Points to consider when interpreting the results and conclusions of this review

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Karagülle M. Z., Kardeş S., Karagülle M.

Cochrane Database Of Systematic Reviews, pp.45-47, 2017 (SCI-Expanded)



Points to consider when interpreting the results and conclusions of this review, 12 April 2017


We read with great interest the Cochrane review on balneotherapy (or spa therapy) for rheumatoid arthritis by Verhagen et al. [1]. However,

we would like to address the points below that should be considered when interpreting the results and conclusions of this review.

1) The review authors considered the intervention of control group as a placebo in a trial included in the review, which tested mud compress

therapy for the hands of rheumatoid arthritis patients [2]. However, the intervention of control group in that study was heated attenuated

mud compress not a placebo [2]. Indeed, that study aimed to investigate whether mineral content of mud would have any additional benefit

in the heated mud compress therapy. In other words, the control group received ‘heated’ attenuated mud compress; and since that therapy

had thermal eGect, categorizing that control therapy as a placebo was inappropriate. Therefore, the results and conclusions regarding

the “balneotherapy versus placebo or no treatment” should be interpreted with caution. Nevertheless, this inappropriate reporting may

be originated from lack of knowledge of basic characteristics of balneological interventions, which include balneotherapy (mineral water

immersion), peloidotherapy/mud therapy (medical peloid or mud applications), hydropinotherapy (mineral water drinking), inhalation

therapy (mineral water inhalation) and hydrotherapy (tap water immersion and exercise), if not from lack of caution to distinguish active

from inactive control intervention. Furthermore, the results of the review do not match those from the original study in terms of response

rate (improvement). The original paper reported statistically significant diGerences (please see Table 4 in original study) [2]; however, the

review authors’ analysis revealed no significant diGerences. We believe that this discrepancy should have mentioned and explained in the

review and needs clarification.

2) The review authors wrongly defined one of the investigated interventions of a study as balneotherapy. However, the tested intervention

in reality was hydrotherapy since tap water was used not mineral water [3]. In fact, that study aimed to investigate whether hydrotherapy

in form of aquatic exercise would result in a greater therapeutic benefit than hydrotherapy in form of seated passive immersion, land

exercise or progressive relaxation [3]. Therefore, classification of that intervention as balneotherapy was ill-chosen since the water

used was not a mineral water. We think that this inaccurate classification additionally must have contributed the heterogeneity of the

balneotherapy interventions observed in the review. Thereby, the results and conclusions regarding the “balneotherapy versus other treatments” should be interpreted with caution. Nevertheless, this approach is not well-structured definition, and once again, may indicate

lack of interpretation of even the basic characteristics and application modes of balneological interventions. (see above).

3) The conclusions of the review authors on two radon therapy studies [4, 5] should also be read with caution: “adding radon to carbon

dioxide baths did not improve pain intensity at three months but may improve overall well-being and pain at six months compared with

carbon dioxide baths without radon, but this may have happened by chance.” However, they failed to explain why the results of these

two studies with low risk of bias might have happened by chance. The review authors should have explained the scientific rationale and

evidence for attributing the diGerences to the chance. On the other hand, the radon studies by Franke and colleagues are spa therapy

trials, in which both groups stayed in a spa resort and received balneotherapy (either baths with natural mineral water rich in radon and

carbondioxide or artificially produced carbondioxide baths of the same carbondioxide concentration to maintain the blinding of patients

and to investigate specific eGects of radon), diseases-specific exercises, physiotherapy, massage therapy, hydrogalvanic baths and were

oGered occupational therapy, leisure time sports and relaxation therapy [4, 5]. In other words, the groups have undertaken the same

package of multiple interventions plus balneotherapy (radon+carbondioxide or only carbondioxide); this may explain why the expected

eGect size would be small which was correctly reported in those two studies.

4) The review authors wrongly stated that information about adverse events was not reported in a radon spa therapy study [5] and a

balneotherapy study [6], in plain language summary section. However, these studies have reported the adverse events. We believe that

that information should be mentioned to provide more comprehensive information on harms of balneotherapy or spa therapy.

5) Due to concerns raised above, the results and conclusions of the Cochrane review on balneotherapy (or spa therapy) for rheumatoid

arthritis may mislead the readers. The Cochrane Handbook states that review teams must include expertise in the topic area being reviewed

[7]; accordingly we would suggest review teams should include expertise in the balneological interventions when further reviews on the

safety and eGectiveness of any balneological intervention will be being conducted, particularly for distinguishing active from inactive

control intervention or hydrotherapy (tap water immersion) from balneotherapy (mineral water immersion), which were confused in this