Participants with OA were significantly older (P = 0.001), had higher BMI (P<0.001) and worse physical function results (TUG; P = 0.029, STS; P = 0.004, WS; P = 0.003), whereas participants with RA had higher CRP-scores (P = 0.006), were more likely to be prescribed glucocorticoid-steroids (P<0.001), experienced worse severity of fatigue (P = 0.050) and had lower grip strength (P<0.001). Here, CRP is linked to rheumatoid arthritis.