Skip to main content
  • Other Publications
  • Subscribe
  • Contact Us
Advertisement
JCORE Reference
this is the JCORE Reference site slogan
  • Home
  • Most Read
  • About Us
    • About Us
    • Editorial Board
  • More
    • Advertising
    • Alerts
    • Feedback
    • Folders
    • Help
  • Patients
  • Reference Site Links
    • View Regions
  • Archive

Author Response

Tasha R. Stanton, Mark J. Hancock, Christopher G. Maher, Bart W. Koes
DOI: 10.2522/ptj.20090233.ar Published 1 June 2010
Tasha R. Stanton
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Mark J. Hancock
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Christopher G. Maher
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Bart W. Koes
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • Article
  • Info & Metrics
  • PDF
Loading

We would like to thank Fitzgerald for his thoughtful and generous commentary1 on our work.2 We believe the recent dialogue on this topic in the physical therapy community is very valuable and a sign of the maturity of the profession. We have only a few points that we would like to add. We agree with Fitzgerald on the key point that a randomized controlled trial (RCT) with appropriate analysis “must be performed to qualify that a CPR [clinical prediction rule] has indeed been developed.” In selecting the potential predictors for investigation in the RCT, we agree that a well-conducted single-arm study may be useful, along with selecting predictors based on a strong theoretical rationale or clinical experience. One note of caution relates to the suggestion by Fitzgerald that using a single-arm trial rather than an underpowered RCT is less likely to miss important predictors. We would argue that single-arm trials may be even more likely to miss true predictors of response to the intervention. As single-arm studies are designed to identify predictors of good prognosis regardless of treatment, a factor associated with a poor prognosis but a good response to treatment will likely not be identified in a single-arm trial. Therefore, single-arm trials can easily miss important predictors of response to treatment. We believe secondary analysis of the thousands of existing RCTs may provide as good, if not better, information than single-arm trials to help in selecting the best predictors for analysis in a prospective, adequately powered RCT. Secondary analyses of existing RCTs also are cheaper and easier to do than performing single-arm trials, which are still expensive to perform.

The language regarding stages of development of CPRs is well defined in the literature.3 This language, however, was developed for studies of diagnosis and prognosis. In the physical therapy literature investigating responders to treatment, this language has been modified, resulting in much confusion. Over recent years in the physical therapy literature, a single-arm study has been considered a derivation study, with the following RCT considered a validation study. As mentioned above, we agree strongly with Fitzgerald's emphasis that an RCT must be performed “to qualify that a CPR has indeed been developed [our emphasis].” Therefore, we do not consider that the first RCT is, in any way, a “validation” study, as referred to in the literature on development of CPRs. The single-arm study is simply a method to generate hypotheses of potential predictors in the same way as a theoretical rationale or clinical experience may be used. Because we do not know what the potential predictors arising from a single-arm study actually are (nonspecific predictors of outcome, treatment effect modifier, or error?), a CPR for a specific intervention cannot exist until we have confirmed that these potential predictors are, in fact, treatment effect modifiers, which is accomplished by performing an RCT and analyzing the predictor variable × treatment group interaction. Therefore, we argue that the initial RCT following a single-arm study confirms only that a CPR exists; it does not validate a CPR, and it should be considered a derivation study according to the original literature on CPR development. A second RCT would be the true validation study. This point has been recommended in recent articles.4,5

We have previously responded to comments about the study by Hancock et al6 mentioned by Fitzgerald and will only briefly comment here. If, as mentioned above, we consider the study by Childs et al7 a derivation study (first RCT on this CPR8), then Hancock and colleagues' study6 is the first attempt at validation. We were interested in whether the rule would generalize to a different setting including a modified treatment. This is not an unreasonable question, as evidenced by the fact that the same researchers also recently published an RCT to investigate the CPR in patients receiving different treatments (alternative manipulation and mobilization).9 To refer to the study by Hancock et al6 as flawed is, in our opinion, a misunderstanding of the aim and interpretation of the study. The study demonstrated the CPR does not generalize to this new setting including a modified treatment but says nothing about whether it will generalize in a new sample of patients if the identical manipulation is used. We await a second appropriately designed RCT to answer that question.

Last, we would like to extend Fitzgerald's call to researchers to test CPRs using RCTs. Beyond derivation and validation of CPRs, it also is important to perform an impact analysis.3 It is essential to know whether the rule changes clinician behavior, whether it improves patient outcomes, and whether it reduces costs. An accurate CPR may not change clinician behavior or improve patient outcomes for many reasons. It may be too difficult and time-consuming to apply to patients, clinicians may not be adequately trained in the treatment specified by the CPR (or may not feel comfortable performing the treatment), or for practical reasons (eg, liability) the CPR may not be used.

    • © 2010 American Physical Therapy Association

    References

    1. ↵
      1. Fitzgerald GK
      . Invited commentary on “Critical appraisal of clinical prediction rules that aim to optimize treatment selection for musculoskeletal conditions.” Phys Ther. 2010;90:855–858.
      OpenUrlFREE Full Text
    2. ↵
      1. Stanton TR,
      2. Hancock MJ,
      3. Maher CG,
      4. Koes BW
      . Critical appraisal of clinical prediction rules that aim to optimize treatment selection for musculoskeletal conditions. Phys Ther. 2010;90:843–854.
      OpenUrlAbstract/FREE Full Text
    3. ↵
      1. McGinn TG,
      2. Guyatt GH,
      3. Wyer PC,
      4. et al.
      ; for the Evidence-Based Medicine Working Group. Users' guides to the medical literature, XXII: how to use articles about clinical decision rules. JAMA. 2000;284:79–84.
      OpenUrlCrossRefPubMedWeb of Science
    4. ↵
      1. Hancock MJ,
      2. Herbert RD,
      3. Maher CG
      . A guide to interpretation of studies investigating subgroups of responders to physical therapy interventions. Phys Ther. 2009;89:698–704.
      OpenUrlAbstract/FREE Full Text
    5. ↵
      1. Kamper SJ,
      2. Maher CG,
      3. Hancock MJ,
      4. et al
      . Treatment-based subgroups of low back pain: a guide to appraisal of research studies and a summary of current evidence. Best Pract Res Clin Rheumatol. 2010;24:181–191.
      OpenUrlCrossRefPubMed
    6. ↵
      1. Hancock MJ,
      2. Maher CG,
      3. Latimer J,
      4. et al
      . Independent evaluation of a clinical prediction rule for spinal manipulative therapy: a randomised controlled trial. Eur Spine J. 2008;17:936–943.
      OpenUrlCrossRefPubMedWeb of Science
    7. ↵
      1. Childs J,
      2. Fritz J,
      3. Flynn T,
      4. et al
      . A clinical prediction rule to identify patients with low back pain most likely to benefit from spinal manipulation: a validation study. Ann Intern Med. 2004;141:920–928.
      OpenUrlPubMedWeb of Science
    8. ↵
      1. Flynn T,
      2. Fritz J,
      3. Whitman J,
      4. et al
      . A clinical prediction rule for classifying patients with low back pain who demonstrate short-term improvement with spinal manipulation. Spine. 2002;27:2835–2843.
      OpenUrlCrossRefPubMedWeb of Science
    9. ↵
      1. Cleland JA,
      2. Fritz JM,
      3. Kulig K,
      4. et al
      . Comparison of the effectiveness of three manual physical therapy techniques in a subgroup of patients with low back pain who satisfy a clinical prediction rule: a randomized clinical trial. Spine. 2009;34:2720–2729.
      OpenUrlCrossRefPubMedWeb of Science
    View Abstract
    Back to top
    Vol 96 Issue 12 Table of Contents
    Physical Therapy: 96 (12)

    Issue highlights

    • Musculoskeletal Impairments Are Often Unrecognized and Underappreciated Complications From Diabetes
    • Physical Therapist–Led Ambulatory Rehabilitation for Patients Receiving CentriMag Short-Term Ventricular Assist Device Support: Retrospective Case Series
    • Education Research in Physical Therapy: Visions of the Possible
    • Predictors of Reduced Frequency of Physical Activity 3 Months After Injury: Findings From the Prospective Outcomes of Injury Study
    • Use of Perturbation-Based Gait Training in a Virtual Environment to Address Mediolateral Instability in an Individual With Unilateral Transfemoral Amputation
    • Effect of Virtual Reality Training on Balance and Gait Ability in Patients With Stroke: Systematic Review and Meta-Analysis
    • Effects of Locomotor Exercise Intensity on Gait Performance in Individuals With Incomplete Spinal Cord Injury
    • Case Series of a Knowledge Translation Intervention to Increase Upper Limb Exercise in Stroke Rehabilitation
    • Effectiveness of Rehabilitation Interventions to Improve Gait Speed in Children With Cerebral Palsy: Systematic Review and Meta-analysis
    • Reliability and Validity of Force Platform Measures of Balance Impairment in Individuals With Parkinson Disease
    • Measurement Properties of Instruments for Measuring of Lymphedema: Systematic Review
    • myMoves Program: Feasibility and Acceptability Study of a Remotely Delivered Self-Management Program for Increasing Physical Activity Among Adults With Acquired Brain Injury Living in the Community
    • Application of Intervention Mapping to the Development of a Complex Physical Therapist Intervention
    Email

    Thank you for your interest in spreading the word on JCORE Reference.

    NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. We do not capture any email address.

    Enter multiple addresses on separate lines or separate them with commas.
    Author Response
    (Your Name) has sent you a message from JCORE Reference
    (Your Name) thought you would like to see the JCORE Reference web site.
    Print
    Author Response
    Tasha R. Stanton, Mark J. Hancock, Christopher G. Maher, Bart W. Koes
    Physical Therapy Jun 2010, 90 (6) 858-859; DOI: 10.2522/ptj.20090233.ar

    Citation Manager Formats

    • BibTeX
    • Bookends
    • EasyBib
    • EndNote (tagged)
    • EndNote 8 (xml)
    • Medlars
    • Mendeley
    • Papers
    • RefWorks Tagged
    • Ref Manager
    • RIS
    • Zotero
    Save to my folders

    Share
    Author Response
    Tasha R. Stanton, Mark J. Hancock, Christopher G. Maher, Bart W. Koes
    Physical Therapy Jun 2010, 90 (6) 858-859; DOI: 10.2522/ptj.20090233.ar
    del.icio.us logo Digg logo Reddit logo Technorati logo Twitter logo CiteULike logo Connotea logo Facebook logo Google logo Mendeley logo
    • Tweet Widget
    • Facebook Like
    • Google Plus One
    • Article
      • References
    • Info & Metrics
    • PDF

    Related Articles

    Cited By...

    More in this TOC Section

    • Reliability and Validity of Force Platform Measures of Balance Impairment in Individuals With Parkinson Disease
    • Predictors of Reduced Frequency of Physical Activity 3 Months After Injury: Findings From the Prospective Outcomes of Injury Study
    • Effects of Locomotor Exercise Intensity on Gait Performance in Individuals With Incomplete Spinal Cord Injury
    Show more Research Reports

    Subjects

    Footer Menu 1

    • menu 1 item 1
    • menu 1 item 2
    • menu 1 item 3
    • menu 1 item 4

    Footer Menu 2

    • menu 2 item 1
    • menu 2 item 2
    • menu 2 item 3
    • menu 2 item 4

    Footer Menu 3

    • menu 3 item 1
    • menu 3 item 2
    • menu 3 item 3
    • menu 3 item 4

    Footer Menu 4

    • menu 4 item 1
    • menu 4 item 2
    • menu 4 item 3
    • menu 4 item 4
    footer second
    footer first
    Copyright © 2013 The HighWire JCore Reference Site | Print ISSN: 0123-4567 | Online ISSN: 1123-4567
    advertisement bottom
    Advertisement Top