Sharon Xiangwen Xie, Ph.D.

Sharon Xiangwen Xie, Professor of Biostatistics, joined the biostatistics faculty in April 2002. Dr. Xie is currently principal investigator of a NIH-funded statistical method R01 grant that aims to develop novel statistical methods for assessing dementia risk in Parkinson's disease and related disorders. Dr. Xie is also the principal investigator of the biostatistics and data management core for three NIH-funded neurodegenerative disease research centers/program project grants: the Alzheimer's Disease Center, the Morris K. Udall Parkinson's Disease Research Center of Excellence, and the frontotemporal lobar degeneration program project grant. Dr. Xie's current research goals are twofold. First, she continues to develop new statistical methods for measurement error problems, missing data, longitudinal analysis, survival analysis, and receiver operating characteristic (ROC) analysis in response to methodological problems arising in her collaborative work in the research of neurodegenerative diseases (e.g., Alzheimer's disease, Parkinson's disease, frontotemporal dementia, amyotrophic lateral sclerosis) and in other collaborative research. She has developed new methods to reduce the biases of relative risk estimators in Cox regression models in the presence of covariate measurement error. She has also developed innovative methods to reduce bias in diagnostic evaluation measures for biomarkers with measurement error and improve efficiency in survival analysis with uncertain endpoints using a validation subsample. Second, she continues to develop techniques and markers to better understand the progression of neurodegenerative diseases. As a primary example, Dr. Xie and colleagues examined the rate of decline in Alzheimer's disease measured by a dementia severity rating scale (DSRS). She found that the rate of decline was linear using this rating scale. This linearity has significant advantages for clinical trials. Treatment effects in a trial would be seen in the DSRS as a slowing of the linear rate of change during some or all stages of the disease. This is much easier than evaluating estimated treatment effects in a measure that does not change linearly.

Awards and Professional Recognition

Dr. Xie was the recipient of the 1999 Young Investigator Award of Statistics in Epidemiology Section of the American Statistical Association, and the 2005 and 2011 recipient of the University of Pennsylvania Graduate Program in Biostatistics Teaching Award. She was an elected standing member of the National Institute of Aging Alzheimer's Disease Center Data Core Steering Committee during 2007 and 2010 (Chair during July 2008 and July 2009). She is an elected standing member of the National Alzheimer's Coordinating Center (NACC) Scientific Review Committee for National Institute of Aging (2015-2019). She is also an elected standing member of the Parkinson Study Group Scientific Review Committee (2016 – present). Dr. Xie is currently an associate editor of Alzheimer's & Dementia.

Selected Publications

  • Xie SX, Wang CY and Prentice RL. A risk set calibration method for failure time regression by using a
    covariate reliability sample. Journal of the Royal Statistical Society, Series B 63(4):855-870, 2001.
  • Xie SX, Liao D and Chinchilli VM. Measurement error reduction using weighted average method for repeated measurements from heterogeneous instruments. Environmetrics 12:785-790, 2001.
  • Clark, C.M., Xie, S., Chittams, J., Ewbank, D., Peskind, E., Galasko, D., Morris, J.C., McKeel, D.W. Jr., Farlow, M., Weitlauf, S.L., Quinn, J., Kaye, J., Knopman, D., Arai, H., Doody, R.S., DeCarli, C., Leight, S., Lee, V.M.-Y., Trojanowski, J.Q.: Cerebrospinal fluid tau and beta-amyloid: How well do these biomarkers reflect autopsy confirmed dementia diagnoses? Archives of Neurology 60(12): 1696-1702, 2003.
  • Brown, G.K., Ten Have, T., Henriques, G.R., Xie, S.X., Hollander, J.E., Beck, A.T.: Cognitive therapy for the prevention of suicide attempts: A randomized controlled trial. Journal of the American Medical Association 294(5): 563-570, 2005.
  • Zhang, B., Maiti, A., Shively, S., Lakhani, F., McDonald-Jones, G., Bruce, J., Lee, E.B., Xie, S.X., Joyce, S., Li, C., Toleikis, P.M., Lee, V.M.-Y., Trojanowski, J.Q.: Microtubule-binding drugs offset tau sequestration by stabilizing microtubules and reversing fast axonal transport deficits in a tauopathy model. Proceedings of the National Academy of Science 102(1): 227-231, 2005.
  • Xie, S.X., Forman, M.S., Farmer J., Moore, P., Wang, Y., Wang, X, Clark, C.M., Coslett, H.B., Chatterjee, A., Arnold, S.E., Rosen, H., Karlawish, J.H., Van Deerlin, V.M., Lee, V.M.-Y., Trojanowski, J.Q., Grossman, M.: Factors associated with survival probability in autopsy-proven frontotemporal lobar degeneration. Journal of Neurology, Neurosurgery & Psychiatry 79(2): 126-129, 2008.
  • Grossman, M., Xie, S.X., Libon, D.J., Wang, X., Massimo, L., Moore, P., Vesely, L., Berkowitz, R., Chatterjee, A., Coslett, H.B., Hurtig, H.I., Forman, M.S., Lee, V.M.-Y., Trojanowski, J.Q. : Longitudinal decline in autopsy-defined frontotemporal lobar degeneration. Neurology 70(22): 2036-2045, 2008.
  • Xie, S.X., Ewbank, D.C., Chittams, J., Karlawish, J.H.T., Arnold, S.E., Clark, C.M. : Rate of decline in Alzheimer disease measured by a dementia severity rating scale. Alzheimer Disease & Associated Disorders 23(3): 268-274, 2009.
  • Xie, S.X., Libon, D.J., Wang, X., Massimo, L., Moore, P., Vesely, L., Khan, A, Chatterjee, A., Coslett, H.B., Hurtig, H.I., Liang, T.-W., Grossman, M.: Longitudinal patterns of semantic and episodic memory in frontotemporal lobar degeneration and Alzheimer's disease. Journal of the International Neuropsychological Society 16(2): 278-286, 2010.
  • Trojanowski, J.Q., Arnold, S., Karlawish, J., Brunden, K., Cary, M., Davatzikos, C.,
  • Detre, J., Gaulton, G., Grossman, M., Hurtig, H., Jedrziewski, K., McCluskey, L., Naylor M, Polsky, D., Schellenberg, G.D., Siderowf, A., Shaw, L.M., Van Deerlin, V., Wang, L.-S., Werner, R, Xie, S.X., Lee, V.M-Y.: Design of comprehensive Alzheimer's Disease Centers to address unmet national needs. Alzheimer's & Dementia 6(2): 150-155, 2010.
  • Geser, F., Robinson, J.L., Malunda, J.A., Xie, S.X., Clark, C.M., Kwong, L.K., Moberg, P.J., Moore, E., Van Deerlin, V.M., Lee, V.M.-Y., Arnold, S.E., Trojanowski, J.Q.: Pathological 43-kDa transactivation response DNA-binding protein in older adults with and without severe mental illness. Archives of Neurology 67(10): 1238-1250, 2010.
  • Siderowf, A., Xie, S.X., Hurtig, H., Weintraub, D., Duda, J., Chen-Plotkin, A., Shaw, L.M., Van Deerlin, V., Trojanowski, J.Q., Clark, C.: CSF Amyloid Beta 1-42 predicts cognitive decline in Parkinson's disease. Neurology 75(12): 1055-1061, 2010.
  • Xie, S.X., Baek, Y., Grossman, M., Arnold, S.E., Karlawish, J., Siderowf, A., Hurtig, H., Elman, L., McCluskey, L., Van Deerlin, V., Lee, V.M.-Y., Trojanowski, J.Q.: Building an integrated neurodegenerative disease database at an academic health center. Alzheimer’s & Dementia 7(4): e84-e93, 2011.
  • Mao, J.J., Palmer, S.C., Desai, K., Li, S.Q., Armstrong, K., Xie, S.X.: Development and validation of an instrument for measuring attitudes and beliefs about Complementary and Alternative Medicine (CAM) use among cancer patients. Evidence-Based Complementary and Alternative Medicine 2012: 798098, 2012 Notes: doi: 10.1155/2012/798098.
  • *Tan, K., Libon, D.J., Rascovsky, K., Grossman, M., Xie, S.X.: Differential Longitudinal Decline on the Mini-Mental State Examination in Frontotemporal Lobar Degeneration and Alzheimer's Disease. Alzheimer Disease & Associated Disorders 27(4): 310-5, 2013 Notes: *first author was a biostatistics M.S. degree student to whom I served as the thesis advisor.
  • *White, M.T., Xie, S.X.: Adjustment for measurement error in evaluating diagnostic biomarkers by using an internal reliability sample. Statistics in Medicine 32(27): 4709-25, 2013 Notes: *first author was a biostatistics doctoral student to whom I served as dissertation advisor. This work earned Dr. White the 2011 Young Investigator Award from Statistics in Epidemiology Section of American Statistical Association and 2012 ENAR Distinguished Student Paper Award.
  • Toledo, J.B., Xie, S.X.#, Trojanowski, J.Q., Shaw, L.M.; for the Alzheimer's Disease Neuroimaging Initiative: Longitudinal change in CSF Tau and Abeta biomarkers for up to 48 months in ADNI. Acta Neuropathologica 126(5): 659-70, 2013 Notes: #Dr. Xie is a co-first author.
  • Papay, K., Xie, S.X., Stern, M., Hurtig, H., Siderowf, A., Duda, J.E., Minger, J., Weintraub, D.: Naltrexone for impulse control disorders in Parkinson’s disease: a placebo-controlled study. Neurology 83(9): 826-33, 2014.
  • Mao, J.J., Farrar, J.T., Bruner, D., Zee, J., Bowman, M., Seluzicki, C., DeMichele, A., Xie, S.X. : Electro-acupuncture for fatigue, sleep, and psychological distress in breast cancer patients with aromatase inhibitor-related arthralgia: A randomized trial. Cancer 120(23): 3744-51, 2014.
  • *Zee, J., Xie, S.X.: Nonparametric discrete survival function estimation with uncertain endpoints using an internal validation subsample. Biometrics 71(3): 772-81, 2015 Notes: *first author was a biostatistics doctoral student to whom I served as the dissertation advisor. This paper earned Dr. J. Zee a 2014 Student Travel Award from the Biometrics Section of the American Statistical Association.
  • *Zee, J., Xie, S.X.; for the Alzheimer's Disease Neuroimaging Initiative: Assessing treatment effects with surrogate survival outcomes using an internal validation subsample. Clinical Trials 12(4): 333-41, 2015 Notes: *first author was a biostatistics doctoral student to whom I served as the dissertation advisor.
  • *Zee, J., Xie, S.X.: The Kaplan-Meier method for estimating and comparing proportions in a randomized controlled trial with dropouts. Biostatistics & Epidemiology Nov 30 2017 (Epub ahead of print) Notes: *first author was a biostatistics doctoral student to whom I served as the dissertation advisor.
  • *Rennert, L., Xie, S.X.: Cox regression model with doubly truncated data. Biometrics Oct 2017 (Epub ahead of print) Notes: *first author is a biostatistics doctoral student to whom I serve as the dissertation advisor. This paper earned Mr. Rennert the W. Edwards Deming Student Scholar Award from the 2017 Annual Deming Conference on Applied Statistics.