Obesity as a Risk Factor in Pediatric Sepsis: A Retrospective Comparative Study Under the Phoenix Definition

<b>Background:</b> The relationship between sepsis outcomes and obesity has attracted significant interest in the medical community. However, this association has not been tested under Phoenix criteria, which represent the new pediatric sepsis definition, defining sepsis as life-threatening organ dysfunction in the setting of infection. <b>Methods:</b> A single-center, observational, retrospective study of pediatric sepsis patients from January 2014 to December 2019. The PICU was located within a tertiary pediatric center in the United States. Children more than one month old, but less than 18 years old, with a diagnosis of sepsis were included. <b>Results:</b> Six hundred and twenty-seven patients with a diagnosis of sepsis based on the Sepsis-2 definition were identified. Within the cohort, 554 patients met the definition of sepsis under the Phoenix criteria. Patients were classified based on the body habitus as underweight, normal, overweight, and obese. Obese patients had significantly higher mortality compared to the normal weight group (<i>p</i> = 0.033). More renal dysfunction was also seen in the obesity group (<i>p</i> = 0.0007). No difference in the frequency of identified Gram-positive, Gram-negative bacterial, viral, or fungal sepsis was observed between normal-weight and obese patients. <b>Conclusions:</b> In our cohort of pediatric sepsis, obesity was significantly associated with a higher degree of organ dysfunction and mortality. However, no difference in the incidence of identified bacterial, fungal, or viral sepsis was observed.