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Dive into the research topics where Andrew L. Singer is active.

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Featured researches published by Andrew L. Singer.


World Journal of Gastroenterology | 2017

Hospital resource intensity and cirrhosis mortality in United States

Apurba K. Chakrabarti; Jessica L. Mellinger; Michael L. Volk; Ryan W. Day; Andrew L. Singer; Winston R. Hewitt; Kunam S. Reddy; Adyr A. Moss

AIM To determine whether hospital characteristics predict cirrhosis mortality and how much variation in mortality is attributable to hospital differences. METHODS We used data from the 2005-2011 Nationwide Inpatient Sample and the American Hospital Association Annual survey to identify hospitalizations for decompensated cirrhosis and corresponding facility characteristics. We created hospital-specific risk and reliability-adjusted odds ratios for cirrhosis mortality, and evaluated patient and facility differences based on hospital performance quintiles. We used hierarchical regression models to determine the effect of these factors on mortality. RESULTS Seventy-two thousand seven hundred and thirty-three cirrhosis admissions were evaluated in 805 hospitals. Hospital mean cirrhosis annual case volume was 90.4 (range 25-828). Overall hospital cirrhosis mortality rate was 8.00%. Hospital-adjusted odds ratios (aOR) for mortality ranged from 0.48 to 1.89. Patient characteristics varied significantly by hospital aOR for mortality. Length of stay averaged 6.0 ± 1.6 days, and varied significantly by hospital performance (P < 0.001). Facility level predictors of risk-adjusted mortality were higher Medicaid case-mix (OR = 1.00, P = 0.029) and LPN staffing (OR = 1.02, P = 0.015). Higher cirrhosis volume (OR = 0.99, P = 0.025) and liver transplant program status (OR = 0.83, P = 0.026) were significantly associated with survival. After adjusting for patient differences, era, and clustering effects, 15.3% of variation between hospitals was attributable to differences in facility characteristics. CONCLUSION Hospital characteristics account for a significant proportion of variation in cirrhosis mortality. These findings have several implications for patients, providers, and health care delivery in liver disease care and inpatient health care design.


Clinical Journal of The American Society of Nephrology | 2016

Progression of Interstitial Fibrosis during the First Year after Deceased Donor Kidney Transplantation among Patients with and without Delayed Graft Function

Raymond L. Heilman; Maxwell L. Smith; Byron H. Smith; Ibrahim Qaqish; H. Khamash; Andrew L. Singer; Bruce Kaplan; Kunam S. Reddy

BACKGROUND AND OBJECTIVES Delayed graft function is a form of AKI resulting from ischemia-reperfusion injury. Our aim was to study the effect of delayed graft function on the progression of interstitial fibrosis after deceased donor kidney transplantation. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Our study is a retrospective study of all patients transplanted at our center between July of 2003 and September of 2014 using a kidney from a deceased donor. The primary outcome was the progression of interstitial fibrosis on serial protocol biopsies done during the first year post-transplant. We analyzed the distribution of the change in the Banff interstitial fibrosis (ci) score between the delayed graft function and nondelayed graft function groups for all of the paired biopsies done at time 0 and 12 months post-transplant (Δfibrosis). We also performed a linear mixed model analyzing the difference in the slopes for the progression of mean Banff ci score for all of the biopsies done at time 0 and 1, 4, and 12 months post-transplant. RESULTS There were 343 (36.7%) in the delayed graft function group and 591 in the control group. The biopsy rates for the delayed graft function and nondelayed graft function groups at time 0 were 65.3% (n=224) and 67.0% (n=396), respectively, and at 12 months, they were 64.4% (n=221) and 68.4% (n=404), respectively. Paired biopsies were available for 155 in the delayed graft function group and 283 in the control group. In a risk-adjusted model, Banff ci score >0 on the time 0 biopsy had a higher odds of delayed graft function (odds ratio, 1.70; 95% confidence interval, 1.03 to 2.82). The distribution of the Δfibrosis between 0 and 12 months was similar in delayed graft function and control groups (P=0.91). The slopes representing the progression of fibrosis were also similar between the groups (P=0.66). CONCLUSIONS Donor-derived fibrosis may increase the odds of delayed graft function; however, delayed graft function does not seem to increase the progression of fibrosis during the first year after transplantation.


American Journal of Transplantation | 2016

Rapid Resolution of Donor-Derived Glomerular Fibrin Thrombi after Deceased Donor Kidney Transplantation

R. K. Batra; Raymond L. Heilman; Maxwell L. Smith; L. F. Thomas; H. Khamash; Nitin Katariya; Winston R. Hewitt; Andrew L. Singer; J. Huskey; Harini M Chakkera; Adyr A. Moss; Kunam S. Reddy

The aim of this study was to determine the clinical and histologic outcomes related to transplanting kidneys from deceased donors with glomerular fibrin thrombi (GFT). We included all cases transplanted between October 2003 and October 2014 that had either a preimplantation biopsy or an immediate postreperfusion biopsy showing GFT. The study cohort included 61 recipients (9.9%) with GFT and 557 in the control group without GFT. Delayed graft function occurred in 49% of the GFT group and 39% in the control group (p = 0.14). Serum creatinine at 1, 4, and 12 months and estimated GFR at 12 months were similar in the two groups. Estimated 1‐year graft survival was 93.2% in the GFT group and 95.1% in the control group (p = 0.22 by log‐rank). Fifty‐two of the 61 patients in the GFT group (85%) had a 1‐month protocol biopsy, and only two biopsies (4%) showed residual focal glomerular thrombi. At the 1‐year protocol biopsy, the prevalence of moderate to severe interstitial fibrosis and tubular atrophy was 24% in the GFT group and 30% in the control group (p = 0.42). We concluded that GFT resolves rapidly after transplantation and that transplanting selected kidneys from deceased donors with GFT is a safe practice.


Journal of the American Heart Association | 2018

Cardiorespiratory fitness (peak oxygen uptake): Safe and effective measure for cardiovascular screening before kidney transplant

Harini A. Chakkera; Siddhartha S. Angadi; Raymond L. Heilman; Bruce Kaplan; Robert L. Scott; Harini Bollempalli; Stephen S. Cha; H. Khamash; J. Huskey; Girish K. Mour; Sumi Sukumaran Nair; Andrew L. Singer; Kunam S. Reddy; Adyr A. Moss; Winston R. Hewitt; Ibrahim Qaqish; Senaida Behmen; Mira T. Keddis; Samuel Unzek; D. Eric Steidley

Background Significant heterogeneity exists in practice patterns and algorithms used for cardiac screening before kidney transplant. Cardiorespiratory fitness, as measured by peak oxygen uptake (VO2peak), is an established validated predictor of future cardiovascular morbidity and mortality in both healthy and diseased populations. The literature supports its use among asymptomatic patients in abrogating the need for further cardiac testing. Methods and Results We outlined a pre–renal transplant screening algorithm to incorporate VO 2peak testing among a population of asymptomatic high‐risk patients (with diabetes mellitus and/or >50 years of age). Only those with VO 2peak <17 mL/kg per minute (equivalent to <5 metabolic equivalents) underwent further noninvasive cardiac screening tests. We conducted a retrospective study of the a priori dichotomization of the VO 2peak <17 versus ≥17 mL/kg per minute to determine negative and positive predictive value of future cardiac events and all‐cause mortality. We report a high (>90%) negative predictive value, indicating that VO 2peak ≥17 mL/kg per minute is effective to rule out future cardiac events and all‐cause mortality. However, lower VO 2peak had low positive predictive value and should not be used as a reliable metric to predict future cardiac events and/or mortality. In addition, a simple mathematical calculation documented a cost savings of ≈


American Journal of Transplantation | 2017

PROviding Better ACcess To ORgans: A comprehensive overview of organ-access initiatives from the ASTS PROACTOR Task Force

Mark J. Hobeika; Charles M. Miller; Timothy L. Pruett; K. A. Gifford; Jayme E. Locke; Andrew M. Cameron; Michael J. Englesbe; Christian S. Kuhr; Joseph F. Magliocca; K. R. McCune; Kristin L. Mekeel; Shawn J. Pelletier; Andrew L. Singer; Dorry L. Segev

272 600 in the cardiac screening among our study cohort of 637 patients undergoing evaluation for kidney and/or pancreas transplant. Conclusions We conclude that incorporating an objective measure of cardiorespiratory fitness with VO 2peak is safe and allows for a cost savings in the cardiovascular screening protocol among higher‐risk phenotype (with diabetes mellitus and >50 years of age) being evaluated for kidney transplant.


Clinical Transplantation | 2016

Glucose homeostasis after simultaneous pancreas and kidney transplantation: a comparison of subjects with C-peptide-positive non-type 1 diabetes mellitus and type 1 diabetes mellitus.

Harini A. Chakkera; Yogish C. Kudva; Yu Hui H Chang; Raymond L. Heilman; Andrew L. Singer; Winston R. Hewitt; H. Khamash; J. Huskey; Nitin Katariya; Adyr A. Moss; Senaida Behmen; Kunam S. Reddy

The American Society of Transplant Surgeons (ASTS) PROviding better Access To Organs (PROACTOR) Task Force was created to inform ongoing ASTS organ access efforts. Task force members were charged with comprehensively cataloguing current organ access activities and organizing them according to stakeholder type. This white paper summarizes the task force findings and makes recommendations for future ASTS organ access initiatives.


Transplantation Proceedings | 2016

Do Patient Assessments of Hospital Quality Correlate With Kidney Transplantation Surgical Outcomes

Apurba K. Chakrabarti; K.H. Sheetz; Nitin Katariya; Andrew L. Singer; Winston R. Hewitt; Raymond L. Heilman; H. Khamash; Kunam S. Reddy; Adyr A. Moss

While simultaneous pancreas kidney transplant (SPKTx) is a therapeutic option for patients with type 1 diabetes (T1DM) and renal failure, few centers offer SPKTx to “select” non‐T1DM patients. To address concerns that existing insulin resistance may limit the benefits of the pancreas allograft among non‐T1DM, we compared several indices of glucose homeostasis, in “select” non‐T1DM and T1DM patients who received SPKTx.


Hpb | 2016

Laparoscopic hand-assisted distal pancreatectomy

Nitin Katariya; Andrew L. Singer; Winston R. Hewitt; Kunam S. Reddy; Adyr A. Moss


Hpb | 2016

Endovascular salvage of a pancreas allograft with large AV fistula and aneurysm

Nitin Katariya; Adyr A. Moss; Kunam S. Reddy; Winston R. Hewitt; E. Huettl; S. Naidu; Andrew L. Singer


Experimental and Clinical Transplantation | 2015

Public health safety and transplant with increased-risk organs: Striking the balance

R. K. Batra; Nitin Katariya; Winston R. Hewitt; Amit Mathur; Sudhakar Reddy; Adyr A. Moss; Dorry L. Segev; Andrew L. Singer

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