Assessing the Risk and Outcome of COVID-19 in Patients with Psoriasis or Psoriatic Arthritis on Biologic Treatment: A Critical Appraisal of the Quality of the Published Evidence

The need to rapidly spread information about the risk of COVID-19 in patients with psoriasis and psoriatic arthritis on biologics may have hampered the methodological rigor in published literature. We analyzed the quality of papers dealing with the risk and outcomes of COVID-19 in patients with psoriasis and psoriatic arthritis receiving biologic therapies. The Newcastle-Ottawa Scale was used to estimate the quality of the published studies. Moreover, to better contextualize results, specific internal and external validity items were further considered, that is, case definition, modality of COVID-19 assessment, evidence for self-selection of participants, percentage of dropout/nonparticipants, and sample size calculation. A total of 25 of 141 papers were selected. The median Newcastle-Ottawa Scale score was 47% for psoriasis and 44% for psoriatic arthritis, indicating an overall high risk of bias. A total of 37% of psoriasis and 44% of psoriatic arthritis studies included patients with suspected COVID-19 without a positive swab. No studies provided a formal sample size calculation. A significant risk of bias in all the published papers was found. Major issues to be considered in future studies are reduction of ascertainment bias, better consideration of nonresponse or participation bias, and provision of formal statistical power calculation.