Abstract
Background:
Narrowband UVB (NBUVB) has recently been used in Vietnam for the treatment of psoriasis. However, there are no data on Vietnamese patients to adopt a uniform national protocol.
Objectives:
This study aimed to establish an optimal NBUVB therapy for the treatment of psoriasis in Vietnamese patients.
Materials and Methods:
One hundred and twenty-two patients with psoriasis vulgaris were included. They were randomly allocated to two groups: the percentage dose (group 1, 62 patients) and the fixed dose (group 2, 60 patients). In group 1, the starting dose was 50% of the minimal erythema dose (MED) and the 10% increment dose adjusted in the next sessions. In group 2, the starting dose was based on Fitzpatrick skin types (fixed dose). Psoriasis area and severity index (PASI) was used to evaluate efficacy.
Results:
More than 68% of the patients get PASI75 at session 36. Group 2 had significantly fewer sessions (20 ± 5 vs 25 ± 7, P- value = 0.0004) and lower cumulative dose than group 1 (14.1 ± 4.3 J/cm2 vs 18.0 ± 8.0 J/cm2, P- value = 0.0075) to achieve PASI75. Adverse effects were more common in group 2 than group 1, including burning sensation/erythema (43.33% vs 14.52%, P- value = 0.0009) and pruritus (75.00% vs 22.58%, P- value <0.0001).
Conclusion:
NBUVB therapy was safe and effective for Vietnamese psoriasis patients. Fixed doses produced a quicker clinical response with fewer sessions and lower cumulative doses. Adverse effects were mild in both groups and less noted for the MED-based dose. For the recommendation, a fixed dose should be applied for patients who have less concern about side effects, while a MED-based dose can be suitable for patients having conditions related to light sensitivity.
KEY WORDS: Fixed dose regimen, minimal erythema dose, NBUVB, plaque psoriasis
Introduction
Psoriasis is a common chronic skin disease that can affect about 2% of the worldwide population.[1,2,3] In the western Pacific region, the prevalence varied from 0.14% in East Asia to 1.99% in Australasia.[4] A survey in 2010 at the National Hospital of Dermatology and Venereology (NHDV) reported the rate of psoriasis was 2.2% of all outpatients.[5] Among patients hospitalised at the NHDV from March 1999 to August 2000, psoriasis patients accounted for 12.4%.[6] Psoriasis aetiology has been studied for ages but is not fully understood.[7,8,9,10] Current treatment can help control psoriasis, but currently there is no cure.[11]
Phototherapy is used for psoriasis treatment based on the suppressive effect of UV light to the IL-23/Th17 axis, keratinocytes, and their cytokines.[12,13] Phototherapy shows advantages in the treatment of psoriasis both in efficacy and cost.[14] In Vietnam, NBUVB has been used widely to treat moderate to severe generalized psoriasis, even safe for patients who are pregnant or breastfeeding.[15] However, there has not been a standard regimen for psoriasis treatment in terms of dose establishment.[16] Thus, this study was carried out to verify the effectiveness and safety of American Academy of Dermatology (AAD) guideline and also compare the effectiveness and adverse effects between MED-based dose and fixed dose of NBUVB in Vietnamese psoriasis patients, who may be different in skin type and response to NBUVB in compare with other countries. This study was expected to guide NBUVB psoriasis treatment in Vietnam.
Materials and Methods
The study subjects were 122 psoriasis vulgaris patients, confirmed by biopsy, moderate (PASI 10–20) to severe psoriasis (PASI >20)[17] at the NHDV from October 2016 to December 2019.
This was a randomized controlled trial comparing the effectiveness and safety of NBUVB 311 nm therapy between a group of MED-based dose (group 1) and a group of fixed dose (group 2).
Randomization sampling was done by choosing patients who had the first visit on even days for group 1 and the ones with the first visit on odd days for group 2. The study randomly recruited 62 patients for group 1 and 60 patients for group 2.[18] Information on psoriasis history such as age, duration of onset, family history of psoriasis, history of psoriasis treatment was collected. Clinical features including skin type, and severity of the disease (PASI), were also obtained.
For the treatment, the patients were irradiated using UVB Medisun 2800 device (Schulze and Bohm GmbH). Each patient was irradiated three times every week on nonconsecutive days until they got 36 treatment sessions. Patients were followed up and clinically assessed by the doctors who were blinded to the treatment. NBUVB treatment was provided by another doctor who did not assess the treatment efficacy.
Group 1 of MED-based dose [Table 1]: MED was measured using Giga machine (Medisun Gigatesst 1 UBV-311). MED tests were performed at six separate 1 cm2 sites in the back or buttocks of each patient.[19] MED-based dose was applied following AAD phototherapy guidelines.[15] The starting dose was 50% of the MED. From the 2nd to the 20th session, the dose was 10% incremental of the initial dose as long as it did not exceed 5000 mJ/cm2 or three times of MED. Each patient was provided three sessions per week until get 36 sessions.
Table 1.
MED values in Group 1
| Minimum erythema dose (MED, mJ/cm2) | Median | Mean | SD | Min | Max | |
|---|---|---|---|---|---|---|
| Overall | 400 | 455.16 | 88.76 | 320 | 660 | |
| By gender | Male | 400 | 440.44 | 92.10 | 320 | 660 |
| Female | 500 | 494.12 | 66.99 | 400 | 600 | |
| By age group | ≤29 years | 400 | 458.18 | 105.99 | 320 | 660 |
| 30-49 years | 500 | 458.71 | 78.64 | 320 | 600 | |
| ≥50 years | 400 | 435.56 | 82.93 | 320 | 600 | |
| By severity | Moderate | 450 | 452.50 | 56.51 | 400 | 520 |
| Severe | 400 | 455.56 | 92.97 | 320 | 660 | |
Group 2 of fixed dose: The patients were provided three sessions per week on nonconsecutive days with fixed dose as shown in Table 2. The dose was adjusted based on clinical responses.
Table 2.
Dose irradiation for group 2[16]
| Skin type | First dose mJ/cm2 | Increasing dose each session mJ/cm2 | Maximum dose mJ/cm2 |
|---|---|---|---|
| I | 130 | 15 | 2000 |
| II | 220 | 25 | 2000 |
| III | 260 | 40 | 3000 |
| IV | 330 | 45 | 3000 |
| V | 350 | 60 | 5000 |
| VI | 400 | 65 | 5000 |
All the patients had their eyes and genitalia shielded during the treatment. They were also advised to avoid sunlight after the irradiation.
PASI was assessed at baseline and every three sessions to evaluate clinical response. Two cut-off points, i.e., 50% (PASI50) and 75% (PASI75) reduction, were used to evaluate treatment efficacy. The number of sessions, cumulative doses to achieve PASI50 and PASI75 were calculated. Adverse effects including burning sensation, erythema, pruritus, and hyperpigmentation during the treatment were noted.
Descriptive statistics were produced for the general characteristics of the study population and treatment outcomes in mean (standard deviation, SD; 95% confidence interval, 95% CI), frequency (percentage), and rate, where appropriate. The differences between the treatment groups were tested using t-test, Chi-square test, or Log-rank test with the statistical significance defined based on P- value <0.05. All statistical analyses were performed using SAS 9.4 (SAS Institute Inc., Cary, NC, USA).
This study has been approved by Ethic Committee of Vietnam National Hospital of Dermatology and Venereology on 22nd December 2015.
Results
The study included 122 patients with a mean age of 34.39 ± 11.14 years, in which males accounted for the majority (68.03%). There was no significant difference between the two groups regarding general demographic information including age, gender, BMI, family history of having psoriasis, psoriasis treatment history, and the disease severity (PASI) as well [Table 3].
Table 3.
General characteristics of participants at baseline (n=122)
| All groups (n=122) | Group 1 (n=62) | Group 2 (n=60) | P | |
|---|---|---|---|---|
| Age, mean (SD) | 34.39 (11.14) | 35.35 (11.97) | 33.38 (10.20) | 0.3301 |
| Male, n (%) | 83 (68.03%) | 45 (72.58%) | 38 (63.33) | 0.2742 |
| BMI (kg/m2), n (%) | 0.2402 | |||
| <23 | 72 (59.01%) | 32 (51.61%) | 40 (66.67%) | |
| 23≤25 | 35 (28.69%) | 21 (33.87%) | 14 (23.33%) | |
| ≤25 | 15 (12.30%) | 9 (14.52%) | 6 (10.00%) | |
| Family history, n (%) | 32 (26.23%) | 18 (29.03%) | 14 (23.33%) | 0.4742 |
| History of treatment, n (%) | ||||
| Topical therapy | 100 (81.97%) | 51 (82.26%) | 49 (81.67%) | 1.0002 |
| Systemic therapy | 64 (52.46%) | 28 (45.16%) | 36 (60.00%) | 0.1442 |
| Psoriasis-related indicators | ||||
| PASI, mean (SD) | 15.42 (4.73) | 15.00 (4.57) | 15.87 (4.89) | 0.3101 |
| Severe psoriasis at baseline (PASI ≥20), n (%) | 24 (19.67%) | 10 (16.13%) | 14 (23.33%) | 0.3172 |
| Duration of onset (month), mean (SD) | 113.71 (70.21) | 104.44 (78.00) | 123.3 (60.31) | 0.1371 |
1Student’s t-test. 2Chi-square test
Each patient got 36 treatment sessions. The initial dose of the two groups was not different (228 ± 44.38 vs 316 ± 28.47, P = 0.31).
The mean PASI decreased steadily over time, from 15.42 (95% CI 14.57–16.27) at baseline to 6.56 (5.66–7.46) at the 36th session in all patients.
Group 2 obtained better PASI reduction in both severe and moderate patients. Better PASI reduction was seen sooner in moderate patients at sessions 15, 18, 21, and 36 and later in severe patients (at session 33, PASIMED 12.00 vs PASIfixed-dose 7.78, P = 0.02) [Figure 1].
Figure 1.
PASI by treatment group and baseline severity: (a) moderate psoriasis, (b) severe psoriasis
Group 2 mostly produced better responses with fewer sessions than group 1. It took 17 ± 7 sessions on average to achieve PASI50 and 20 ± 5 sessions to achieve PASI75 for group 2 versus 20 ± 8 and 25 ± 7 for group 1 (P- value = 0.0283 and 0.0004), respectively. Group 2 also had a significantly lower cumulative dose than group 1 to achieve PASI75 (14.1 ± 4.3 J/cm2 vs 18 ± 8 J/cm2, P- value = 0.0075) [Table 4].
Table 4.
Number of treatments and cumulative doses to achieve PASI50, PASI75
| Endpoints | PASI50 | PASI75 | ||||||
|---|---|---|---|---|---|---|---|---|
|
| ||||||||
| All groups | Group 1 | Group 2 | P 1 | All groups | Group 1 | Group 2 | P 1 | |
| No. of treatments, mean (SD) | 19 (7) | 20 (8) | 17 (7) | 0.0283 | 22 (6) | 25 (7) | 20 (5) | 0.0004 |
| Cumulative doses, mean (SD), J/cm2 | 13.1 (7.3) | 14.3 (7.6) | 12.1 (6.9) | 0.1091 | 16.1 (6.7) | 18.0 (8.0) | 14.1 (4.3) | 0.0075 |
1Student’s t-test
After 36 treatment sessions, the therapy was effective last 4.5 months for all of the subjects and there is no statistical difference between the two groups (4.7 ± 4.0 months in group 1 vs 4.3 ± 3.3 months in group 1, P = 0.58). The effective duration was defined as the disease beginning to advance in comparison with the time of the 36th session.
Assessment of treatment safety
The burning/erythema was reported in 35 (28.69%) patients and pruritus in 59 (48.36%), mostly mild symptoms [Table 5]. Burning sensation and pruritus were more common in group 2 in comparison to group 1 with P (26 patients (43.33%) vs 9 patients (14.52%) (P- value = 0.0009) and 45 patients (75.00%) vs 14 (22.58%) (P- value <0.0001), respectively) [Table 5]. Hyperpigmentation at the second session (3% in group 1 and 15% in group 2, P = 0.023). At the sixth session, nearly half of the patients got hyperpigmentation. From 18th session to the 36th session, nearly all patients got hyperpigmented [Table 5].
Table 5.
Adverse effects and effective duration
| All groups (n=122) | Group 1 (n=62) | Group 2 (n=60) | P | |
|---|---|---|---|---|
| Adverse effects | n (%) | n (%) | n (%) | |
| Burning/erythema | 35 (28.69) | 9 (14.52) | 26 (43.33) | 0.0009 1 |
| First degree | 32 (26.23) | 7 (11.29) | 25 (41.67) | 0.0003 1 |
| Second degree | 3 (2.46) | 2 (3.23) | 1 (1.67) | 1.002 |
| Pruritis | 59 (48.36) | 14 (22.58) | 45 (75.00) | <0.0001 1 |
| Mild | 46 (37.70) | 13 (20.97) | 33 (55.00) | 0.0002 1 |
| Moderate | 12 (9.84) | 1 (1.61) | 11 (18.33) | 0.0052 1 |
| Severe | 1 (0.82) | 0 (0) | 1 (1.67) | 0.992 |
| Hyperpigmentation | ||||
| At the 2nd session | 11 (9.02) | 2 (3.23) | 9 (15.00) | 0.02 1 |
| At the 6th session | 51 (41.80) | 25 (40.32) | 26 (43.33) | 0.731 |
| From the 18-36th session | 120 (98.36) | 60 (96.77) | 60 (100) | 0.492 |
| Preference of patients | ||||
| Effectiveness preference | 61 (50.00) | 31 (50.00) | 30 (50.00) | 0.921 |
| Safety preference | 60 (49.18) | 31 (50.00) | 29 (48.33) | 0.921 |
| Effective duration (months) | m (SD) | m (SD) | m (SD) | |
| 4.5 (3.7) | 4.7 (4.0) | 4.3 (3.3) | 0.583 |
1Chi-squared test, 2Fisher’s exact test, 3Student’s t-test
Discussion
Although NBUVB has been used for a long time in many countries, Vietnam has only applied NBUVB for psoriasis treatment in recent years. In this study, patients were treated according to AAD guidelines to verify the effectiveness and adverse effects in Vietnamese patients.
This study also showed that NBUVB is effective in vulgaris psoriasis treatment with 68.03% of patients getting PASI75 by 36 sessions. This was suitable to the study of Yones (2006) with 65% of the participants getting PASI75.[20] The number of treatments to get PASI75 in our study was 22 ± 6; the same was also seen in the study of T. Markham of 25.5 treatments.[21]
NBUVB can be delivered based on MED doses or fixed doses. Fixed dose seems to be convenient and easier to apply in clinical settings as it does not require measuring MED. Many studies showed that MED-based dose and fixed dose were similarly effective.[16,22] However, our study showed that a fixed dose resulted in better outcomes. The number of NBUVB treatments and the cumulative dose until getting PASI75 in group 2 (fixed dose) were significantly lower than in group 1 (MED-based dose). This meant that fixed dose regimen brought sooner response and lower risk of long-term side effects. The difference may be a result of the difference in skin type between Vietnamese patients and patients in other studies.
Also, there was a difference in dose increment between studies. In our study, the initial dose of the MED dose group was 50% of MED and dose increment was 10% MED; meanwhile, in Parlak’s study, the dose increment was 20% MED, making the dose in the MED group increased quicker than that of our study. Parlak found there was no significant difference between PASI90 rates as well as cumulative dose, total number of treatment sessions, and adverse effects of the two regimens, but their MED-based dose patients had quicker PASI75 than the other.[23] Kwon’s study compared the efficacy and the safety of NBUVB with 20% incremental dose and 10% incremental dose in psoriasis. The results showed that the higher the dose increment the quicker the improvement, with the same cumulative dose and the same risk of adverse effects.[24] Some other studies also found that low-dose NBUVB (first low dose, low increment, and low frequency) brought less effectiveness compared to the high-dose regimen.[21,25,26,27] In our study, the doses of group 2 (fixed dose) were significantly higher than in group 1 (MED-based dose) at sessions 18, 21, and 36. This could lead to better response seen in group 2.
Erythema has been seen in many studies with different frequencies, which may range from 10% to 94% according to treatment protocol.[28] Our result showed 28.69% of patients got erythema and most of them got mild erythema that was also reported in other studies.[20,22] Pruritus was noted in 48.36% of our patients, more common than numbers in studies of T. Markham (20%)[21] and of Boztepe G (24%),[23] which may be explained by the different doses. Besides, pruritus may come from psoriasis itself.
In our study, erythema, skin irritation and burning were more frequently seen in the group of fixed doses. Therefore, MED-based doses is better for people with sensitive skin. We found that hyperpigmentation adverse effects were common and shared the same rates in both groups. This could be explained by the fact that most Vietnamese people have skin type 3 and 4, which are sensitive to UV light and tend to develop hyperpigmentation after UV exposure. Therefore, patients should be aware of hyperpigmentation side effects, especially when concerning cosmetic issues. There was no patient in our study suffering from severe adverse effects. Although both NBUVB regimens are safe for the treatment of plaque psoriasis, MED-based dose is superior due to lower doses. Scottish Managed Clinical Network for Phototherapy (2002) also recommended low-intensive doses to minimize the adverse effects particularly in patients who have conditions related to light sensitivity.[16]
Conclusion
AAD guideline for NBUVB treatment is safe and effective to treat vulgaris psoriasis in Vietnamese. The adverse effects are mild and acceptable. To recommend for the national protocol, fixed-dose has more advantages with sooner clinical improvement, fewer treatment sessions, and lower cumulative dose than MED-based dose. Meanwhile, MED-based dose NBUVB should be applied for patients who have sensitive skin or who are concern about adverse effects.
Annex
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
References
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