Association of Multimorbidity in Children Undergoing Ambulatory Surgical Procedures With Same‐Day Admissions

Background Chronic health conditions affect approximately 27% of children in the United States and about 1 in 15 has multimorbidity (MM), defined as the coexistence of two or more chronic conditions. Despite its prevalence, the effect of MM on outcomes after ambulatory surgery remains poorly understood. Hospital admission following a scheduled outpatient procedure is an important measure of perioperative quality and safety. We therefore aimed to estimate the prevalence of MM among children scheduled for elective ambulatory surgery and to evaluate its association with same‐day hospital admission. Methods We conducted a retrospective cohort study using the multicenter Pediatric Health Information System (PHIS) database (2010–2022). We included children aged 2–18 years undergoing elective, non‐otolaryngologic ambulatory surgery. MM was defined using complex chronic conditions and categorized as no chronic condition, mild–moderate MM (1–2 conditions), or severe MM (≥ 3 conditions). The primary outcome was same‐day hospital admission, defined as hospital length of stay ≥ 1 day among children who were scheduled for ambulatory surgery. Logistic regression estimated odds ratios (ORs) and 95% confidence intervals (CIs), adjusting for sex, age, insurance status, and procedural group. Results Among 1 609 584 children who underwent outpatient surgery, 7.6% ( n = 126 403) had MM, including 6.9% ( n = 111 090) with Mild–moderate MM and 0.7% ( n = 15 313) with severe MM. Same‐day admission occurred in 4.1% (60 576/1483181) of children without MM, 10.0% (11 131/111090) with mild–moderate MM, and 11.1% (1699/15313) with severe MM. Compared with children without MM, adjusted odds of same‐day admission were higher for mild–moderate MM (OR: 1.94; 95% CI: 1.90–1.99) and severe MM (OR: 2.30; 95% CI: 2.18–2.43). Conclusions MM is prevalent among pediatric ambulatory surgical patients. Children with MM have higher rates of same‐day hospital admission following elective ambulatory surgery compared to their peers, a factor that should be considered in scheduling these patients.