Renal safety of initial combination versus single DMARD therapy in patients with early rheumatoid arthritis: an 11-year experience from the FIN-RACo Trial.

OBJECTIVE: To evaluate the renal safety of traditional disease-modifying antirheumatic drugs (DMARDs) in early rheumatoid arthritis (RA).

METHODS: One hundred and ninety-five DMARD-naïve patients with recent-onset RA were randomised to receive combination DMARD therapy (n=97) starting with sulfasalazine, methotrexate, hydroxychloroquine, and prednisolone (COMBI) or monotherapy (n=98), initially with sulfasalazine, with or without prednisolone (SINGLE). After two years, the choice and dosing of DMARDs and prednisolone were not restricted, but the treatment was still targeted to achieve or maintain remission. Urinalysis, serum creatinine and glomerular filtration rate (GFR; estimated according to the Cockcroft-Gault formula [eGFRCG]) were analysed at baseline and at months 6, 9, 12, 18, 24 and thereafter yearly up to 11 years.

RESULTS: The cumulative incidence of repeated (>or=3 times) abnormal renal findings during the 11-year follow-up period were as follows (COMBI versus SINGLE; p-values adjusted for age and sex): proteinuria (dipstick positive) 4.8% (95%CI 1.8-12.2) vs. 5.3% (95%CI 2.0-13.7, p=0.93), haematuria (dipstick positive) 14.1% (95%CI 8.0-24.2) vs. 22.1 % (95%CI 14.5-33.0, p=0.14), raised serum creatinine (>or=100 micromol/l in females and >or=115 micromol/l in males) 4.4% (95%CI 1.7-11.4) vs. 6.7% (3.0-14.3, p=0.87) and eGFRGC<60 ml/min/1.73 m2 11.9% (95%CI 6.8-20.5) vs. 10.5% (95%CI 5.8-18.7, p=0.85).

CONCLUSION: Initial remission targeted therapy with the FIN-RACo DMARD combination in early RA is safe for kidneys and does not induce more short- or long-term renal complications compared to traditional therapy with a single DMARD.