Balneo-phototherapy: trials demonstrate additional benefit in patients with psoriasis

Patients with psoriasis vulgaris profit more from bath and UV light therapy (balneo-phototherapy) than from UVB light therapy alone. In patients with atopic dermatitis, at least indications of an additional benefit exist; however, this only applies to so-called synchronous balneo-phototherapy, where the patient is exposed to UV radiation during a bath. This is the result of the final report of the Institute for Quality and Efficiency in Health Care, which the Institute's researchers published on 28 December 2006.

On behalf of the Federal Joint Committee, IQWiG investigated the benefits and harms of various types of balneo-phototherapy. These therapies are used to treat skin diseases, and combine baths containing medication or salt with UV radiation. The bath and UV-light therapy can take place successively (asynchronous therapy) or simultaneously (synchronous therapy).

Diversity of therapies makes summarising evaluation difficult

In Germany, the only type of relevant synchronous balneo-phototherapy is the so-called ToMeSa therapy (Totes Meer Salz = Dead Sea salt). Regarding asynchronous therapies, IQWiG investigated two types of treatment: A) Bath-psoralen ultraviolet A therapy ("bath-PUVA”), where the bath water contains psoralen, which makes the skin more sensitive to light. After the bath, the patients are exposed to UVA light. B) Photo-brine therapy, where patients initially bathe in a concentrated salt solution and are then exposed to UVB light.

In practice, the 3 therapy options are applied in various forms: Not only do the substances and concentrations of the bath solutions vary, but also the duration of the bath, the temperature of the bath water, and the type of radiation used. For example, three different types of UVB light are used, although the differences in their benefits have not so far been definitely clarified.

This diversity makes a comparison and a summarising evaluation of balneo-phototherapy difficult. Although the IQWiG researchers could identify 11 trials that fulfilled the inclusion and exclusion criteria, these trials included 11 different treatment comparisons.

Study quality partly poor

A total of 13 controlled trials including 2326 patients were considered in the evaluation. However, many issues in these trials remained open, as important aspects were not taken into account in study planning and publication. Seven of the 13 trials showed minor deficiencies; 6 trials showed major deficiencies.

IQWiG regarded the reduction (or clearance) of skin symptoms over a preferably long period of time and the improvement in disease-related quality of life as therapy goals relevant to the patient. The improvement in treatment convenience and the rate of adverse effects were also regarded as relevant outcomes.

Only the outcome "skin symptoms” evaluated in all therapy options

The evaluation of the studies showed that for all three types of balneo-phototherapy, skin symptoms in patients with psoriasis improved more than with UV monotherapy. In addition, fewer adverse effects occurred with bath-PUVA. The comparison of the two asynchronous procedures showed better outcomes for bath-PUVA than for photo-brine therapy with regard to both skin symptoms and adverse effects.

No conclusions on changes in quality of life of patients with psoriasis can be inferred from the available trials investigating asynchronous procedures. An improvement in quality of life was only indicated for the synchronous procedure (balneo-phototherapy with Dead Sea salt). However, the only study investigating this issue was of poor quality; this finding therefore should be interpreted with caution. Comparative statements on treatment convenience are not possible for most treatment options, as only few data are available or are not interpretable.

Unclear situation in patients with atopic dermatitis

Only one study was available on atopic dermatitis, which investigated balneo-phototherapy with Dead Sea Salt. In contrast to its use in patients with psoriasis, no clear evidence but only indications were available that patients profit more from this therapy option than from UV monotherapy. Moreover, this was only the case for the outcome "skin symptoms” and not for any other outcomes.

Bath-PUVA: Only weak indications of a lower cancer risk

Psoralen, which sensitizes the skin to light, is not only absorbed by the skin during a bath, but is also administered as a tablet ("oral-PUVA”). Some researchers favour bath-PUVA, as they assume that, compared with oral-PUVA, there is a lower risk of certain types of skin cancer and other adverse effects. Moreover, treatment is more convenient for patients.

IQWiG compared oral-PUVA with bath-PUVA. In some comments submitted on the preliminary report it was criticized that the advantages of bath-PUVA were not sufficiently considered. Therefore, IQWIG subsequently included retrospective comparative studies in the evaluation. Even after the evaluation of these studies, the IQWiG researchers see the question of a cancer risk associated with PUVA as still largely unresolved. A conclusive weighing of benefits and harms is not possible on the basis of the studies currently available.

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