Factors Associated with Long COVID in the Pediatric Population: A Retrospective Case-Control Study.

Background

Long COVID in children is increasingly recognized, yet its clinical predictors and objective biological correlates remain insufficiently characterized.

Objectives

The objective was to compare clinical, demographic, and laboratory characteristics between children with and without long COVID and to identify associated variables.

Methods

We conducted a retrospective observational case-control study at the "Dr. Victor Gomoiu" Children's Clinical Hospital, including pediatric patients with confirmed SARS-CoV-2 infection. Cases were defined as children with symptoms persisting ≥12 weeks after acute infection, while controls had no persistent symptoms at ≥12 weeks.

Results

Eighty-nine children with long COVID and 88 matched controls were included. Children with long COVID were significantly older (1.79 ± 0.90 vs. 1.14 ± 0.80 years, p < 0.001) and more frequently from urban areas (86.5% vs. 69.3%, p = 0.0099). Lymphocyte, monocyte, and basophil counts were significantly lower in the Long COVID group, while D-dimer, ferritin, serum iron, urea, and creatinine levels were significantly higher. A multivariate predictive model demonstrated excellent discrimination (AUC = 0.94), with optimal sensitivity (84.3%) and specificity (89.8%) at a probability threshold of 0.48.

Conclusions

Long COVID in children was associated with identifiable clinicobiological features. An exploratory composite model showed good discrimination but requires external validation.