The aim of this study was to investigate the prevalence of chronic kidney disease (CKD) among comparable patients with rheumatoid arthritis (RA) and seronegative inflammatory arthritis, and to explore any predictive factors for renal impairment.
Consecutive patients with peripheral joint disease (oligo and polyarthritis) were recruited from our inflammatory arthritis clinics. We divided patients in two groups: RA group and seronegative inflammatory arthritis group. The cohort consisted of 183 patients (RA = 107, seronegative arthritis = 76 [psoriatic arthritis = 69, undifferentiated oligoarthritis = 7]). Estimated glomerular filtration rate (eGFR) was calculated using the established Modification of Diet in Renal Disease equation. Demographic details, disease-specific characteristics, anti-rheumatic drugs and the presence of cardiovascular diseases were recorded.
In total, 17.48% (n = 32) of the cohort had CKD. There was no statistically significant variation between the two groups as regards baseline demographics, disease characteristics, use of anti-rheumatic drugs and the presence of individual cardiovascular diseases. We found that eGFR and the presence of CKD were similar among these groups. Among patients with CKD, 72% had undiagnosed CKD. No association of statistical significance was noted between CKD and the use of corticosteroids, disease-modifying antirheumatic drugs and anti-tumor necrosis factor agents. The association of cardiovascular diseases with CKD remained significant after adjusting for confounders (age, gender, duration of arthritis, high C-reactive protein, use of anti-rheumatic drugs).
Patients with inflammatory arthritis are more prone to have CKD. This could have serious implications, as the majority of rheumatology patients use non-steroidal anti-inflammatory drugs and different immunosuppressives, such as methotrexate. No association of kidney dysfunction was noted with inflammatory disease-specific characteristics; rather it appears to have a positive independent association with cardiovascular diseases.