Outcomes of Vaccine-preventable Pneumonia in Pediatric Patients with Congenital Heart Disease

Background: Congenital heart disease (CHD) occurs in about 1% of all newborns. Higher cardiopulmonary demand as well as impaired lung function often associated with CHD leave these children more vulnerable to pneumonia. Vaccinations have proven effective in preventing several types of pneumonia, including those caused by Streptococcus pneumoniae, Haemophilus influenzae, and influenza. However, there is a lack of studies reporting how CHD affects cases of pneumonia. Thus, we set out to assess the impact of CHD on vaccine-preventable pneumonia incidence, morbidity, and mortality. We hypothesized that children with CHD would show increases in each of these metrics due to their more vulnerable physiological states.

Methods: We analyzed retrospective, cross-sectional data from the Kids’ Inpatient Database (KID) published from 2003-2016. Approval from the institutional review board was not needed as data have been de-identified. The analysis was restricted to children above 1 year of age admitted with a diagnosis of pneumonia from vaccine-preventable sources such as Streptococcus pneumoniae, Haemophilus influenzae, or Influenza (N = 47,242). Information on CHD diagnosis, pneumonia hospitalizations, all-cause mortality, length of stay, and other comorbidities were analyzed. We developed weighted-adjusted logistic regression models adjusted for age, sex, race/ethnicity, chromosomal anomalies, respiratory tract anomalies, and musculoskeletal anomalies.

Results: Out of the 47,242 pediatric pneumonia cases within the sample group, 1,026 children (2%) had a diagnosis of CHD. After adjusting for age, sex, race/ethnicity, and anatomical or chromosomal anomalies, this cohort did not have a greater overall risk of hospitalization due to pneumonia (aOR 0.94, 95% CI: 0.84-1.03). A sub-group analysis showed that there was a significantly increased risk of hospitalization from pneumonia due to Haemophilus influenzae (aOR 2.1, 95% CI: 1.6-2.7) and a slightly decreased risk from influenza (aOR 0.85, 95% CI: 0.75-0.96) and Streptococcus pneumoniae (aOR 0.9, 95% CI: 0.77-1.04). The risk of mortality increased in children with CHD (aOR 3.1, 95% CI: 1.8-5.2). Length of stay was increased in children with CHD (IQR: 3-15 days) compared to those without CHD (IQR: 2-7 days). The CHD cohort also experienced an increased frequency of comorbidities such as respiratory failure (aOR 1.9, 95% CI: 1.5-2.3), acute kidney injury (aOR 2.8, 95% CI: 1.9-4.3), and sudden cardiac arrest (aOR 3.8, 95% CI: 1.8-7.7) when compared to those without CHD. Children with CHD also more frequently required advanced cardiopulmonary support such as mechanical ventilation (aOR 2.5, 95% CI: 2.1-3.0) and ECMO (aOR 3.9, 95% CI: 1.6-9.8).

Conclusion: CHD in children increases the hospitalization risk of pneumonia caused by Haemophilus influenzae. Children with CHD who are hospitalized due to pneumonia are at greater risk for comorbidities, advanced cardiopulmonary support, and mortality. This study emphasizes the need for increased clinical surveillance as well as increased advocacy in cases of vaccine hesitancy.