Email updates

Keep up to date with the latest news and content from BMC Musculoskeletal Disorders and BioMed Central.

Open Access Highly Accessed Open Badges Research article

Systematic review with meta-analysis: cytokines in fibromyalgia syndrome

Nurcan Üçeyler*, Winfried Häuser and Claudia Sommer

BMC Musculoskeletal Disorders 2011, 12:245  doi:10.1186/1471-2474-12-245

PubMed Commons is an experimental system of commenting on PubMed abstracts, introduced in October 2013. Comments are displayed on the abstract page, but during the initial closed pilot, only registered users can read or post comments. Any researcher who is listed as an author of an article indexed by PubMed is entitled to participate in the pilot. If you would like to participate and need an invitation, please email, giving the PubMed ID of an article on which you are an author. For more information, see the PubMed Commons FAQ.

Error in meta-analysis regarding plasma IL-6.

Ellen Generaal   (2014-05-30 14:38)  GGZingeest/VU University Medical Center email

In this meta-analyses, Uceyler et al. state as one of their main findings that fibromyalgia patients had higher plasma levels of IL-6 than controls. For this result, they refer to Table 4, which should be Table 9 (findings from meta-analysis are only shown in Table 9). The presented data (SMD[95%CI] = -0.34 [-0.64, -0.03]) shows that their conclusion is incorrect: mean plasma IL-6 levels of controls are higher than the values for fibromyalgia patients. The three studies that were examined in this analysis (Togo, 2009; Schwarz, 2002; Bazzichi, 2007) show similar data as presented in Table 9. Thus, although perhaps unexpected, the conclusion should be that fibromyalgia patients had lower plasma levels of IL-6 than controls.

Subsequently, in the discussion, authors should have explained why results of plasma IL-6 differ between their systematic review and the meta-analyses. Also, the same caveats should have been made as the authors partly do now: the conclusion is based on only three studies, there are differences in assessment methods, basal cytokine levels show variability and circadian rhythmicity, and the impact of lifestyle and disease was not taken into account (Generaal et al., Pain, 2014).

Competing interests

There are no competing interests.


Post a comment