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Bio

Clinical Focus


  • Nephrology

Academic Appointments


Professional Education


  • Master of Public Health, University of North Carolina, Chapel Hill (2013)
  • Doctor of Medicine, University of North Carolina, Chapel Hill (2014)
  • Bachelor of Arts, Princeton University (2009)
  • Fellowship: Stanford University Nephrology Fellowship (2020) CA
  • Board Certification: American Board of Internal Medicine, Internal Medicine (2017)
  • Residency: University of Miami Jackson Memorial Hospital Internal Med Residency (2017) FL
  • Medical Education: University of North Carolina School of Medicine (2014) NC

Stanford Advisors


Publications

All Publications


  • Karnofsky Performance Score-Failure to Thrive as a Frailty Proxy? Transplantation direct Stedman, M. R., Watford, D. J., Chertow, G. M., Tan, J. C. 2021; 7 (7): e708

    Abstract

    Among patients listed for kidney transplantation, the Karnofsky Performance Status (KPS) Scale has been used as a proxy for frailty and proposed as a predictor of long-term posttransplant outcomes. The KPS is required by the Organ Procurement and Transplantation Network for all transplants; however, the interrater reliability of KPS reporting in kidney transplant candidates has not been well investigated, and there is concern regarding limitations of using KPS that may influence transplant eligibility.Methods: We performed an observational study using existing Scientific Registry of Transplant Recipients data from 2006 to 2020 to examine the variability, reliability, and trends in the KPS among patients on the kidney transplant waitlist.Results: Our analysis included 8197 kidney transplant candidates with >1 KPS in a 3-mo period. We observed 2-7 scores per patient with an average score of 78.9 (SD = 12, 95% confidence interval, 78.8-79.1). We found substantial variability in KPS reporting, in which 27% of the patients had scores that varied widely with 20-80 points in difference. Interrater reliability in the 10-point scale was poor (30%). When using a condensed 4-category scale (disabled, requires assistance, capable of self-care, normal activity), 38% of patients experienced at least a 1-category shift in their score.Conclusions: The lack of reliability in KPS reporting raises concerns when applying the KPS as a proxy for frailty and a metric to be considered when evaluating candidacy for kidney transplantation.

    View details for DOI 10.1097/TXD.0000000000001164

    View details for PubMedID 34124344

  • Performance versus Risk Factor-Based Approaches to Coronary Artery Disease Screening in Waitlisted Kidney Transplant Candidates. Cardiorenal medicine Cheng, X. S., Watford, D. J., Arashi, H., Stedman, M. R., Chertow, G. M., Tan, J. C., Fearon, W. F. 2021: 1-11

    Abstract

    INTRODUCTION: Current screening algorithms for coronary artery disease (CAD) before kidney transplantation result in many tests but few interventions.OBJECTIVE: The aim of this study was to study the utility of 6-minute walk test (6MWT), an office-based test of cardiorespiratory fitness, for risk stratification in this setting.METHODS: We enrolled 360 patients who are near the top of the kidney transplant waitlist at our institution. All patients underwent CAD evaluation irrespective of 6MWT results. We examined the association between 6MWT and time to CAD-related events (defined as cardiac death, revascularization, nonfatal myocardial infarction, and removal from the waitlist for CAD), treating noncardiac death and waitlist removal for non-CAD reasons as competing events.RESULTS: The 6MWT-based approach designated approximately 45% of patients as "low risk," whereas a risk factor- or symptom-based approach designated 14 and 81% of patients as "low risk," respectively. The 6MWT-based approach was not significantly associated with CAD-related events within 1 year (subproportional hazard ratio [sHR] 1.00 [0.90-1.11] per 50 m) but was significantly associated with competing events (sHR 0.70 [0.66-0.75] per 50 m). In a companion analysis, removing waitlist status from consideration, 6MWT result was associated with the development of CAD-related events (sHR 0.92 [0.84-1.00] per 50 m).CONCLUSIONS: The 6MWT designates fewer patients as high risk and in need of further testing (compared to risk factor-based approaches), but its utility as a pure CAD risk stratification tool is modulated by the background waitlist removal rate. CAD screening before kidney transplant should be tailored according to a patient's actual chance of receiving a transplant.

    View details for DOI 10.1159/000516158

    View details for PubMedID 34034263

  • Race and Place in ESKD. Kidney international reports Watford, D. J., Chertow, G. M. 2021; 6 (2): 252?53

    View details for DOI 10.1016/j.ekir.2020.11.027

    View details for PubMedID 33617609

  • Physical Performance Testing in Kidney Transplant Candidates at the Top of the Waitlist. American journal of kidney diseases : the official journal of the National Kidney Foundation Cheng, X. S., Myers, J. n., Han, J. n., Stedman, M. R., Watford, D. J., Lee, J. n., Discipulo, K. V., Chan, K. N., Chertow, G. M., Tan, J. C. 2020

    Abstract

    Frailty and poor physical function are associated with adverse kidney transplant outcomes, but how to incorporate this knowledge into clinical practice is uncertain. We studied the association between measured physical performance and clinical outcomes among patients on kidney transplant waitlists.Prospective observational cohort study.We studied consecutive patients evaluated in our Transplant Readiness Assessment Clinic, a top-of-the-waitlist management program, from May 2017 through December 2018 (N=305). We incorporated physical performance testing, including the 6-minute walk test (6MWT) and the sit-to-stand (STS) test, into routine clinical assessments.6MWT and STS test results.Primary - Time to adverse waitlist outcomes (removal from waitlist or death). Secondary - Time to transplantation, time to death.We used linear regression to examine the relationship between clinical characteristics and physical performance test results. We used subdistribution hazards models to examine the association between physical performance test results and outcomes.Median 6MWT and STS results were 393 meters (25th- 75th percentile range 305-455) and 17 repetitions (25th- 75th percentile range 12-21), respectively. Clinical characteristics and Estimated Post-Transplant Survival scores only accounted for 14-21% of the variance in 6MWT/STS results. 6MWT/STS results were associated with adverse waitlist outcomes (adjusted subdistribution hazard ratio [sHR] of 1.42 [95% confidence interval 1.30-1.56 per 50-meter lower in 6MWT and 1.53 [95% confidence interval 1.33-1.75] per 5-repetition lower in STS), and with transplantation (adjusted sHR of 0.80 [95% confidence interval 0.72-0.88] per 50-meter lower in 6MWT and 0.80 [95% confidence interval 0.71-0.89] per 5-repetition lower in STS). Addition of either STS or 6MWT to survival models containing clinical characteristics enhanced fit (likelihood ratio test p<0.001).Single-center observational study. Other measures of global health status (e.g., Fried frailty index or short physical performance battery) were not examined.Among waitlisted kidney transplant candidates with high Kidney Allocation Scores, standardized and easily performed physical performance test results are associated with waitlist outcomes and contain information beyond what is currently routinely collected in clinical practice.

    View details for DOI 10.1053/j.ajkd.2020.04.009

    View details for PubMedID 32512039

  • Toward telemedicine-compatible physical functioning assessments in kidney transplant candidates. Clinical transplantation Watford, D. J., Cheng, X. S., Han, J. n., Stedman, M. R., Chertow, G. M., Tan, J. C. 2020: e14173

    Abstract

    Frailty is associated with adverse kidney transplant outcomes and can be assessed by subjective and objective metrics. There is increasing recognition of the value of metrics obtainable remotely. We compared the self-reported SF-36 physical functioning subscale score (SF-36 PF) with in-person physical performance tests (6-minute walk and sit-to-stand) in a prospective cohort of kidney transplant candidates. We assessed each metric's ability to predict time to the composite outcome of waitlist removal or death, censoring at transplant. We built time-dependent receiver operating characteristic curves and calculated the area under the curve [AUC(t)] at 1 year, using bootstrapping for internal validation. In 199 patients followed for a median of 346 days, 41 reached the composite endpoint. Lower SF-36 PF scores were associated with higher risk of waitlist removal/death, with every 10-point decrease corresponding to a 16% increase in risk. All models showed an AUC(t) of 0.83-0.84 that did not contract substantially after internal validation. Among kidney transplant candidates, SF-36 PF, obtainable remotely, can help to stratify the risk of waitlist removal or death, and may be used as a screening tool for poor physical functioning in ongoing candidate evaluation, particularly where travel, increasing patient volume, or other restrictions challenge in-person assessment.

    View details for DOI 10.1111/ctr.14173

    View details for PubMedID 33247983

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