Background: The most commonly used types of phototherapy for treating psoriasis are narrow-band ultraviolet B (NB-UVB); broad-band ultraviolet B (BB-UVB), which includes selective (delivering radiation with a wavelength range of 305 to 325 nm) and conventional BB-UVB (280 to 320 nm); and psoralen ultraviolet A photochemotherapy (oral or bath PUVA). There is substantial controversy regarding their efficacy when compared with each other.
Objectives: To assess the effects of narrow-band ultraviolet B phototherapy versus broad-band ultraviolet B or psoralen ultraviolet A photochemotherapy for psoriasis.
Search methods: We searched the following databases up to August 2013: the Cochrane Skin Group Specialised Register, CENTRAL in The Cochrane Library (2013, Issue 7), MEDLINE (from 1946), and EMBASE (from 1974). We searched the following databases up to November 2012: CNKI (from 1974) and CBM (from 1978). We also searched trials registers and the OpenGrey database.
Selection criteria: We included all randomised controlled trials (RCTs) that compared NB-UVB phototherapy with BB-UVB or PUVA for treating psoriasis, which included chronic plaque psoriasis (CPP), guttate psoriasis (GP), and palmoplantar psoriasis (PPP).
Data collection and analysis: Two review authors independently conducted the study selection, 'Risk of bias' assessment, and data extraction.
Main results: We included 13 RCTs, with a total of 662 participants. We report the results of intention-to-treat analyses (ITT) here. Our primary outcomes of interest were as follows: Participant-rated global improvement, Percentage of participants reaching Psoriasis Area and Severity Index (PASI) 75 (which meant equal to or more than 75% reduction in PASI score), Withdrawal due to side-effects, and Clearance rate.In one RCT of NB-UVB compared with oral PUVA in participants with CPP, the difference in PASI 75 was not statistically significant (risk ratio (RR) 0.91, 95% confidence interval (CI) 0.63 to 1.32; N = 51; low quality). In three other RCTs of CPP, the clearance rates were inconsistent because in one, there was no difference between the groups (RR 1.01, 95% CI 0.91 to 1.12; N = 54), and in the other two, the clearance rates were statistically significantly in favour of oral PUVA: RR 0.66, 95% CI 0.47 to 0.93; N = 93 and RR 0.75, 95% CI 0.59 to 0.96; N = 100, respectively. Pooled data from these three studies indicated that withdrawals due to adverse events were not significantly different between either group (RR 0.71, 95% CI 0.20 to 2.54; N = 247; low quality).The evidence from the comparison of NB-UVB with bath PUVA in terms of clearance rate for CPP was also inconsistent: Pooled data from two left-right body comparison RCTs found no significant difference between the NB-UVB and bath PUVA groups (RR 1.79, 95% CI 0.46 to 6.91; N = 92; low quality), while a parallel RCT favoured bath PUVA (RR 0.18, 95% CI 0.05 to 0.71; N = 36; low quality).In participants with PPP, one RCT found there were no significant differences between NB-UVB treated sides and topical PUVA treated sides in terms of clearance rate (RR 0.09, 95% CI 0.01 to 1.56; N = 50; low quality).Two RCTs found NB-UVB plus retinoid (re-NB-UVB) and PUVA plus retinoid (re-PUVA) had similar effects for treating people with CPP or GP in terms of clearance rate (RR 0.93, 95% CI 0.79 to 1.10; N = 90; low quality).One RCT in people with CPP found no significant differences between NB-UVB and selective BB-UVB in terms of clearance rate (RR 1.40, 95% CI 0.92 to 2.13; N = 100; low quality) and withdrawals due to adverse events (RR 3.00, 95% CI 0.32 to 27.87; N = 100; low quality).No studies reported our primary outcomes for NB-UVB compared with conventional BB-UVB.
Authors' conclusions: Current evidence is very heterogeneous and needs to be interpreted with caution. The clearance rate between oral PUVA and NB-UVB is inconsistent among the included studies. Evidence regarding NB-UVB versus bath PUVA is also inconsistent. Re-NB-UVB and re-PUVA are similarly effective for treating people with CPP or GP. In practice, NB-UVB may be more convenient to use since exogenous photosensitiser is not required before phototherapy.NB-UVB is considered ineffective for PPP in clinical practice, and a small RCT did not detect a statistically significant difference between NB-UVB and topical PUVA for clearing PPP. NB-UVB seemed to be similar to selective BB-UVB for clearing CPP.Larger prospective studies are needed to confirm the long-term safety of NB-UVB.