Chronic pain treatment preferences change following participation in N-of-1 trials, but not always in the expected direction

Richard L. Kravitz, Maria Marois, Ida Sim, Deborah Ward, Samika S. Kanekar, Allison Yu, Peach Dounias, Jiabei Yang, Youdan Wang, Christopher H. Schmid

Research output: Contribution to journalArticlepeer-review


Objective: To examine pain treatment preferences before and after participation in an N-of-1 trial. Study Design and Setting: In this observational study nested within a randomized trial, we examined chronic pain patients’ preferences before and after treatment in relation to N-of-1 trial results; assessed the influence of different schemes for defining comparative “superiority” on potential conclusions; and generated classification trees illustrating the relationship between pre-treatment preferences, N-of-1 trial results, and post-treatment preferences. Results: Treatment preferences differed pre- and post-trial for 40% of participants. The proportion of patients whose N-of-1 trials demonstrated “superiority” of one treatment regimen over the other varied depending on how superiority was defined and ranged from 24% (using criteria that required statistically significant differences between regimens) to 62% (when relying only on differences in point estimates). Regardless of criteria for declaring treatment superiority, nearly three-fourths of patients with equivocal N-of-1 trial results nevertheless expressed definite preferences post-trial. Conclusion: A large segment of patients undergoing N-of-1 trials for chronic pain altered their treatment preferences. However, the direction of preference change did not necessarily correspond to the N-of-1 results. More research is needed to understand how patients use N-of-1 trial results, why preferences are “sticky” even in the face of personalized data, and how patients and clinicians might be educated to use N-of-1 trial results more informatively.

Original languageEnglish (US)
Pages (from-to)167-176
Number of pages10
JournalJournal of Clinical Epidemiology
StatePublished - Nov 2021


  • Chronic pain
  • Data science
  • N-of-1 trial
  • Observational study
  • Personalized trial
  • Shared decision-making
  • Treatment preferences

ASJC Scopus subject areas

  • Epidemiology


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