Identification of existing knowledge deficits provides insights for future research that can further improve care for patients with psoriasis.
Findings from research conducted in the last 10 years have led to significant advances in the care of patients with psoriasis. At the same time, however, these developments have highlighted important gaps in knowledge and brought to the forefront issues requiring further study, says Joel M. Gelfand, M.D., M.S.C.E.
“The number of published scientific publications about psoriasis has increased exponentially since the early 2000s, and this research has led to enormous progress, including the introduction of better therapies and increased understanding of health outcomes related to psoriasis. Yet there are several major fundamental questions that we still need to answer,” he says.
Dr. Gelfand is associate professor of dermatology and epidemiology, and director, Psoriasis and Phototherapy Treatment Center, University of Pennsylvania Perelman School of Medicine, Philadelphia. Speaking at the 74th Annual Meeting of the American Academy of Dermatology, he highlighted the need for further research on topics relating to natural history, various public health and health economics issues, pediatric and long-term care, cardiometabolic comorbidities, and genetics. These and other research gaps in psoriasis were reviewed in a 2014 article co-authored by Dr. Gelfand.1
The fact that there have never been any inception cohort studies for psoriasis leaves a gap in knowledge about its natural history. One important consequence of this deficit is that patient questions about prognosis may be unanswerable.
“A patient who first develops psoriasis appearing as a small plaque may wonder about the future likelihood of having widespread disease. We need large, broadly representative, prospective longitudinal studies to answer that question,” Dr. Gelfand says.
In the realm of public health issues, research is needed to better understand health and healthcare disparities. Dr. Gelfand notes that in 2015, he and colleagues published a paper that is the first to evaluate racial factors associated with biologic treatment of moderate-to-severe psoriasis.2 Looking at a Medicare population, they found that African Americans were 70% less likely to receive biologics compared with white patients.
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“This type of finding is just the tip of the iceberg and points to the need for additional research to determine, for example, the reasons for the disparity and whether there are racial disparities in patient outcomes,” he says.
As another barrier to care issue, Dr. Gelfand notes there is evidence that moderate-to-severe psoriasis is significantly undertreated. He cites a study reporting that only about 10% of patients with moderate-to-severe psoriasis were receiving systemic therapies for disease control.3
“Now we need research that will allow us to understand why the majority of patients with bad disease are living with their psoriasis and not receiving appropriate care,” he says.
Studies are also needed to evaluate the use of traditional systemic and biologic agents in the treatment of moderate-to-severe psoriasis in children. Ideally, studies would be conducted to support FDA approval of an indication for pediatric patients.
“Although there are some excellent data supporting the efficacy and safety of newer therapies when used to treat moderate-to-severe psoriasis in children, access to these modalities may be limited because none are approved for pediatric use. As a result, children are often channeled to management with therapies that are difficult to do, like phototherapy, or to systemic agents that are less expensive, but that also may be less effective or more poorly tolerated than the biologics,” he says.
Studies are also needed to understand interactions between psoriasis and cardiometabolic comorbidities. Dr. Gelfand explains that it is apparent, based on available evidence, that the prevalence and risk of diabetes and cardiovascular disease is higher among patients with moderate-to-severe psoriasis compared with the general population. What is not known, however, is whether the comorbidity risks are lowered by effective control of the skin disease and if patients with psoriasis would benefit from aggressive intervention to reduce cardiometabolic risk.
“There are observational data suggesting that controlling moderate-to-severe psoriasis also lowers risks of diabetes, cardiovascular disease, and cardiovascular-related mortality, but more definitive understanding of these associations requires evidence from randomized placebo controlled trials,” Dr. Gelfand says.
“We also need studies to help guide optimal management of cardiovascular risk factors for patients with moderate-to-severe psoriasis. For example, it has been advocated that patients with rheumatoid arthritis should be started earlier on a statin to manage their increased risk for cardiovascular disease. We don’t know if the same approach should be followed for patients with moderate-to-severe psoriasis.”
There is also a need for real-world studies to evaluate the effectiveness of treatment strategies and comparing different modalities. Dr. Gelfand notes that the limited research of this type suggests that outcomes in clinical practice do not match those achieved in clinical trials.
“Efficacy endpoints in clinical trials may assess responses after 12 weeks of treatment, but those data do not reflect what happens over the long-term. We need research to identify how to provide psoriasis patients with more durable disease control,” he says.
Finally, there is a need for translational research in the area of genetics. Although understanding of genetic risk factors for psoriasis has been expanding, the relevance of that information to patient care remains to be determined.
“We are not at the point where we can use our knowledge of genetics to inform treatment decisions or determine prognosis. Studies are now needed to address those issues,” Dr. Gelfand says.
Disclosure: Dr. Gelfand is an investigator and/or consultant for several companies that market or are developing products for the treatment of psoriasis.
1. Ryan C, Korman NJ, Gelfand JM, Lim HW, Elmets CA, Feldman SR, et al. Research gaps in psoriasis: opportunities for future studies. J Am Acad Dermatol. 2014;70(1):146-67.
2. Takeshita J, Gelfand JM, Li P, et al. Psoriasis in the US Medicare population: prevalence, treatment, and factors associated with biologic use. J Invest Dermatol. 2015;135(12):2955-63.
3. Lebwohl MG, Bachelez H, Barker J, Girolomoni G, Kavanaugh A, Langley RG, et al. Patient perspectives in the management of psoriasis: results from the population-based Multinational Assessment of Psoriasis and Psoriatic Arthritis Survey. J Am Acad Dermatol. 2014;70(5):871-81.