Background: Biomarkers play an important role in COVID-19, and more research in this regard is needed, especially in the case of children. This study aimed to look for a link between the C reactive protein (CRP), lactate dehydrogenase (LDH), creatine kinase (CK), vitamin D and COVID-19 in pediatric patients.
Methods: This is a retrospective cohort study, performed on children diagnosed positively with COVID-19 at a children's hospital in western Romania. Available CRP, LDH, CK vitamin D and clinical severity were recorded. For each biomarker, groups were formed by patients' age. Mean/median group differences were assessed using Student's t test or Mann-Whitney and Kruskal-Wallis with Dunn's post hoc tests. Association was assessed using the chi2 test, while correlation was assessed using Spearman's rank correlation.
Results: 181 positive children were studied between 1 August 2021 and 1 February 2022. Average age was 8.76 years (SD = 3.93). There were 94 (51.93%) males and 87 (48.07%) females. The cases were: 62 asymptomatic (34.25%), 107 mild (59.12%), 9 moderate (4.97%), 3 severe (1.66%). Regarding CRP, a significant difference between older and younger patients was observed (p = 0.0034). Clinical severity was associated with CRP (p = 0.0281), LDH (p = 0.0410) and vitamin D (p = 0.0444). Regarding CK, no differences or associations proved significant. Correlation testing was conducted for CRP, LDH, vitamin D and clinical signs. With the exception of LDH-CRP and LDH-vitamin D, all relationships proved statistically significant.
Conclusions: CRP, LDH and vitamin D levels are important biomarkers for COVID-19-positive pediatric patients, while CK was mostly within normal ranges.
Keywords: C reactive protein; COVID-19; SARS-CoV-2; children; creatine kinase; lactate dehydrogenase; vitamin D.