# Association of rheumatoid arthritis with chronic kidney disease

## TL;DR

People with rheumatoid arthritis are more likely to have chronic kidney disease, especially with albuminuria, and this may be linked to metabolic issues rather than inflammation alone.

## Contribution

Identifies albuminuria at preserved kidney function as the main renal phenotype in RA patients with CKD, independent of inflammation.

## Key findings

- RA patients had higher CKD prevalence compared to controls (11.8% vs 6.7%).
- Albuminuria at preserved kidney function was more common in RA patients (6.8% vs 4.2%).
- The RA-CKD association was largely explained by metabolic comorbidities rather than inflammation.

## Abstract

Rheumatoid arthritis (RA) has been linked to an increased risk of chronic kidney disease (CKD), but the predominant renal phenotype and its independence from established risk factors remain unclear. We examined the RA–CKD association in a large, population-based cohort.

RA and CKD were defined using American College of Rheumatology/European Alliance of Associations for Rheumatology and KDIGO criteria. Logistic regression models were employed with stepwise adjustment: first for cardiovascular risk [Systematic COronary Risk Evaluation 2 (SCORE2)], followed by a model including age, sex, metabolic syndrome, smoking status, non-steroidal anti-inflammatory drug (NSAID) use and high-sensitivity C-reactive protein. Interaction terms were tested to evaluate effect modification.

Among 9665 participants from the Paracelsus 10,000 cohort, 296 (3.1%) had RA. CKD prevalence was higher in the RA group compared with controls (11.8% vs 6.7%, P < .001). Albuminuria at preserved estimated glomerular filtration rate was the dominant renal manifestation in RA (6.8% vs 4.2%, P = .027). In unadjusted analyses, RA was associated with higher odds of CKD [odds ratio (OR) 1.86, 95% confidence interval (CI) 1.30–2.68], an association that persisted after cardiovascular risk adjustment. However, the association was attenuated and no longer statistically significant in the fully adjusted model (OR 1.43, 95% CI 0.96–2.13). A significant interaction was observed with NSAID use (P = .042), whereby the association was largely confined to RA patients not using NSAIDs.

RA is associated with a higher prevalence of CKD, primarily driven by albuminuria at preserved kidney function. This distinct renal phenotype appears largely mediated by metabolic comorbidities rather than inflammation alone. Our findings highlight the need for systematic albuminuria screening in RA patients to enable earlier detection and intervention.

GRAPHICAL ABSTRACT