Objective: To evaluate the efficacy of psoralens dissolved in a warm-water bath followed by exposure to UV-A irradiation (bath PUVA) or saltwater phototherapy (SW UV-B) compared with tap-water phototherapy (TW UV-B) or UV-B irradiation alone in psoriasis.
Design: Multisite, prospective, randomized, controlled trial with 4 parallel groups.
Setting: Total of 102 dermatologic outpatient clinics.
Patients: Total of 1241 patients with stable psoriasis vulgaris and a Psoriasis Area and Severity Index score of 7 or greater.
Interventions: Four-times-weekly UV-B, TW UV-B, SW UV-B, or bath-PUVA with baths preceding UV irradiation over a maximum of 8 weeks. The UV dose was adapted to erythemal response.
Main outcome measures: Incidence of therapeutic success, defined as a reduction of the Psoriasis Area and Severity Index or affected body surface area of 50% or more.
Results: Patients who received TW UV-B had a significantly higher incidence of therapeutic success than did patients treated with UV-B alone (60.7% vs 43.3%; P<.001; number needed to treat, 5.8; 95% confidence interval [CI], 3.9-10.9). Patients who received SW UV-B or bath PUVA had a significantly higher incidence of therapeutic success than did patients treated with TW UV-B (74.9% vs 60.7%; P<.001; number needed to treat, 7.0; 95% CI, 4.6-14.9; and 78.4% vs 60.7%; P<.001; number needed to treat, 5.7; 95% CI, 4.0-9.7, respectively). Bath PUVA was not superior to SW UV-B (78.4% vs 74.9%; P = .34).
Conclusion: Bath PUVA and SW UV-B are comparably effective treatments in psoriasis and superior to UV-B and TW UV-B.