COVID-19 and Psoriasis Treatment: The Clinician’s Role in Navigating Uncertainty
Let’s start with what we currently know about COVID-19, an illness caused by severe acute respiratory syndrome coronavirus 2, also known as SARS-CoV-2. It is a single-stranded RNA virus transmitted primarily by respiratory droplets from coughs and sneezes.
The virus may remain viable on surfaces such as plastic and steel for up to 3 days. COVID-19 illness is highly variable; many people are asymptomatic (and can spread the virus), and a minority require hospitalization, ventilators and ultimately die. Estimates of mortality rates range from less than 0.5% to 2% or higher. The wide variation in mortality rates is likely due to under-ascertainment of mild or asymptomatic infections, as well as variation in the populations studied. Older age, male sex and comorbidities such as hypertension, obesity, diabetes, cardiovascular disease and chronic lung disease all appear to increase the risk for severe outcomes and death from COVID-19.
COVID-19 is the gravest infectious disease threat to the public health in more than a millennium because it is novel (and thus there is no immunity in humans) and more contagious than influenza, and its highly variable course allows for rapid, silent spread throughout communities, which does not become apparent, in the absence of widespread testing, until hundreds to thousands of people are infected. Even if the absolute risk of mortality for individuals is lower than current estimates, particularly those who are young and without the aforementioned comorbidities, hundreds of thousands of Americans are at risk for death from SARS-CoV-2.
What do we know about psoriasis that is relevant to the COVID-19 pandemic? First, psoriasis is an autoimmune disease in which the risk for hypertension, diabetes, cardiovascular disease, chronic lung disease and premature mortality increases with increasing severity of skin disease. Thus, as a population, patients with psoriasis, particularly those with more severe disease, are at risk for worse outcomes from COVID-19. Second, most of our treatments, aside from perhaps acitretin and phototherapy, are “immunosuppressive” and typically have warnings for infection in FDA prescribing information.
What we do not know about psoriasis treatment and the risk for COVID-19 far outweighs what we do know currently. One model about COVID-19 is that immunosuppression is harmful early on, making a patient more susceptible to and at risk for progression of infection with SARS-CoV-2, but immunosuppression may be helpful later in the course of the illness by suppressing the dysregulated immune response in the lungs that leads to acute respiratory distress syndrome and death. This model is simply a hypothesis that is being tested in clinical trials of COVID-19 patients with severe disease of agents such as adalimumab, Taltz (ixekizumab, Lilly), apremilast (Otezla, Amgen), JAK inhibitors and IL-6 blockers. Preliminary studies in psoriasis patients are starting to emerge. A study from New York of 86 patients with immune-mediated disease and COVID-19 (of whom 14 and 21 had psoriasis or psoriatic arthritis, respectively) did not find a relationship between biologic treatment and worse COVID-19 outcomes. A study from Northern Italy found that patients with psoriasis on biologics had a higher risk for becoming infected with SARS-CoV-2 and hospitalized for COVID-19 but saw no difference in mortality or use of a ventilator. Neither of these studies were adequately powered or used the type of statistical analysis necessary to determine if the associations observed were due to biologic treatment or confounding factors such as age or comorbidity.
Recently we calculated a meta-estimate of the risk for respiratory tract infections (RTI) and symptoms in patients with psoriasis treated with IL-17 inhibitors in phase 3 trials. This analysis demonstrated a 30% to 60% increased risk for RTI caused by IL-17 inhibitors; however, we do not know if these symptoms of RTI were due to viral, bacterial, allergic or fungal causes. This meta-estimate suggests a potential safety signal for RTI associated with IL-17 inhibition, which may not have been clinically important before the pandemic but in the time of COVID-19 highlights the need for more data.
The absence of rigorous data to guide psoriasis treatment decisions in the time of COVID-19 emphasizes the need for clinicians to do what they do best: balance uncertainty of relevant safety concerns with proven benefits of treatment. Guidance issued by the American Academy of Dermatology recommends that clinicians use their clinical judgment to stop or continue patients on biologics or immunosuppressive agents in those who have not tested positive or exhibited symptoms of COVID-19 and to stop these agents in patients who test positive or exhibit COVID-19 symptoms (www.aad.org/member/practice/coronavirus/clinical-guidance/biologics).
As dermatologists, we are fortunate to have a variety of safe and effective treatments for psoriasis, which allows us to balance our current scientific insights with the art of helping our patients select the right treatment choice that reflects their underlying health status and unique individual circumstances and preferences. In my experience, weighing the known benefit of their treatment with the uncertainties, nearly all of my patients have elected to continue their psoriasis treatment.
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