Low Vitamin D Concentration Is Not Associated with Increased Mortality and Morbidity after Cardiac Surgery

<div><p>Objective</p><p>To determine the effect of vitamin D on postoperative outcomes in cardiac surgical patients.</p><p>Design</p><p>Retrospective study.</p><p>Setting</p><p>Single institution-teaching hospital.</p><p>Participants</p><p>Adult cardiac surgical patients with perioperative 25-hydroxyvitamin D measurements.</p><p>Interventions</p><p>None. We gathered information from the Cardiac Anesthesiology Registry that was obtained at the time of the patients’ visit/hospitalization.</p><p>Measurements and Main Results</p><p>We used data of 18,064 patients from the Cardiac Anesthesiology Registry; 426 patients with 25-hydroxyvitamin D measurements met our inclusion criteria. Association with Vitamin D concentration and composite of 11 cardiac morbidities was done by multivariate (i.e., multiple outcomes per subject) analysis. For other outcomes separate multivariable logistic regressions and adjusting for the potential confounders was used. The observed median vitamin D concentration was 19 [Q1-Q3∶12, 30] ng/mL. Vitamin D concentration was not associated with our primary composite of serious cardiac morbidities (odds ratio [OR], 0.96; 95% CI, 0.86–1.07). Vitamin D concentration was also not associated with any of the secondary outcomes: neurologic morbidity (P = 0.27), surgical (P = 0.26) or systemic infections (P = 0.58), 30-day mortality (P = 0.55), or length of initial intensive care unit (ICU) stay (P = 0.04).</p><p>Conclusions</p><p>Our analysis suggests that perioperative vitamin D concentration is not associated with clinically important outcomes, likely because the outcomes are overwhelmingly determined by other baseline and surgical factors.</p></div

Severity-adjusted^* average relative effect of vitamin D concentration across 11 cardiac morbidities among 426 cardiac surgical patients.

*<p>Weights were determined as the median score for that morbidity (from 1 to 100, 100 being most severe) scored by nine independent anesthesiologists who were otherwise not involved in this study (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0063831#pone.0063831.s002" target="_blank">appendix S2</a>).</p>¶<p>Potential confounders: age, gender, race, body mass index, smoking status, dialysis, and ethanol alcohol (ETOH).</p>§<p>Mediator variables: congestive heart failure, hypertension, vascular surgery dilatations, vascular heart disease, carotid surgery, carotid disease, stroke, atrial fibrillation, atrial flutter, ventricular tachycardia, ventricular fibrillation, junctional, and myocardial infarction.</p>#<p>Odds ratio for a 5-unit increase in vitamin D concentration.</p

The associations between serum vitamin D concentration and individual cardiac morbidities among 426 cardiac surgical patients.

<p>IABP = Intra-aortic balloon pump, ECMO = Extra corporeal membrane oxygenator, VT/VF = Ventricular tachycardia/Ventricular fibrillation.</p>*<p>Odds ratio for a 5-unit increase in vitamin D concentration, after adjusting for potential confounders: age, gender, race, body mass index, smoking status, dialysis, and ethanol alcohol (ETOH).</p>†<p>A Bonferroni correction was used to adjust for multiple testing. Thus, the 99.55% CIs are presented, and the significance criterion for each individual outcome is P<0.0045 (i.e., 0.05/11). None of the individual cardiac morbidities thus met our <i>a priori</i> criteria for statistical significance.</p

The associations between serum vitamin D concentration and secondary outcomes among 426 cardiac surgical patients.

<p>ICU = Intensive care unit; LOS = length of stay.</p>*<p>Odds ratio or hazard ratio for a 5-unit increase in vitamin D concentration, after adjusting for potential confounders: age, gender, race, body mass index, smoking status, dialysis, and ethanol alcohol (ETOH).</p>¶<p>There summary statistics were length of stay for discharged alive patients. Six patients died in ICU; those patients were analyzed as never being discharged alive by assigning a follow-up time one day longer than the longest observed discharged alive time.</p