title: The Incidence and Predictors of Infection in Psoriasis and Psoriatic Arthritis: Results from Longitudinal Observational Cohorts.
abstract: OBJECTIVE
  To investigate the rate, type, characteristics, and predictors of infection in a cohort of patients with psoriatic arthritis (PsA) and a cohort of patients with psoriasis without arthritis (PsC).
  
  
  METHODS
  A cohort of patients with PsA and a cohort of patients with PsC were followed according to a standard protocol and information on the occurrence of infections was recorded. The rate of infection was estimated by fitting an exponential model. A Weibull regression model was fitted to estimate the relative risk of first infection associated with a number of covariates. Risk factors for recurrent infections were investigated using generalized estimating equations.
  
  
  RESULTS
  There were 498 and 74 infections reported among 695 and 509 patients with PsA and PsC, respectively, with an incidence rate of 19.6 per 100 person-years in the PsA cohort compared with 12.2 in the PsC cohort. The HR of the time to the first infection in PsA versus PsC was 1.6 (p = 0.002), and higher in patients treated with biologics versus nonbiologics at 1.56 (95% CI 1.22-2.00) in PsA and 1.50 (95% CI 0.64-3.54) in the PsC cohorts. Female sex and treatment with biologics were associated with infection in the PsA cohort, whereas a lower Psoriasis Area and Severity Index score and a higher Functional Comorbidity Index were associated with infection in the PsC cohort. Ultraviolet treatment was protective against infection in both cohorts. No difference in rates of hospitalization was found (p = 0.66). There were no infection-related deaths in either cohort.
  
  
  CONCLUSIONS
  The incidence rate of infection was higher in the PsA than the PsC cohort and higher among patients treated with biologics. The data confirm the association between infection and biologic treatment in psoriatic disease.
authors.affiliation: From the Division of Rheumatology, Department of Medicine, University of Toronto; Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases; Toronto Western Hospital, University Health Network, Toronto; Department of Statistics and Actuarial Science, University of Waterloo, Waterloo, Ontario, Canada.A. Haddad, MD, Clinical Research Fellow, Division of Rheumatology, Department of Medicine, University of Toronto, and Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network; S. Li, MMath, Biostatistician, Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network; A. Thavaneswaran, MMath, Research Associate, Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network; R.J. Cook, PhD, Professor, Canada Research Chair, Department of Statistics and Actuarial Science, University of Waterloo; V. Chandran, MBBS, MD, DM, PhD, Assistant Professor, Department of Medicine, Division of Rheumatology, University of Toronto, and Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network; D.D. Gladman, MD, FRCPC, Professor of Medicine, Department of Medicine, Division of Rheumatology, University of Toronto, and Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network.
authors.forename: Amir
authors.initials: A
authors.lastname: Haddad
authors.affiliation: From the Division of Rheumatology, Department of Medicine, University of Toronto; Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases; Toronto Western Hospital, University Health Network, Toronto; Department of Statistics and Actuarial Science, University of Waterloo, Waterloo, Ontario, Canada.A. Haddad, MD, Clinical Research Fellow, Division of Rheumatology, Department of Medicine, University of Toronto, and Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network; S. Li, MMath, Biostatistician, Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network; A. Thavaneswaran, MMath, Research Associate, Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network; R.J. Cook, PhD, Professor, Canada Research Chair, Department of Statistics and Actuarial Science, University of Waterloo; V. Chandran, MBBS, MD, DM, PhD, Assistant Professor, Department of Medicine, Division of Rheumatology, University of Toronto, and Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network; D.D. Gladman, MD, FRCPC, Professor of Medicine, Department of Medicine, Division of Rheumatology, University of Toronto, and Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Li
authors.affiliation: From the Division of Rheumatology, Department of Medicine, University of Toronto; Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases; Toronto Western Hospital, University Health Network, Toronto; Department of Statistics and Actuarial Science, University of Waterloo, Waterloo, Ontario, Canada.A. Haddad, MD, Clinical Research Fellow, Division of Rheumatology, Department of Medicine, University of Toronto, and Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network; S. Li, MMath, Biostatistician, Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network; A. Thavaneswaran, MMath, Research Associate, Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network; R.J. Cook, PhD, Professor, Canada Research Chair, Department of Statistics and Actuarial Science, University of Waterloo; V. Chandran, MBBS, MD, DM, PhD, Assistant Professor, Department of Medicine, Division of Rheumatology, University of Toronto, and Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network; D.D. Gladman, MD, FRCPC, Professor of Medicine, Department of Medicine, Division of Rheumatology, University of Toronto, and Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network.
authors.forename: Arane
authors.initials: A
authors.lastname: Thavaneswaran
authors.affiliation: From the Division of Rheumatology, Department of Medicine, University of Toronto; Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases; Toronto Western Hospital, University Health Network, Toronto; Department of Statistics and Actuarial Science, University of Waterloo, Waterloo, Ontario, Canada.A. Haddad, MD, Clinical Research Fellow, Division of Rheumatology, Department of Medicine, University of Toronto, and Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network; S. Li, MMath, Biostatistician, Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network; A. Thavaneswaran, MMath, Research Associate, Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network; R.J. Cook, PhD, Professor, Canada Research Chair, Department of Statistics and Actuarial Science, University of Waterloo; V. Chandran, MBBS, MD, DM, PhD, Assistant Professor, Department of Medicine, Division of Rheumatology, University of Toronto, and Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network; D.D. Gladman, MD, FRCPC, Professor of Medicine, Department of Medicine, Division of Rheumatology, University of Toronto, and Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Cook
authors.affiliation: From the Division of Rheumatology, Department of Medicine, University of Toronto; Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases; Toronto Western Hospital, University Health Network, Toronto; Department of Statistics and Actuarial Science, University of Waterloo, Waterloo, Ontario, Canada.A. Haddad, MD, Clinical Research Fellow, Division of Rheumatology, Department of Medicine, University of Toronto, and Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network; S. Li, MMath, Biostatistician, Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network; A. Thavaneswaran, MMath, Research Associate, Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network; R.J. Cook, PhD, Professor, Canada Research Chair, Department of Statistics and Actuarial Science, University of Waterloo; V. Chandran, MBBS, MD, DM, PhD, Assistant Professor, Department of Medicine, Division of Rheumatology, University of Toronto, and Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network; D.D. Gladman, MD, FRCPC, Professor of Medicine, Department of Medicine, Division of Rheumatology, University of Toronto, and Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network.
authors.forename: Vinod
authors.initials: V
authors.lastname: Chandran
authors.affiliation: From the Division of Rheumatology, Department of Medicine, University of Toronto; Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases; Toronto Western Hospital, University Health Network, Toronto; Department of Statistics and Actuarial Science, University of Waterloo, Waterloo, Ontario, Canada.A. Haddad, MD, Clinical Research Fellow, Division of Rheumatology, Department of Medicine, University of Toronto, and Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network; S. Li, MMath, Biostatistician, Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network; A. Thavaneswaran, MMath, Research Associate, Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network; R.J. Cook, PhD, Professor, Canada Research Chair, Department of Statistics and Actuarial Science, University of Waterloo; V. Chandran, MBBS, MD, DM, PhD, Assistant Professor, Department of Medicine, Division of Rheumatology, University of Toronto, and Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network; D.D. Gladman, MD, FRCPC, Professor of Medicine, Department of Medicine, Division of Rheumatology, University of Toronto, and Psoriatic Arthritis Program, Centre for Prognosis Studies in the Rheumatic Diseases, and Toronto Western Hospital, University Health Network. dafna.gladman@utoronto.ca.
authors.forename: Dafna D
authors.initials: DD
authors.lastname: Gladman
mesh_terms: D000328:Adult; D015535:Arthritis, Psoriatic / Q000150:complications*; D005260:Female; D006801:Humans; D015994:Incidence; D007239:Infections / Q000453:epidemiology* / Q000209:etiology*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011565:Psoriasis / Q000150:complications*; D012307:Risk Factors; D012737:Sex Factors
keywords: INFECTION; PSORIASIS; PSORIATIC ARTHRITIS