Vitamin D status and its association with season, hospital and sepsis mortality in critical illness.

INTRODUCTION: Vitamin D plays a key role in immune function. Deficiency may aggravate the incidence and outcome of infectious complications in critically ill patients. We aimed to evaluate the prevalence of vitamin D deficiency and the correlation between serum 25-hydroxyvitamin D (25(OH) D) and hospital mortality, sepsis mortality and blood culture positivity. METHODS: In a single-center retrospective observational study at a tertiary care center in Graz, Austria, 655 surgical and nonsurgical critically ill patients with available 25(OH) D levels hospitalized between September 2008 and May 2010 were included. Cox regression analysis adjusted for age, gender, severity of illness, renal function and inflammatory status was performed. Vitamin D levels were categorized by month-specific tertiles (high, intermediate, low) to reflect seasonal variation of serum 25(OH) D levels. RESULTS: Overall, the majority of patients were vitamin D deficient (<20 ng/ml; 60.2%) or insufficient (≥20 and <30 ng/dl; 26.3%), with normal 25(OH) D levels (>30 ng/ml) present in only 13.6%. The prevalence of vitamin D deficiency and mean 25(OH) D levels was significantly different in winter compared to summer months (P <0.001). Hospital mortality was 20.6% (135 of 655 patients). Adjusted hospital mortality was significantly higher in patients in the low (hazard ratio (HR) 2.05, 95% confidence interval (CI) 1.31 to 3.22) and intermediate (HR 1.92, 95% CI 1.21 to 3.06) compared to the high tertile. Sepsis was identified as cause of death in 20 of 135 deceased patients (14.8%). There was no significant association between 25(OH) D and C-reactive protein (CRP), leukocyte count or procalcitonin levels. In a subgroup analysis (n = 244), blood culture positivity rates did not differ between tertiles (23.1% versus 28.2% versus 17.1%, P = 0.361). CONCLUSIONS: Low 25(OH) D status is significantly associated with mortality in the critically ill. Intervention studies are needed to investigate the effect of vitamin D substitution on mortality and sepsis rates in this population.

Morphometric parameters of muscle and bone in critically ill patients : Post hoc analysis of the VITdAL-ICU trial.

BACKGROUND: Sarcopenia, defined as loss of muscle mass, quality and function, is a part of the frailty syndrome. In critical illness, sarcopenia has rarely been evaluated regarding clinical outcomes. Therefore, we evaluated the association of sarcopenia with both hospital length of stay (HLOS) and 6­month mortality in critically ill patients using abdominal computed tomography (CT) scans. METHODS: In a post hoc analysis from the high dose vitamin D3 vs. placebo in adult vitamin D deficient patients (VITdAL-ICU) trial, we retrospectively reviewed all available abdominal CT scans (18 women, 19 men). We measured and calculated total psoas area (TPA), psoas muscle density (PMD), skeletal muscle index (SMI) and bone mineral density (BMD) and analyzed the relation of these endpoints with HLOS and mortality. Defining sarcopenia we used cut-off values for TPA as 642.1 mm2/m2 in women and 784 mm2/m2 in men and PMD as 31.1 Hounsfield units (HU) in women and 33.3 HU in men, both measured at the level of L3, as well as for SMI (38.5 cm2/m2 in women and 52.4 cm2/m2 in men). Likely osteoporosis was defined by L1 trabecular attenuation of ≤110 HU. Values for TPA, PMD and SMI could not be obtained in 11 patients and BMD in 1 patient. RESULTS: Mean adjusted TPA was lower in women versus men (478 vs. 749 mm2/m2) as well as PMD (34.6 vs. 41.3 HU), SMI (62.36 vs. 76.81 cm2/m2) and BMD (141.1 vs. 157.2 HU). No significant influence on hospital length of stay and on 6­month mortality was found, irrespective of the morphometric parameter used (TPA, PMD, SMI, BMD; p > 0.05). Survivors showed statistically nonsignificantly better values than nonsurvivors: TPA: 652 vs. 530 mm2/m2 (p = 0.27); PMD: 38.4 vs. 37.4 HU (p = 0.85); SMI: 70.32 vs. 69.54 cm2/m2 (p = 0.91); BMD: 156 vs. 145.8 HU (p = 0.81). CONCLUSION: Although the study is limited by the small sample size, our data do not support a strong predictive value for TPA/PMD/SMI or BMD for HLOS or mortality in critically ill patients with vitamin D deficiency.

Sclerostin and its association with physical activity, age, gender, body composition, and bone mineral content in healthy adults.

CONTEXT: Sclerostin is produced by osteocytes and inhibits bone formation through the Wnt/ß-catenin-signaling pathway. Only limited data are available on circulating sclerostin levels in healthy subjects. OBJECTIVE: We aimed to evaluate the correlation between sclerostin and physical activity, anthropometric, and biochemical variables. DESIGN, SETTING, AND PARTICIPANTS: We conducted a cross-sectional observational study in 161 healthy adult men and premenopausal women aged 19 to 64 yr (mean age, 44 ± 10). INTERVENTION(S): There were no interventions. MAIN OUTCOME MEASURE(S): Serum sclerostin levels were associated with body composition, bone mineral density, physical activity, and various biochemical parameters. RESULTS: A positive correlation between age and sclerostin in both men (r = 0.37; P < 0.001) and premenopausal women (r = 0.66; P < 0.001) was found. Men had significantly higher sclerostin levels than women (49.8 ± 17.6 vs. 37.2 ± 15.2 pmol/liter; P < 0.001). However, after adjustment for age, bone mineral content (BMC), physical activity, body mass index (BMI), and renal function, sclerostin levels did not differ (P = 0.543). Partial correlation analysis adjusted for age, gender, and kidney function revealed a significant positive correlation between sclerostin levels and BMC, bone mineral density, BMI, and android/gynoid fat and a significant negative correlation with serum osteocalcin and calcium. The most physically active quartile had significantly lower sclerostin levels compared to the least active quartile in a univariate analysis. CONCLUSIONS: In healthy adults, sclerostin serum levels correlate positively with age, BMI, and BMC and negatively with osteocalcin and calcium. Further studies in larger populations are needed to confirm our findings and to better understand their clinical implications.