Analysis of Data Recorded by the German Statutory Health Insurance on Outpatient Care of Subjects Suffering from Rheumatoid Arthritis: Ensuring the quality of the outpatient treatment of subjects suffering from rheumatoid arthritis requires an assessment of the treatment to 1) evaluate the present state of the treatment, 2) make suggestions towards optimisation and 3) evaluate the translation into reality of these suggestions for optimisation. The data of the (statutory) health insurance are a suitable basis for evaluation [L. von Ferber (ed.) 1994], since outpatient treatment can be analysed by means of person-related long-term observations encompassing all institutions even for illnesses that progress in phases (such as rheumatoid arthritis). Consulting an illness-specific, 45% random sample of all insured members with inflammatory joint diseases a prevalence of 0.44% (n=268) was calculated for rheumatoid arthritis. A total prevalence of 0.06% was revealed for other rheumatic illnesses, such as ankylosing spondylitis (n=27), psoriasis arthritis (n=8) and Sjorgen's syndrome (n=4). Considerable additional extra demand was found for the 307 patients suffering from rheumatic diseases: They visited approx. 1.5 times more different doctors and received 2.5 times as many medical services in comparison to a control group of ''average'' insured persons (matched pairs according to age and sex). The care of the rheumatic diseases was predominantly (224 of 307) patients in the hands of one specialist (mostly the GP). Referral to other specialists with a specific diagnosis of rheumatoid disease occurred only with one quarter of the patients. Only small differences in the spectrum of substance classes employed could be seen in drug therapy, according to the age of the patient or the medical discipline of the prescribing doctor. Analgesics are mainly prescribed on a short-term basis (one treatment quarter). However, so-called ''basic therapeutics'' (remission-inducing drugs) are employed only on a long-term basis (3 or 4 treatment quarters) in less than 50 per cent of the cases. Marked differences were found when comparing outpatient primary medical prescription data with those from specialised institutions (rheumatism centres, established rheumatologists): Basis therapeutics are employed less frequently and analgesics more frequently in outpatient treatment than in the special institutions. Non steroid antirheumatics are employed with a similar frequency (71 to 89%) in all institutions. A clear difference was also seen in the spectrum of the basic therapeutics employed depending on the prescribing institution. Analysis of treatment data by statutory health insurance shows that the rheumatoid arthritis patient has an outstanding access to the medical care system but that the quality of treatment cannot be considered sufficient. The differences seen in the comparison between the special institutions and the outpatient sector should give rise to critical discussion, and to carrying out further comparative analyses in the treatment research of patients suffering from rheumatic diseases.