- Email: [email protected]
In Reply: Response to Letter to the Editor
THE EFFICIENCY OF MULTIPLE IMPULSE THERAPY FOR MUSCULOSKELETAL COMPLAINTS To the Editor : Survival analysis is an important tool for understanding the treatment course of a condition. Its use by Collins et al 1 exemplifies misunderstanding of the rules that enhance external validity and credibility of clinical designs. This is an uncontrolled retrospective case series on a heterogeneous population, without blinding, with rate of recovery selectively contrasted against the literature. Literature control and statistical analysis cannot alter that fact. Such methods are unintended for clinicians, rather than are a basis for hypothesis development. It provides no real evidence of treatment effectiveness. The researchers discuss chronicity but ignore severity. Evidence exists that subgroups with differing severity/ chronicity combinations respond differently. With severity being omitted, understanding of the dominant subgroup is lost. Instead, the authors cite disagreement over interpretation of the visual analog scale in the study of pain itself. The authors admit obtaining severity data that methodologically should define the population. At the same time, they used literature that categorized severity to contrast perceived differences in outcome. The preponderance of evidence supports pain scale use. If the authors did not like the visual analog scale, other ways to report severity exist. Besides making the designing of the next study more difficult, these omissions give little confidence in the interpretation of results. From the authors’ references, different chronicity/ severity patient mix skewed the result to lengthier duration of treatment. Quoting from the original work,2
In general, patients with less severe low back pain participated less often or did not complete the follow-up study. . . . Approximately three of every four patients whose index episode ended before the end of the followup period had one or more relapses within a year. The analysis resulted in a model with four variables predicting the duration of the low back pain, including dthe duration of the low back pain preceding the initial visit,T dreceiving physical therapy,T dpain intensityT, and dhistory of back surgery.T By failing to report severity, an alternate explanation of results is that lesser severity patients were studied. The Kaplan-Meier analysis accurately reflects the recovery but will not show effectiveness. Further contrasts made are misleading. The comparison study designs were different and unrelated. They had a predetermined follow-up interval and examined pain results. Collins et al report regular questioning on brelief,Q a significantly different question from quantitative self-reporting pain, to which you expect a different answer. When at btotal relief,Q the study participation ended. This ignores the 502
brecurrentQ pain issues as is reflected by van den Hoogen et al2 and many others. Patients in practice and in clinical trials report occasional days of complete relief as a part of the episode course. Mixing basis of comparisons, as appears to have occurred, is a form of reporting bias that may well exaggerate the apparent outcome. In all, this is an observational retrospective case series with some interesting results on an incompletely specified sample. Patient responses may be confounded with efforts to please their clinician (eg, exaggerating relief to their clinician—a known source of bias), and severity issues were not reported. The logic in comparing results to others is faulty. These limitations and their effects are largely ignored in the enthusiasm of the report. John J. Triano DC, PhD Research Professor, University of Texas, Arlington, TX Marion McGregor DC, MSc, PhD(c) University of Texas, Dallas, TX 0161-4754/$32.00
DOI of original article 10.1016/j.jmpt.2005.12.010 Copyright D 2006 National University of Health Sciences doi:10.1016/j.jmpt.2006.06.008
REFERENCES 1. Collins DL, Evans JM, Grundy RH. The efficiency of multiple impulse therapy for musculoskeletal complaints. J Manipulative Physiol Ther 2006;29:162.e1- e9. 2. van den Hoogen HJ, Koes BW, Deville W, van Eijk JT, Bouter LM. The prognosis of low back pain in general practice. Spine 1997;22:1515 - 21.
RESPONSE TO LETTER TO THE EDITOR In Reply: Survival analysis is more than an important tool for understanding the treatment course of conditions such as lowback pain.1,2 The study discussed hereinabove by Triano and McGregor was preceded by a pilot study3 using the same methodology and, like the study of van den Hoogen et al,4 which used the same criterion and served as a historic control, is prospective and designed to document clinical practice rather than a simple research construct. We reported the results of treatment of 8 homogenous groups of patients. The authors hypothesized in the pilot study that if a treatment were effective, there would be no observed effect of chronicity. This hypothesis was supported. The major finding of Collins et al for low-back pain was that 50% of the patients reported symptom resolution in 9 to 16 days, and the average number of visits required to achieve that status was 4. We compared these results in this and previous work not with just 1 but with 4 studies of back pain, including a study of osteopathic manipulation,5
Journal of Manipulative and Physiological Therapeutics Volume 29, Number 6
where the results were indistinguishable from the van den Hoogen study (hazard ratio = 1) and 2 studies of neck pain. These comparisons are an alternative to subjective peer review of the literature and expert ranking as exemplified by Gatterman et al.6 These results were noted in the Discussion section of the report as is common practice, for example, a study by Hurwitz et al.7 We did not claim any causality. We have found no basis in the literature for the writers’ opinion regarding the usefulness of severity. As far as we are aware, no measure of severity has been found to provide clinically useful prediction of treatment outcomes. In the van den Hoogen study where predictive value is claimed for bpain intensity,Q careful reading of the study reveals that the prognostic factor reported was the pain component of the Nottingham Health Profile, a series of byesQ and bnoQ answers to 8 pain-related questions accounting for 1% lower probability of recovery (hazard ratio = 0.99 for pain). This pain component has a negative correlation with the SF-36 bodily pain scale8 and did not contribute significantly to the model. Our results may be due to severity or some other unknown factor. However, this assumption requires that we believe that patients with this factor selectively flock to the Collins Clinic rather than to other sites. We know of no studies in the literature that report an effect size close to the achievement of pain-free status in half the time of other treatments (hazard ratio = 0.5 for no treatment). These results are not simply binteresting,Q they are potentially revolutionary. As we stated in our article, causal relationship cannot be inferred from this research; however, the results suggest a treatment effect and support the need for further research to explain and expand upon these results.
Letters to the Editor
Joseph M. Evans PhD Sense Technology Inc Pittsburgh, PA 0161-4754/$32.00
DOI of original article 10.1016/j.jmpt.2006.06.008 Copyright D 2006 National University of Health Sciences doi:10.1016/j.jmpt.2006.06.014
REFERENCES 1. Evans JM. The use of survival analysis for the evaluation of musculoskeletal therapy. J Manipulative Physiol Ther 2005; 28:374. 2. Evans JM. A proposed method for estimating the efficiency and effectiveness of techniques of musculoskeletal therapy. J Manipulative Physiol Ther 2005;28:206 - 10. 3. Evans JM, Collins DL, Grundy RH. Pilot study of patient response to multiple impulse therapy for musculoskeletal complaints. J Manipulative Physiol Ther 2006;29: 51.e1 - 51.e7. 4. van den Hoogen HJ, Koes BW, Deville W, van Eijk JT, Bouter LM. The prognosis of low back pain in general practice. Spine 1997;22:1515 - 21. 5. MacDonald RS, Bell CM. An open controlled assessment of osteopathic manipulation in nonspecific low-back pain. Spine 1990;15:364 - 70. 6. Gatterman MI, Cooperstein R, Lantz C, Perle SM, Schneider MJ. Rating specific chiropractic technique procedures for common low back conditions. J Manipulative Physiol Ther 2001;24:449 - 56. 7. Hurwitz EL, Morgenstern H, Kominski GF, Yu F, Chiang LM. A randomized trial of chiropractic and medical care for patients with low back pain: eighteen-month follow-up outcomes from the UCLA low back pain study. Spine 2006;31:611 - 21 [discussion 22]. 8. Von Korff M, Jensen MP, Karoly P. Assessing global pain severity by self-report in clinical and health services research. Spine 2000;25:3140 - 51.
503
In general, patients with less severe low back pain participated less often or did not complete the follow-up study. . . . Approximately three of every four patients whose index episode ended before the end of the followup period had one or more relapses within a year. The analysis resulted in a model with four variables predicting the duration of the low back pain, including dthe duration of the low back pain preceding the initial visit,T dreceiving physical therapy,T dpain intensityT, and dhistory of back surgery.T By failing to report severity, an alternate explanation of results is that lesser severity patients were studied. The Kaplan-Meier analysis accurately reflects the recovery but will not show effectiveness. Further contrasts made are misleading. The comparison study designs were different and unrelated. They had a predetermined follow-up interval and examined pain results. Collins et al report regular questioning on brelief,Q a significantly different question from quantitative self-reporting pain, to which you expect a different answer. When at btotal relief,Q the study participation ended. This ignores the 502
brecurrentQ pain issues as is reflected by van den Hoogen et al2 and many others. Patients in practice and in clinical trials report occasional days of complete relief as a part of the episode course. Mixing basis of comparisons, as appears to have occurred, is a form of reporting bias that may well exaggerate the apparent outcome. In all, this is an observational retrospective case series with some interesting results on an incompletely specified sample. Patient responses may be confounded with efforts to please their clinician (eg, exaggerating relief to their clinician—a known source of bias), and severity issues were not reported. The logic in comparing results to others is faulty. These limitations and their effects are largely ignored in the enthusiasm of the report. John J. Triano DC, PhD Research Professor, University of Texas, Arlington, TX Marion McGregor DC, MSc, PhD(c) University of Texas, Dallas, TX 0161-4754/$32.00
DOI of original article 10.1016/j.jmpt.2005.12.010 Copyright D 2006 National University of Health Sciences doi:10.1016/j.jmpt.2006.06.008
REFERENCES 1. Collins DL, Evans JM, Grundy RH. The efficiency of multiple impulse therapy for musculoskeletal complaints. J Manipulative Physiol Ther 2006;29:162.e1- e9. 2. van den Hoogen HJ, Koes BW, Deville W, van Eijk JT, Bouter LM. The prognosis of low back pain in general practice. Spine 1997;22:1515 - 21.
RESPONSE TO LETTER TO THE EDITOR In Reply: Survival analysis is more than an important tool for understanding the treatment course of conditions such as lowback pain.1,2 The study discussed hereinabove by Triano and McGregor was preceded by a pilot study3 using the same methodology and, like the study of van den Hoogen et al,4 which used the same criterion and served as a historic control, is prospective and designed to document clinical practice rather than a simple research construct. We reported the results of treatment of 8 homogenous groups of patients. The authors hypothesized in the pilot study that if a treatment were effective, there would be no observed effect of chronicity. This hypothesis was supported. The major finding of Collins et al for low-back pain was that 50% of the patients reported symptom resolution in 9 to 16 days, and the average number of visits required to achieve that status was 4. We compared these results in this and previous work not with just 1 but with 4 studies of back pain, including a study of osteopathic manipulation,5
Journal of Manipulative and Physiological Therapeutics Volume 29, Number 6
where the results were indistinguishable from the van den Hoogen study (hazard ratio = 1) and 2 studies of neck pain. These comparisons are an alternative to subjective peer review of the literature and expert ranking as exemplified by Gatterman et al.6 These results were noted in the Discussion section of the report as is common practice, for example, a study by Hurwitz et al.7 We did not claim any causality. We have found no basis in the literature for the writers’ opinion regarding the usefulness of severity. As far as we are aware, no measure of severity has been found to provide clinically useful prediction of treatment outcomes. In the van den Hoogen study where predictive value is claimed for bpain intensity,Q careful reading of the study reveals that the prognostic factor reported was the pain component of the Nottingham Health Profile, a series of byesQ and bnoQ answers to 8 pain-related questions accounting for 1% lower probability of recovery (hazard ratio = 0.99 for pain). This pain component has a negative correlation with the SF-36 bodily pain scale8 and did not contribute significantly to the model. Our results may be due to severity or some other unknown factor. However, this assumption requires that we believe that patients with this factor selectively flock to the Collins Clinic rather than to other sites. We know of no studies in the literature that report an effect size close to the achievement of pain-free status in half the time of other treatments (hazard ratio = 0.5 for no treatment). These results are not simply binteresting,Q they are potentially revolutionary. As we stated in our article, causal relationship cannot be inferred from this research; however, the results suggest a treatment effect and support the need for further research to explain and expand upon these results.
Letters to the Editor
Joseph M. Evans PhD Sense Technology Inc Pittsburgh, PA 0161-4754/$32.00
DOI of original article 10.1016/j.jmpt.2006.06.008 Copyright D 2006 National University of Health Sciences doi:10.1016/j.jmpt.2006.06.014
REFERENCES 1. Evans JM. The use of survival analysis for the evaluation of musculoskeletal therapy. J Manipulative Physiol Ther 2005; 28:374. 2. Evans JM. A proposed method for estimating the efficiency and effectiveness of techniques of musculoskeletal therapy. J Manipulative Physiol Ther 2005;28:206 - 10. 3. Evans JM, Collins DL, Grundy RH. Pilot study of patient response to multiple impulse therapy for musculoskeletal complaints. J Manipulative Physiol Ther 2006;29: 51.e1 - 51.e7. 4. van den Hoogen HJ, Koes BW, Deville W, van Eijk JT, Bouter LM. The prognosis of low back pain in general practice. Spine 1997;22:1515 - 21. 5. MacDonald RS, Bell CM. An open controlled assessment of osteopathic manipulation in nonspecific low-back pain. Spine 1990;15:364 - 70. 6. Gatterman MI, Cooperstein R, Lantz C, Perle SM, Schneider MJ. Rating specific chiropractic technique procedures for common low back conditions. J Manipulative Physiol Ther 2001;24:449 - 56. 7. Hurwitz EL, Morgenstern H, Kominski GF, Yu F, Chiang LM. A randomized trial of chiropractic and medical care for patients with low back pain: eighteen-month follow-up outcomes from the UCLA low back pain study. Spine 2006;31:611 - 21 [discussion 22]. 8. Von Korff M, Jensen MP, Karoly P. Assessing global pain severity by self-report in clinical and health services research. Spine 2000;25:3140 - 51.
503