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.

Subjects: 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.