Commentary on selected evidence

With advice from topic experts we selected 2 studies for further commentary.

Assessment and referral – weight loss through diet and exercise to improve psoriasis

We selected the systematic review and meta-analysis by Upala and Sanguankeo (2015) for a full commentary because topic experts drew attention to lifestyle interventions for psoriasis. They stated that this was an important area particularly given that many patients with psoriasis are overweight or obese. Experts also noted that cardiovascular disease risk factors (including obesity and inactivity) may not always be addressed as part of consultations. The evidence also addresses a NICE research recommendation about whether reduction of relevant, modifiable cardiovascular risk factors (for example weight loss, exercise or statins) improves psoriasis.

What the guideline recommends

NICE's guideline on psoriasis recommends that patients are given information about relevant lifestyle risk factors, that the presence of comorbidities should be assessed, and that risk factors for cardiovascular comorbidities should be discussed with advice and support offered in line with the relevant NICE guidance (including guidance on obesity and increasing physical activity), see recommendations 1.1.1.1, 1.2.1.1 and 1.2.3.1–2. However, the advice is focussed on the relationship between comorbidities and cardiovascular risk rather than any potential benefits for psoriasis. Recommendations specifically linking diet, exercise and weight loss to psoriasis outcomes are not currently made.

Methods

The systematic review and meta-analysis by Upala and Sanguankeo (2015) examined the effect of weight loss interventions (diet, exercise, or both) on psoriasis severity in overweight and obese patients aged 18 or over with any type of psoriasis. Participants on a diet or medication to lose weight were excluded, as were studies of bariatric surgery. The review found 7 randomised controlled trials (RCTs) which included a total of 878 patients. Risk of bias was assessed for the included studies according to the Cochrane handbook. The primary outcome was psoriasis severity assessed by a 100, 75 and 50% reduction in Psoriasis Area and Severity Index (PASI) score.

Results

Significantly more patients receiving a weight loss intervention achieved a 75% reduction in PASI score than controls (odds ratio=2.92, 95% confidence interval [CI] 1.39 to 6.13, p=0.005; 4 RCTs, n=649). Weight loss interventions also led to a significantly greater reduction in PASI score versus controls (mean difference=−2.49, 95% CI −3.90 to −1.08, p=0.004; 4 RCTs, n=460). A sensitivity analysis using the risk ratio rather than the odds ratio and fixed-effects rather than random-effects model did not affect the direction or significance of the result.

Strengths and limitations

Strengths
  • The review included only RCTs.

Limitations
  • Of the primary outcomes, only data for PASI 75 was meta-analysed (and only 4 of the 7 included trials reported this outcome and therefore contributed to the analysis). Data for PASI 100 and PASI 50 were reported by a total of 3 trials (all of which showed weight loss was numerically more effective than control, though significance was not stated).

  • Only 1 study examined exercise as the weight loss intervention alongside diet (all others involved diet alone) so the review was unable to compare different methods of weight loss on psoriasis.

  • Most included studies were short (the longest follow-up was 6 months), therefore maintenance of weight loss and long-term impact on psoriasis was not addressed.

  • Heterogeneity was substantial in the 2 meta-analyses (I2=67% and 77%) but this was not investigated further because there were too few included studies.

  • Publication bias was not checked with a funnel plot because there were too few included studies.

  • Several included studies failed on 2 or more domains of the risk of bias assessment. All studies failed on blinding of participants/personnel (though blinding of outcome assessment was reported in all but 2 studies).

Impact on guideline

The new evidence suggests that weight loss through diet or exercise appears to reduce the severity of psoriasis over 6 months. NICE's guideline on psoriasis does not currently make recommendations specifically linking weight loss to psoriasis outcomes. However it does recommend that patients are given information about relevant lifestyle risk factors, that the presence of comorbidities should be assessed, and that risk factors for cardiovascular comorbidities should be discussed with advice and support offered in line with the relevant NICE guidance (including guidance on obesity and increasing physical activity). Offering advice on weight loss is already covered by current recommendations, and no immediate need to update the guideline was identified.

Topical therapy (trunk and limbs) – calcipotriol/betamethasone combination (aerosol foam)

We selected the randomised controlled trial (RCT) by Koo et al. (2016) for a full commentary because evidence is emerging on foam formulations, but the guideline does not currently mention foam as a treatment option. Topic experts also noted that it may be helpful to re-examine the place in the treatment pathway of combined formulations, because a single product is likely to be easier for patients than 2 separate products.

What the guideline recommends

For topical treatment of psoriasis affecting the trunk and limbs, NICE's guideline on psoriasis recommends offering adults a combined product containing calcipotriol monohydrate and betamethasone dipropionate applied once daily for up to 4 weeks. However this is only recommended after a sequence of other separately applied topical treatments has been offered (or cannot be used), or if a once-daily preparation would improve adherence in adults (see recommendations 1.3.2.1–4).

The guideline does not specify the formulation of calcipotriol monohydrate and betamethasone dipropionate to use. Nor does it include foam in the list of formulations that should be discussed with the patient for use depending on preference (currently: cream, lotion or gel for widespread psoriasis; lotion, solution or gel for the scalp or hair-bearing areas; and ointment to treat areas with thick adherent scale) (see recommendation 1.3.1.4).

Methods

The RCT by Koo et al. (2016) compared topical aerosol foam and ointment formulations of combined calcipotriol (0.005%) plus betamethasone (0.064%) among 376 adults aged 18 or over with plaque psoriasis having lasted at least 6 months. Inclusion criteria were: at least mild psoriasis on the Physician's Global Assessment of disease severity scale (PGA) covering 2–30% of body surface area; and modified Psoriasis Area and Severity Index (mPASI; head excluded as it was not treated) score of 2 or more. Main exclusion criteria were: treatment within 2–16 weeks (depending on the treatment) before randomisation with systemics, psoralen combined with ultraviolet light A (PUVA) or UVB therapy, or topicals; planned prolonged exposure to natural or artificial sunlight; commencing or changing other medications that may affect psoriasis; and guttate, erythrodermic, exfoliative or pustular psoriasis.

Patients were assigned to 1 of 4 treatments: calcipotriol/betamethasone aerosol foam; calcipotriol/betamethasone ointment; aerosol foam vehicle; and ointment vehicle (randomised 3:3:1:1 respectively). Only the trunk, arms and legs were treated, using a maximum 90 g of product per week. Psoriasis severity was assessed on the 5-point PGA scale (clear, almost clear, mild, moderate, severe). The primary outcome was treatment success (clear or almost clear plus a minimum 2-step improvement on the PGA) at week 4. Treatment was stopped in patients who were clear on the PGA at week 1 and 2, but restarted if psoriasis reappeared. Patients also assessed their itch severity in the 24 hours before their treatment visit on a visual analogue scale (VAS; 0=none, 100=most severe).

Results

For the primary outcome, treatment success at week 4 was achieved in significantly more patients using calcipotriol/betamethasone aerosol foam (77/141, 54.6%) than among those using calcipotriol/betamethasone ointment (58/135, 43.0%; mean difference=11.6%; odds ratio 1.7; 95% CI 1.1 to 2.8, p=0.025). Itch relief was similar for the 2 active treatments, with a rapid and continuous reduction in score on the VAS between weeks 0 and 4 for both foam (−39.8) and ointment (−36.5; significance not stated).

The number of adverse events was also similar with foam (20 events in 16 patients; 11.3%) and ointment (23 events in 14 patients; 10.4%). One adverse drug reaction (application site itch) occurred with foam versus 4 reactions (application-site dryness, application-site pain, psoriasis, itch) with ointment.

Strengths and limitations

Strengths
  • The use of foam and ointment vehicle controls meant patients were blinded to their treatment, and investigators were blinded by separating out duties related to study procedures and clinical assessments.

  • The primary outcome was based on the PGA, which is an assessment tool recommended by NICE's guideline on psoriasis.

Limitations
  • Although patients were shown how to apply treatments and the first application was supervised, no data on the amount of product actually used were reported.

  • Patient satisfaction with the treatments was not measured therefore acceptability (such as cosmetic appeal, or ease of use) could not be compared.

  • The final assessment was at 4 weeks; topic experts noted that longer follow up on efficacy and relapse would have been useful.

Impact on guideline

The new evidence suggests that over 4 weeks, calcipotriol/betamethasone aerosol foam is significantly more effective than a calcipotriol/betamethasone ointment formulation for psoriasis of the trunk and limbs. NICE's guideline on psoriasis recommends offering adults with psoriasis of the trunk and limbs calcipotriol/betamethasone after a sequence of other separately applied topical treatments has been offered (or cannot be used), or if a once-daily preparation would improve adherence in adults.

As the guideline does not specify the formulation of calcipotriol monohydrate and betamethasone dipropionate to use, treatment with the foam formulation is covered by current recommendations. No immediate need to update the guideline was identified.


This page was last updated: 15 June 2017