(826) Pertussis Hospitalizations and Complications in Infants From 1997 to 2019

Introduction: Vaccine hesitancy and misinformation have led to outbreaks of pertussis and its effect on national prevalence of pertussis-associated hospitalization is unknown. We aimed to analyze trends in the prevalence of pertussis hospitalization and associated complications and outcomes in infants in the U.S.

Methods: A retrospective analysis using the Healthcare Cost and Utilization Project’s Kids’ Inpatient database from the years 1997 to 2019 was performed. Hospitalized children from 1 month to 1 year with a diagnosis of pertussis were selected using the respective ICD-9 and ICD-10 codes. Univariate and multivariate analysis was performed using SPSS. Results are presented as an odds ratio with 95%CI. Analyses were performed to evaluate the trend of prevalence of pertussis and mortality rate. Continuous variables are presented as median with interquartile ranges.

Results: During the study period, 17,251 children had a diagnosis of pertussis out of total discharges of 2,371,050 infants with a prevalence of 0.7%. The prevalence decreased from 1.09% in 1997 to 0.32% in 2019 (p < 0.001). However, the case fatality rate was 0.5% with no significant trend. In comparison to other hospitalizations, children with pertussis were predominantly Hispanic (33.9% vs. 27.1%), female (50.1% vs. 46.2%), had government insurance (63.0% vs. 49.4%), and were from lower-income groups (34.2% vs. 29.8%) (p < 0.05). In infants with pertussis, pulmonary hypertension was observed in 0.5%, while 4.8% required invasive mechanical ventilation (IMV), 0.5% needed ECMO, and 0.03% underwent plasmapheresis. On binary logistic regression analysis, mortality was associated with IMV (10.2%, OR=72.6, 95%CI: 31.2-168.9), pulmonary hypertension (36.0%, OR=4.0, 95%CI: 1.8-8.6), ECMO (61.4%, OR=33.1, 95%CI: 16.3-67.2), and cardiac arrest (38.2%, OR=18.0, 95%CI: 8.8-36.5). The median length of stay was 4 days (IQR: 2-7). However, it was higher in those requiring IMV (16 days (IQR: 9-27); p< 0.001).

Conclusions: From 1997 to 2019, we observed a downtrend in infants hospitalized with pertussis but the case fatality rate has remained the same. Pertussis is more prevalent in females, lower-income groups, and the Hispanic population. The development of pulmonary hypertension in infants with pertussis carries a high risk for mortality.