Evidence Hub

Evaluating the antibiotic spectrum index in a stewardship-focused clinical trial for childhood pneumonia

Carro SE, Gargurevich N, Sekmen M, Suresh S, Martin JM, Williams DJ

Infection control and hospital epidemiology, 2025

Abstract

Objective: The antibiotic spectrum index (ASI) outcome quantifies antibiotic exposure based on spectrum of activity. Our objective was to examine ASI as an exploratory outcome in the context of a recent stewardship-focused, clinical trial in childhood pneumonia that originally used a binary guideline-concordant outcome.

Design: Secondary analysis of a randomized clinical trial.

Setting: Two tertiary pediatric hospitals.

Methods: Encounters were randomly assigned to clinical decision support (CDS) or usual care treatment arm. The ASI was calculated by summing daily ASI scores for each unique antibiotic administered. It was evaluated as a continuous and ordinal measure: No Antibiotics (ASI = 0), Narrow (1-2), Intermediate (3-4), Broad (5-7), and Very Broad (≥8). Proportional odds regression modeled the ordinal ASI outcome in the first 24 hours by treatment arm and compared to the guideline-concordance outcome. Results were stratified by emergency department (ED) disposition. We also conducted a longitudinal, descriptive analysis of day-to-day ASI for those with in-hospital dispositions.

Results: We included 1027 encounters, 549 (53%) were randomized to CDS and 478 (47%) usual care respectively. ASI Category did not differ by treatment arm overall (Odds Ratio: 0.88[95% Confidence Interval: 0.70,1.09]), which mirrored binary guideline-concordance. Mean ASI was lower for concordant encounters (2.1 vs 8.4, P < 0.001) and across all ED dispositions. In the longitudinal analysis,…

How strong is the evidence?

Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 2 of 5 (High · randomized trial). Randomized trials of a reasonable size are the strongest single-study design.

How the five levels of evidence work. The level is assigned automatically from the abstract and can be wrong, so check the paper.

Read the paper

Related studies

Go deeper in Evidence Hub

Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.

Open this study Sign up free