Therapeutic Benefit of Preoperative Supplemental Vitamin D in Patients Undergoing Major Surgical Procedures.

Overview

Vitamin D (Vitamin D) deficiency is very common. We recently showed that 97% of 204 patients admitted to Truman Medical Center were Vitamin D deficient (\<30 ng/ml). However, the consequences of Vitamin D deficiency, particularly with respect to infection, are not well understood. It is known that production of cathelicidin, an important antimicrobial peptide, is critically dependent upon Vitamin D. It is also established that levels of cathelicidin correlate inversely with urinary tract infection risk. We hypothesize that restoration of Vitamin D levels to normal in patients undergoing major surgery will result in significant decreases in levels of perioperative infections due to restoration of normal levels of circulating Vitamin D, which in turn will elevate cathelicidin levels. As an initial test of this hypothesis, we propose a double-blind, prospective, randomized study of pre-operative Vitamin D supplementation. Fifty subjects undergoing surgery will receive daily Vitamin D3 (50,000 IU) for five days pre-operatively, with controls receiving placebo. Levels of Vitamin D, calcium, cathelicidin, and the pro-inflammatory protein resistin, will be monitored before Vitamin D supplementation (pre-operatively) and after Vitamin D supplementation (post-operative days 1 and 2). The effect of these changes should be to decrease the incidence of infectious complications. We expect to observe Vitamin D levels increase to normal, and cathelicidin levels become elevated. We expect to see increased levels of resistin in patients developing infections. This study will provide strong pilot evidence for future NIH funding.

The long term goal in our research is to develop and implement effective, evidence-and mechanism-based interventions to improve outcomes for surgical and trauma patients. Of potential importance, findings from our own recent pilot studies have established that \> 95% of patients seen at Truman Medical Center (TMC) are seriously Vitamin D deficient with plasma levels significantly lower than normal. Our objective in this application, therefore, is to assess the short term therapeutic benefit of high dose Vitamin D in patients admitted to TMC for elective major abdominal surgery. We propose to measure plasma Vitamin D and Calcium levels before supplementation (pre-operatively), and after supplementation (post-operatively), and monitor the biomarker proteins cathelicidin and resistin at the same times. Data on Vitamin D levels will be used to assess direct biochemical effects. Measurement of cathelicidin levels will provide additional information. Since Vitamin D has been shown to induce increased expression of this antimicrobial protein. Monitoring of circulating levels of resistin provides a highly sensitive early measure of infection (unpublished observations). Calcium levels will also be monitored since there is a significant chance that pre-operative calcium levels will be low in some patients, and that supplementation with vitamin D may increase the calcium level. Measures of secondary clinical outcomes will include length of hospital stay and incidence of post-operation infection. Our central hypothesis is that, relative to patients receiving peri-operative standard of care, patients receiving 250,000 units of Vitamin D pre-operatively will manifest levels of Vitamin D to within the normal range and will have elevated levels of cathelicidin. We further hypothesize that patients receiving Vitamin D will have reduced incidence of infection, which will correlate with lower levels of resistin, and will exhibit trends toward shorter hospital stay. Our proposed specific aims are: Specific Aim #1: Determine biochemical consequences of Vitamin D supplementation in elective surgery patients We hypothesize that preoperative supplementation with high dose Vitamin D will result in levels of Vitamin D in treated patients within the normal range, corresponding with significant increases in plasma levels of cathelicidin, relative to control patients receiving standard of care. Specific Aim # 2: Evaluate clinical benefits of Vitamin D supplementation in post-elective surgery patients We postulate that patients given Vitamin D will trend toward lower rates of post-surgery infection, as evidenced by the absence of circulating resistin and decreased detection of pulmonary or wound-site infection, and will have shorter hospital stays relative to patients receiving standard of care. It is our expectation that, at the completion of this pilot study, we will have provided strong evidence that plasma levels of Vitamin D, as measured by 25-OHD, can be reproducibly raised to normal levels as measured in post-surgery patients and that the administered Vitamin D will have detectable biochemical benefits. We further expect that, while the power of the proposed study will not be sufficient for statistically valid results, there will be trends toward clinical benefits in Vitamin D treated patients. Collectively, these findings would provide strong evidence to support feasibility of an NIH-supported Phase I trial to assess Vitamin D benefits in surgery and/or trauma.