Surrogate evaluation: identification and evaluation of surrogate biomarkers so that reliable surrogates can be used in future studies to infer treatment effect on the primary clinical endpoint.
Wang, X., Cai, T., Tian, L. and Parast, L., 2025. Model‐Free Approach to Evaluate a Censored Intermediate Outcome as a Surrogate for Overall Survival. Statistics in medicine, 44(20-22), p.e70268.
Wang, X., Zhou, J., Parast, L. and Greene, T., 2025. Semiparametric joint modeling to estimate the treatment effect on a longitudinal surrogate with application to chronic kidney disease trials. Biometrics, 81(3), p.ujaf104.
Wang, X., Parast, L., Tian, L. and Cai, T., 2025. TOWARDS OPTIMAL USE OF SURROGATE MARKERS TO IMPROVE POWER. Statistica Sinica, 35, pp.1-19.
Wang, X., Parast, L., Han, L., Tian, L. and Cai, T., 2023. Robust approach to combining multiple markers to improve surrogacy. Biometrics, 79(2), pp.788-798.
Han, L., Wang, X. and Cai, T., 2022. Identifying surrogate markers in real‐world comparative effectiveness research. Statistics in Medicine, 41(26), pp.5290-5304.
Wang, X., Cai, T., Tian, L., Bourgeois, F. and Parast, L., 2021. Quantifying the feasibility of shortening clinical trial duration using surrogate markers. Statistics in medicine, 40(28), pp.6321-6343.
Wang, X., Parast, L., Tian, L.U. and Cai, T., 2020. Model-free approach to quantifying the proportion of treatment effect explained by a surrogate marker. Biometrika, 107(1), pp.107-122.
Survival Analysis
Wang, Y., Zhou, Q., Cai, T. and Wang, X.*, 2023. Semi-supervised Estimation of Event Rate with Doubly-censored Survival Data. arXiv preprint arXiv:2311.02574.
Wang, X., Ludmir, E.B., Wei, L.J., 2025. Assessing clinical utility of datopotamab deruxtecan versus chemotherapy for breast cancer. Journal of Clinical Oncology, 43(18), pp.2136-2137.
Wang, X., Claggett, B.L. and Tian, L., 2023. Use the Receiver Operating Characteristic to Assess Model Accuracy—Reply. JAMA cardiology, 8(10), pp.998-999.
Hou, J., Chan, S.F., Wang, X. and Cai, T., 2023. Risk prediction with imperfect survival outcome information from electronic health records. Biometrics, 79(1), pp.190-202.
Wang, X., Claggett, B.L., Tian, L., Malachias, M.V.B., Pfeffer, M.A. and Wei, L.J., 2023. Quantifying and interpreting the prediction accuracy of models for the time of a cardiovascular event—moving beyond C statistic: a review. JAMA cardiology, 8(3), pp.290-295.
Zhou, Q.M., Wang, X., Zheng, Y. and Cai, T., 2022. New weighting methods when cases are only a subset of events in a nested case‐control study. Biometrical Journal, 64(7), pp.1240-1259.
Wang, X., Zhang, H.G., Xiong, X., Hong, C., Weber, G.M., Brat, G.A., Bonzel, C.L., Luo, Y., Duan, R., Palmer, N.P. and Hutch, M.R., 2022. SurvMaximin: robust federated approach to transporting survival risk prediction models. Journal of biomedical informatics, 134, p.104176.
Zhang, J., Wang, Q. and Wang, X., 2022. Surrogate-variable-based model-free feature screening for survival data under the general censoring mechanism. Annals of the Institute of Statistical Mathematics, 74(2), pp.379-397.
Wang, X., Zheng, Y., Jensen, M.K., He, Z. and Cai, T., 2021. Biomarker evaluation under imperfect nested case‐control design. Statistics in medicine, 40(18), pp.4035-4052.
Chan, S., Wang, X.*, Jazić, I., Peskoe, S., Zheng, Y. and Cai, T., 2021. Developing and evaluating risk prediction models with panel current status data. Biometrics, 77(2), pp.599-609.
Wang, X., Kim, D.H. and Wei, L.J., 2021. Quantifying and interpreting efficacy of reduced-intensity chemotherapy with oxaliplatin and capecitabine on cancer control for advanced gastroesophageal cancer among an older population. JAMA oncology, 7(11), pp.1723-1724.
Wang, X. and Zhou, X.H., 2018. Semiparametric maximum likelihood estimation for the Cox model with length-biased survival data. Journal of statistical planning and inference, 196, pp.163-173.
Wang, Q. and Wang, X., 2018. Analysis of censored data under heteroscedastic transformation regression models with unknown transformation function. Canadian Journal of Statistics, 46(2), pp.233-245.
Wang, X., Wang, Q. and Zhou, X.H.A., 2015. Partially varying coefficient single-index additive hazard models. Annals of the Institute of Statistical Mathematics, 67(5), pp.817-841.
Wang, X. and Wang, Q., 2015. Semiparametric linear transformation model with differential measurement error and validation sampling. Journal of Multivariate Analysis, 141, pp.67-80.
Wang, X. and Wang, Q., 2015. Estimation for semiparametric transformation models with length-biased sampling. Journal of Statistical Planning and Inference, 156, pp.80-89.
Causal Inference
Wang, X., Plantinga, A.M., Xiong, X., Cromer, S.J., Bonzel, C.L., Panickan, V., Duan, R., Hou, J. and Cai, T., 2024. Comparing insulin against glucagon-like peptide-1 receptor agonists, dipeptidyl peptidase-4 inhibitors, and sodium-glucose cotransporter 2 inhibitors on 5-year incident heart failure risk for patients with type 2 diabetes mellitus: real-world evidence study using insurance claims. JMIR diabetes, 9(1), p.e58137.
Wang, X., Ayakulangara Panickan, V., Cai, T., Xiong, X., Cho, K., Cai, T. and Bourgeois, F.T., 2023. Endovascular aneurysm repair devices as a use case for postmarketing surveillance of medical devices. JAMA Internal Medicine, 183(10), pp.1090-1097.
Maier, M.M., Zhou, X.H., Chapko, M., Leipertz, S.L., Wang, X. and Beste, L.A., 2018. Hepatitis C cure is associated with decreased healthcare costs in cirrhotics in retrospective Veterans Affairs cohort. Digestive diseases and sciences, 63(6), pp.1454-1462.
Wang, X., Beste, L.A., Maier, M.M. and Zhou, X.H., 2016. Double robust estimator of average causal treatment effect for censored medical cost data. Statistics in medicine, 35(18), pp.3101-3116.
EHR Data Analysis
Cheng, D., Wang, X.*, McDermott, G.C., Hanberg, J.S., Love, Z., Zhong, K., Jeffway, M., Hou, J., Panickan, V., Sangar, R. and Qi, Y., 2025. Inferring rheumatoid arthritis disease activity status from the electronic health records across health systems to enable real-world data studies. medRxiv, pp.2025-11.
Hutch, M.R., Son, J., Le, T.T., Hong, C., Wang, X.*, Abad, Z.S.H., Morris, M., Gutiérrez-Sacristán, A., Klann, J.G., Spiridou, A. and Batugo, A., 2025. Correction: Neurological diagnoses in hospitalized COVID-19 patients associated with adverse outcomes: A multinational cohort study. PLOS Digital Health, 4(7), p.e0000957.
Hutch, M.R., Son, J., Le, T.T., Hong, C., Wang, X.*, Shakeri Hossein Abad, Z., Morris, M., Gutiérrez-Sacristán, A., Klann, J.G., Spiridou, A. and Batugo, A., 2024. Neurological diagnoses in hospitalized COVID-19 patients associated with adverse outcomes: A multinational cohort study. PLOS Digital Health, 3(4), p.e0000484.
Wang, X., Liu, M., Nogues, I.E., Chen, T., Xiong, X., Bonzel, C.L., Zhang, H., Hong, C., Xia, Y., Dahal, K. and Costa, L., 2024. Heterogeneous associations between interleukin-6 receptor variants and phenotypes across ancestries and implications for therapy. Scientific reports, 14(1), p.8021.
Wang, L., Wang, X., Liao, K.P. and Cai, T., 2024. Semisupervised transfer learning for evaluation of model classification performance. Biometrics, 80(1), p.ujae002.
Tong, J., Huang, J., Chubak, J., Wang, X., Moore, J.H., Hubbard, R.A. and Chen, Y., 2020. An augmented estimation procedure for EHR-based association studies accounting for differential misclassification. Journal of the American Medical Informatics Association, 27(2), pp.244-253.
Others
Chen, A.W., Hong, C., Ho, Y.L., Link, N., Honerlaw, J.P., Tanukonda, V., Orkaby, A.R., Qazi, S., Melley, C., Galloway, A. and Costa, L., 2026. Improving classification of myocardial infarction with machine learning in a diverse population. American Journal of Epidemiology, 195(3), pp.841-849.
Hong, C., Wen, J., Zhang, H.G., Ayakulangara Panickan, V., Yang, D.Y., Chen, A.W., Xiong, X., Wang, X., Morris, M., Morini, S. and Sangar, R., 2025. Label efficient phenotyping for Long COVID using electronic health records. NPJ Digital Medicine, 8(1), p.405.
Akcicek, E.Y., Hashemizadeh, K., Akcicek, H., Kim, S.E., Hadley, J.R., Roberts, J., Wang, X., Guo, Y., Balu, N., McNally, J.S. and Parker, D.L., 2025. Qualitative and quantitative reproducibility of 3D MERGE and SNAP sequences for carotid vessel wall imaging across Siemens and Philips 3T scanners. Quantitative Imaging in Medicine and Surgery, 15(4), pp.3111-3122.
Tan, A.L., Gonçalves, R.S., Yuan, W., Brat, G.A., Gentleman, R. and Kohane, I.S., 2024. Implications of mappings between International Classification of Diseases clinical diagnosis codes and Human Phenotype Ontology terms. JAMIA open, 7(4), p.ooae118.
Verma, A., Huffman, J.E., Rodriguez, A., Conery, M., Liu, M., Ho, Y.L., Kim, Y., Heise, D.A., Guare, L., Panickan, V.A. and Garcon, H., 2024. Diversity and scale: Genetic architecture of 2068 traits in the VA Million Veteran Program. Science, 385(6706), p.eadj1182.
Maripuri, M., Dey, A., Honerlaw, J., Hong, C., Ho, Y.L., Tanukonda, V., Chen, A.W., Panickan, V.A., Wang, X., Zhang, H.G. and Yang, D., 2024. Characterization of post–COVID-19 definitions and clinical coding practices: longitudinal study. Online Journal of Public Health Informatics, 16, p.e53445.
Dagliati, A., Strasser, Z.H., Abad, Z.S.H., Klann, J.G., Wagholikar, K.B., Mesa, R., Visweswaran, S., Morris, M., Luo, Y., Henderson, D.W. and Samayamuthu, M.J., 2023. Characterization of long COVID temporal sub-phenotypes by distributed representation learning from electronic health record data: a cohort study. EClinicalMedicine, 64.
Sperotto, F., Gutiérrez-Sacristán, A., Makwana, S., Li, X., Rofeberg, V.N., Cai, T., Bourgeois, F.T., Omenn, G.S., Hanauer, D.A., Sáez, C. and Bonzel, C.L., 2023. Clinical phenotypes and outcomes in children with multisystem inflammatory syndrome across SARS-CoV-2 variant eras: a multinational study from the 4CE consortium. EClinicalMedicine, 64.
Zhang, H.G., Honerlaw, J.P., Maripuri, M., Samayamuthu, M.J., Beaulieu-Jones, B.R., Baig, H.S., L’yi, S., Ho, Y.L., Morris, M., Panickan, V.A. and Wang, X., 2023. Potential pitfalls in the use of real-world data for studying long COVID. Nature medicine, 29(5), pp.1040-1043.
Tan, A.L., Getzen, E.J., Hutch, M.R., Strasser, Z.H., Gutiérrez-Sacristán, A., Le, T.T., Dagliati, A., Morris, M., Hanauer, D.A., Moal, B. and Bonzel, C.L., 2023. Informative missingness: What can we learn from patterns in missing laboratory data in the electronic health record?. Journal of biomedical informatics, 139, p.104306.
Moal, B., Orieux, A., Ferté, T., Neuraz, A., Brat, G.A., Avillach, P., Bonzel, C.L., Cai, T., Cho, K., Cossin, S. and Griffier, R., 2023. Acute respiratory distress syndrome after SARS-CoV-2 infection on young adult population: International observational federated study based on electronic health records through the 4CE consortium. PLoS One, 18(1), p.e0266985.
Tan, B.W., Tan, B.W., Tan, A.L., Schriver, E.R., Gutiérrez-Sacristán, A., Das, P., Yuan, W., Hutch, M.R., Barrio, N.G., Jimenez, M.P. and Morris, M., 2023. Long-term kidney function recovery and mortality after COVID-19-associated acute kidney injury: an international multi-centre observational cohort study. EClinicalMedicine, 55.
Gutiérrez-Sacristán, A., Serret-Larmande, A., Hutch, M.R., Sáez, C., Aronow, B.J., Bhatnagar, S., Bonzel, C.L., Cai, T., Devkota, B., Hanauer, D.A. and Loh, N.H.W., 2022. Hospitalizations associated with mental health conditions among adolescents in the US and France during the COVID-19 pandemic. JAMA network open, 5(12), p.e2246548.
Fan, C., Song, Y., Wang, X., Mao, C. and Xiong, Y., 2022. Identification of early derangements of coagulation, hematological and biochemical profiles in patients with acute pancreatitis. Clinical Biochemistry, 109, pp.37-43.
Weber, G.M., Hong, C., Xia, Z., Palmer, N.P., Avillach, P., L’yi, S., Keller, M.S., Murphy, S.N., Gutierrez-Sacristan, A., Bonzel, C.L. and Serret-Larmande, A., 2022. International comparisons of laboratory values from the 4CE collaborative to predict COVID-19 mortality. NPJ digital medicine, 5(1), p.74.
Hong, C., Zhang, H.G., L'Yi, S., Weber, G., Avillach, P., Tan, B.W., Gutierrez-Sacristan, A., Bonzel, C.L., Palmer, N.P., Malovini, A. and Tibollo, V., 2022. Changes in laboratory value improvement and mortality rates over the course of the pandemic: an international retrospective cohort study of hospitalised patients infected with SARS-CoV-2. BMJ open, 12(6), p.e057725.
Klann, J.G., Strasser, Z.H., Hutch, M.R., Kennedy, C.J., Marwaha, J.S., Morris, M., Samayamuthu, M.J., Pfaff, A.C., Estiri, H., South, A.M. and Weber, G.M., 2022. Distinguishing admissions specifically for COVID-19 from incidental SARS-CoV-2 admissions: national retrospective electronic health record study. Journal of medical Internet research, 24(5), p.e37931.
Weber, G.M., Zhang, H.G., L'Yi, S., Bonzel, C.L., Hong, C., Avillach, P., Gutiérrez-Sacristán, A., Palmer, N.P., Tan, A.L.M., Wang, X. and Yuan, W., 2021. Authorship correction: international changes in COVID-19 clinical trajectories across 315 hospitals and 6 countries: retrospective cohort study. Journal of Medical Internet Research, 23(11), p.e34625.
Weber, G.M., Zhang, H.G., L'Yi, S., Bonzel, C.L., Hong, C., Avillach, P., Gutierrez-Sacristan, A., Palmer, N.P., Tan, A.L.M., Wang, X. and Yuan, W., 2021. International changes in COVID-19 clinical trajectories across 315 hospitals and 6 countries: retrospective cohort study. Journal of medical Internet research, 23(10), p.e31400.
Estiri, H., Strasser, Z.H., Brat, G.A., Semenov, Y.R., Patel, C.J. and Murphy, S.N., 2021. Evolving phenotypes of non-hospitalized patients that indicate long COVID. BMC medicine, 19(1), p.249.
Chepelev, L.L., Wang, X., Gold, B., Bonzel, C.L., Rybicki Jr, F., Uyeda, J.W., Sheikh, A., Anderson, D., Lindaman, J., Mogel, G. and Mitsouras, D., 2021. Improved appropriateness of advanced diagnostic imaging after implementation of clinical decision support mechanism. Journal of Digital Imaging, 34(2), pp.397-403.
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Our research is supported by NIH R01DK147734.