Single-dose azithromycin for infant growth in Burkina Faso: Prespecified secondary anthropometric outcomes from a randomized controlled trial.

Background: Antibiotic use during early infancy has been linked to childhood obesity in high-income countries. We evaluated whether a single oral dose of azithromycin administered during infant-well visits led to changes in infant growth outcomes at 6 months of age in a setting with a high prevalence of undernutrition in rural Burkina Faso. Methods and findings: Infants were enrolled from September 25, 2019, until October 22, 2022, in a randomized controlled trial designed to evaluate the efficacy of a single oral dose of azithromycin (20 mg/kg) compared to placebo when administered during well-child visits for prevention of infant mortality. The trial found no evidence of a difference in the primary endpoint. This paper presents prespecified secondary anthropometric endpoints including weight gain (g/day), height change (mm/day), weight-for-age Z-score (WAZ), weight-for-length Z-score (WLZ), length-for-age Z-score (LAZ), and mid-upper arm circumference (MUAC). Infants were eligible for the trial if they were between 5 and 12 weeks of age, able to orally feed, and their families were planning to remain in the study area for the duration of the study. Anthropometric measurements were collected at enrollment (5 to 12 weeks of age) and 6 months of age. Among 32,877 infants enrolled in the trial, 27,298 (83%) were followed and had valid anthropometric measurements at 6 months of age. We found no evidence of a difference in weight gain (mean difference 0.03 g/day, 95% confidence interval (CI) −0.12 to 0.18), height change (mean difference 0.004 mm/day, 95% CI −0.05 to 0.06), WAZ (mean difference −0.004 SD, 95% CI −0.03 to 0.02), WLZ (mean difference 0.001 SD, 95% CI −0.03 to 0.03), LAZ (mean difference −0.005 SD, 95% CI −0.03 to 0.02), or MUAC (mean difference 0.01 cm, 95% CI −0.01 to 0.04). The primary limitation of the trial was that measurements were only collected at enrollment and 6 months of age, precluding assessment of shorter-term or long-term changes in growth. Conclusions: Single-dose azithromycin does not appear to affect weight and height outcomes when administered during early infancy. Trial registration: ClinicalTrials.govNCT03676764 Ali Sié and colleagues present pre-specified anthropometric outcomes from a randomized controlled trial that assessed the impact of a single-dose of oral azithromycin on infant mortality in Burkina Faso. Author summary: Why was this study done?: Antibiotics have been linked to obesity in children in nonrandomized studies in high-income settings. In low-income settings, malnutrition is a strong risk factor for child mortality, and interventions that increase weight gain may be beneficial. Single-dose azithromycin has previously been shown to reduce child mortality in sub-Saharan Africa, and it is possible that some of this effect is via weight gain. Why did the researchers do and find?: We conducted a randomized controlled trial in which infants aged 5 to 12 weeks were randomly assigned to a single dose of azithromycin or a matching placebo. The primary outcome of the parent trial was all-cause mortality, and the trial found no evidence of a benefit of azithromycin for prevention of mortality. Infants were followed until 6 months of age and had anthropometric measurements, including height, weight, and mid-upper arm circumference, collected. We found no evidence of a difference in any anthropometric endpoint in infants randomized to azithromycin compared to placebo. What do these findings mean?: Single-dose azithromycin does not appear to affect growth when administered to healthy infants who are 5 to 12 weeks of age. Growth outcomes were only measured at 6 months of age, and thus, any shorter or longer-term effects of azithromycin would not be detected by this study. This study only considered a single dose of azithromycin, as is used for prevention of child mortality and trachoma, and thus, it is possible that higher doses or longer duration of antibiotics could have a different effects on child growth. [ABSTRACT FROM AUTHOR]