MICROALBUMINURIA IN PATIENTS WITH RHEUMATOID-ARTHRITIS

Objectives-To assess (a) the prevalence of microalbuminuria in patient s with rheumatoid arthritis, (b) the association between urinary album in excretion and disease activity as estimated by the erythrocyte sedi mentation rate and C reactive protein (CRP), and (c) the association b etween urinary albumin excretion and treatment with antirheumatic drug s. Methods-Sixty five patients with rheumatoid arthritis attending two rheumatology clinics were compared with 51 control subjects matched b y age and sex. The controls consisted of 20 healthy subjects, 16 patie nts with osteoarthritis and 15 with non-articular rheumatism. Patients with hypertension, diabetes mellitus, or evidence of previous renal d isease were not included. Urinary albumin was assayed by immunoturbidi metry in random urine samples on two occasions within seven months. Th e results were expressed as the ratio of urine albumin to urinary crea tinine ratio. Disease activity was assessed by the erythrocyte sedimen tation rate and CRP. A drug history for the year before entry to the s tudy was obtained for each patient. Results-Urinary albumin to creatin ine ratio in patients with rheumatoid arthritis was significantly grea ter than in controls (p < 0.01). Microalbuminuria (urinary albumin to creatinine ratio 3-30 mg/mmol in either or both urine samples) was pre sent in of patients with 27.7% rheumatoid arthritis and 7.8% of the co ntrol subjects. A significant relation was noted between urinary album in to creatinine ratio and CRP, duration of disease. The number patien ts treated with either gold or penicillamine was significantly greater in patients with microalbuminuria than in patients with normoalbuminu ria. Conclusions-Microalbuminuria is frequently present in patients wi th rheumatoid arthritis. Treatment with gold and penicillamine seems t o increase the risk of developing microalbuminuria. Urinary albumin me asured by immunochemical methods is a simple and sensitive test to det ect early subclinical renal dysfunction and drug induced renal damage in rheumatoid arthritis. Urinary albumin excretion was found to be sig nificantly correlated with CRP and may be a sensitive indicator of dis ease activity in patients with rheumatoid arthritis.