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Extended report
The risk and nature of flares in juvenile idiopathic arthritis: results from the ReACCh-Out cohort
  1. Jaime Guzman1,
  2. Kiem Oen2,
  3. Adam M Huber3,
  4. Karen Watanabe Duffy4,
  5. Gilles Boire5,
  6. Natalie Shiff6,
  7. Roberta A Berard7,
  8. Deborah M Levy8,
  9. Elizabeth Stringer3,
  10. Rosie Scuccimarri9,
  11. Kimberly Morishita1,
  12. Nicole Johnson10,
  13. David A Cabral1,
  14. Alan M Rosenberg6,
  15. Maggie Larché11,
  16. Paul Dancey12,
  17. Ross E Petty1,
  18. Ronald M Laxer8,
  19. Earl Silverman8,
  20. Paivi Miettunen10,
  21. Anne-Laure Chetaille13,
  22. Elie Haddad14,
  23. Kristin Houghton1,
  24. Lynn Spiegel8,
  25. Stuart E Turvey1,
  26. Heinrike Schmeling10,
  27. Bianca Lang3,
  28. Janet Ellsworth15,
  29. Suzanne E Ramsey3,
  30. Alessandra Bruns5,
  31. Johannes Roth4,
  32. Sarah Campillo9,
  33. Susanne Benseler10,
  34. Gaëlle Chédeville9,
  35. Rayfel Schneider8,
  36. Shirley M L Tse8,
  37. Roxana Bolaria16,
  38. Katherine Gross16,
  39. Brian Feldman8,
  40. Debbie Feldman17,
  41. Bonnie Cameron8,
  42. Roman Jurencak4,
  43. Jean Dorval13,
  44. Claire LeBlanc9,
  45. Claire St. Cyr14,
  46. Michele Gibbon4,
  47. Rae S M Yeung8,
  48. Ciarán M Duffy4,
  49. Lori B Tucker1
  50. for the ReACCh-Out investigators
  1. 1British Columbia Children's Hospital and University of British Columbia, Vancouver, British Columbia, Canada
  2. 2Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, Manitoba, Canada
  3. 3IWK Health Centre and Dalhousie University, Halifax, Nova Scotia, Canada
  4. 4Children's Hospital of Eastern Ontario and University of Ottawa, Ottawa, Ontario, Canada
  5. 5Centre Hospitalier Universitaire de Sherbrooke and Departments of Medicine and Pediatrics, Université de Sherbrooke, Sherbrooke, Québec, Canada
  6. 6Royal University Hospital and University of Saskatchewan, Saskatoon, Saskatchewan, Canada
  7. 7London Health Sciences Centre and Western University, London, Ontario, Canada
  8. 8Hospital for Sick Children and University of Toronto, Toronto, Ontario, Canada
  9. 9McGill University Health Centre and McGill University, Montréal, Québec, Canada
  10. 10Alberta Children's Hospital and University of Calgary, Calgary, Alberta, Canada
  11. 11Department of Medicine, McMaster University, Hamilton, Ontario, Canada
  12. 12Janeway Children's Health and Rehabilitation Centre and Memorial University, Saint John's, Newfoundland, Canada
  13. 13Centre Hospitalier Universitaire de Laval and Université Laval, Quebec, Québec, Canada
  14. 14Centre Hospitalier Universitaire Ste. Justine and Université de Montréal, Montréal, Québec, Canada
  15. 15Stollery Children's Hospital and University of Alberta, Edmonton, Alberta, Canada
  16. 16Department of Pediatrics University of British Columbia, Vancouver, British Columbia, Canada
  17. 17Université de Montréal, Montréal, Québec, Canada
  1. Correspondence to Dr Jaime Guzman, Division of Pediatric Rheumatology, BC Children's Hospital, 4500 Oak St, Suite K4-122, Vancouver BC, Canada V6H 3N1; jguzman{at}


Objective To describe probabilities and characteristics of disease flares in children with juvenile idiopathic arthritis (JIA) and to identify clinical features associated with an increased risk of flare.

Methods We studied children in the Research in Arthritis in Canadian Children emphasizing Outcomes (ReACCh-Out) prospective inception cohort. A flare was defined as a recurrence of disease manifestations after attaining inactive disease and was called significant if it required intensification of treatment. Probability of first flare was calculated with Kaplan–Meier methods, and associated features were identified using Cox regression.

Results 1146 children were followed up a median of 24 months after attaining inactive disease. We observed 627 first flares (54.7% of patients) with median active joint count of 1, physician global assessment (PGA) of 12 mm and duration of 27 weeks. Within a year after attaining inactive disease, the probability of flare was 42.5% (95% CI 39% to 46%) for any flare and 26.6% (24% to 30%) for a significant flare. Within a year after stopping treatment, it was 31.7% (28% to 36%) and 25.0% (21% to 29%), respectively. A maximum PGA >30 mm, maximum active joint count >4, rheumatoid factor (RF)-positive polyarthritis, antinuclear antibodies (ANA) and receiving disease-modifying antirheumatic drugs (DMARDs) or biological agents before attaining inactive disease were associated with increased risk of flare. Systemic JIA was associated with the lowest risk of flare.

Conclusions In this real-practice JIA cohort, flares were frequent, usually involved a few swollen joints for an average of 6 months and 60% led to treatment intensification. Children with a severe disease course had an increased risk of flare.

  • Disease Activity
  • Epidemiology
  • Juvenile Idiopathic Arthritis

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