Serum procalcitonin as a predictor of severity of pneumonia in under-five children: A prospective observational study

Abstract

BACKGROUND

Despite recent advancements in healthcare facilities, the early identification and assessment of pneumonia severity remain major challenges that affect clinical outcomes. These challenges emphasise the necessity for reliable biomarkers that can predict disease severity promptly and precisely. Unlike other markers like C-reactive protein or white blood cell count, procalcitonin (PCT) levels specifically increase in bacterial infections, which are a common cause of severe pneumonia in children.

AIM

To evaluate the predictive value of serum PCT in assessing pneumonia severity and clinical outcomes in under-five children.

METHODS

This prospective observational study was conducted in a tertiary care teaching hospital in Eastern India from August 2022 to July 2024. Children aged 2 to 59 months admitted with pneumonia underwent serum PCT estimation on day 1 and day 5 of admission. The pneumonia severity was classified as follows: (1) Very severe (intubation, shock, or death); (2) Severe (intensive care admission without very severe features and/or high-flow nasal canula); (3) Moderate (hospitalization without very severe or severe features); and (4) Mild (discharge). Correlation analysis and receiver operating characteristic (ROC) curve analysis were performed to assess the predictive utility of PCT.

RESULTS

Two hundred children were included. Majority were < 6 months of age, and male (64%). Children in the viral pneumonia group were significantly younger. The pneumonia severity was as follows: (1) Very severe (18%); (2) Severe (24.5%); and (3) Moderate (57.5%). Eighteen (9%) children died. On day 1, the mean ± SD level of serum PCT level for different pneumonia severity was as follows: (1) Moderate (0.47 ± 0.42); (2) Severe (2.04 ± 1.5); and (3) Very severe (4.29 ± 2.37). The differences across the groups were statistically significant (P < 0.01). By day 5, the pattern of increasing PCT levels with greater disease severity persisted: (1) Moderate (0.26 ± 0.18); (2) Severe (3.14 ± 4.1); and (3) Very severe (9.51 ± 3.62). The differences observed on day 5 were statistically significant (P < 0.01). PCT levels were significantly higher in bacterial pneumonia compared to viral and atypical pneumonia. On day 1, the AUC of PCT in predicting mortality was 0.946 (95%CI: 0.905-0.973), and on day 5, the AUC was 0.948 (95%CI: 0.908-0.975).

CONCLUSION

The present study found that serum PCT can predict pneumonia severity including mortality in under-five children. The PCT elevation was significantly higher in bacterial pneumonia compared to viral and atypical pneumonia.

Keywords: Biomarker; Etiology; Lower respiratory tract infection; Pediatric; Bacterial pneumonia; Atypical pneumonia

Core Tip: Severe pneumonia in children is commonly caused by bacteria. Unlike C-reactive protein, procalcitonin (PCT) levels specifically increase in bacterial infections. In this study, we included 200 children with pneumonia and investigated the role of PCT in predicting the severity and mortality due to pneumonia. The serum PCT level paralleled with the severity of pneumonia, and the day 5 level was higher than the day 1 level. PCT elevation was significantly higher in bacterial pneumonia compared to viral and atypical pneumonia. A higher level of PCT on day 5 predicted a longer duration of antibiotics use, prolonged hospitalization, and increased mortality.