Onchee Yu, MS


"At KPWHRI, I apply statistical methods to studies ranging from women’s health to pharmacoepidemiology to vaccine safety and effectiveness, in an effort to improve health care for patients.”

Onchee Yu, MS

Principal Collaborative Biostatistician, Kaiser Permanente Washington Health Research Institute



Onchee Yu, MS, is a biostatistician who has contributed her extensive experience in statistical applications to electronic health records (EHR) data to studies related to women’s health, pharmacoepidemiology, and vaccine safety and effectiveness. Ms. Yu has been a key member of Kaiser Permanente Washington Health Research Institute’s (KPWHRI) immunization research program for 20 years. Her work focuses on applying statistical methods to evaluate vaccine effectiveness, side effects, and safety. In collaboration with KPWHRI biostatisticians Jennifer Nelson, PhD, and Andrea Cook, PhD, Ms. Yu developed and improved statistical methods for monitoring the safety of postmarketing vaccines in the Vaccine Safety Datalink project.

Much of Ms. Yu's recent research is in pharmacoepidemiology, which is studying how drugs are used in a population and their impact on public health. She is an expert in statistical analysis in a complex, clinically important area—determining if taking medicine for one condition (for example, cardiovascular medications) affects risk of other illnesses (for example, cancer outcomes).

Ms. Yu also contributes to women’s health. Using extensive EHR data and in collaboration with University of Washington clinician and KPWHRI affiliate researcher Susan D. Reed, MD, MPH, Ms. Yu has estimated incidences and prevalences, validated diagnosis codes, and developed automated case-finding algorithms for women’s health conditions including uterine fibroids, adenomyosis and endometriosis.  

Ms. Yu obtained her MS in biostatistics from the University of Washington in 1999. She is a member of the American Statistical Association and the International Society for Pharmacoepidemiology. Her statistical methodological expertise includes classification and regression tree analysis, and survival analysis.

Research interests and experience

  • Biostatistics

    Survival analysis; classification and regression tree analysis

  • Cancer

    Biostatistics; medication use and cancer outcomes

  • Vaccines & Infectious Diseases

    Biostatistics; vaccine safety and efficacy; postmarketing vaccine safety study design and analysis

    Women's Health

    Biostatistics; incidence and prevalence estimations; validation of diagnosis codes; automated case-finding algorithms

  • Medication Use & Patient Safety

    Biostatistics; medication use and cancer outcomes; postmarketing drug and vaccine safety study design and analysis; safety signal detection methods

Recent publications

Jackson ML, Yu O, Nelson JC, Naleway A, Belongia EA, Baxter R, Narwaney K, Jacobsen SJ, Shay DK, Jackson LA. Further evidence for bias in observational studies of influenza vaccine effectiveness: the 2009 Influenza A(H1N1) pandemic. Am J Epidemiol. 2013 Oct 15;178(8):1327-36. doi: 10.1093/aje/kwt124. Epub 2013 Aug 26. PubMed

Torrone EA, Satterwhite C, Scholes D, Yu O, Berman S, Peterman T. Estimating Chlamydia re-infection rates: an empirical example. Sex Transm Infect. 2013 Aug;89(5):388-90. doi: 10.1136/sextrans-2012-050970. Epub 2013 May 4. PubMed

Chubak J, Yu O, Buist DS, Wirtz HS, Boudreau DM. Time scale in follow-up studies: considering disease prognosis.  Epidemiology. 2013;24(4):628-9. doi: 10.1097/EDE.0b013e3182961708. PubMed

Boudreau DM, Yu O, Spangler L, Do TP, Fujii M, Ott SM, Critchlow CW, Scholes D. Accuracy of ICD-9 codes to identify nonunion and malunion and developing algorithms to improve case-finding of nonunion and malunion.  Bone. 2013 Feb;52(2):596-601. doi: 10.1016/j.bone.2012.11.013. Epub 2012 Nov 19. PubMed

Spangler L, Yu O, Loggers E, Boudreau DM. Bone mineral density screening among women with a history of breast cancer treated with aromatase inhibitors.  J Womens Health (Larchmt). 2013 Feb;22(2):132-40. doi: 10.1089/jwh.2012.3687. Epub 2013 Jan 30. PubMed




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