Knoop T, et al. - In this study, researchers focused on the long-term prognosis in patients with assumed benign immunoglobulin A nephropathy (IgAN). Findings demonstrated that after a median duration of 22 years, progressive disease was reported in 18.6% of patients with assumed benign IgAN and these patients could not be predicted at the time of biopsy. An extended follow-up period in these patients is needed when assessing prognosis.

Methods

• Researchers selected patients from the Norwegian Kidney Biopsy Registry based on the following criteria: diagnostic renal biopsy performed in the period 1988–99, with estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m² and proteinuria <1 g/24 h at the time of biopsy.
• They performed a nephrological examination in patients, reviewed medical history and investigated blood pressure, urinary findings and eGFR.

Results

• Data showed that overall 145 patients attended the examination, performed by the first author, after a median of 22 (interquartile range 19–25) years after diagnosis.
• Researchers found that at the examination, 27 patients (18.6%) had a ≥50% decrease in GFR, of whom 4 (2.8%) had developed end-stage renal disease (ESRD).
• They also noted that the mean duration from renal biopsy to ≥ 50% decrease in GFR was 17.3 ± 5.1 years in their cohort.
• They observed clinical remission in 42 (29.0%) patients.
• Utilizing the Oxford classification criteria, they re-evaluated renal biopsies.
• Findings demonstrated that mesangial hypercellularity was found in 12.3%, endocapillary proliferation was detected in 10.7% and segmental glomerulosclerosis was observed in 23.8%.
• All biopsies were scored as T0 (tubular atrophy in < 25% of the cortical area).
• In addition, patients with progressive disease could not be identified with any of the clinical or histopathological variables recorded at the time of biopsy.
• Results revealed that cumulative risks of ≥50% decrease in eGFR were 2.1% after 10 years, 4.1% after 15 years, 13.9% after 20 years and 24.7% after 25 years.