Background: Hand osteoarthritis (OA) and its more severe subset erosive hand OA are common causes of pain and morbidity. Some metabolic factors were suggested to be implicated in erosive disease. Few studies investigated differences in systemic bone loss between erosive and non-erosive hand OA.

Objectives: To compare the change of bone mineral density (BMD) between patients with erosive and non-erosive hand OA in a longitudinal study after three years.

Methods: American College of Rheumatology (ACR) criteria were used to assess hand OA. Erosive hand OA was defined by at least one erosive interphalangeal joint. All patients underwent clinical assessments of joint swelling and radiographs of both hands. DEXA examination of lumbar spine, total femur and femur neck was performed at baseline and after three years. Metabolic risk factors (body mass index, hypertension, diabetes, dyslipidaemia) were collected.

Results: Altogether, 144 patients (15 male) with symptomatic nodal HOA were included in this study and followed between ^{April 2012} and January 2018. Out of these patients, 82 had erosive disease after three years. The disease duration (p<0.01) was significantly higher in patients with erosive compared with non-erosive disease.

Most patients took symptomatic slow acting drugs (SYSADOA) twice a year, non-steroidal anti-inflammatory drugs (NSAIDs) and analgesics on demand.

Baseline population characteristics did not differ between both groups. Osteoporosis (T-score <-2.5 SD) was diagnosed in 12.5% (9/72) of patients with erosive hand OA and in 8.06% (5/57) of patients with non-erosive hand OA. Although BMD did not significantly differ between the groups (BMD of lumbar spine 1,05 g/cm2 vs 1,13 g/cm2, p<0.05, total femur 0,90 g/cm2 vs 0,97 g/cm2, p<0.01 and femur neck 0,86 g/cm2 vs 0,91, p<0.05), T-scores of lumbar spine (−0.96 vs −0,41 SD, p<0.05), total femur (−0.69 vs.

−0,33SD, p<0.05) and femur neck (−1,14 vs −0,88 SD, p<0.05) were significantly lower in patients with erosive compared with non-erosive disease.

After three years, the decrease in T- score of lumbar spine was significantly higher in erosive hand OA compare to non-erosive disease (−3,66% vs 15,52%, p<0.01), also the decrease of T-score in total femur was significantly higher in erosive hand OA compare to non-erosive disease (−4,29% vs 7,68%, p<0.05).

The decrease of bone mineral density was also significantly higher in patients with erosive hand OA after three years. The decrease of BMD of lumbar spine was significantly higher in erosive hand OA after three years compare to non-erosive disease (−3,30% vs 1,06%, p<0,05), the decrease of BMD in femur neck was significantly higher in erosive hand OA after three years compare to non-erosive disease (−3,2% vs 0,02%, p<0,05), the decrease of BMD total femur neck was significantly higher in erosive hand OA after three years compare to non-erosive disease (−1,58% vs 0,82%, p<0,05).

Conclusions: These results suggest that patients with erosive hand OA are at higher risk for development of deep general bone loss.

Acknowledgement: This work was supported by the project MHCR No. 0 23 728.

Disclosure of Interest: None declared

DOI: 10.1136/annrheumdis-2018-eular.6324