As far as I know the only good evidence for efficacy of gold containing compounds comes from use of soluble sodium aurothiomalate, although there is some evidence for aurothioglucose. I am not aware that metallic gold is of any value. There are reasons for thinking that the active agent is the thiol group. Gold itself may be of little relevance. Since nobody knows what the mode of action is I think it is difficult to establish these things.
I don't think that metallic complimentary therapy is the most useful therapy clinically.
R.A.etiology is desperately needed to be defined, understood and used for proper diagnosis of the R.A. Otherwise, this trial and error and costly psudotherapies are going to further give rise to physiological and anatomical anomalies.
Our research paper is underway to reveal the real etiology of R.A. i WILL BE POSTING IT ON THIS WEB AS SOON AS IT IS PUBLISHED.
Over an almost 40 year career in rheumatology, I have only used sodium aurothiomalate and aurothioglucose (no observed differences in efficacy between these two compounds), and have no basis for comparing other gold compounds in clinical practice. The mechanism of action remains, so far as I know, totally obscure.