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Delayed timing of physical therapy initiation increases the risk of future opioid use in individuals with knee osteoarthritis: a real-world cohort study
  1. Deepak Kumar1,2,
  2. Tuhina Neogi2,
  3. Christine Peloquin2,
  4. Lee Marinko1,
  5. James Camarinos1,
  6. Kosaku Aoyagi2,3,
  7. David T Felson2,
  8. Maureen Dubreuil2,4
  1. 1Department of Physical Therapy, Boston University, Boston, Massachusetts, USA
  2. 2Section of Rheumatology, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, USA
  3. 3Physical Therapy Program, The University of Texas at El Paso, El Paso, Texas, USA
  4. 4Visiting Scholar, Optum Labs, Eden Prairie, Minnesota, USA
  1. Correspondence to Dr Deepak Kumar, Physical Therapy, Boston University, Boston, MA 02215, USA; krdeepak2pro{at}


Objective We assessed whether late versus early initiation of physical therapy (PT) was related to greater risk of future opioid use in people with knee osteoarthritis (OA) who receive PT.

Methods We used Commercial and Medicare Advantage claims data from 1999 to 2018 from American adults with incident knee OA referred for PT within 1 year of diagnosis. We categorised people as opioid naïve or opioid experienced based on prior prescriptions. We examined the association of timing of PT initiation with any and chronic opioid use over 1 year.

Results Of the 67 245 individuals with incident knee OA, 35 899 were opioid naïve and 31 346 were opioid experienced. In the opioid naïve group, compared with PT within 1 month, PT 1 to <3, 3 to <6, 6 to <9, 9–12 months from diagnosis was associated with adjusted risk ratio (aRR (95% CIs)) for any opioid use of 1.18 (1.10 to 1.28), 1.49 (1.37 to 1.61), 1.73 (1.58 to 1.89) and 1.93 (1.76 to 2.12), respectively; aRRs (95% CIs) for chronic opioid use were 1.25 (1.01 to 1.54), 1.83 (1.48 to 2.26), 2.29 (1.82 to 2.89) and 2.50 (1.96 to 3.19). Results were similar among opioid experienced; aRRs (95% CIs) for any opioid use were 1.19 (1.14 to 1.24), 1.32 (1.26 to 1.37), 1.39 (1.32 to 1.45) and 1.54 (1.46 to 1.61); aRRs (95% CIs) for chronic opioid use were 1.25 (1.17 to1.34), 1.43 (1.33 to 1.54), 1.53 (1.41 to 1.66) and 1.65 (1.51 to 1.80).

Conclusion Compared with PT initiation within 1 month, delayed PT initiation was associated with higher risk of opioid use in people with incident knee OA. The longer the delay in PT initiation, the greater was the risk.

  • exercise
  • knee
  • cohort studies
  • rehabilitation

Data availability statement

Data may be obtained from a third party and are not publicly available. Data used for this study are owned by Optum Labs.

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Data availability statement

Data may be obtained from a third party and are not publicly available. Data used for this study are owned by Optum Labs.

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  • Contributors CP and DK had full access to all of the data in the study and take responsibility for the integrity of the data and accuracy of the data analysis. Concept and design: DK, TN, CP, MD, LM, JC and DTF. Acquisition, analysis or interpretation of data: DK, TN, CP, KA, MD, JC, LM and DTF. Drafting of the manuscript: DK, CP and KA. Critical revision of the manuscript for important intellectual content: DK, TN, CP, KA, LM, JC, DTF and MD. Statistical analysis: CP, DK, TN, MD. Obtained funding: DK, TN and DTF. Administrative, technical or material support: DK, MD, DTF and TN. Supervision: DK, TN, DTF and MD.

  • Funding This work is supported by NIH-NIAMS K01AR069720 (DK), K24AR070892 (TN), P30 AR0702571 (DTF) and K23AR069127 (MD).

  • Disclaimer The sponsors had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication. Author DK accepts full responsibility for the work, had access to the data, and controlled the decision to publish

  • Competing interests TN served as a consultant for Pfizer/Lilly, Regeneron, and Novartis outside the submitted work. DK received grants from the National Institutes of Health during the conduct of the study and grants from Pfizer Inc for unrelated projects outside the submitted work. MD and DTF received grants from the National Institutes of Health.

  • Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.