Published online Mar 25, 2022. doi: 10.5527/wjn.v11.i2.73
Peer-review started: December 7, 2021
First decision: January 25, 2022
Revised: January 31, 2022
Accepted: March 23, 2022
Article in press: March 23, 2022
Published online: March 25, 2022
Nephritic syndrome (NiS) is a major indicator of serious renal diseases necessitating kidney biopsies for histopathological evaluations, but due to the lack of comprehensive reviews in the literature, the current understanding of the syndrome and its significance is limited.
To collect all the evidence retrievable from the literature on the diagnoses made on the renal biopsies performed for NiS as the indication to the procedure.
A literature search was conducted to find studies reporting final diagnoses on renal biopsies in NiS patients. Data were pooled and analyzed with stratifications on age and regions. Meta-analyzes were performed using Stata v.9.
Overall, 26414 NiS patients from the total number of 96738 kidney biopsy diagnoses reported by 47 studies from 23 countries from all continents (except sub-Saharan Africa) were found and analyzed. NiS was the indication for renal biopsy in 21% of the patient populations across the reviewed studies. Immunoglobulin A (IgA) nephropathy was the single most frequent diagnosis in these patients (approximately 38%) followed by lupus nephritis (approximately 8%) and Henoch Schönlein purpura (approximately 7%). IgA nephropathy was the most frequent diagnosis reported for the NiS patients from the East Asia, comprising half of all the cases, and least prevalent in South Asia. Considering the age subgroups, adult (vs pediatric or elderly) patients were by far the most likely age group to be diagnosed with the IgA nephropathy. A myriad of such regional and age disparities have been found and reported.
As the indication for renal biopsy, NiS represents a very distinctive epidemiology of final renal disease diagnoses compared to the other major syndromes.
Core Tip: Despite the extreme relevance of the renal biopsies in patients with different clinical syndromes and the final diagnoses that are being assigned to them, the current knowledge on the epidemiology of such diagnoses for nephritic syndrome is limited. This lack of understanding becomes more prominent when it comes to specific subpopulations, for example subgroups regarding age, ethnicity and global regions. This study tried to answer these questions, finding quite unprecedented, interesting, and clinically relevant findings.