An Expression of Concern has been published | View Update to April 27th, 2023: The Publisher is glad to inform the readers that the issue discussed in the Expression of Concern has been favorably resolved and we have no longer cause of concern regarding this paper. The deficiency of vitamin D (VD) amongst Iranian people is high and also is related on hyperglycemia. This study aims to evaluate the association of VD levels with the required dose of insulin prescribed based on an insulin therapy protocol in critical condition patients admitted to intensive care unit (ICU), in an investigation based in Iran. This cross-sectional study was performed on patients who required insulin due to hyperglycemia. The relationship between serum VD level and the required dose of insulin prescribed based on insulin therapy protocol in this group of patients was investigated. A total of 172 patients with a mean age of 46.93 ± 31.9 years were included in this study. Across the included participants, 78.8% of patients had VD deficiency, 11.9% had insufficient VD and 9.3% had normal VD levels. There was a significant difference in mean blood sugar between the VD deficiency group and the normal group. VD levels were also significantly higher in men than women. Furthermore, the HbA1C hemoglobin level in patients with VD deficiency was significantly higher compared to the group with normal levels of VD. Our findings suggest that decreased VD is associated with increased blood sugar and insulin requirements in patients admitted to ICU. Women are at a higher risk for VD deficiency. We hope that these findings may help inform relevant treatment strategies.