Psoriasis: future research needs and goals for the twenty-first century

Topical treatments for chronic plaque psoriasis

BACKGROUND

Chronic plaque psoriasis is the most common type of psoriasis, and it is characterised by redness, thickness, and scaling. First-line management of chronic plaque psoriasis is with topical treatments, including vitamin D analogues, topical corticosteroids, tar-based preparations, dithranol, salicylic acid, and topical retinoids.

OBJECTIVES

To compare the effectiveness, tolerability, and safety of topical treatments for chronic plaque psoriasis, relative to placebo, and to similarly compare vitamin D analogues (used alone or in combination) with other topical treatments.

SEARCH METHODS

We updated our searches of the following databases to February 2011: the Cochrane Skin Group Specialised Register, CENTRAL in The Cochrane Library (2011, Issue 2), MEDLINE (from 1948), EMBASE (from 1980), Science Citation Index (from 2008), Conference Proceedings Citation Index - Science (from 2008), BIOSIS (from 1993), Dissertation Abstracts via DialogClassic (all publication years), and Inside Conferences (all publication years).We identified ongoing and unpublished studies from the UK Clinical Research Network Study Portfolio and the metaRegister of Controlled Trials. We checked the bibliographies of published studies and reviews for further references to relevant trials, and we contacted trialists and companies for information about newly published studies.A separate search for adverse effects was undertaken in February 2011 using MEDLINE and EMBASE (from 2005).Final update searches for both RCTs and adverse effects were undertaken in August 2012. Although it has not been possible to incorporate RCTs and adverse effects studies identified through these final searches within this review, we will incorporate these into the next update.

SELECTION CRITERIA

Randomised trials comparing active topical treatments against placebo or against vitamin D analogues (used alone or in combination) in people with chronic plaque psoriasis.

DATA COLLECTION AND ANALYSIS

One author extracted study data and assessed study quality. A second author checked these data. We routinely contacted trialists and companies for missing data. We also extracted data on withdrawals and on local and systemic adverse events. We defined long-term trials as those with a duration of at least 24 weeks.

MAIN RESULTS

This update added 48 trials and provided evidence on 7 new active treatments. In total, the review included 177 randomised controlled trials, with 34,808 participants, including 26 trials of scalp psoriasis and 6 trials of inverse psoriasis, facial psoriasis, or both. The number of included studies counted by Review Manager (RevMan) is higher than these figures (190) because we entered each study reporting a placebo and an active comparison into the 'Characteristics of included studies' table as 2 studies.When used on the body, most vitamin D analogues were significantly more effective than placebo, with the standardised mean difference (SMD) ranging from -0.67 (95% CI -1.04 to -0.30; 1 study, 119 participants) for twice-daily becocalcidiol to SMD -1.66 (95% CI -2.66 to -0.67; 1 study, 11 participants) for once-daily paricalcitol. On a 6-point global improvement scale, these effects translate into 0.8 and 1.9 points, respectively. Most corticosteroids also performed better than placebo; potent corticosteroids (SMD -0.89; 95% CI -1.06 to -0.72; I² statistic = 65.1%; 14 studies, 2011 participants) had smaller benefits than very potent corticosteroids (SMD -1.56; 95% CI -1.87 to -1.26); I² statistic = 81.7%; 10 studies, 1264 participants). On a 6-point improvement scale, these benefits equate to 1.0 and 1.8 points, respectively. Dithranol, combined treatment with vitamin D/corticosteroid, and tazarotene all performed significantly better than placebo.Head-to-head comparisons of vitamin D for psoriasis of the body against potent or very potent corticosteroids had mixed findings. For both body and scalp psoriasis, combined treatment with vitamin D and corticosteroid performed significantly better than vitamin D alone or corticosteroid alone. Vitamin D generally performed better than coal tar, but findings relative to dithranol were mixed. When applied to psoriasis of the scalp, vitamin D was significantly less effective than both potent corticosteroids and very potent corticosteroids. Indirect evidence from placebo-controlled trials supported these findings.For both body and scalp psoriasis, potent corticosteroids were less likely than vitamin D to cause local adverse events, such as burning or irritation. Combined treatment with vitamin D/corticosteroid on either the body or the scalp was tolerated as well as potent corticosteroids, and significantly better than vitamin D alone. Only 25 trials assessed clinical cutaneous dermal atrophy; few cases were detected, but trials reported insufficient information to determine whether assessment methods were robust. Clinical measurements of dermal atrophy are insensitive and detect only the most severe cases. No comparison of topical agents found a significant difference in systemic adverse effects.

AUTHORS' CONCLUSIONS

Corticosteroids perform at least as well as vitamin D analogues, and they are associated with a lower incidence of local adverse events. However, for people with chronic plaque psoriasis receiving long-term treatment with corticosteroids, there remains a lack of evidence about the risk of skin dermal atrophy. Further research is required to inform long-term maintenance treatment and provide appropriate safety data.

Guidelines of care for the management of psoriasis and psoriatic arthritis: section 6. Guidelines of care for the treatment of psoriasis and psoriatic arthritis: case-based presentations and evidence-based conclusions

Psoriasis is a common, chronic, inflammatory, multisystem disease with predominantly skin and joint manifestations affecting approximately 2% of the population. In the first 5 parts of the American Academy of Dermatology Psoriasis Guidelines of Care, we have presented evidence supporting the use of topical treatments, phototherapy, traditional systemic agents, and biological therapies for patients with psoriasis and psoriatic arthritis. In this sixth and final section of the Psoriasis Guidelines of Care, we will present cases to illustrate how to practically use these guidelines in specific clinical scenarios. We will describe the approach to treating patients with psoriasis across the entire spectrum of this fascinating disease from mild to moderate to severe, with and without psoriatic arthritis, based on the 5 prior published guidelines. Although specific therapeutic recommendations are given for each of the cases presented, it is important that treatment be tailored to meet individual patients' needs. In addition, we will update the prior 5 guidelines and address gaps in research and care that currently exist, while making suggestions for further studies that could be performed to help address these limitations in our knowledge base.

Post-genomics and skin inflammation

Atopic dermatitis and psoriasis are two chronic skin inflammatory diseases that have so far received a greater attention within the scientific community through different post-genomic approaches; on the contrary, acne, which is undoubtedly one of the most common skin disorders involving inflammatory processes, seems to be still quite neglected under the post-genomic point of view. In this paper, we will review how post-genomic technologies have provided new fundamental tools for the analysis of these three conditions and we will cast light on their potential in addressing future research challenges.

Topical treatments for chronic plaque psoriasis

BACKGROUND

Chronic plaque psoriasis is the most common type of psoriasis and is characterised by redness, thickness and scaling. First line management of chronic plaque psoriasis is with topical treatments, including vitamin D analogues, topical corticosteroids, tar-based preparations, dithranol, salicylic acid and topical retinoids.

OBJECTIVES

To compare the effectiveness, tolerability and safety of topical treatments for chronic plaque psoriasis with placebo; to compare vitamin D analogues with other topical treatments.

SEARCH STRATEGY

The Cochrane Skin Group's Trials Register was searched (2004/12). To update an unpublished 2002 review we also searched CENTRAL in The Cochrane Library (Issue 1,2005); MEDLINE (to 2005/02); EMBASE (to 2005/08); Science Citation Index (to 2005); Biosis (to 2005); Dissertation Abstracts (all publication years); Inside Conferences (all publication years); SIGLE (to 2005); National Research Register (all projects with a start date of 2001 to 2005); metaRegister of Current Controlled Trials.

SELECTION CRITERIA

Randomised trials comparing treatments against placebo or against vitamin D analogues in people with chronic plaque psoriasis.

DATA COLLECTION AND ANALYSIS

One author extracted study data and assessed study quality. A second author checked these data. We routinely contacted triallists and companies for missing data. We extracted data on withdrawals and adverse events.

MAIN RESULTS

The review included 131 RCTs with 21,448 participants. Vitamin D was significantly more effective than placebo, although there was a wide variation in effect size with the standardised mean difference (SMD) ranging from -0.82 (95% CI -1.34 to -0.29) to -1.90 (95% CI -2.09 to -1.71). With one exception, all corticosteroids performed better than placebo, with potent corticosteroids (SMD: -0.95 (95% CI: -1.11 to -0.80; I(2): 61.1%; 17 studies; 2386 participants)) having smaller benefits than very potent corticosteroids (SMD: -1.29 (95% CI: -1.45 to -1.13; I(2): 53.2%; 11 studies; 1571 participants)). Dithranol and tazarotene performed better than placebo. Head-to-head comparisons of vitamin D against potent or very potent corticosteroids found no significant differences. However, combined treatment with vitamin D /corticosteroid performed significantly better than either vitamin D alone or corticosteroid alone. Vitamin D performed better than coal tar, but findings relative to dithranol were mixed. Potent corticosteroids were less likely than vitamin D to cause local adverse events. No comparison of topical agents found a significant difference in systemic adverse effects.

AUTHORS' CONCLUSIONS

Corticosteroids perform as well as vitamin D analogues and are associated with a lower incidence of local adverse events. Further research is required to inform long-term maintenance treatment.

Trends in incidence of adult-onset psoriasis over three decades: a population-based study

BACKGROUND

Incidence studies of psoriasis are rare, mainly due to lack of established epidemiological criteria and the variable disease course. The objective of this study is to determine time trends in incidence and survival of psoriasis patients over three decades.

METHODS

We identified a population-based incidence cohort of 1633 subjects aged > or = 18 years first diagnosed with psoriasis between January 1, 1970 and January 1, 2000. The complete medical records for each potential psoriasis subject were reviewed and diagnosis was validated by either a confirmatory diagnosis in the medical record by a dermatologist or medical record review by a dermatologist. Age- and sex-specific incidence rates were calculated and were age- and sex-adjusted to the 2000 US white population.

RESULTS

The overall age- and sex-adjusted annual incidence of psoriasis was 78.9 per 100,000 (95% confidence interval [CI]: 75.0-82.9). When psoriasis diagnosis was restricted to dermatologist-confirmed subjects, the incidence was 62.3 per 100,000 (95% CI: 58.8-65.8). Incidence of psoriasis increased significantly over time from 50.8 in the period 1970-1974 to reach 100.5 per 100,000 in the 1995-1999 time period (P = .001). Although the overall incidence was higher in males than in females (P = .003), incidence in females was highest in the sixth decade of life (90.7 per 100,000). Survival was similar to that found in the general population (P = .36).

LIMITATIONS

The study population was mostly white and limited to adult psoriasis patients.

CONCLUSION

The annual incidence of psoriasis almost doubled between the 1970s and 2000. The reasons for this increase in incidence are currently unknown, but could include a variety of factors, including a true change in incidence or changes in the diagnosing patterns over time.

Potential misclassification of patients with psoriasis in electronic databases

BACKGROUND

Electronic claims and medical record databases are increasingly used for observational studies of psoriasis. The purpose of this study was to assess the validity of psoriasis diagnostic codes in an electronic database.

METHODS

This study was performed in a population-based setting in Olmsted County, Minnesota, where all diagnoses and procedures from all health care providers in a large community are indexed and recorded in an electronic database. The database was searched for patients aged 18 years or older with diagnostic codes consistent with psoriasis for the time period January 1, 1976, to January 1, 2000. The complete medical records of all patients were reviewed manually for validation of psoriasis diagnoses.

RESULTS

We reviewed the complete medical records of 2556 patients with at least one diagnostic code consistent with psoriasis. Based on medical record review, 1458 (57.0%) patients were confirmed to have psoriasis, of which the majority (81%) received confirmation by a dermatologist. The most commonly used diagnostic codes for psoriasis were International Classification of Diseases, Ninth Revision 696.1 (psoriasis, not otherwise specified) with a positive predictive value of 68.7% (95% confidence interval: 66.5%, 70.9%). Increasing frequency of codes in a given time window was associated with positive predictive values. However, positive predictive value for only one code in a 5-year time window was still as high as 60% (95% confidence interval: 57%, 63%).

LIMITATIONS

Differences between individual electronic medical record databases may limit the ability to form a general conclusion from these findings. The remitting, relapsing course of psoriasis and the heterogeneity in clinical presentation create challenges in case ascertainment.

CONCLUSION

Electronic identification of patients with psoriasis by diagnostic codes alone may lead to misclassification in database studies.

Observations of Psoriasis in the Absence of Therapeutic Intervention Identifies Two Unappreciated Morphologic Variants, Thin-Plaque and Thick-Plaque Psoriasis, and their Associated Phenotypes

Psoriatic plaque thickness is a clinical measure of psoriasis severity. We have observed that patients tend to revert to a baseline thickness of psoriatic plaques when in an untreated state, and hypothesized that other features of psoriasis could associate with this trait. Data prospectively collected on 500 participants in the Utah Psoriasis Initiative were used for the study. In response to a question assessing plaque thickness when disease was at its worst, 144 (28.8%) reported thick plaques, 123 (24.6%) reported thin plaques, and 233 (46.6%) reported intermediate thickness. For patients with "worst-ever" disease at enrollment (n=122), there was significant correlation of thickness between assessment by the patient and the physician (r=0.448, P-value 0.01). Thick plaques associated with male gender, increased body mass index, nail disease, psoriatic arthritis, larger plaques, more body sites, and greater total body surface area affected. Thin plaques associated with eczema, guttate psoriasis, and skin cancer. We suggest that this is preliminary evidence that plaque thickness is an easily measured trait that associates with other clinical features of psoriasis, and that stratification on this phenotype may be useful in further defining the genetic basis of this disease.