Objective: The object of this study was to determine the effect of EAS (Equine-Assisted Services) on arthritis conditions, as measured by the sTnT (Skeletal troponin) and COMP (cartilage oligomeric matrix proteins) biomarkers, compared to an exercise attention control intervention.

Design: This was a secondary analysis of a randomized clinical trial comparing equine-assisted therapy to exercise education attention-control on cartilage and skeletal biomarkers in adults with arthritis. Twenty-one adults (M(age) = 64 years) with arthritis who attended rheumatology clinics in the midwestern United States participated.

Results: No changes were found in sTnT from baseline to week six within either intervention nor were there differences in changes between the two groups (p = 0.91). COMP increased from baseline to week six for both conditions, suggesting increased deterioration of cartilage and joints. Although the attention-control condition demonstrated larger increases in cartilage oligomeric matrix proteins level, compared to the EAS condition, these differences were not statistically (p = 0.58) or clinically significant (i.e., trivial effect, d = -0.16). When 3 outliers were removed, the differences in changes between EAT and attention-control group could be arguably of clinical significance (d = - 0.33), suggesting that the attention-control group demonstrated larger increases in levels of COMP than those in the EAS condition, though this difference was not statistically significant (p = 0.28).

Conclusion: Although equine-assisted therapy may reduce pain and improve quality of life for adults with arthritis, findings here are not fully corroborated with biomarkers.