CORRELATION BETWEEN URINARY CASTS ANDBIOCHEMICAL MARKERS OF RENAL FUNCTION IN CHILDREN WITH ACUTE GLOMERULONEPHRITIS

Abstract

BACKGROUND:Acute glomerulonephritis (AGN), particularly post-streptococcalglomerulonephritis (PSGN), remains a significant cause of pediatric renal morbidity in Pakistan,especially in rural and low-income urban communities where overcrowding, poor sanitation, andlimited access to healthcare prevail. Urinary sediment analysisparticularly the presence of red bloodcell (RBC) castsis a key diagnostic indicator, while serum creatinine and blood urea serve as standardbiochemical markers of renal dysfunction. However,the quantitative correlation between urinarycast types and the severity of renal impairment in Pakistani children has not been systematicallyevaluated.
OBJECTIVE:To assess the correlation between urinary casts (RBC and granular) and biochemicalmarkers of renal function (serum creatinine and blood urea) in children diagnosed with AGN at atertiary care hospital in Lahore, Pakistan.
MATERIALS AND METHODS:A prospective observational study was conducted atTheChildren Hospital and the Institute of Child Health, Multan, from January 2023 to December 2024.Sixty-five children aged 2–12 years with confirmed AGN were enrolled. Diagnosis was based onclinical features (hematuria, edema, hypertension) and evidence of recent streptococcal infection
(elevated ASO titer, skin or throat infection). Urine microscopy for casts, serum creatinine, and bloodurea were measured at admission. Statistical analyses included Pearson’s correlation, independent t-tests, and linear regression (p < 0.05 considered significant).

RESULTS:RBC casts were present in 72.3% of patients, granular casts in 7.7%, and no casts in20.0%. Elevated blood urea (>40 mg/dL) was observed in 32.3% of cases; serum creatinine >1.0mg/dL in 10.8%.
A strong positive correlation existed between RBC casts and blood urea (r = 0.64, p < 0.001) andserum creatinine (r = 0.59, p = 0.001). Mean blood urea was significantly higher in RBC cast-positivepatients (49.2 ± 13.1 mg/dL vs. 31.8 ± 10.2 mg/dL; p < 0.001). Similarly, mean serum creatinine waselevated in this group (1.14 ± 0.33 mg/dL vs. 0.82 ± 0.20 mg/dL; p = 0.002). Granular casts correlatedmoderately with azotemia but were infrequent.
CONCLUSION:The presence of RBC casts strongly correlates with impaired renal function inPakistani children with AGN, underscoring their value as a bedside predictor of disease severity.Early identification of casts in urine sediment can guide timely intervention and monitoring inresource-limited settings.