Outcome and predictive factors in children with chronic idiopathic musculoskeletal pain

Abstract

Objective: The aim of the present study was to describe the outcome and determine predictors of persisting chronic idiopathic musculoskeletal pain in children.

Methods: A prospective 9-year follow-up of 37 children with musculoskeletal pain of at least 3 months duration for which no physical origin could be found, was carried out. The study comprised those patients with idiopathic pain in a cohort of 117 first admissions to a pediatric rheumatology clinic; 72 patients with juvenile chronic arthritis (JCA) were used as a comparison group.

Results: Twenty-two patients (59%) still had chronic idiopathic musculoskeletal pain at the 9-year follow-up, while 15 patients no longer had pain after a median of 2.1 years (range 0.3-8.9). Compared with the patients with resolved pain, those with chronic pain had a longer disease duration before admission (median 1.4 versus 0.5 years, P < 0.01), more frequent generalised pain (86 versus 47%, P < 0.05), more intense pain (median 4.3 versus 0.5 cm VAS, P < 0.05), a lower parental education level (mean 10 versus 14 years, P < 0.01) and more chronic family difficulties (mean score 4.3 versus 2.9, P < 0.01) on first admission. Predictors of persistent pain were generalised pain on first admission (OR = 84) and a low mother's education level (OR = 0.31 per year of increased education). At follow-up, 16 patients (73%) with persistent chronic pain reported some disability according to the childhood or the adult Health Assessment Questionnaire (CHAQ/HAQ). The patients with chronic pain had as high a pain intensity (median 2.7 versus 2.0 cm VAS, NS), as much disability (median CHAQ/HAQ 0.3 versus 0.3) and as much impact on overall well-being (median 2.9 versus 3.2 cm VAS, NS) as patients with active JCA, but they had more fatigue (median 5.1 versus 1.3 cm VAS, P < 0.05), lower levels of psychosocial functioning (median score 74 versus 80, P < 0.05) and more chronic family difficulties (median score 3.3 versus 2.3, P < 0.001) than the JCA patients.

Conclusion: Chronic idiopathic musculoskeletal pain in children had an unfavourable outcome in the present study, especially in children with generalised pain and a low parental education level.