A pragmatic randomized controlled trial on the effectiveness of low concentrated saline spa water baths followed by ultraviolet B (UVB) compared to UVB only in moderate to severe psoriasis

Objective To evaluate whether low concentrated saline spa water baths followed by ultraviolet B (LC-SSW-UVB) are superior to UVB alone in moderate to severe psoriasis. Background There is a lack of sufficiently large randomized controlled clinical trial evaluating the additional benefit of saltwater baths followed by UVB compared to UVB only in psoriasis. Study design Partly evaluator blind, multicentre, pragmatic, randomized controlled trial. Setting Five German spa centres. Subject One hundred and forty-three adults with stable psoriasis during the last month and a Psoriasis Area and Severity Index (PASI) of > 10 and/or an affected body surface area of > 15%. Interventions LC-SSW-UVB or UVB thrice a week until remission (PASI < 5) or for a maximum of 6 weeks. Sodium chloride concentrations of natural springs varied between 4.5% and 12%. Conventional UVB (broadband UVB or selective UVB phototherapy) was used as irradiation source. Main outcome Reduction of PASI and/or affected body surface area of 50% at the end of the intervention period (PASI-50). Only participants receiving at least one intervention were included in the primary analysis. Results Patients allocated to LC-SSP-UVB attained a statistically significantly higher rate of PASI-50 at the end of the intervention period than patients allocated to UVB [58/79 (73%) vs. 32/64 (50%); P = 0.01; NNT, 4.3, 95% CI, 2.4-18.1]. Benefit persisted until 3 months only for one of two secondary outcomes considered. Conclusions In routine clinical practice balneophototherapy using conventional UVB is superior to conventional UVB only at the end of a 6-week treatment course.