Background: Many children are affected by pneumonia and its complications annually, despite the fact that there are several known risk factors; vitamin D deficiency may play a role in this disease. 

Objective: The aim of this study was to determine the efficacy of vitamin D supplementation in Respiratory Index of Severity in Children (RISC) hospitalized clinical outcomes of hospitalized patients with community-acquired pneumonia.

Methods: This randomized double-blind clinical trial was conducted on children from 2 months to 6 years old with pneumonia, hospitalized at Bandar Abbas Pediatric Hospital of Iran between January 2015 and 2016. Children were randomly divided into two groups of A: received vitamin D (at a dose of 50,000 IU per day for 2 days) in addition to routine treatment of pneumonia, and B: received placebo instead of vitamin D. The primary outcome was RISC alterations before and after interventions. The statistical software SPSS 16 and Chi-square and Independent Samples T tests were used for analysis.

Results: One hundred patients were studied. The demographic variables were similar in two groups (P>0.05).  There was no significant difference between the vitamin D group and control group in percentage of patients with wheezing (P=0.408), fever (P=0.393), retraction (P=0.146), crackles (P=0.753), tachypnea (P=0.105), and poor feeding (P=0.157). The duration of antibiotic use was significantly lower in vitamin D group (4.18 ± 1.40 versus 3.22 ± 1.32 days; P=0.001).

Conclusion: According to the results, it seems that vitamin D supplementation may reduce the duration of antibiotic therapy in children with pneumonia.

Clinical Trial Registration: The trial was registered at the Registry of Clinical Trials (http://www.clinicaltrials.gov) with the ID: NCT02936895.