We read the article by Dusunceli et al. (1) about the efficacy of neck stabilization exercises for neck pain with interest. The authors present a well-designed study with interesting findings, which concludes that neck stabilization exercises in conjunction with physical therapy agents are superior to isometric and stretching exercises in conjunction with physical therapy agents and to physical therapy agents alone. However, we have some difficulty in interpreting their findings.
First, the authors did not specify how the participants were recruited. We consider this information essential in order to assess the applicability of the results from this study to patients with neck pain in general. Participants recruited from, for instance, primary care may differ from those recruited from specialized clinics, regarding severity or duration of complaints. Furthermore, it is unclear how patients with neck pain were informed about the existence of the study. We assume that an advertisement in a newspaper attracts a different kind of patients from a referral by a general practitioner. Again, in order to assess the external validity of the study results, this information is necessary.
Secondly, we have some questions about the statistical analysis. In the results section, the authors reported that a significant difference in visual analogue scale (VAS) pain scores among the groups was found at 9 and 12 months follow-up. However, the p-values in Table II in our judgement represent merely the comparison of VAS pain score at follow-up with VAS pain score at baseline. As a result, no conclusions about the significance of the difference between the groups and the efficacy of the treatments can be drawn.
We would be interested in the authors’ thoughts on these comments.
Submitted July 27, 2009; accepted September 28, 2009
Pauline van Es, MSc*, Jurgen Damen, MD MSc and Jos Runhaar, MSc
From the Department of General Practice, Erasmus MC, University Medical Center, Rotterdam, The Netherlands. *E-mail: P.email@example.com
RESPONSE TO LETTER TO THE EDITOR by van Es et al.
In reply to the questions in the letter: first, participants for our study were recruited from among patients with neck pain referred to our clinic by their primary care physicians. A total of 80 participants were provided with information about the study by a specialist physician, and gave their written informed consent to participate in the study.
VAS values for the follow-up are given in Table II for all groups. Although p-values for comparison of the groups are not given in this table, we have described this finding in the results section as “p < 0.05” (in the second paragraph on page 629). For this reason, we drew this conclusion about the significance of the difference among the groups.
I hope these explanations are helpful to the authors of the letter.
Submitted August 18, 2009; accepted September 28, 2009
Funda Atamaz, MD,
From Ege University Medical Faculty, Department of Physical Therapy and Rehabilitation, Bornova, Izmir, Turkey. E-mail: firstname.lastname@example.org