A Cochrane review «Balneotherapy for osteoarthritis»1 «Verhagen AP, Bierma-Zeinstra SM, Boers M, Cardoso JR, Lambeck J, de Bie RA, de Vet HC. Balneotherapy for osteoarthritis. Cochrane Database Syst Rev 2007 Oct 17;(4):CD006864. »1 included 7 studies with a total of 498 subjects. The studies included participants with knee, hip or lumbar osteoarthritis (OA). Two studies compared spa-treatment with no treatment. One study evaluated baths as an add-on treatment to home exercises and another compared thermal water from Cserkeszölö with tap water (placebo). Three studies evaluated sulphur or Dead Sea baths with no treatment or mineral baths with tap water baths or no treatment. Mineral baths compared to no treatment had beneficial effects on pain, quality of life and analgesic intake in three studies out of four (SMD between 1.82 and 0.34), the difference between groups varying from 6.6% to 56.6%.There was also a statistically significant difference in pain and function of Dead Sea + sulphur versus no treatment, only at end of treatment (WMD 5.7, 95% CI 3.3 to 8.1), but not at 3 month follow-up (WMD 2.6, 95% CI -1.1 to 6.3).
Comment: The quality of evidence is downgraded by study quality (inadequate or unclear allocation concealment, lack of blinding) and by inconsistency (heterogeneity in interventions and outcomes). Also language-based reporting bias was likely