Epidemiology and Clinical Characteristics of Pediatric Acute Postinfectious Glomerulonephritis in Montenegro: A Nationwide Retrospective Study

Acute postinfectious glomerulonephritis (APIGN) remains a leading cause of acute nephritic syndrome in children, particularly in lowand middle-income countries. 1,2Although its incidence has declined markedly in high-income regions, APIGN continues to reflect disparities in socioeconomic status, access to primary healthcare, and the effectiveness of prevention and early treatment of common infectious diseases. [3][4]4][5] Data from the Balkan region are limited, with most studies being single-center or including mixed adult and pediatric populations. [6][7]7][8] To date, no nationwide pediatric data from Montenegro have been reported.We retrospectively reviewed medical records of patients under 16 years of age diagnosed with APIGN and treated at the Institute for Children's Diseases, Clinical Center of Montenegro-the country's only tertiary pediatric referral center-between 2006 and 2022.The study was approved by the Ethical Committee of the Clinical Center of Montenegro (approval number 03/01-6507/1, date: 21.03.2025).Because all children in Montenegro requiring hospital-based nephrology care are treated at this facility, this cohort provides a comprehensive overview of the national pediatric burden of APIGN.Clinical, laboratory, and demographic data were extracted from medical records.Diagnosis was based on evidence of acute nephritic syndrome following a documented infection. 1,5 total of 64 children were included.Based on an estimated pediatric population of 100,000-120,000, the average annual incidence was approximately four cases per 100,000 children, consistent with other middle-income countries and substantially higher than rates reported in high-income regions. 2,9Most patients were boys (73%), with a median age of 7.8 years.APIGN was uncommon in children under three years, consistent with previous observations that immune