Objectives To examine the incidence and temporal trends of psoriatic arthritis (PsA) in the general population in Denmark.
Methods Using nationwide registry data, we estimated the number of patients with incident PsA within each 1-year period between 1997 and 2011 and calculated the rate of PsA cases within gender and age subgroups. Incidence rates were presented per 100 000 person-years.
Results There was a female predominance ranging from 50.3% (1998) to 59.2% (2010), and the mean age at time of diagnosis was 47–50 years. We identified a total of 12 719 patients with PsA (prevalence=0.22%), including 9034 patients where the PsA diagnosis was made by a rheumatologist (prevalence=0.16%). Incidence rates of PsA (per 100 000 person-years) increased from 7.3 in 1997 to a peak incidence of 27.3 in 2010. Incidence rates were highest for women and patients aged 50–59 years, respectively. The use of systemic non-biologic agents, that is, methotrexate, leflunomide, ciclosporin or sulfasalazine increased over the 15-year study course and were used in 66.3% of all patients. Biologic agents (etanercept, infliximab, adalimumab, certolizumab pegol, golimumab or ustekinumab) were used in 17.7% of patients with PsA.
Conclusions We found a clear trend of rising PsA incidence on a national level. While the cause remains unclear, our findings might be explained by increased attention by patients and physicians.
- Psoriatic arthritis
- Time trends
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Contributors AE and GHG had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Study concept and design: AE. Acquisition, analysis and interpretation of data: all authors. Drafting of the manuscript: AE. Critical revision of the manuscript for important intellectual content: all authors. Statistical analysis: AE and GHG. Obtained funding: AE and LM. Administrative, technical or material support: AE and GHG. Study supervision: AE and GHG.
Disclaimer Eli Lilly and Company, the funding source, participated in interpretation of the final analysed study results, but had no access to the raw data and did not participate in data collection, management or analysis.
Competing interests AE has received research funding from Pfizer and Eli Lilly and honoraria as consultant and/or speaker from Pfizer, Eli Lilly, Novartis, Galderma and Janssen Pharmaceuticals. LEK has received fees for speaking and consultancy from Pfizer, MSD, AbbVie, UCB, Eli Lilly, Novartis, Celgene, Janssen Pharmaceuticals, Roche, Forward Pharma and BMS. JPT is supported by an unrestricted grant from the Lundbeck Foundation and has received speaker honoraria from Galderma and MEDA. GHG is supported by an unrestricted research scholarship from the Novo Nordisk Foundation. ABG has received honoraria as consultant and/or speaker from Amgen Inc.; Astellas, Akros, Centocor (Janssen), Inc.; Celgene Corp., Bristol Myers Squibb Co., Beiersdorf, Inc., Abbott Labs. (Abbvie), TEVA, Actelion, UCB, Novo Nordisk, Novartis, Dermipsor Ltd, Incyte, Pfizer, Canfite, Lilly, Coronado, Vertex, Karyopharm, CSL Behring Biotherapies for Life, Glaxo Smith Kline, Xenoport, Catabasis, Meiji Seika Pharma Co., Ltd, Takeda, Mitsubishi, Tanabe Pharma Development America, Inc., Genentech, Baxalta, Kineta One, KPI Therapeutics, Crescendo Bioscience, Aclaris, Amicus and Reddy Labs and received research funding (paid to Tuft Medical Center) from Centocor (Janssen), Amgen, Abbott (Abbvie), Novartis, Celgene, Pfizer, Lilly, Levia, Merck, Xenoport, Dermira and Baxalta. LCC has reported no conflicts of interest. DJ has received research funding from Pfizer and honoraria as consultant and/or speaker from Abbvie, Amgen, Celgene, Eli Lilly, Janssen Pharmaceuticals, MSD, Novartis and Pfizer. PG has received honoraria as consultant and/or speaker from AbbVie, Celgene, Eli Lilly, Janssen, Leo Pharma, MSD, Novartis, Pfizer and UCB. DDG has received consultancy fees and/or grant support from AbbVie, Amgen, BMS, Celgene, Eli Lilly, Janssen, Pfizer, Novartis and UCB. LS has received consultancy and/or speaker honoraria from Abbvie, Pfizer, Janssen-Cilag, Merck Sharp & Dohme and Leo Pharma and is a member of the advisory boards of Abbvie, Pfizer, Leo Pharma, Janssen-Cilag, Merck Sharp & Dohme, Eli Lilly, Celgene and Novartis. LM is currently employed by Eli Lilly and Company.
Patient consent Patient consent is not required for register studies per Danish law.
Provenance and peer review Not commissioned; externally peer reviewed.
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