PREEMPT Study Icon

Welcome to the PREEMPT study

PREEMPT seeks to develop a smartphone app called Trialist that allows chronic pain patients and clinicians to run personalized experiments (n-of-1 trials), comparing two different pain treatments. The goal is to help patients engage actively and collaboratively with their clinicians to identify the best pain treatment for them. 



PREEMPT was set up through a collaboration between researchers at UC Davis, Veteran’s Administration-Northern California Health Care System (VANCHCS), UC San Francisco, Brown University, and Cornell Tech as an effort to develop better medicine management for chronic pain patients.

Clinicians often begin treating chronic pain with acetaminophen or non-steroidal anti-inflammatory drugs, and prescribing opioids when pain is severe or unresponsive. These approaches are usually employed in a trial-and-error fashion. Trial and error can work but may lead to poor therapeutic decisions in the long run. To improve treatment precision, n-of-1 trials can be conducted. N-of-1 trials are single-subject crossover experiments where a patient completes repeated treatments comparing two treatment regiments.

PREEMPT partnered with Open mHealth to develop the technology to make n-of-1 trials easier to complete. PREEMPT is a National Institute of Nursing Research funded study (RO1 NR013938).

The following video provides a brief overview about the PREEMPT study

Our app, Trialist, which was built by Open mHealth allows chronic pain patients and their health care providers to run personalized experiments (n-of-1 trials) comparing two different pain treatments with the goal to identify effective treatments more quickly.

Once downloaded, the patient works with their clinician to design a trial. The clinician and patient choose the pain treatments they want to compare and how long their trial will last. Using the Trialist, the patient answers questions to track levels of pain and side effects of treatment, such as fatigue and drowsiness on a daily basis.  After the trial has ended the data collected are analyzed and processed to produce a statistical report, including graphs on the outcomes of each pain treatment. The patient and clinician review the graphs to make treatment decisions during a regular clinic visit.

In the PREEMPT study, around 250 patients will be enrolled. Half the patients will use Trialist app and half will continue with their regular care (i.e., will not use the app). These two groups of patients will be compared to see if the Trialist app is successful in improving long term pain outcomes.

Image of Trialist App Image of the Trialist App Image of the Trialist App

The following videos allow patient and clinicians in the PREEMPT study to review the steps involved in 1) setting up a trial; 2) using the Trialist app; and 3) reviewing trial results. Anyone can view the videos if they would like to find out more information about PREEMPT. 

Setting up a Trial
A trial is set up during a regularly scheduled primary care appointment. Clinicians work with their patient to set up a trial.


The Trialist App
Once a trial is set up, patients will use the Trialist app to track levels of pain and side effects of treatment.


Reviewing Trial Results
After the patients trial is complete, the clinician and patient review the trial results during a regularly scheduled primary care appointment.

Photo of Dr. Kravitz

Richard L. Kravitz, M.D., M.S.P.H
Principal Investigator
Dr. Kravitz is a professor and attending physician in the UC Davis Health System. As principal investigator on the PREEMPT study, Dr. Kravitz oversees the daily operations of the study and is involved in clinician recruitment.



Photo of Dr. Barth Wilsey

Barth Wilsey, M.D.
Dr. Wilsey is a Pain Medicine specialist and holds appointments at the UC Davis Medical Center and at the VA Northern California Health Care System.



Photo of Dr. MaroisMaria Marois, Ph.D.
Project Manager
Dr. Marois began her career at UC Davis in 1992 as a health educator for the Center for Aging and Health. As the project manager on the PREEMPT study, Maria is responsible for the day-to-day running of study, including recruitment and protocol development. 


Photo of Rima coming soonRima Cabrera, M.S.W.
Research Assistant
 As a part of the PREEMPT Study, Rima is primarily responsible for patient recruitment, and for the day-to-day implementation of study. Before joining the PREEMPT Study, Rima previously worked for UC Davis with the Departments of Family Medicine and Pediatrics.


Photo of Navjot DhammiNavjot Dhammi, B.S.
Research Assistant
As a part of the PREEMPT Study, Navjot is primarily responsible for patient recruitment, and for the day-to-day implementation of study. Prior to her work with PREEMPT, she was an undergraduate student at the University of California, Davis 

Logo for Open mHealth
Open mHealth

Open mHealth is a non-profit start-up unlocking the potential for data-driven, integrated, personalized healthcare through and open architecture and intelligent software. Open mHealth built the Trialist app and provided technical support throughout the project.

Contact: David Haddad


Logo for OhmageOhmage
Ohmage is an open-source participatory technology platform developed by Open mHealth, and was used as the foundation for Trialist. Ohmage supports expressive project authoring, including mobile phone-based data capture through inquiry-based surveys, automated data capture, temporally and/or spatially triggered reminders, data visualization and real-time feedback.  

Contact: Josh Selsky


Photo of Marc SchwartzMarc Schwartz 
Marc Schwart holds a B.F.A. from Rhode Island School of Design and a M.S. from MIT. Marc continued his education by accepting a Fulbright Scholarship to study uses of mobile telephony in Japan. Since then, Marc has worked on a series of diverse software projects for varying clients and communities. His body of work ranges from operating systems to surgical simulators to mobile software for conducting scientific and medical clinical trials.

Contact: Marc Schwartz




Dr. Ida Sim, M.D., Ph.D. General Internal Medicine, UC San Francisco
Dr. Barth Wilsey, M.D. Pain Medicine, Anesthesiology
Dr. Deborah Ward, R.N., Ph.D. Betty Irene Moore School of Nursing at UC Davis
Dr. Chris Schmid, Ph.D. Professor of Biostatistics, Brown University


PREEMPT Publications

  • Barr, C., Marois, M., Sim, I., ... Kravitz, R. L. (2015). The PREEMPT study - evaluating smartphone assisted n-of-1 trials in patients with chronic pain: study protocol for a randomized controlled trial. Trials, 16:67. Doi:

Other Relevant Publications

N-of-1 Trials

Kravitz, R. L., & Duan, N. (Ed.), & the DEciDE Methods Center N-of-1 Guidance Panel (2014). Design and implementation of N-of-1 Trials: A user's guide. Rockville, MD: Agency for Healthcare Research and Quality. AHRQ Publication No. 13(14)-EHC122-EF.

Duan, N., Kravitz, R. L., & Schmid, C. H. (2013). Single-patient (n-of-1) trials: a pragmatic clinicial decision methodology for patient-centered comparative effectivess research. Journal of Clinical Epidemiology, 66, S21-S28. Doi:

Gabler, N. B., Duan, N., Vohra, S., & Kravitz, R. L. (2011). N-of-1 trials in the medical literature: a systematic review. Medical Care, 49, 761-768. Doi:

Open mHealth

Chen, C., Haddad, D., Selsky, J., Hoffman, J. E., Kravitz, R. L., Estrin, D. E., Sim, I. (2012). Making sense of mobile health data: An open architecture to improve individual- and population-level health. Journal of Medical Internet Research, 14(4), e112. Doi:

Estrin, D., & Sim, I. (2010). Open mHealth architecture: an engine for health care innovation. Science, 330, 759-760. Doi:

If you are a clinician in the UC Davis Primary Care Network or a clinician from the VANCHCS and are interested in learning more about the PREEMPT study, please contact our research team. We would be happy to schedule a visit to your primary care site and discuss in person how the PREEMPT study may be beneficial to your patients and your clinical practice.

Phone: Toll-free 1-844-PREEMPT (773-3678)



Clinician login
The above link allows PREEMPT clinicians to create a trial and review trial results