all Medicare beneficiaries with a new diagnosis of claudication between January 2015 and June 2017. A hierarchical logistic regression model accounting for patient age, sex, comorbidities; county region and setting; and a patient race-county median income interaction was used to assess the associations of race and income with a high PVI rate.

RESULTS

We identified 1,201,234 patients with a new diagnosis of claudication for analysis. Of these, 15,227 (1.27%) underwent a PVI. Based on hierarchical logistic regression accounting for patient and county-level factors, black patients residing in low-income counties had a significantly higher odds of undergoing PVI than their white counterparts (odds ratio [OR], 1.30; 95% confidence interval [CI], 1.20-1.40), whereas the odds of PVI for black versus white patients was similar in high-income counties (OR, 1.06; 95% CI, 0.99-1.14). PVI rates were higher for low versus high-income counties in both the black (OR, 1.46; 95% CI, 1.31-1.64) and white (OR, 1.19; 95% CI, 1.12-1.27) groups. There were no significant associations of Hispanic, Asian, North American native, or other races with PVI in either low- or high-income counties after risk adjustment (all P ≥ .09).

CONCLUSIONS

In the Medicare population, the mean rate of PVI of 12.7 per 1000 claudication patients varies significantly based on race and income. Our data suggest there are racial and socioeconomic differences in the treatment of claudication across the United States.

Race and sex-based disparities associated with carotid endarterectomy in the Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND AND AIMS

The indications for carotid endarterectomy (CEA) are well established. The aim of the current study was to investigate sex and race-based disparities in the incidence of CEA after adjusting for carotid artery stenosis risk factors.

METHODS

We conducted a prospective cohort analysis of 14,492 black and white participants in the Atherosclerosis Risk in Communities (ARIC) study without prevalent stroke at baseline (1987-1989). We used Kaplan-Meier curves and Cox proportional hazards models adjusting for sociodemographic, cardiovascular, and disease severity risk factors to quantify the associations of sex and race with incident CEA.

RESULTS

CEA was performed in 330 of 14,492 ARIC participants during a median of 27 years of follow-up [incidence rate 1.00 (95% CI 0.90-1.12) per 1000 persons-years]. The crude incidence of CEA varied significantly by sex [female vs. male: HR 0.60 (95% CI 0.48-0.74)] and race [black vs. white: HR 0.65 (95% CI 0.49-0.86)]. Adjustment for sociodemographic and cardiovascular risk factors, carotid intima-media thickness, and symptomatic status attenuated the association of sex with CEA [females vs. males HR 0.96 (0.76-1.22)], but black participants had a lower risk of incident CEA after adjustment [HR 0.68 (95% CI 0.49-0.95)].

CONCLUSIONS

We found significant variation in the incidence of CEA procedures based on race that was independent of traditional risk factors and carotid IMT. Whether this disparity is a reflection of differences in disease presentation or access to care deserves investigation.