Chronic kidney disease, inflammation, and cardiovascular disease risk in rheumatoid arthritis

Rheumatoid arthritis (RA), a prototypic systemic autoimmune inflammatory condition, confers an increased risk of cardiovascular disease (CVD). Recently, chronic kidney disease (CKD) was suggested to increase the risk of CVD in RA patients, and inflammation was identified as a critical, nontraditional CKD-associated risk factor for CVD. This study aimed to examine the combined effects of CKD and CVD in RA patients.

In this retrospective evaluation of 428 RA patients, the outcome of interest was the incidence of CVD. CKD was defined as an estimated glomerular filtration rate of <60mL/min/1.73m² and/or positive dipstick tests for proteinuria of ≥3 months duration. C-reactive protein (CRP) was used as an inflammation marker, and a high CRP level was defined as a mean CRP value of ≥0.57mg/dL during the first 6 months of follow-up. Patients were categorized as follows: non-CKD with low CRP, non-CKD with high CRP, CKD with low CRP, and CKD with high CRP.

During a median follow-up of 89 months, 67 patients (16%) had CKD, and 38 (9%) developed CVD. Using patients with non-CKD and low CRP as a reference group, the adjusted hazard ratios (HR, 95% confidence interval) for CVD were 1.88 (0.25-9.44) for patients with CKD/low CRP and 9.71 (3.27-31.97) for those with CKD/high CRP.

The coexistence of CKD and inflammation was associated with a higher risk of CVD than either condition alone in RA patients. Inflammation might increase the risk of CVD especially in patients with CKD.