Objective To systematically review and provide information on the incidence of psoriasis and quantify global, regional, and country specific estimates of its prevalence. Design Systematic review and meta-analysis. Data sources Medline, Embase, Web of Science, SciELO, Korean Journal Databases, Russian Science Citation Index, WPRIM, SaudiMedLit, Informit, IndMed, and HERDIN were searched systematically from their inception dates to October 2019. Methods Studies were included if they reported on the incidence or prevalence of psoriasis in the general population. Incidence data were summarised descriptively, whereas bayesian hierarchical models were fitted to estimate the global, regional, and country specific prevalence of psoriasis. Results 41 164 records were identified and 168 studies met the inclusion criteria. In adults, the incidence of psoriasis varied from 30.3 per 100 000 person years (95% confidence interval 26.6 to 34.1) in Taiwan to 321.0 per 100 000 person years in Italy. The prevalence of psoriasis varied from 0.14% (95% uncertainty interval 0.05% to 0.40%) in east Asia to 1.99% (0.64% to 6.60%) in Australasia. The prevalence of psoriasis was also high in western Europe (1.92%, 1.07% to 3.46%), central Europe (1.83%, 0.62% to 5.32%), North America (1.50%, 0.63% to 3.60%), and high income southern Latin America (1.10%, 0.36% to 2.96%). Conclusions Eighty one per cent of the countries of the world lack information on the epidemiology of psoriasis. The disease occurs more frequently in adults than in children. Psoriasis is unequally distributed across geographical regions; it is more frequent in high income countries and in regions with older populations. The estimates provided can help guide countries and the international community when making public health decisions on the appropriate management of psoriasis and assessing its natural history over time. Systematic review registration PROSPERO CRD42019160817.

Little is known about the drug survival of second-line biologic therapies for psoriasis in routine clinical practice. We assessed drug survival of second-line biologic therapies and estimated the risk of recurrent discontinuation due to adverse events or ineffectiveness in patients with psoriasis who had failed a first biologic therapy and switched to a second in a large, multicenter pharmacovigilance registry (n = 1,239; adalimumab, n = 538; etanercept, n = 104; ustekinumab, n = 597). The overall drug survival rate in the first year after switching was 77% (95% confidence interval = 74–79%), falling to 58% (55–61%) in the third year. Female sex, multiple comorbidities, concomitant therapy with cyclosporine, and a high Psoriasis Area and Severity Index at switching to the second-line biologic therapy were predictors of overall discontinuation (multivariable Cox proportional hazard model). Compared to adalimumab, patients receiving etanercept were more likely to discontinue therapy (hazard ratio = 1.87, 95% confidence interval = 1.24–2.83), whereas patients receiving ustekinumab were more likely to persist (hazard ratio = 0.46; 95% confidence interval = 0.33–0.64). Discontinuation of the first biologic therapy because of adverse events was associated with an increased rate of second drug discontinuation because of adverse events (hazard ratio = 2.55; 95% confidence interval = 1.50–4.32). In conclusion, drug survival rates differed among biologic therapies and decreased over time; second-line discontinuation because of adverse events was more common among those who discontinued first-line treatment for this reason. The results of this study should support clinical decision making when choosing second-line biologic therapy for patients with psoriasis.

More than one-third of patients experienced treatment modifications within the first year of initiating a biologic. Conventional systemic therapies, particularly methotrexate, were commonly used concurrently, which should be considered when evaluating treatment response and adverse events to biologics in real-world observational studies.

Summary Background There is a lack of any overview of changes over time and variation in the epidemiology of psoriasis with age and between genders. Objectives To perform a systematic review of published population‐based studies on variations in psoriasis incidence and prevalence with age and between genders, and to explore trends in psoriasis epidemiology over time. Methods Eleven electronic and regional databases were searched from their inception dates to October 2019. No language restrictions were applied. Studies were eligible if they reported on changes in psoriasis incidence and/or prevalence over time and/or by age group and gender. Results In total 308 papers were critically appraised, from which 90 studies from 22 countries were included. Incidence data confirmed a clear bimodal age pattern in psoriasis onset, with the first and second peaks at around 30–39 and 60–69 years of age, respectively, and evidence suggesting that it presents slightly earlier in women than in men. Prevalence data showed an increasing trend with age until around 60 or 70 years, after which it decreases. Although there was lack of agreement on specific gender differences in psoriasis incidence and prevalence, a slight male predominance was reported in several studies. Studies worldwide suggested a stable or slightly decreasing trend in psoriasis incidence, while an increasing trend in psoriasis prevalence has been consistently reported. One particular challenge faced was the vastly different methodologies used in the included studies, which contributed to some of the heterogeneity of the results. Conclusions Studies on changes over time in the occurrence of psoriasis have contributed to a greater appreciation of the increasing burden of the disease. However, further research is required to determine the reasons driving the increase in psoriasis prevalence over time.

BADBIR is an invaluable resource to study the safety and effectiveness of both biologic and conventional systemic therapies. Understanding differences in baseline characteristics between cohorts is crucial in undertaking future pharmacovigilance studies.

In routine clinical practice biological therapies produce marked improvement in HRQoL, which is influenced by the choice of biological therapy, baseline impairment in HRQoL, lifestyle characteristics and comorbidities. These findings should help inform selection of optimal biological therapy for patients related to improvements in HRQoL.

Background Psoriasis is a common chronic inflammatory skin disease associated with a heavy burden of morbidity, disability and cost. The occurrence of the disease in Israel has not been previously investigated. Objectives To provide standardized estimates of trends in psoriasis incidence, prevalence and mortality among patients in Israel between 2011 and 2017. Methods Using electronic health records from Clalit Health Services, the largest nationwide public health provider in Israel, we conducted a population‐based study investigating trends in the annual incidence and prevalence of psoriasis between the years 2011 and 2017. We report age‐ and sex‐adjusted rates, using the standard European population as a reference. Results We identified 71 094 incident psoriasis cases. The mean (SD) age of onset was 42.4 (21.0) years with a bimodal distribution, peaking in the early ‘30s and early ‘60s. Late‐onset psoriasis, occurring after 40 years of age, accounted for 51.1% of incident cases. The annual psoriasis incidence rate was constant throughout the study period (280/100 000 person‐years). Psoriasis prevalence rose from 2.5% in 2011 to 3.8% in 2017. Conclusions Psoriasis prevalence is increasing in Israel, although its incidence is stable. Clinicians and policymakers should plan to address the growing demands in the clinical, economic and societal burden of psoriasis.

The Investigating Medication Adherence in Psoriasis (iMAP) study was initially funded by a Medical Research Council (MRC) doctoral fellowship and studentship award by the Psoriasis Association of Great Britain and Ireland awarded to R.J.T. Subsequent funding came from an MRC (MR/ 1011808/1) award to the Psoriasis Stratification to Optimise Relevant Therapy (PSORT) consortium. The British Association of Dermatologists Biologics and Immunomodulators Register (BAD-BIR) is coordinated by the University of Manchester. The BADBIR is funded by the British Association of Dermatologists. The British Association of Dermatologists has received income from AbbVie, Eli Lilly, Janssen Cilag, Novartis, Pfizer, and Samsung Bioepis for providing pharmacovigilance services. This income finances a separate contract between the British Association of Dermatologists and the University of Manchester, which coordinates the BADBIR. C.E.M.G. and D.M.A. are funded in part by the MRC (MR/ L011808/1) and the NIHR Manchester Biomedical Research Centre. The funders/sponsors had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review or approval of the manuscript; and decision to submit the manuscript for publication.