Faculty Profile: Orna Intrator, PHD

Orna Intrator
Orna Intrator, PHD
Assoc Professor of Health Services Policy & Practice (Rsch)
Public Health-Health Services Policy & Practice
Work: +1 401-863-3579
I am a health services researcher educated in statistics and applied mathematics. My research has focused on health care utilization and cost of care of nursing home residents and the organization of professional medical staff in nursing homes. I seek to understand potentially modifiable organizational behavior and strategies and the effect of implementation of policies on those organizational behaviors. In my research I have emphasized the use of novel statistical methods, building sophisticated data systems for complex analyses, and designing statistical models and methods. I have been particularly concerned with the way in which methods and models are used, developing methods to more clearly present and understand their results.


Brief Bio

Dr. Intrator is an applied statistician and health services researcher. A faculty in the Department of Community Health since 1993, Dr. Intrator has also held a faculty position in the Statistics Department at the Hebrew University in Jerusalem (1993-1995 and 1997-1999), and has directed the Laboratory for Applied Statistics (1993-1995). Dr. Intrator's work has been funded by grants from AHRQ, NIA, the Israeli National Science Foundation, and the Israel National Institute for Health Care Policy and Research. Dr. Intrator is a Fellow of InterRAI, an organization devoted to the development of standardized assessment tools for evaluation of care of the elderly world-wide, and to the conduction of cross-national studies.

Dr. Intrator studies health care utilization of elderly residing in nursing homes, especially hospitalizations, with particular emphasis on the effects of their nursing home's organizational structure and its market, as well as states' Medicaid policies. Dr. Intrator has led the development of the Residential History File, a methodology which uses Medicare claims and nursing home MDS assessments data to create a file that tracks Medicare beneficiaries' health service utilization and residences, including permanent nursing home placement. This new research tool has been used in several studies ranging from assessment of post acute care to end of life care.

Dr. Intrator utilizes state of the art statistical methods such as Markov Chain Monte Carlo estimation of multilevel models, and has been developing methods to jointly study different services utilization in models that uses informative censoring due to death. In a recent collaboration with Drs. Jason Roy and Susan Miller, she has been modeling total costs of dually-eligible nursing home patients at the end of life. Dr. Intrator has also been studying interpretation of results from new sophisticated models such as neural networks and multilevel models.



Research Description

There are several avenues of my statistical and methodological research: (1) development of data structures: tracking individuals through health care settings and following nursing home characteristics over time; (2) development of models for informative censoring; (3) developments of tools for exploring and interpreting results of novel statistical methods; (4) utilization of novel statistical methods in HSR. This includes selection bias in observational data, multilevel models for nested data, and utilizing population average models for studying the effects of policies in longitudinal studies.
As a researcher I have been acutely aware of the need for integrated quality data. This was necessary to allow the study of post acute care service provision and outcomes, to identify particular populations in data, and to monitor changes longitudinally. To study health care utilization by nursing home residents, I have developed the Residential History File (RHF) that combines information from the Minimum Dataset assessments of nursing home residents with Medicare claims to track individuals' health service locations continuously over time. Recently, I have imported this method to the VA, adding to it information from VA data sources.
While studying inpatient utilization of HIV positive patients, I became acutely aware of the potential for confounding from informative censoring due to death. Consequently, in a collaboration with Tony Lancaster from the Economics Department at Brown University, we developed a method that jointly models hospitalizations and mortality, and disentangles the effects of the same factor on hospitalization and death. This novel method appears to have inspired a line of research on joint modeling.
As a follow-up to the work on joint modeling of mortality and hospitalization, I examined health care costs at the end of life prospectively in a cross-sectional cohort. Till now, all analyses of costs at the end of life used a cohort of decedents, and examined their patterns of utilization and costs in the months preceding death. I was concerned that by selecting to study decedents, there was no comparable comparison group. In addition, the non-random selection of hospice, given an individual's proximity to death, had never been accounted for prospectively. I used a longitudinal model where for each time period the predicted probability of death and of hospice selection were used as inverse probability weights in a model for costs.

Nursing homes are complex organizations, providing services to residents from the community and from hospital, drawing from market resources, and regulated by local, state, and federal standards. Individually, and collaboratively, I have addressed many of these issues in my studies. With Jackie Zinn, I have mostly examined the relationship of institutions and markets; with Vince Mor, I have primarily examined the effects of policy on nursing home behaviors, including hospitalizations. With Fox Wetle I have been looking at the organization of medical staff in nursing homes. With Susan Miller I have been developing methods to study end of life care using the RHF.
I have been particularly interested in hospitalization from nursing home, as it is a potential marker of quality of care and of increased costs. One aspect of my study has been to define the double-edges of this sword: hospitalizations are both necessary in some cases and potentially avoidable in other cases. Drawing upon work on ambulatory care sensitive hospitalizations, in collaboration with several physicians, we have developed a measure of potentially preventable hospitalizations from nursing home. The innovations of this study were the distinction of hospitalization of long-stay nursing home residents from community patients admitted to hospital, and the use of both admission and discharge diagnoses. A survey of leading experts, primarily from the U.S. and Canada, confirmed most of the definitions. The new measure allows us to investigate the geo-temporal difference s in nursing home hospitalizations.
A recent avenue of research is the study of the provision of physician services in nursing homes. This work continues my interest in examining the availability of nurse practitioners and physician assistants in nursing homes, and the associated reduction in hospitalization rates, especially potentially preventable ones. Since 2001 I have been working with Paul Katz and Jurgis Karuza from the University of Rochester examining data that they collected from Medical Directors in nursing homes. Three papers have been published by our group and several are in preparation.
As a fellow of InterRAI, an organization devoted to the development of standardized assessment tools for evaluation of care of the elderly world-wide, and to the conduction of cross-national studies, I continue collaborations with other Israeli members. We implement the MDS suite of instruments in various settings in Israel, and conduct research that assists in their improvement.
I have been instrumental in the development of a PO1 program project proposal (PI Vince Mor) that includes 4 projects and 3 cores (2007-2013). In this effort, I am PI on the statistics and data management core and PI on one of a project "Nursing Home Medical Staff Missing in Action". My involvement in many of the studies looking at state policies regarding nursing homes, and their effects on nursing home behaviors and resident outcomes will continue to inspire my future research.
Since April 2004, I have been involved with the Providence VA Health Services Research and Development group (currently a REAP). I provide statistical consultation to several proposals developed by investigators. I have been site PI on a VA HSR&D funded grant to study medical staff organization in VA Community Living Centers (CLCs are VA owned and operated nursing homes). I am currently PI on "Determinants and Consequences of Veterans' Access to Nursing Home Care" (2010-2013). Since June 2011 I have been developing the Geriatrics and Extended Care (GEC) Data and Analysis Center (GEC DAC project described under projects).

My future plans are to continue to study the organization of physicians and medical staff in nursing homes, their quality correlates, and policy and market factors impacting on their formation. On the methodological side, I continue to collaborate with colleagues in developing new methods to estimate the impact of state policy effects on nursing home quality, and in particular on hospitalizations.

Grants and Awards

1991 Sigma-Xi Society, Brown University Chapter
1995 Golda Meir Scholar, Hebrew University
1996 Who's Who in Science and Engineering
1997 Strathmore's Who's Who
2000 Who's Who in the World
2001 Fellow InterRAI
2004 Outstanding Abstract, Annual Meeting of the Academy for Health Services Research


Providence VA Medical Center
American Statistical Association
Gerontological Society of America
Academy for Health Services Research
InterRAI Fellow

Funded Research

1. (PI) 1/1/2012 – 9/30/2013. Geriatrics and Extended Care Data and Analysis Center Development. VA T21 Program.
2. (PI) 9/30/2007 – 6/30/2013. "MDs Missing In Action", NIA. Project 3 of P01 "Shaping LTC in America".
3. (PI) 9/30/2007 – 6/30/2012. "Core C: Statistics, Measurement, and Data Management". NIA Core for P01 "Shaping LTC in America."
4. (PI Brown University Subcontract) 4/2008-8/2012. "The Effects of Acute Events on ADL Trajectories of Nursing Home Residents". PI: Robin Kruse (U. Missouri). NIA.
5. (PI) 6/2010 – 11/2013: "Determinants and Consequences of Veterans' Access to Nursing Home Care". VA HSR&D.
6. (Investigator and Statistician) 10/2008-9/2013: VA HSR&D REAP "ROQCR: Research in Outcomes and Quality in Chronic Disease and Rehabilitation". PI: Peter Friedman.
7. (Primary Mentor) 6/2010-5/2013: VA HSR&D. Career Development Award CDII: Dosa, D (PI). Medication Use as a Quality Indicator in VA Nursing Home Care Units.

Selected Publications

  • Lima J, Intrator O, Karuza J, Wetle T, Mor V, Katz P. Nursing Home Medical Staff Organization and 30-Day Rehospitalizations. JAMDA. To Appear, July 2012. (2012)
  • Intrator O, Hiris J, Berg K, Miller S, Mor V. The Residential History File: Development and Validation. Health Services Research. 46(1): 120-137, 2011. http://www.pubmedcentral.gov/articlerender.fcgi?artid=3015013 (2011)
  • Mor V, Intrator O, Feng Z, Grabowski DC. The revolving door of rehospitalization from skilled nursing facilities. Health Aff (Millwood) 29(1):57-64, 2010 (2010)
  • Katz P, Karuza J, Intrator O, Zinn J, Mor V, Caprio T, Caprio A, Dauenhauer J, Lima J. Medical Staff Organization in Nursing Homes: Scale Development and Validation. Journal of the American Medical Association, 10(7): 498-504, 2009. (2009)
  • Intrator O, Schleinitz MD, Grabowski D, Zinn J, Mor V. Maintaining Continuity of Care for Nursing Home Residents: The Effect of States' Medicaid Bed-Hold Policies and Reimbursement Rates. Health Services Research, 44(1): 33-55, 2008. (2008)
  • Dosa D, Intrator O, McNicoll L, Cang Y, Teno J. Preliminary Derivation of a Nursing Home Confusion Assessment Method Based on Data from the Minimum Data Set. Journal of the American Geriatrics Society. 55(7): 1099-1105, 2007. (2007)
  • Intrator O, Grabowski D, Zinn J, Schleinitz M, Feng Z, Miller S, Mor V. Hospitalizations of Nursing Home Residents: The Effects of States' Medicaid Payment and Bedhold Policies. Health Services Research. 42(4): 1651-1671,2007. (2007)
  • Feng Z, Grabowski D, Mor V, Intrator O. The Effect of state Medicaid case-mix payment on nursing home resident acuity. Health Serv Res. 41(4 Pt 1):1317-36, 2006. (2006)
  • Intrator O, Feng Z, Mor V, Gifford D, Bourbonierre M, Zinn, J. The availability of nurse practitioners and physician assistants in nursing homes. The Gerontologist, 45(4): 486-495, 2005. (2005)
  • Intrator O, Mor V, Zinn J. Nursing Homes Characteristics and Potentially Preventable Hospitalization of Long-Stay Residents. Journal of the American Geriatrics Society, 52:1730-1736, 2004. (2004)
  • Miller SC, Intrator O, Gozalo P, Roy J, Barber J, Mor V. Government Expenditures at the End of Life for Short- and Long-Stay Nursing Home Residents: Differences by Hospice Enrollment Status. Journal of the American Geriatrics Society, 52(8): 1284-1292, 2004. (2004)
  • Intrator O, Mor V. Impact of State Medicaid Payment Rates on Hospitalizations from Nursing Home. Journal of the American Geriatrics Society, 52: 393-398, 2004. (2004)
  • Gindin J, Levi S, Intrator O, Stessman J. MDS (Minimum Data Set) Assessments for Policy Making and Evaluations in Israel. Milbank Quarterly, May 2003. http://www.milbank.org/reports/interRAI/030222interRAI.html#israel. (2003)
  • Intrator O, Intrator N. Interpreting Neural Network Results: A Simulation Study. Computational Statistics and Data Analysis, 37(3): 373-393, 2001. (2001)
  • Intrator O, Castle N, Mor V. Facility Characteristics Associated With Hospitalization of Nursing Home Residents: Results of a National Study. Medical Care, 37(3):228-237, 1999. (1999)
  • Intrator O, Berg K. Benefits of Home Health Care Following Inpatient Rehabilitation for Hip Fracture: Health Service Use by Medicare Beneficiaries: 1987-1992. Archives of Physical Medicine and Rehabilitation, 79: 1195-1199, 1998. (1998)
  • Lancaster T, Intrator O. Panel Data With Survival: Hospitalization of HIV Patients. Journal of the American Statistical Association, 93(441): 46-53, 1998. (1998)
  • Mor V, Intrator O, Fries B, Phillips C, Teno J, Hiris J, Hawes C, Morris J. Changes in hospitalization and other nursing home discharge rates associated with introducing the MDS. Journal of the American Geriatrics Society, 45(8):1002-1010, 1997. (1997)
  • Intrator O, Kooperberg C. Trees and Spline in Survival Analysis. Statistical Methods in Medical Research, 4:3: 237-261, 1995. (1995)
  • Mor V, Intrator O, Laliberte LL. Factors Affecting Conversion Rates to Medicaid Among New Admissions to Nursing Homes. Health Service Research, 28:1, pp 1-25, 1993. (1993)
  • Piette J, Intrator O, Zierler S, Mor V, Stein M. Differences in Case Fatality Rates for Aids Patients: Application of a New Methodology for Survival Research. Epidemiology:310-318, 1992. (1992)