To evaluate bone mineral status over 1 yr of etanercept treatment in juvenile idiopathic arthritis (JIA).
Twenty children (13 female, 7 male) aged 5.2-11.4 yr, with active polyarticular JIA were prospectively enrolled to receive etanercept (0.4 mg/kg, twice weekly). Responders were defined according to the American College of Rheumatology Pediatric 50 definition of improvement. Broadband ultrasound attenuation (BUA) by bone was determined at the left calcaneus to assess bone status at baseline and at 1-yr follow-up.
After 12 months of treatment, 15 (75%) patients were considered as responders. At baseline, responders and non-responders did not differ with regard to age, disease duration, core-set variables or BUA and Z-score values (patient's value--age specific normal value/normal group's s.d.). At 6-month and 1-yr follow-up in the whole group, BUA and Z-score values were not significantly different compared with baseline. At 1-yr follow-up, but not at 6 months, all 15 responders, differently from non-responders, showed a significant increase in both BUA and Z-score values: BUA at 1 yr 55.2 +/- 3.3 vs baseline 43.5 +/- 3.2 dB/MHz, P<0.001; Z score at 1 yr -0.3 +/- 0.2 vs baseline 1.5 +/- 0.4, P<0.002.
For the first time in childhood rheumatic disease this pilot prospective study, although in a small group, shows evidence that 1 yr of etanercept therapy by controlling the underlying disease activity induces a sustained benefit on JIA bone loss. Prospective studies in larger patient samples are needed to confirm these data.