Rheumatoid Arthritis and the Kidney: Uneasy Companions

Rheumatoid arthritis and the risk of end-stage renal disease: A nationwide, population-based study

Introduction

Despite the risk of incident chronic kidney disease among the patients with rheumatoid arthritis (RA), the association of RA and the risk of end-stage renal disease (ESRD) has not been clearly elucidated. We aimed to investigate the association of RA and the risk of ESRD.

Materials and methods

A total of 929,982 subjects with (n = 154,997) or without (n = 774,985) RA from the National Health Insurance Service (NHIS) database in Koreas (corresponding to the period between 2009 and 2017) were retrospectively analyzed. RA was defined by the International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM), codes plus any dispensing of disease-modifying anti-rheumatic drugs. The primary outcome was incident ESRD, identified by a combination of the ICD-10-CM codes and a special code assigned to patients receiving maintenance dialysis for ≥ 3 months or those with a transplant kidney.

Results

Compared to the subjects without RA, the subjects with RA resulted in an increased incidence of ESRD (incidence rates of 0.374 versus 0.810 cases per 1,000 person-years). Accordingly, compared to the subjects without RA, the risk of ESRD was significantly increased among the subjects with RA (adjusted hazard ratio 2.095, 95% confidence interval 1.902-2.308). Subgroup analyses revealed that the risk of ESRD imposed by RA is relatively higher in relatively young and healthy individuals.

Conclusion

Rheumatoid arthritis (RA) increase the risk of ESRD. As the risk of ESRD imposed by RA is relatively higher in relatively young and healthy individuals, kidney-protective treatment, such as biologic agents, should be preferentially considered among these patients with RA.

Renal dysfunction among rheumatoid arthritis patients: A retrospective cohort study

Background

Rheumatoid arthritis (RA) is a common rheumatological disease which can involve a variety of different renal manifestations. This may be explained by disease effect itself or by medications used for treatment that may lead to renal dysfunction and its complications.

We aimed to identify the prevalence and factors that played a role in renal dysfunction among RA Jordanian patients.

Method

285 patients with RA visiting outpatient clinic between March 2016 and March 2017 were included in a retrospective study design. Age, gender, comorbidities, duration of the disease, medications and laboratory results were gathered and scoring of RA activity was done.

Results

Data gathered from the 285 patients showed a female predominance with 88.4% female and 11.6% male. The average disease duration was 6.7 years. Age, DM, HTN, and serum CRP were associated with worse renal function on univariate analysis. 44 patients (18.8%) presented with microscopic hematuria, 16 (6.9%) with proteinuria and only 5 (2.1%) patients presented with both microscopic hematuria and proteinuria. Patients with eGFR <60 ml/min had longer disease duration with a mean of 11 years (±7.7) in comparison to 6.4 years (±6.1) for those with eGFR>90 ml/min (P = 0.001).

Conclusion

Renal dysfunction is not common in RA Jordanian population and has variable presentations. Age and the duration of illness play a major role in the progression of CKD if present. Future prospective studies evaluating renal biopsies in RA patients are needed.

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First study in the country to discuss the prevalence of renal involvement in rheumatoid arthritis.

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Renal involvement is rare in rheumatoid arthritis patients.

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Different drugs can affect renal outcome in a different ways.

Hydroxychloroquine Use and Risk of CKD in Patients with Rheumatoid Arthritis

BACKGROUND AND OBJECTIVES

Hydroxychloroquine is widely used in patients with rheumatoid arthritis. However, large-scale studies examining the long-term effects of hydroxychloroquine on the development of kidney disease in patients with rheumatoid arthritis are lacking. We aimed to assess the long-term association of hydroxychloroquine use with the risk of developing CKD in this population.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted an observational cohort study for patients with newly diagnosed rheumatoid arthritis who were enrolled prospectively in Taiwan's National Health Insurance Research Database between January 1, 2000 and December 31, 2013. We used multivariable Cox proportional hazard regression to analyze the association of hydroxychloroquine use with incident CKD.

RESULTS

A total of 2619 patients, including 1212 hydroxychloroquine users and 1407 hydroxychloroquine nonusers, were analyzed. Incident CKD was reported in 48 of 1212 hydroxychloroquine users and 121 of 1407 hydroxychloroquine nonusers. The incidence rate of CKD was lower in hydroxychloroquine users than in hydroxychloroquine nonusers (10.3 versus 13.8 per 1000 person-years). After multivariable adjustment, hydroxychloroquine users still had a lower risk of incident CKD (adjusted hazard ratio, 0.64; 95% confidence interval, 0.45 to 0.90; P=0.01) than hydroxychloroquine nonusers. The lower risk of subsequent CKD development was dose dependent and consistent across subgroup analyses.

CONCLUSIONS

Hydroxychloroquine use in patients with newly diagnosed rheumatoid arthritis is associated with a significantly lower risk of incident CKD compared with in nonusers.

Cystatin C concentration is correlated with disease activity in rheumatoid arthritis patients

OBJECTIVES

Rheumatoid arthritis (RA) is a systemic, inflammatory disease. Renal involvement worsens the course of RA and increases mortality. It is suggested that chronic inflammatory processes may contribute to renal impairment. The aim of this study was to investigate the impact of chronic inflammation and RA activity on glomerular filtration rate (GFR).

METHODS

The study population consisted of 140 RA patients. High disease activity was observed in 42 patients (30%), and long-term RA (duration ≥ 10 years) in 64 (45.7%). Measures of renal function included: serum cystatin C, serum creatinine (SCr), and creatinine-based estimated GFR (eGFR) calculated by Cockcroft and Gault (CG) and Modification of Diet in Renal Disease (MDRD) formulas.

RESULTS

The mean (SD) cystatin C concentration was 0.77 (0.2) mg/L, SCr 0.71 (0.23) mg/dL, eGFR(CG) 110.5 (37.8) mL/min/1.73 m², and eGFR(MDRD) 109.5 (34.5) mL/min/1.73 m². Cystatin C levels correlated positively with creatinine, and negatively with eGFR(CG) and eGFR(MDRD). Cystatin C concentration was significantly higher in patients with high disease activity, long-term RA, and hypertension, and in males. Patients currently being treated with biologics had non-significantly lower cystatin C levels than those treated with conventional modifying drugs. Cystatin C levels were significantly associated with markers of clinical, functional disease activity, and markers of inflammation. By contrast, there were no such correlations with other parameters of renal function.

CONCLUSIONS

In patients with RA, cystatin C may be not only an indicator of GFR but also a marker of intensity of chronic inflammatory processes.