Background/Purpose: Patients with elderly-onset arthritis have greater comorbidity than young patients, with a higher incidence of osteoporosis (OP), probably mediated by increased bone resorption. However, there are few data on bone metabolism mediators in this population.

Methods: Longitudinal observational study that included patients with elderly-onset arthritis ( > 65 years) without diagnosis of OP or on antiosteoporotic treatment. Phospho-calcium metabolism, quantification of bone remodeling mediators (DKK1, sclerostin, OPG and RANKL; ELISA, R&D systems) and bone densitometry were determined in all patients at diagnosis and at 12 months. The results were compared with a control group of the same age and sex (n=14). The statistical study was performed using SPSS.

Results: We included 73 patients (37F: 36M), with a mean age of 75±7 years. Most were diagnosed with rheumatoid arthritis (RA) (n=43), followed by polymyalgia rheumatica (n=16) and others (n=14). Fifteen patients were rheumatoid factor (RF) positive and 23 were ACA positive. Five patients had erosions at the diagnosis. 88.64% of patients with RA had an initial DAS28-ESR >5.1. Only 3 patients had previous fragility fractures (2 vertebral and 1 femur fractures). At diagnosis, patients with elderly-onset arthritis had higher levels of DKK1 and CTX than the control group, with no statistically significant differences in sclerostin, OPG, and RANKL values (table 1). In addition, DKK1 values were negatively correlated with sclerostin (r=-0.286, p=0.016) and OPG (r=-0.276, p=0.020).  31.9% had densitometric OP at baseline. We found no significant differences in bone remodeling mediators between patients with/without basal OP. At 12 months, DAS28-ESR was < 2.6 in 38.1%. The mean corticosteroid dose was 5.5 mg/day with a cumulative dose of 1630±426 mg. 45.8% received antiosteoporotic treatment (28 patients’ bisphosphonates and 5 denosumab). The prevalence of OP at 12 months was 31.3% and 4 patients had new fractures (4 vertebral and 1 femur fractures). We observed a marked decrease in the values of DKK1 (-18.89%, p< 0.001) and sclerostin (-46.76%, p< 0.001) and an increase in OPG (11.97%, p=0.018). We didn´t found relationship between bone metabolism mediators and cumulative corticosteroid dose. There were not differences in terms of diagnosis (RA or PRM), ACA positivity, activity scores or treatment with bisphosphonates.

Conclusion: Patients with elderly-onset arthritis have higher Dkk1 values than the control group, and this correlate negatively with sclerostin and OPG. The marked decrease in Dkk-1 and sclerostin at 12 months, and the increase in OPG, suggests a role for these mediators in the bone metabolism of this population. It is important to note the high prevalence of OP in this group of patients.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/mediators-of-bone-metabolism-dkk1-opg-sclerostin-and-rankl-in-a-cohort-of-patients-with-elderly-onset-arthritis/