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. 2020 May 5;2020(5):CD011941. doi: 10.1002/14651858.CD011941.pub2

Klein 2011.

Study characteristics
Methods Two‐group parallel, phase III randomised controlled trial

  • Setting: multi‐centre study (30 centres) located in Germany

  • Duration of enrolment: not reported

  • Follow‐up time: 6 months
Participants Inclusion criteria of the trial

  • Psoriasis vulgaris proved by a dermatologist, age ≥ 18 years, Caucasian, having PASI at baseline > 5


Exclusion criteria of the trial

  • Pregnancy ⁄ lactation, incompatibility to treatment interventions, erosions, ulcers, viral or bacterial superinfection, generalised psoriasis pustulosa, severe general disease, intake of medication with effects on photosensitivity, concomitant or previous malignant skin tumours, violation against wash‐out criteria (topical treatment excluding emollients within the last week, systemic treatment within the last 4 weeks, UV‐treatment within the last 4 months, intake of medication inducing psoriasis within the last 4 weeks)


Characteristics (intervention versus control): balanced

  • Age: mean age in years (SD): 45.0 (14.4) versus 45.8 (14.7), number assessed: 179 versus 177

  • Gender (M/F, %): 100 (56%) / 79 (44%) versus 107 (60.5%) / 70 (39.5%), number assessed: 179 versus 177

  • Skin type (N, %): I: 9 (5.0%) versus 10 (5.6%); II: 68 (37.8%) versus 64 (35.8%); III: 72 (40.0%) versus 72 (40.2%); IV: 28 (15.6%) versus 32 (17.9%); V: 3 (1.7%) versus 1 (0.6%)

  • Severity: median (interquartile range) PASI score (0 to 72): 15.1 (10.9 to 24.3) versus 15.3 (10.0 to 23.7), number assessed: 179 versus 177

  • Previous treatment:

    • any experience of former phototherapy: 13.5% (28 of 179) versus 13% (26 of 177);

    • previous systematic antipsoriatic agents: 2.4% (5 of 179) versus 1% (2 of 177);

    • topical treatment: 55.8% (116 of 179) versus 55% (110 versus 177).

  • duration of condition: not reported
Interventions Intervention (n = 183)

  • Dead Sea salt soaks : a 10% Dead Sea salt solution was used as analogue to the ion‐formation of the Dead Sea. Concentration: 100 g/L NaCl dissolved in tap water.

  • Artificial narrowband UVB : using a continuously adjustable and individually dispensable light console with a reflector system located above the tub using TL‐01 UVB lamps including a gauged dosimeter (311 nm, Philips). The mean starting UVB dose was 0.38 J/cm2. After increasing doses according to skin type, the mean UVB dose at the 35th session was 2.74 J/cm2. The total mean dosage of irradiation was 50.7 J/cm2 at the 35th treatment session. Irradiation was performed in mean 31.9 sessions.


Control intervention (n = 184)

  • Artificial narrowband UVB alone : the same divide as reported for the intervention. The mean starting UVB dose was 0.38 J/cm2. After increasing doses according to skin type, the mean UVB dose at the 35th session was 2.96 J/cm2. The total mean dosage of irradiation was 41.3 J/cm2 at the 35th treatment session. Irradiation was performed in mean 26.8 sessions.


The interventions were applied once a day, three to five days a week, and reaching a maximum number of 35 applications. Duration of UV irradiation was not reported.
Outcomes Primary outcomes of the trial

  1. Primary outcome parameter was the PASI. PASI score was evaluated during the therapy period at baseline, after 10, 15, 20, 25, 30 and 35 treatment sessions by the trial physicians and during follow‐up 1 and 6 months after treatment session 35. Primary endpoint was the relative improvement of PASI from baseline to the end of therapy period (session 35 or clearance). Clearance was defined as PASI improvement of at least 75% from baseline to the end of therapy period.


Secondary outcomes of the trial

  1. Psoriasis Disability Index (PDI)

  2. Freiburg Life Quality Assessment (FLQA‐d)

  3. Sickness Impact Profile (SIP)

  4. Willingnes to pay

  5. Adverse events were coded according to the Medical Dictionary for Regulatory Activities


The authors reported early withdrawal before treatment session 35, which might be projected to a time point of about eight weeks after start of treatment. The authors also reported that some people or limbs had an early withdrawal because of adverse events.
Notes Figure 1 states that 137 patients participated in the follow‐up six months after treatment. However, figure 1 also states that only 106 participants were treated through to the end of treatment at session 35 which equals eight weeks after start of treatment. We suppose that this might be a spelling error.
The trial was sponsored by the primary health insurance companies in Bavaria, Germany, and completely independent from the producers of any of the medical devices used. The Bavarian ministry of social affairs approved and supervised all procedures.
Conflicts of interest: the authors declared that there are none.
Risk of bias
Bias Authors' judgement Support for judgement
Random sequence generation (selection bias) Low risk Quote (page 571): "Randomization was performed by an independent organization so that trial physicians had no influence on the allocated treatment strategy."
Quote (page 572): "Randomization was performed centrally by an independent organization (central telephone randomization). Randomization was stratified by centre and skin type. Treatments were randomly assigned in a 1: 1 ratio with a block size of 6."
Comment: the authors clearly described an adequate random sequence generation, which was judged as low risk of bias.
Allocation concealment (selection bias) Low risk Quote (page 572): "Allocation concealment was assured until the end of the study phase. Allocation concealment was broken before realizing the statistical analysis."
Comment: the authors clearly described an adequate concealment of the allocation, which was judged as low risk of bias.
Blinding of participants and personnel (performance bias)
All outcomes High risk Quote (page 571): "Blinding of patients was not possible."
Comment: the authors reported that they did not blind investigators and patients and we judged a high risk of performance bias.
Blinding of outcome assessment (detection bias)
All outcomes High risk Quote (page 577): "This study was not conducted at special skilled PT departments of university institutions, but at private practices of single dermatologists. Patients and evaluator were unblinded. Therefore, we categorised the trial as effectiveness study."
Comment: the authors reported that they did not blind outcome assessors and we judged a high risk of detection bias.
Incomplete outcome data (attrition bias)
All outcomes Unclear risk Quote (page 574, figure 1): "Intervention group: 3 did not start treatment; 1 no second PASI available; 35 early withdrawal, 6 with clearance; follow‐up 6 months after treatment: 136 of 183 randomized (179 included in ITT analysis)"
Quote (page 574, figure 1): "Control group: 5 did not start treatment; 2 no second PASI available; 71 early withdrawal, 1 with clearance; follow‐up 6 months after treatment: 137 of 184 randomized (177 included in ITT analysis)"
Comment: the authors reported a considerable proportion of dropouts. However, they including the data of almost all randomised participants in an intention‐to‐treat analysis. We are unsure if the dropouts may affect the outcome and therefore we judged an unclear risk of attrition bias.
Selective reporting (reporting bias) Unclear risk Quote (page 576, table 4): "Patients with adverse events with an incidence of ≥5%" Patients with adverse events with an incidence of <5% were not reported.
Comment: we are not positive if this may considerably affect the outcome and thus we judged an unclear risk of bias.
Other bias Unclear risk Comment: we did not identify other bias such as design‐specific risks of bias, baseline imbalance, blocked randomisation in unblinded trials, and differential diagnostic activity.
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