Background

Pneumonia kills more children than other infectious diseases, especially in children under five. Although the implementation of safe, effective, and affordable interventions has reduced pneumonia mortality from four million in 1981 to just over one million in 2013, pneumonia still accounts for nearly one-fifth of childhood deaths worldwide. Almost 808,000 children died from pneumonia in 2017, accounting for 15% of child deaths globally, with more than 90% occurring in develo** countries [1]. Based on Indonesia Health Profile Report in 2020, pneumonia, besides diarrhea, is one of the causes of high infant (14.5%) and toddler (5.05%) mortality in Indonesia [2].

The World Health Organization (WHO) has classified childhood community-acquired pneumonia (CAP) by clinical characteristics, dividing them into non-severe and severe pneumonia. WHO defines non-severe pneumonia in children as the presence of cough or difficulty breathing associated with fast breathing or chest indrawing in children 2–59 months of age. Severe pneumonia is defined as pneumonia plus the inability to drink, persistent vomiting, convulsions, lethargy, stridor, or severe malnutrition [1]. Studies show that clinical definitions of severity correlate with case fatality rates. Most childhood pneumonia deaths are due to severe pneumonia [3].

Case management is one of the cornerstones of CAP management strategies [4]. Early identification of cases using simple clinical signs and appropriate treatment is needed. Recognizing the risk for the severe outcome is essential to further morbidity and mortality. Identifying children at risk of pneumonia-related mortality could signal the need for closer monitoring, hospital admission, or more intensive therapy [34] and may be more appropriate for identifying children at risk of increased mortality.

Underweight or wasting are nutritional conditions associated with the severity of pneumonia [33]. Although the WHO classification does not include malnutrition, several risk scores to identify children at risk of hospitalized pneumonia-related mortality, such as the Respiratory Index of Severity in Children (RISC) [7], the RISC-Malawi [8], and the Pneumonia Etiology Research for Child Health (PERCH) [9], include malnutrition in their scoring systems. Agweyu et al. [18] find that children classified with non-severe pneumonia with a weight-for-age Z score of less than − 3 standard deviation are associated with a 3.8 times mortality risk.

There are several limitations to our study. Firstly, our study is a retrospective cohort study. Therefore, we could not control for some variables such as birth weight, parental smoking status, or immunization status, which may play a role in determining the severity status of childhood CAP. Secondly, our study is based on two hospitals where the catchment area of pneumonia cases may not be comprehensive. However, the nature of the two differing hospitals means that we could include children from various background demographics, ensuring that children from low- and middle-income parents and high-income parents are included in this study. Lastly, some variables are underpowered for analysis due to missing data (such as oxygen saturation) or laboratory data that were not analyzed. This reason may explain why some of the variables are insignificant, while other studies have identified hypoxemia [20] and CRP [35] as predictors of severe pneumonia.

Conclusion

Our study attempts to elucidate some of the factors associated with severe pneumonia. We find that fever lasting > 7 days and an increase in RR are predictors of severe pneumonia. At the same time, a normal hematocrit level and a normal BMI are protective factors for severe pneumonia. These findings suggest that an increase in RR should not be used only to diagnose pneumonia but should also determine the severity of pneumonia. While the revised WHO classification does not include fever duration as a component for severe pneumonia, clinicians should be wary of childhood CAP cases with fever lasting > 7 days.