Primary glomerular nephropathy among hospitalized patients in a national database in China

Background. Primary glomerular nephropathy (PGN) is a leading cause of end-stage renal disease in developing countries, however, nationwide studies investigating the spectrum of PGN are limited. Methods. To evaluate the composition of various pathological types of PGN in a comprehensive geographic coverage in China, a national inpatient database covering 43.7 million patients was used in this analysis. Diagnoses were extracted from the discharge diagnoses. Results. The percentage of patients with PGN in hospitalized patients decreased from 0.80% in 2010 to 0.67% in 2015. Among hospitalized patients with PGN, a decreasing trend of immunoglobulin A nephropathy (from 19.0% in 2010 to 10.6% in 2015) and an increasing trend of idiopathic membranous nephropathy (from 4.5% in 2010 to 8.8% in 2015) were revealed. A positive association between the percentage of idiopathic membranous nephropathy (iMN) and the exposure of particulate matter with a diameter < 2.5 mu m was observed north of the Yangtze River (P < 0.001, R-2 = 0.828). South of the Yangtze River, the proportion of the Zhuang population was positively correlated to the frequency of iMN (P = 0.012, r = 0.697). Conclusions. In conclusion, a changing spectrum of PGN was observed between 2010 and 2015 in China and both environmental and genetic factors might play pivotal roles in the pathogenesis of iMN in the Chinese population.