Low vitamin C concentrations and prognosis in critically ill children

The administration of high-dose vitamins has been focused on in critically ill patients as adjunctive therapy for life-threatening conditions. We evaluated the association between serum vitamin C concentrations and patient prognosis. We retrospectively reviewed and collected clinical and biochemical data, including thiamine and vitamin C levels, of patients admitted to the pediatric intensive care unit (PICU). In total, 177 patients were admitted to the PICU during the study period, and 63 children were enrolled in this study. The most common reason for PICU admission was sepsis (33.3%). The median thiamine and vitamin C levels were 3.6 µg/dl (interquartile range [IQR], 2.9-4.5 µg/dl) and 2.84 µg/ml (IQR, 1.61-4.55 µg/ml), respectively. Thiamine deficiency was observed in 10 patients (15.9%), and 17 (27.0%) had vitamin C deficiency. There were no differences in the vitamin levels according to the reason for PICU admission. Vitamin C levels were affected by nutritional status. The length of stay in the PICU and duration of mechanical ventilation were longer in patients with vitamin C deficiency than in those without (P=0.035 and P=0.010, respectively). The serum delta neutrophil index and C-reactive protein and lactate levels increased in the vitamin C-deficient group (P=0.028 and P=0.039, respectively). There was a significant difference in Pediatric Index of Mortality 3 scores according to vitamin C levels but not in mortality directly. Vitamin C deficiency was associated with elevated inflammatory marker levels, increased mechanical ventilation durations, and PICU admission. Our results support the potential benefits of vitamin C administration in critically ill children.