Proteinuria is a common condition with lupus but I don't know about RA. I had it and it went away after taking lisinopril. The swelling I had also went away.
I would advise you to see a nephrologist and get it checked out. Whatever is causing it should be treated so that you do not have kidney damage. Mine had early stage 2 but have recovered fully and they function normally now.
Mixed connective tissue disease (systemic lupus, scleroderma, polymyositis), Raynauds phenomena, Hypertension, Barrett's esophagus.
Meds: prednisone (7mg & tapering), 100mg imuran, lisinopril 40mg, maxide 37.5/25mg, norvasc 5 mg, folic acid, potassium, aciphex 20mg, multi vitamins.
Maintain your optimism and you can beat the odds.
"Although the world is full of suffering, it is also full of the overcoming of it." Helen Keller