Effect of Mobile Device-Assisted N-of-1 Trial Participation on Analgesic Prescribing for Chronic Pain: Randomized Controlled Trial

David D. Odineal, Maria T. Marois, Deborah Ward, Christopher H. Schmid, Rima Cabrera, Ida Sim, Youdan Wang, Barth Lance Wilsey, Naihua Duan, Stephen G. Henry, Richard L. Kravitz

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


Objectives: Opioids and non-steroidal anti-inflammatory drugs (NSAIDs) are frequently prescribed for chronic musculoskeletal pain, despite limited evidence of effectiveness and well-documented adverse effects. We assessed the effects of participating in a structured, personalized self-experiment (“N-of-1 trial”) on analgesic prescribing in patients with chronic musculoskeletal pain. Methods: We randomized 215 patients with chronic pain to participate in an N-of-1 trial facilitated by a mobile health app or to receive usual care. Medical records of participating patients were reviewed at enrollment and 6 months later to assess analgesic prescribing. We established thresholds of ≥ 50, ≥ 20, and > 0 morphine milligram equivalents (MMEs) per day to capture patients taking relatively high doses only, patients taking low-moderate as well as relatively high doses, and patients taking any dose of opioids, respectively. Results: There was no significant difference between the N-of-1 and control groups in the percentage of patients prescribed any opioids (relative odds ratio (ROR) = 1.05; 95% confidence interval [CI] = 0.61 to 1.80, p = 0.87). There was a clinically substantial but statistically not significant reduction of the percentage of patients receiving ≥ 20 MME (ROR = 0.58; 95% CI = 0.33 to 1.04, p = 0.07) and also in the percentage receiving ≥ 50 MME (ROR = 0.50; 95% CI = 0.19 to 1.34, p = 0.17). There was a significant reduction in the proportion of patients in the N-of-1 group prescribed NSAIDs compared with control (relative odds ratio = 0.53; 95% CI = 0.29 to 0.96, p = 0.04), with no concomitant increase in average pain intensity. There was no significant change in use of adjunctive medications (acetaminophen, gabapentenoids, or topicals). Discussion: These exploratory results suggest that participation in N-of-1 trials may reduce long-term use of NSAIDs; there is also a weak signal for an effect on use of opioids. Additional research is needed to confirm these results and elucidate possible mechanisms. Trial Registration: ClinicalTrials.gov Identifier: NCT02116621.

Original languageEnglish (US)
JournalJournal of general internal medicine
StateAccepted/In press - Jan 1 2019


  • analgesic
  • chronic pain
  • N-of-1 trials
  • non-steroidal anti-inflammatory agent
  • opioid

ASJC Scopus subject areas

  • Internal Medicine


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