Nathanael R. Fillmore
Topics / Hospitalization Metrics
Topic

Hospitalization Metrics

Fillmore has investigated the drivers and measurement of unplanned hospitalizations, particularly in older adults with hematologic malignancies and respiratory cancers. His research demonstrates that frailty, multimorbidity, and the use of potentially inappropriate medications are independent predictors of increased hospitalization risk. Additionally, he has developed objective metrics for COVID-19 hospitalizations, finding that accounting for disease severity and oxygen requirements provides a more accurate assessment of vaccine effectiveness than simple admission rates.

U.S. Veterans and VA Data 9 Retrospective Cohort Study 9 Frailty 6 Overall Survival 6 Survival Analysis 6 Real World Evidence 6 Patient Outcomes 5 Electronic Frailty Index 5 Cox Proportional Hazards Model 4 Electronic Health Records 4 Geriatric Oncology 4 Cancer Patients 3

Publications (9)

2026

Association of Frailty With Transfusions, Hospitalizations, and Survival in Patients With Myelodysplastic Syndrome Initiating Hypomethylating Agents.

Anahid Hamparsumian†, Jennifer La†, Mayuri Dharne, Gary Gilbert, Mary T. Brophy, Nhan V. Do, Dae Hyun Kim, Jane A. Driver, Nathanael R. Fillmore‡, Clark DuMontier‡† Equal first authorship · ‡ Equal senior authorship

EJHaem7(4), e70352
U.S. Veterans and VA Data Retrospective Cohort Study Frailty Overall Survival Hospitalization Metrics
2025

Potentially Inappropriate Medications, Frailty, and Outcomes in Patients With Cancer Managed in a National Health Care System.

Jennifer La, Tammy Hshieh, Anahid Hamparsumian, Robert Zwolinski, Jameson Wood, Mayuri Dharne, J. Michael Gaziano, Mary T. Brophy, Nhan V. Do, Nikhil C. Munshi, Jane A. Driver, Gregory A. Abel, Nathanael R. Fillmore‡, Clark DuMontier‡‡ Equal senior authorship

Journal of the National Comprehensive Cancer Network23(9), 363-370
U.S. Veterans and VA Data Retrospective Cohort Study Electronic Health Records Frailty Overall Survival
2023

More intensive therapy as more effective treatment for frail patients with multiple myeloma [corrected].

Clark DuMontier†, Jennifer La†, John Bihn, June Corrigan, Cenk Yildirim, Mayuri Dharne, Hamza Hassan, Sarvari Yellapragada, Gregory A. Abel, J. Michael Gaziano, Nhan V. Do, Mary Brophy, Dae H. Kim, Nikhil C. Munshi, Nathanael R. Fillmore‡, Jane A. Driver‡† Equal first authorship · ‡ Equal senior authorship

Blood Advances7(20), 6275-6284
U.S. Veterans and VA Data Retrospective Cohort Study Multiple Myeloma Frailty Overall Survival
2023

Coronavirus disease 2019 (COVID-19) hospitalization metrics that do not account for disease severity underestimate protection provided by severe acute respiratory coronavirus virus 2 (SARS-CoV-2) vaccination and boosting: A retrospective cohort study.

June K. Corrigan†, Jennifer La†, Nathanael R. Fillmore, Nhan V. Do, Mary Brophy, Shira Doron, Paul A. Monach‡, Westyn Branch-Elliman‡† Equal first authorship · ‡ Equal senior authorship

Infection Control and Hospital Epidemiology44(1), 149-151
U.S. Veterans and VA Data Retrospective Cohort Study Electronic Health Records COVID-19 Vaccine Effectiveness
2022

The COVID-19 hospitalization metric in the pre- and postvaccination eras as a measure of pandemic severity: A retrospective, nationwide cohort study.

Nathanael R. Fillmore†, Jennifer La†, Chunlei Zheng, Shira Doron, Nhan V. Do, Paul A. Monach‡, Westyn Branch-Elliman‡† Equal first authorship · ‡ Equal senior authorship

Infection Control and Hospital Epidemiology43(12), 1767-1772
U.S. Veterans and VA Data Retrospective Cohort Study COVID-19 Vaccine Effectiveness Hospitalization Metrics
2021

Defining Multimorbidity and Its Impact in Older United States Veterans Newly Treated for Multiple Myeloma.

Nathanael R. Fillmore†, Clark DuMontier†, Cenk Yildirim, Jennifer La, Mara M. Epstein, David Cheng, Diana Cirstea, Sarvari Yellapragada, Gregory A. Abel, J. Michael Gaziano, Nhan Do, Mary Brophy, Dae H. Kim, Nikhil C. Munshi, Jane A. Driver† Equal first authorship

Journal of the National Cancer Institute113(8), 1084-1093
U.S. Veterans and VA Data Retrospective Cohort Study Multiple Myeloma Overall Survival Geriatric Oncology
2021

Contemporary Analysis of Electronic Frailty Measurement in Older Adults with Multiple Myeloma Treated in the National US Veterans Affairs Healthcare System.

Clark DuMontier†, Nathanael R. Fillmore†, Cenk Yildirim, David Cheng, Jennifer La, Ariela R. Orkaby, Brian Charest, Diana Cirstea, Sarvari Yellapragada, John Michael Gaziano, Nhan Do, Mary T. Brophy, Dae H. Kim, Nikhil C. Munshi, Jane A. Driver† Equal first authorship

Cancers13(12)
U.S. Veterans and VA Data Retrospective Cohort Study Electronic Health Records Multiple Myeloma Frailty