Given that the treatment strategy for adolescent PNS has a significant impact on growth and development, but there are few cases and a lack of clinical research, this study plans to collaborate with several domestic top-tier children's nephrology centers to conduct a retrospective real-world study of adolescent PNS. The aim is to understand the current diagnosis and treatment status of adolescent PNS and compare the advantages and disadvantages of various therapies, in order to provide a more scientific, rational, and effective treatment plan for adolescent PNS.

Pediatric kidney disease, especially primary nephrotic syndrome (PNS), is a common urinary system disease in pediatric clinical practice. The core pathophysiological process of nephrotic syndrome involves damage to the glomerular filtration membrane, resulting in massive proteinuria and subsequent hypoproteinemia, hyperlipidemia, and edema. PNS in children is more prevalent in the preschool age group, with minimal change disease (MCD) accounting for approximately 77.1% of pathological types. MCD is sensitive to corticosteroids, and the traditional initial treatment regimen is standard-dose corticosteroid induction therapy. In foreign countries, the pathological types of PNS in adolescents are mainly MCD and focal segmental glomerulosclerosis (FSGS). In mainland China, the proportion of mesangial proliferative glomerulonephritis (MsPGN) is increasing, but MCD remains the main pathological type. Currently, there is no consensus among guidelines from various countries on whether to perform renal biopsy and the indications for it in adolescent PNS. The Chinese pediatric PNS evidence-based guideline does not specify the age factor for renal biopsy. In the treatment protocol debate of the International Pediatric Nephrology Association (IPNA), some scholars advocate corticosteroid treatment first, while others believe that renal biopsy first can reduce steroid exposure and its side effects. However, there is still a lack of large-scale clinical data for comparison. Given that the treatment strategy for adolescent PNS has a significant impact on growth and development, but there are few cases and a lack of clinical research, this study plans to collaborate with several domestic top-tier children's nephrology centers to conduct a retrospective real-world study of adolescent PNS. The aim is to understand the current diagnosis and treatment status of adolescent PNS and compare the advantages and disadvantages of various therapies, in order to provide a more scientific, rational, and effective treatment plan for adolescent PNS.

Inclusion Criteria:

1. Clinical diagnosis met the criteria for PNS from January 2014 to December 2023 (①Nephrotic-range proteinuria: 24-h urine protein ≥50 mg/kg or morning urine protein/creatinine (mg/mg) ≥2.0, three consecutive morning urine protein tests (＋＋＋) to (＋＋＋＋) within 1 week. ②Hypoproteinemia: serum albumin <25 g/L. ③Hyperlipidemia: serum cholesterol >5.7 mmol/L. ④Edema to varying degrees. Among the above four criteria, 1 and 2 are essential for diagnosis.);
2. Regular follow-up for at least 1 year;
3. Compliance with the requirements of the revised Helsinki Declaration of 2013, with informed consent obtained from patients and their families.

Exclusion Criteria:

1. Nephrotic syndrome secondary to other diseases;
2. Patients requiring dialysis or after kidney transplantation;
3. Presence of genetic defects or hereditary metabolic diseases;
4. Concurrent with severe primary diseases such as cardiovascular, liver, brain, hematopoietic system diseases, or mental disorders;
5. Incomplete clinical data.

Clinical data of PNS patients aged 10-18 years who met the diagnostic criteria for pediatric PNS established by the Pediatric Nephrology Group of the Chinese Medical Association in 2016, from multiple medical institutions over the past decade.