Bio

Honors & Awards


  • Clinical Scientist in Nephrology Clinical Scholar, American Kidney Fund (2010-2012)

Professional Education


  • Master of Science, Stanford University, EPIDM-MS (2012)
  • Doctor of Medicine, Columbia University, M.D. (2006)
  • Bachelor of Science, Harvard University, Chemistry (2001)
  • Residency, UCLA Medical Center, Internal Medicine (2009)

Stanford Advisors


Research & Scholarship

Current Research and Scholarly Interests


My research interest is in the chronic dialysis population and improving its outcomes, particularly those on home therapies, including peritoneal dialysis. I am currently working on a project to determine the associations among heparin dose during chronic hemodialysis and the risks of important clinical events.

Publications

Journal Articles


  • Use and safety of heparin-free maintenance hemodialysis in the USA NEPHROLOGY DIALYSIS TRANSPLANTATION Shen, J. I., Mitani, A. A., Chang, T. I., Winkelmayer, W. C. 2013; 28 (6): 1589-1602

    Abstract

    BACKGROUND: Although heparin is used to anticoagulate the extracorporeal circuit for most patients on maintenance hemodialysis (HD), some patients undergo heparin-free HD. We describe the determinants of heparin-free HD and its association with adverse outcomes using data from a national dialysis provider merged with Medicare claims. METHODS: We identified patients aged ≥67 years with no recent history of warfarin use who initiated maintenance HD from 2007 to 2008. We applied the Cox regression to a propensity score-matched cohort to estimate the hazards of all-cause mortality, bleeding (gastrointestinal hemorrhage, hemorrhagic stroke, other hemorrhage), atherothrombosis (ischemic stroke, myocardial infarction) and venous thromboembolism (VTE) (deep vein thrombosis, pulmonary embolism). RESULTS: Among 12 468 patients, 836 (6.7%) were dialyzed heparin-free. In multivariable-adjusted analyses, a history of gastrointestinal bleeding, hemorrhagic stroke and lower hemoglobin and platelet counts were associated with higher odds of heparin-free HD. Heparin-free HD use also varied as much as 4-fold by facility region. We found no significant association of heparin-free HD with all-cause mortality [hazard ratio (HR) 1.08; 95% confidence interval (CI): 0.94-1.26], bleeding (HR 1.15; 95% CI: 0.83-1.60), atherothrombosis (HR 1.09, 95% CI: 0.90-1.31) or VTE (HR 1.23, 95% CI: 0.93-1.64) compared with HD with heparin. CONCLUSIONS: Patient markers of increased risk of bleeding and facility region associated with heparin-free HD use. Despite the potential benefits of avoiding heparin use, heparin-free HD was not significantly associated with decreased hazards of death, bleeding or thrombosis, suggesting that it may be no safer than HD with heparin.

    View details for DOI 10.1093/ndt/gft067

    View details for Web of Science ID 000321057700040

    View details for PubMedID 23563280

  • DETERMINANTS OF PERITONEAL DIALYSIS TECHNIQUE FAILURE IN INCIDENT US PATIENTS PERITONEAL DIALYSIS INTERNATIONAL Shen, J. I., Mitani, A. A., Saxena, A. B., Goldstein, B. A., Winkelmayer, W. C. 2013; 33 (2): 155-166

    Abstract

    Switching from peritoneal dialysis (PD) to hemodialysis (HD) is undesirable, because of complications from temporary vascular access, disruption of daily routine, and higher costs. Little is known about the role that social factors play in technique failure. DESIGN, SETTING, PARTICIPANTS, MEASUREMENTS: We followed for 3 years a nationally representative cohort of US patients who initiated PD in 1996 - 1997. Technique failure was defined as any switch from PD to HD for 30 days or more. We used Cox regression to examine associations between technique failure and demographic, medical, social, and pre-dialysis factors. We estimated hazard ratios (HRs) with 95% confidence intervals (CIs).We identified an inception cohort of 1587 patients undergoing PD. In multivariate analysis, female sex (HR: 0.78; 95% CI: 0.64 to 0.95) was associated with lower rates of technique failure, and black race [compared with white race (HR: 1.48; 95% CI: 1.20 to 1.82)] and receiving Medicaid (HR: 1.48; 95% CI: 1.17 to 1.86) were associated with higher rates. Compared with patients who worked full-time, those who were retired (HR: 1.49; 95% CI: 1.07 to 2.08) or disabled (HR: 1.38; 95% CI: 1.01 to 1.88) had higher rates of failure. Patients with a systolic blood pressure of 140 - 160 mmHg had a higher rate of failure than did those with a pressure of 120 - 140 mmHg (HR: 1.24; 95% CI: 1.00 to 1.52). Earlier referral to a nephrologist (>3 months before dialysis initiation) and the primary decision-maker for the dialysis modality (physician vs patient vs shared) were not associated with technique failure.This study confirms that several socio-demographic factors are associated with technique failure, emphasizing the potential importance of social and financial support in maintaining PD.

    View details for DOI 10.3747/pdi.2011.00233

    View details for Web of Science ID 000315995000007

    View details for PubMedID 23032086

  • Anticoagulation for atrial fibrillation in patients on dialysis: are the benefits worth the risks? CURRENT OPINION IN NEPHROLOGY AND HYPERTENSION Shen, J. I., Turakhia, M. P., Winkelmayer, W. C. 2012; 21 (6): 600-606

    Abstract

    Atrial fibrillation is common among patients with end-stage renal disease undergoing hemodialysis. Although oral anticoagulation is recommended for stroke prevention in most patients with atrial fibrillation, limited evidence is available to guide treatment in hemodialysis patients with this arrhythmia. We summarize the available evidence on the epidemiology of atrial fibrillation in dialysis patients and review the data on the effectiveness of oral anticoagulation in this population.Atrial fibrillation is increasingly common in patients undergoing chronic hemodialysis, especially among older patients wherein one in six patients is diagnosed with this arrhythmia. Patients with atrial fibrillation experience double the mortality of otherwise similar patients without it. Few hemodialysis patients with atrial fibrillation receive oral anticoagulation, which is consistently associated with excess risks of hemorrhagic stroke. Observational studies did not detect a beneficial association of oral anticoagulation with the risk of ischemic stroke, with some studies describing higher risks of ischemic stroke among warfarin users. New therapeutic options including one oral direct thrombin inhibitor and two oral factor Xa inhibitors have become available, but were not tested in patients with advanced kidney disease.Atrial fibrillation is increasingly common in patients undergoing hemodialysis, yet little is known about the optimal management of these patients. The current evidence does not support net benefits from oral anticoagulation in the dialysis population.

    View details for DOI 10.1097/MNH.0b013e32835856fd

    View details for Web of Science ID 000310061500006

    View details for PubMedID 23079746

  • Use and Safety of Unfractionated Heparin for Anticoagulation During Maintenance Hemodialysis AMERICAN JOURNAL OF KIDNEY DISEASES Shen, J. I., Winkelmayer, W. C. 2012; 60 (3): 473-486

    Abstract

    Anticoagulation is essential to hemodialysis, and unfractionated heparin (UFH) is the most commonly used anticoagulant in the United States. However, there is no universally accepted standard for its administration in long-term hemodialysis. Dosage schedules vary and include weight-based protocols and low-dose protocols for those at high risk of bleeding, as well as regional anticoagulation with heparin and heparin-coated dialyzers. Adjustments are based largely on clinical signs of under- and overanticoagulation. Risks of UFH use include bleeding, heparin-induced thrombocytopenia, hypertriglyceridemia, anaphylaxis, and possibly bone mineral disease, hyperkalemia, and catheter-associated sepsis. Alternative anticoagulants include low-molecular-weight heparin, direct thrombin inhibitors, heparinoids, and citrate. Anticoagulant-free hemodialysis and peritoneal dialysis also are potential substitutes. However, some of these alternative treatments are not as available as or are more costly than UFH, are dependent on country and health care system, and present dosing challenges. When properly monitored, UFH is a relatively safe and economical choice for anticoagulation in long-term hemodialysis for most patients.

    View details for DOI 10.1053/j.ajkd.2012.03.017

    View details for Web of Science ID 000307941200022

    View details for PubMedID 22560830

  • Outcomes of renal transplantation in recipients with Wegener's granulomatosis CLINICAL TRANSPLANTATION Shen, J., Gill, J., Shangguan, M., Sampaio, M. S., Bunnapradist, S. 2011; 25 (3): 380-387

    Abstract

    Wegener's granulomatosis (WG) is the leading cause of rapidly progressive glomerulonephritis-induced end-stage renal disease (ESRD). In this study, we compared transplant outcomes between recipients with ESRD caused by WG to recipients with ESRD secondary to other causes. Using OPTN/UNOS data from 1996 to 2007, 919 recipients with WG were identified. Post-transplant outcomes included rates of delayed graft function, acute rejection within one-yr post-transplant, overall and death-censored graft survival, and patient survival and were compared between recipients with ESRD secondary to WG versus ESRD from other causes. Recipients with ESRD because of WG had superior unadjusted and adjusted rates of graft loss, patient death, and functional graft loss (adjusted hazard ratio [HR] 0.711, 0.631, and 0.625 respectively, p < 0.001). When we compared the WG cohort to a non-WG, non-diabetic population, the HR for graft loss was still significant, but patient death and death-censored graft loss were not. Subgroup analysis of recipients aged over 60 confirmed that WG recipients had better unadjusted outcomes. This study supports the notion that renal transplantation is an effective treatment option for patients with ESRD secondary to WG. They fare similarly, if not better, than other patients.

    View details for DOI 10.1111/j.1399-0012.2010.01248.x

    View details for Web of Science ID 000291226000026

    View details for PubMedID 20394635

  • Biochemical and genetic conservation of fission yeast dsk1 and human SR protein-specific kinase 1 MOLECULAR AND CELLULAR BIOLOGY Tang, Z. H., Kuo, T., Shen, J., Lin, R. J. 2000; 20 (3): 816-824

    Abstract

    Arginine/serine-rich (RS) domain-containing proteins and their phosphorylation by specific protein kinases constitute control circuits to regulate pre-mRNA splicing and coordinate splicing with transcription in mammalian cells. We present here the finding that similar SR networks exist in Schizosaccharomyces pombe. We previously showed that Dsk1 protein, originally described as a mitotic regulator, displays high activity in phosphorylating S. pombe Prp2 protein (spU2AF59), a homologue of human U2AF65. We now demonstrate that Dsk1 also phosphorylates two recently identified fission yeast proteins with RS repeats, Srp1 and Srp2, in vitro. The phosphorylated proteins bear the same phosphoepitope found in mammalian SR proteins. Consistent with its substrate specificity, Dsk1 forms kinase-competent complexes with those proteins. Furthermore, dsk1(+) gene determines the phenotype of prp2(+) overexpression, providing in vivo evidence that Prp2 is a target for Dsk1. The dsk1-null mutant strain became severely sick with the additional deletion of a related kinase gene. Significantly, human SR protein-specific kinase 1 (SRPK1) complements the growth defect of the double-deletion mutant. In conjunction with the resemblance of dsk1(+) and SRPK1 in sequence homology, biochemical properties, and overexpression phenotypes, the complementation result indicates that SRPK1 is a functional homologue of Dsk1. Collectively, our studies illustrate the conserved SR networks in S. pombe consisting of RS domain-containing proteins and SR protein-specific kinases and thus establish the importance of the networks in eucaryotic organisms.

    View details for Web of Science ID 000084733900010

    View details for PubMedID 10629038

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