185 - POST-ADMISSION ANTIBIOTICS USE AND RISK OF IVIG RESISTANCE IN PATIENTS WITH KD AND MIS-C

Background: Antibiotics are often prescribed empirically or for concomitant infection during admission for KD or MIS-C. As these are inflammatory diseases, not associated with bacterial infection, the risk/benefit of antibiotics for these patients remains unclear.

Methods: Patients meeting the criteria for either confirmed KD or MIS-C, admitted between 2020-2022, were enrolled in an international multicenter observational cohort study performed by the International KD Registry. The odds of IVIG resistance, defined as persistent or recurrent fever >2 days after initiation of IVIG, were compared between patients receiving post-admission antibiotics versus no-antibiotics. A multivariable logistic regression model for IVIG resistance including various classes of antibiotics and potential confounding factors, including concomitant infection, was created using a stepwise variable selection algorithm.

Results: We compared 388 who received antibiotics to 306 patients who did not (365 KD; 329 MISC). The majority (61%) of patients receiving antibiotics received beta-lactams. Patients with antibiotics were generally older (median 5.8 vs. 3.2 years, p< 0.001) but had shorter symptom duration prior to admission (5.2±3.4 vs. 6.1±4.0 days, p=0.001) and shorter time from admission to IVIG treatment (0.8±0.9 vs. 1.0±1.3 days, p=0.009). They also exhibited fewer classic KD criteria (2.5±1.4 vs. 3.1±1.4, p< 0.001) and higher CRP at admission (mean: 121 vs. 85 mg/L, p< 0.001). IVIG resistance in patients receiving antibiotics (27.5%) was significantly higher than in those not receiving antibiotics (19.9%) (p=0.009). In multivariable logistic regression models, treatment with multiple classes of antibiotics were associated with IVIG resistance including: clavulanic acid (OR:3.6, 95%CI:1.0-13.2, p=0.06), carboxypenems (OR:1.8, 95%CI:1.8-17.9) and lincomycins (OR:3.4, 95%CI:1.6-7.2). Other classes of antibiotics (lactams, glycopeptides, macrolides, tetracycline) were not associated with increased risk. Statistically significant covariates included the number of days between admission and treatment, complete vs. incomplete KD and BNP at admission. Being on antibiotics prior to admission was not significantly associated with the odds of IVIG resistance. These associations held true when patients with KD and MIS-C were analyzed separately.

Conclusions: The administration of some classes of antibiotics concurrent to IVIG were associated with increased odds of IVIG resistance. These data reflect the practice of empiric antibiotic treatment for inflammatory diseases in children. However, these data support that empiric post-admission treatment with certain classes of antibiotics does not provide benefit and might confer increase risk of IVIG failure.