Causes of nephrotic syndrome and nephrotic‐range proteinuria are different in adult Chinese patients: A single centre study over 33 years

Abstract Aim The reported causes of nephrotic syndrome (NS) varies between different countries. Less is known about the causes of nephrotic‐range proteinuria (NPU). We aimed to evaluate the underlying causes of NS and NPU. Methods This was a single‐centre, retrospective study of adult patients who underwent renal biopsy between 1983 and 2015 in a tertiary referral hospital in Hong Kong. We determined the distribution of histopathological diagnoses with regard to the age subgroups and time periods. Results Among 7456 patients who underwent renal biopsy, 982 and 838 patients had NS and NPU, respectively. The most common diagnosis in NS was minimal change disease (MCD) (33.3%), followed by membranous nephropathy (MN) (23.6%) and lupus nephritis (LN) (12.8%); whereas the most common diagnosis in NPU was LN (27.4%), followed by immunoglobulin A nephropathy (IgAN) (21.4%) and diabetic nephropathy (DN) (9.3%). In the NS group, MCD was the most common diagnosis in young adults while MN was the leading cause in the elderly. On the other hand, LN was the most common pathology in the NPU group until the age of 60. Over the past three decades, there was a trend of decrease in the proportion of IgAN in both NS and NPU group, while a combined pathology of hypertensive nephrosclerosis and diabetic nephropathy (HTNS and DN) increased significantly. Conclusions The causes of NS and NPU in Chinese adults were different and may represent two distinct pathological identities. The spectrum of renal histopathology among these two groups changed significantly over time.