Therapeutic Benefit of Balneotherapy and Hydrotherapy in the Management of Fibromyalgia Syndrome

A Qualitative Systematic Review and Meta-analysis of Randomized Controlled Trials

Johannes Naumann; Catharina Sadaghiani

Disclosures

Arthritis Res Ther. 2014;16(R141) 

In This Article

Discussion

Summary of Evidence

The primary aim of this systematic review and meta-analysis was to determine the therapeutic benefit of BT and HT in the management of FMS, with special focus on separate analyses of the different treatment modalities. For HT with exercise we found moderate-to-strong evidence (consistent findings among ≥3 RCTs with low risk of bias) for a small improvement in pain (eight studies, 462 participants; including three low-risk studies, 223 participants) and HRQOL (seven studies, 398 participants; including three low-risk studies, 223 participants). Follow-up data provided moderate evidence (consistent findings among multiple high-risk RCTs and/or one low-risk RCT) for maintenance of improvement, at least with regard to pain (four studies, 254 participants; including one low-risk study, 125 participants). However, no evidence was found for improvement of depressive symptoms (BDI) and TPC. Furthermore, no group difference was found when comparing water-based exercise to land-based exercise. This is in accordance with the review by Häuser et al. from 2010.[81]

We found moderate evidence of a medium-to-large effect on pain and TPC for BT with mineral/thermal water (five studies, 177 participants; including three high-risk and two unclear-risk studies), a medium effect on HRQOL, and no significant effect on depressive symptoms (BDI). Moderate evidence for maintenance of these improvements was found at follow up. However, the effects were smaller. The results confirm the conclusions of other reviews on BT.[6,82]

Besides these two larger groups, further subgroup analyses were not possible due to the limited number of available studies and/or provided data. This is also true of the follow-up data provided, where only a few studies remained for statistical analyses. The evidence on the long-term effects that can be concluded from this meta-analysis is limited.

No conclusions can be drawn on hydrogalvanic/Stanger baths, thalassotherapy, mud baths, phytothermotherapy or sulfur baths, which were only represented by one study each. So as not to lose the information provided by these studies, we pooled all the available studies in an overall analysis, which showed similar effects (reduction of pain) to HT or BT.

Concerning safety, only preliminary conclusions can be drawn, because reporting of adverse events and the reasons for dropouts was poor. The data suggest that HT and BT are safe and well-accepted treatments, which is in line with other recommendations,[10,83] and we should not forget the daily experience of patients and the general population practising some kind of BT or HT.

Male participants were rarely included in the study populations, and separate gender comparisons were not reported. Evidence for treatment effects in the management of FMS in men is limited. Furthermore, it has to be taken into account that the population of FMS patients participating in a trial is selected. Generalisability may be restricted.[84]

Limitations

As so often in evidence-based approaches to nonpharmacological modalities, limitations are inherent and inevitable. This is especially true for BT, which depends on local conditions such as climate or water composition and provides a large variety of treatment modalities. Absence of blinding is also inevitable wherever treatment requires active participation on the part of the study subjects and clinicians.

There are also several methodological limitations. The analyses were underpowered due to the small number of studies and patients included. Analysis according to sample size (<25, >25) showed a slightly larger effect size and broader CIs in small studies (P = 0.54). The methodological quality (risk of bias) of the included studies varied, and was slightly better in HT studies than BT studies. Although some studies had low risk of bias, the majority - especially older studies - were associated with unclear or high risk of bias. Nevertheless, sensitivity analyses could show, at least in HT studies, that the effect sizes were not affected by methodological bias. Due to the limited number of BT studies, sensitivity analyses could not be performed here. Furthermore, the sample sizes in the BT studies were very small (<25 per treatment arm), except for one study.[79] Unfortunately, in this study, no results were collected for the control group after treatment. Thus, the data were not analyzed and only follow-up data were used.

Heterogeneity was not present in the HT studies, in contrast to considerable heterogeneity in the BT studies. This could be explained by the fact that co-therapies were not allowed in one study, which also had a non-interventional control group.[69] As far as selection bias is concerned, it is not possible to assess the extent to which the results may be influenced. Most of the studies reported unclear randomization methods as well as insufficient allocation concealment. The studies that allowed co-therapies did not control their effects for dosage or changes in concomitant therapies.

A strength of this review is the homogenous pool of treatment approaches selected for subgroup analyses, based on the professional expertise in the field of balneology of one of the authors (JN). The evidence of the integrated effect sizes seems robust, especially since publication bias is not plausible after visual analysis of the funnel plot, showing a symmetric picture, except for one outlier study[69] already identified by sensitivity analysis. Commencing from a systematic and thorough search of the literature (CS) we are confident not to have missed any larger important study.

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