Efficacy and safety of 5-day versus 7-day antibiotic therapy for spontaneous bacterial peritonitis in children with idiopathic nephrotic syndrome: an open-label randomized controlled trial.

Spontaneous bacterial peritonitis (SBP) is a life-threatening complication of idiopathic nephrotic syndrome (INS) in children. Evidence on the optimal duration of antibiotics in this population is limited. We investigated whether 5-day antibiotic therapy is non-inferior to 7-day therapy for SBP in children with INS. In this single-center, open-label, randomized controlled non-inferiority trial, 50 children aged 1-14 years with INS and SBP were allocated 1:1 to intravenous ceftriaxone for 5 days (Group A, n = 25) or 7 days (Group B, n = 25). The primary outcome was composite clinical response (resolution of fever, abdominal pain, and tenderness) at the end of treatment, analyzed by intention-to-treat. The pre-specified non-inferiority margin was -15%. Secondary outcomes included bacteriological cure, cytological response, and the need for additional antibiotics. Fifty children [median age 50 (30.8-92) months] were randomized. Composite clinical response was achieved in 25/25 (100%) in Group A versus 22/25 (88%) in Group B (risk difference 12%, 95% CI -3.5% to 30.0%; P = 0.23); the lower CI bound exceeded the -15% non-inferiority margin, establishing non-inferiority. Bacteriological cure was achieved in 96% of both groups. Cytological response (64% vs 72%; P = 0.54) was inconclusive for non-inferiority. Additional or modified antibiotic therapy was required in 16% versus 20% (P = 1.00). Median hospitalization was comparable (10 vs 11 days; P > 0.05). No ceftriaxone-related adverse events were recorded. Five-day intravenous ceftriaxone is non-inferior to 7-day therapy for SBP in children with INS, with respect to composite clinical response; the secondary outcome of cytological response was inconclusive for non-inferiority.