BACKGROUND:

Synchronous balneophototherapy (sBPT) simulates treatment conditions at the Dead Sea for outpatient use. In the past, sBPT proved to be an effective treatment for psoriasis. However, there is a lack of sufficiently large randomized controlled clinical trials evaluating the additional benefit of sBPT compared with ultraviolet B (UVB) monotherapy.

OBJECTIVES:

The purpose of this study was to compare the effectiveness and safety of sBPT with UVB phototherapy (PT) alone in a randomized controlled effectiveness study.

METHODS:

In this phase III, multicentre effectiveness study, 367 patients with moderate to severe psoriasis were randomly allocated in a 1 : 1 ratio to receive either sBPT consisting of narrowband UVB PT with 311 nm and synchronous bathing in 10% Dead Sea salt solution or PT with 311 nm alone. Primary endpoint, analysed on an intention-to-treat basis (n = 356), was the relative improvement of the Psoriasis Area and Severity Index (PASI) from baseline to end of treatment (35 sessions or clearance). Sample size calculation aimed at the detection of superiority of at least 10%.

RESULTS:

Median PASI values were comparable at baseline (sBPT: 15.1, interquartile range: 10.9-24.3; PT: 15.3, interquartile range: 10.0-23.7). A clinically relevant and statistically significant difference of 49.5% between sBPT and PT could be proven at the end of the therapy phase (P < 0.001; Wilcoxon-Mann-Whitney test). Exploratory testing showed a statistically significant superiority of sBPT after 6 months.

CONCLUSIONS:

In routine clinical practice, sBPT is superior to PT alone after 35 treatment sessions and a follow-up of 6 months. Both treatments demonstrated to be safe.