Focal Erosions in the Hands and Feet in Persons with Rheumatoid Arthritis and Their Relationship with Generalized Bone Loss

SLR - March 2012 - Nathan Young

Reference: Rossini M, Bagnato G, Frediani B, et al. Relationship of Focal Erosions, Bone Mineral Density, and Parathyroid Hormone in Rheumatoid Arthritis. J Rheumatol 2011; 38:997-1002.

Scientific Literature Review

Reviewed by: Nathan Young, DPM
Residency Program: Southern Arizona VA Healthcare System

Podiatric Relevance: 
Focal bone erosions can be seen in 30-50 percent of patients with Rheumatoid Arthritis (RA) after onset of the disease. The interaction of the patient’s cells with cytokines and chemokines in the synovium and surrounding tissue can result in bone erosions. In addition to being a joint destructive process, RA is also associated with generalized bone loss and patients have a higher prevalence of osteoporosis. Patients with RA constitute a small but significant portion of the typical podiatric practice due to their joint pain, stiffness, and foot deformities. The disease process itself coupled with the fact that many RA patients use long-term glucocorticoids can leave these individuals with bone erosions and osteoporosis. In RA patients with focal foot erosions it is important to evaluate the likelihood of osteoporosis when considering surgery any surgery involving bone, especially joint arthrodesis.

Methods: 
1191 patients from 22 rheumatology centers distributed across Italy were included in the study. Radiographs of hands and feet were evaluated using the van der Heijde modification of the Sharp erosion score. Serum samples were taken from patients to analyze serum intact parathyroid hormone (PTH) and Vitamin D. DEXA scans were also performed on each of the patients.

Results: 
The mean age was 58.911.1 years. Evidence of typical bony erosions on radiographs of hands or forefeet was found in 64.1 percent of subjects. When controlled for multiple variables (including but not limited to age, sex, menopausal state, disease duration, mobility ADLs, functional state, calcium intake, smoking, BMI, bisphosphonate treatment, serum Vitamin D and serum PTH) were found to be as follows: Serum Vitamin D in patients with erosions and with Vitamin D supplementation 23.312.1 ng/ml and without Vitamin D supplementation 21.811.1 ng/ml versus 24.811.0 ng/ml and 20.29.0 ng/ml in patients without erosions and with or without Vitamin D supplementation respectively. PTH was found to be 25.713.7 pg/ml in patients with bone erosion on Vitamin D supplementation and 26.313.1 pg/ml in patients without bone erosion without Vitamin D supplementation versus 23.313.1 pg/ml and 22.911.0 pg/ml in patients withoug bone erosions and with or without Vitamin D supplementation respectively. In patients with bone erosions the DEXA scans revealed mean BMD Z scores of the spine -0.751.19 and of the hip -0.751.07 compared to those without bone erosions of -0.461.31 and -0.151.23 respectively.

Conclusions: 
The authors found that nearly two-thirds of RA patients included in this study had focal bone erosions in their hands or forefeet. These patients had significantly lower Bone Mineral Densities in their hip and lumbar spine. Patients with focal bony erosions had higher serum PTH levels and lower Vitamin D levels than their non-focal erosion counterparts. The authors recommend consideration of anti-resorption agents for the management of RA at the onset of disease.