Background Patient's age at RA onset predefines the course of the disease, rate of progression and severity of erosive-destructive changes in hand and feet joints, mineral bone density (BMD) and deformities of the spine vertebrae.

Objectives To compare the changes in axial and peripheral skeleton in pts in relation to the age of RA onset.

Methods 164 females with RA aged 20 -65 y. were included. Mean age was 47,9±12,9 y., RA duration - 12,1±9,3 y. Genant semiqiantitative radiographic morphometry of lumbar and thoracic spine was obtained for all patients, erosive and destructive changes assessed using Sharp/van der Heijde scoring system. BMD was measured at lumbar spine level (L1–4), femoral neck (FM) and distal forearm (DF) of a non-dominant arm using Hologic “Discovery A” system. Data analysis was made with Statistica 6.0 software.

Results All pts were grouped into 3 arms depending on the age at RA onset: Group 1 – 63 (38,4%) pts, whose age at RA onset was ≥18 ≤30 y., Group 2 – 78 (47,6%) pts, ≥31 ≤50 y. age at RA onset, Group 3 – 23 (14,0%) pts, ≥51 y. age at RA onset. Mean age of pts from Group 1 was 37,8±12,7 y, Group 2 – 51,9±7,8 y., Group 3 – 62,1 ±2,6 y (p<0.05), disease duration - 15,1±12,3 y., 11,0±6,6 y., and 7,1±3,1 y., respectively (p<0.05). Menopause was established in 30% of pts in Group 1, in 60% - in Group 2, in 100% - in Group 3; peripheral fractures in past medical history were documented in 19 (30%), 28 (36%), and 11 (49%) pts from Groups 1, 2, and 3, respectively (p>0.05), 50% of fractures occurred before RA onset. The groups were comparable in terms of the number of RF-positive pts, receiving DMARDs, the duration and cumulative dose of GCs. DAS28 RA activity score, the number of pts with extra-articular RA manifestations and the number of pts taking GCs by the moment of examination were less in Group 1vs Group 2 (p<0.05). Lumbar vertebral deformity scores (VDS), BMD values of L1–4, FN, DF, narrowed joint spaces and total Sharp score were comparable in all groups (p>0,05). Number of erosions in Group 1 was 46,3±59,7 scores, in Group 2 - 30,8±38,5 scores, in Group 3 - 19,3±27,4 scores (Groups 1 and 3 p<0,05). Vertebral deformities were found in 19% pts from Groups 1 and 2, and in 39% pts from Group 3 (Groups 2–3 p<0,05). Thoracic VDS was 0,78±0,08, 0,78±0,07 and 0,73±0,13, respectively (Groups 3 and 1; 3 and 2 p<0,05).

Conclusions RA onset during attainment of peak bone mass and long lasting disease produced negative effect on axial and peripheral skeleton. Despite young age and absence of menopause the majority of pts presented with OP, peripheral fractures, BMD in all skeletal sites, and lumbar VDS values that were comparable to those in pts with later onset of the disease. Pts with RA onset after menopause and shorter duration of the disease present with equal to pts with early onset degree of joint space narrowing and total Sharp score, but not with similar number of erosions. Early onset of RA and therefore longer duration of disease is associated with more amount of erosions.

Disclosure of Interest None declared