May 15–19, 2023 S63 Abstract citation ID: irad045.080 107 Meta-Analysis of Clinical and Preclinical Microbiome Data from Studies of Burn Injury Timothy Horseman, Andrew Frank, Jefrey Shupp, MD, FACS, David Burmeister, PhD Uniformed Services University of the Health Sciences, Bethesda, Maryland; Uniformed Services University of the Health Sciences, Bethesda, Maryland; Firefghters' Burn and Surgical Research Laboratory, MedStar Health Research Institute, Georgetown University School of Medicine, Washington, DC; Uniformed Services University of the Health Sciences, Bethesda, Maryland Introduction: Following burn injury, the ecology of the host microbiota is disrupted to varying degrees and may leave the patient susceptible to opportunistic pathogens or disrupt the endogenous fora needed to potentiate recovery and home- ostasis. Studies examining the microbiome post-burn injury usually have a limited sample size which, coupled with exper- imental and analysis variation, impacts overall interpretation of data. Methods: We performed a meta-analysis of publicly available sequencing data from burn patients and burn animals to de- termine if there were consistent alterations in the microbiome across various anatomical sites and species. A MEDLINE search was used to identify applicable publications. Corresponding authors of papers without available data were contacted, and data were used if a response occurred. Ten human and animal 16S rRNA sequencing studies spanning respiratory, urinary, cutaneous, and gastrointestinal microbiomes were included. Raw sequencing data were systematically analyzed with taxo- nomic classifcation and α and β diversity metrics generated. Results: Alpha diversity was consistently lower post-burn, except for human skin (Figure 1) due to perianal skin sam- pling of burn patients resulting in higher species richness than controls. Weighted UniFrac distance analysis showed that rodent specimens clustered less closely to humans than pig samples (P < 0.0001) for both rectal and skin samples. Host species (R2 = 0.21, P = 0.001), and institute (R2 = 0.35, P = 0.001) had a signifcant impact on the β diver- sity. In rectal samples, bacterial composition in pig and human burn samples included Bacteroidetes, Firmicutes, and Proteobacteria, while rodent samples were dominated by over 90% Firmicutes. Burns induced an increase of Proteobacteria and a decrease in Bacteroidetes and Firmicutes in pig rectal samples. Proteobacteria and Firmicutes increased on burned skin in each host species. Longitudinal studies revealed a de- crease in α diversity upon burn injury with β diversity and taxa shifts. Conclusions: Overall, our results suggest that host species and the sequencing site strongly infuence microbiome struc- ture. Burn-induced alterations in microbiome diversity and taxa exist across hosts, with certain metrics more infuenced by host. Applicability of Research to Practice: Coordinated, multi- center studies, both clinical and pre-clinical, are needed to truly realize the diagnostic and therapeutic potential of the microbiome for improving outcomes post-burn. Abstract citation ID: irad045.081 108 Efects of Prior Hyperthyroidism Diagnosis on Burn Patient Outcomes Chris Soudah, BSA, Kathleen Karam, BS, Dalton Amador, BA, Isabel Obias, BSA, Amy Arceneaux, BS, Steven Wolf, MD, Juquan Song, MD, Amina El Ayadi, PhD, Georgiy Golovko, PhD Te University of Texas Medical Branch, Galveston, Texas; Te University of Texas Medical Branch, Galveston, Texas; Te University of Texas Medical Branch, Galveston, Texas; Te University of Texas Medical Branch, Galveston, Texas; Te University of Texas Medical Branch, Galveston, Texas; Te University of Texas Medical Branch, Galveston, Texas; Te University of Texas Medical Branch, Galveston, Texas; Te University of Texas Medical Branch, Galveston, Texas; Te University of Texas Medical Branch, Galveston, Texas Introduction: Te metabolic response to severe burns is described by an initial hypometabolic ‘ebb’ phase and followed by a hypermetabolic ‘fow’ phase. Te hypermetabolic phase is mediated by hormonal and cellular dysregulation with elevated catecholamine levels. Te role of thyroid hormone, however, is not described well. Tis study investigates relative risks of var- ious outcomes in those with a previous diagnosis of hyperthy- roidism following severe burn compared to those without. Methods: Tis study obtained data from the TriNetX Research Network, a national database of de-identifed elec- tronic medical data from a secure network. Te population was stratifed to compare patients with and without a prior diagnosis of hyperthyroidism who sustained burns. Outcomes were measured within three years of injury in order to assess long-term efects occurring alongside the hypermetabolic phase. Outcomes observed for both groups included systemic infammation and infection, sepsis, mortality, and infections of the skin and subcutaneous tissue. Results: Tis study identifed 5,250 patients with a prior di- agnosis of hyperthyroidism who sustained burn injuries and 648,336 patients without hyperthyroidism prior to matching for demographics and diagnoses. Propensity score matching then yielded 5,077 patients with and without a prior diagnosis of hyperthyroidism. Both cohorts were balanced using pro- pensity score matching for age, sex, race, ethnicity, and TBSA burned. After assessing the outcomes for a three-year span since burn injury, patients with a prior diagnosis of hyperthyroidism had a higher risk of systemic infammation and infection (risk ratio [RR], 1.599, p < 0.0003), sepsis ([RR], 1.572, p < 0.0001), mortality ([RR], 1.488, p < 0.0001), and devel- oping infections of the skin and subcutaneous tissue ([RR], 1.332, p < 0.0001) compared to patients without prior diag- nosis history. Conclusions: Burned patients with a prior history of hyper- thyroidism have increased risk of systemic infammation and infection, sepsis, mortality, and infections of the skin and sub- cutaneous tissue. Tus, history of this condition or concomi- tant diagnosis with the injury is warranted. Applicability of Research to Practice: Tis study encourages further insight into the relationship between the metabolic efects of burn injuries and concurrent metabolic conditions to modify patient treatment plans and customize practices. Downloaded from https://academic.oup.com/jbcr/article/44/Supplement_2/S63/7162916 by guest on 17 May 2023