We studied children enrolled within 90 days of juvenile idiopathic arthritis diagnosis in the Research in Arthritis in Canadian Children Emphasizing Outcomes (ReACCh-Out) prospective inception cohort to identify longitudinal trajectories of pain severity and features that may predict pain trajectory at diagnosis. A total of 1062 participants were followed a median of 24.3 months (interquartile range = 16.0-37.1 months). Latent trajectory analysis of pain severity, measured in a 100-mm visual analogue scale, identified 5 distinct trajectories: (1) mild-decreasing pain (56.2% of the cohort); (2) moderate-decreasing pain (28.6%); (3) chronically moderate pain (7.4%); (4) minimal pain (4.0%); and (5) mild-increasing pain (3.7%). Mean disability and quality of life scores roughly paralleled the pain severity trajectories. At baseline, children with chronically moderate pain, compared to those with moderate-decreasing pain, were older (mean 10.0 vs 8.5 years, P = 0.01) and had higher active joint counts (mean 10.0 vs 7.2 joints, P = 0.06). Children with mild-increasing pain had lower joint counts than children with mild-decreasing pain (2.3 vs 5.2 joints, P < 0.001). Although most children with juvenile idiopathic arthritis in this cohort had mild or moderate initial levels of pain that decreased quickly, about 1 in 10 children had concerning pain trajectories (chronically moderate pain and mild-increasing pain). Systematic periodic assessment of pain severity in the months after diagnosis may help identify these concerning pain trajectories early and lay out appropriate pain management plans. Focused research into the factors leading to these concerning trajectories may help prevent them.
aDepartment of Pediatrics, University of Florida, Gainesville, FL, USA
bDepartment of Community Health and Epidemiology, University of Saskatchewan, Saskatoon, SK, Canada
cDepartment of Pediatrics, University of Saskatchewan, Saskatoon, SK, Canada
dDepartment of Pediatrics, University of Manitoba, Winnipeg, MB, Canada
eDepartment of Pediatrics, British Columbia Children's Hospital, University of British Columbia, Vancouver, BC, Canada
fDepartment of Pediatrics, IWK Health Centre, Dalhousie University, Halifax, NS, Canada
gDepartment of Medicine, Centre hospitalier universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC, Canada
hDepartment of Pediatrics, Janeway Children's Health and Rehabilitation Centre, Memorial University, St. John's, NL, Canada
iDepartment of Pediatrics, Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
jDepartment of Pediatrics, Alberta Children's Hospital, University of Calgary, Calgary, AB, Canada
kDepartment of Pediatrics, Children's Hospital of Eastern Ontario, University of Ottawa, Ottawa, ON, Canada
lDepartment of Pediatrics, University of British Columbia, Vancouver, BC, Canada
mDepartment of Pediatrics, Montreal Children's Hospital, McGill University Health Centre, McGill University, Montreal, QC, Canada
nSchool of Rehabilitation, Université de Montréal; Department of Social and Preventive Medicine, School of Public Health, Université de Montréal; Institute of Research in Public Health, Université de Montréal; Centre for Interdisciplinary Research in Rehabilitation of Montreal, Montreal, QC, Canada
oDepartment of Pediatrics, Centre hospitalier universitaire Sainte-Justine, Université de Montréal, Montreal, QC, Canada
pDepartment of Medicine, McMaster University, Hamilton, ON, Canada
Corresponding author. Address: Division of Immunology, Rheumatology, and Allergy, Department of Pediatrics, Shands Children's Hospital, PO Box 100296, 1600 SW Archer Rd, Gainesville, FL 32610, USA. Tel.: 352-294-5252; fax: 352-294-8068. E-mail address: firstname.lastname@example.org (N.J. Shiff).
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Received February 24, 2017
Received in revised form August 23, 2017
Accepted September 07, 2017