Outcome and predictive factors in children with chronic idiopathic musculoskeletal pain.

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.