A new Japanese study has identified a potential connection between rheumatoid arthritis and kidney dysfunction. The researchers used absolute estimated eGFR levels to determine that a significant 33.8% of rheumatoid arthritis sufferers also exhibited some form of kidney disease or impaired kidney function.
This statistic was most widely observed in older female patients who also had a history of hypertension and/or diabetes.
Earlier studies describing biopsy and clinical renal findings in patients with RA suggested that the dominant manifestations were secondary amyloidosis, membranous nephropathy, mesangial glomerulonephritis, and vasculitis. However, those studies were based on patients being treated with older antirheumatic drugs such as gold and penicillamine, which have been associated with nephrotoxicity, and secondary amyloidosis is now uncommon because of improved RA treatment.
Nonetheless, renal involvement in RA may be increasing despite modern treatments, and may be contributing to RA patients’ persistently increased mortality.
To examine current patterns of renal dysfunction in RA, Mori’s group conducted a cross-sectional study, recruiting 1,908 patients from three outpatient centers in Japan during 2014 and 2015. For each patient, they collected demographic characteristics, RA disease features such as duration, disease activity, and seropositivity, medication use, and traditional cardiovascular risk factors such as hypertension and diabetes.
Another significant finding were the reported treatments these patients were receiving. A total of 51.6% received methotrexate while 33.6% were being treated with biologics. Among the RA sufferers with kidney disease, methotrexate was used less frequently, while biologics and steroids were more often used by kidney disease sufferers, perhaps hinting at a correlation there as well.
As people age, they become more prone to inflammatory diseases like rheumatoid arthritis and this can also put them at risk of developing kidney disease which is also characterized by marked inflammation and impaired filtration function.
