RA. Etiology (cause) is unknown. There may be a genetic component, but not a cause. It has been proposed (not proven) that an infection may be a triggering factor in genetically suceptible patient (no specific infection has been identified). This is clinical diagnosis (symptioms and physical findings). Labs and xrays provide prognostic information. Simply stated there is no cause for ra.
Medicine. Another way to frame this is to say that NSAID therapy reduces symptoms but only "dmards" (disease modifying anti rheumatic agents) like methotrexate, other pills, and the biologics really stop the underlying process.