Spectrum and prognosis of renal histopathological lesions in 56 Chinese patients with rheumatoid arthritis with renal involvement

The objective of the study was to evaluate the characteristics and prognosis of 56 patients with rheumatoid arthritis (RA)-associated renal involvement by retrospective review of their renal biopsy specimens. Included in this cross-sectional study were 56 RA patients with renal involvement, in whom renal biopsy was performed to analyze the histological pattern and renal prognosis. IgA nephropathy (IgAN) was detected in 48.2% of the 56 included patients as the most common renal histological pattern, followed by membranous nephropathy (MN) in 23.2% cases, focal segmental glomerular sclerosis (FSGS) in 19.6% cases, chronic interstitial nephritis (CIN) in 5.4% cases, membranoproliferative glomerulonephritis (MPGN) in 1.8% cases, and non-IgA mesangial proliferative glomerulonephritis in 1.8% cases. No significant relationship was observed between the histopathologic type and the RA duration, joint deformity or treatment. Renal dysfunction was mainly found in IgAN patients, and MN occurred more frequently in older patients. Renal function decline occurred in two IgAN patients, one with FSGS and the other with MPGN. Another CIN patient progressed to dialysis during the follow-up period. The patients with renal function decline had a significantly higher level of serum creatinine at presentation. The high percentage of glomeruli sclerosis and interstitial fibrosis/tubular atrophy was also related to renal function decline. IgAN was the major RA-associated renal histological lesion in our series. Renal biopsy can provide useful information about the histological pattern and renal prognosis and therefore should be considered in RA patients with renal involvement.