Effect of eligibility for referral following mass screening for severe acute malnutrition using mid-upper arm circumference: A prospective regression discontinuity design

Background Severe Acute Malnutrition (SAM) is a major cause of morbidity and mortality in children under five. Mid-upper arm circumference (MUAC) is widely used for community screening, but the effect of referral eligibility on subsequent outcomes is uncertain. Objective This study assesses the intention-to-treat effect of eligibility for referral to a nutritional program, triggered by MUAC below 11.5 cm, on subsequent nutritional status and all-cause mortality among children in Burkina Faso. Methods A prospective regression discontinuity (RD) analysis was nested within the Community Health with Azithromycin Treatment (CHAT) trial, a cluster-randomized controlled trial in Nouna District, Burkina Faso (ClinicalTrials.gov NCT03676764). Children aged 6–59 months were screened during twice-yearly censuses; MUAC <11.5 cm triggered a referral recommendation. Because treatment uptake was unmeasured, the estimand was referral eligibility, not treatment receipt. Outcomes were MUAC at the next census and death before that census. Primary analyses used outcome-specific Imbens–Kalyanaraman bandwidths and mixed-effects models with a child random intercept. Results Among 65,554 children, 226 (0.34%) met the referral threshold at least once. The selected bandwidth included 2,901 observations for the MUAC outcome (158 below and 2,743 above the cutoff) and 2,628 observations for mortality (148 below and 2,480 above). The estimated mean difference in MUAC at the cutoff was 0.21 cm (95% CI, −0.22 to 0.65), and the mortality odds ratio was 0.95 (95% CI, 0.03 to 31.37). Most sensitivity analyses were similar, although the widest fixed bandwidth produced discordant and unstable estimates. Conclusions Near the 11.5-cm cutoff, we found no evidence that referral eligibility changed next-census MUAC or all-cause mortality. These findings do not evaluate SAM treatment receipt or effectiveness, and the mortality estimate was highly imprecise. Stronger mechanisms may be needed to complete referral and link children to treatment.