Clinical manifestations and proportions of severe outcomes in pediatric acute post-streptococcal glomerulonephritis: a systematic review and meta-analysis of predominantly hospital-based cohorts.

Objective: To systematically evaluate the proportions of major clinical manifestations and severe outcomes in children with acute post-streptococcal glomerulonephritis (APSGN). Methods: PubMed, Embase, Web of Science, the Cochrane Library, Scopus, and ClinicalTrials.gov were systematically searched for observational studies reporting clinical manifestations or outcomes of APSGN in children. Outcomes of interest included hypertension, gross hematuria, study-defined AKI/acute kidney dysfunction, nephrotic-range proteinuria, severe complications, an exploratory RPGN/crescentic-lesion composite (rapidly progressive glomerulonephritis and/or crescentic lesions), and renal replacement therapy (RRT). Random-effects single-proportion meta-analyses were performed to estimate pooled proportions and 95% confidence intervals (CIs). Robustness was assessed using heterogeneity and sensitivity analyses, with funnel plots and Egger's regression used to evaluate possible small-study effects. Results: Eighteen studies involving 2,191 children were included, predominantly from APSGN cohorts, with some studies using broader acute glomerulonephritis (AGN) or postinfectious glomerulonephritis (PIGN) definitions. Across these predominantly hospital-based cohorts, hypertension was the most commonly reported clinical manifestation, with a pooled proportion of 65.0% (17 studies, 2,164 children; 95% CI, 53.3%-79.2%). The pooled proportions of gross hematuria, study-defined AKI/acute kidney dysfunction, and nephrotic-range proteinuria were 47.5% (14 studies, 1,665 children; 95% CI, 34.0%-66.4%), 40.1% (18 studies, 2,173 children; 95% CI, 28.4%-56.7%), and 35.9% (11 studies, 887 children; 95% CI, 26.2%-49.0%), respectively. The pooled proportions of severe complications, the exploratory RPGN/crescentic-lesion composite, and RRT were 12.9% (16 studies, 1,722 children; 95% CI, 8.2%-20.3%), 12.9% (10 studies, 699 evaluable children; 95% CI, 4.1%-40.8%), and 4.0% (15 studies, 1,465 children; 95% CI, 1.4%-11.2%), respectively. The exploratory composite combined three clinically defined RPGN entries with seven crescentic-lesion entries and should not be interpreted as the prevalence of either clinical RPGN or crescentic glomerulonephritis separately. Significant between-study heterogeneity was observed for all outcomes (I Conclusion: Hypertension, gross hematuria, study-defined AKI/acute kidney dysfunction, and nephrotic-range proteinuria were commonly reported across the predominantly hospital-based cohorts, whereas RRT and severe complications were reported less often. The heterogeneous exploratory RPGN/crescentic-lesion composite should not be interpreted as the prevalence of either clinical RPGN or crescentic glomerulonephritis separately. Given the clinically heterogeneous evidence base and substantial statistical uncertainty, these pooled proportions summarize published clinical cohorts and are not stable population-level frequencies applicable to all children with APSGN. Close monitoring of blood pressure, volume status, and kidney function is warranted during the acute phase. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/view/CRD420261464457. PROSPERO CRD420261464457.