The B-APNEIC score: distilling the STOP-Bang questionnaire to identify patients at high risk for severe obstructive sleep apnoea.

The STOP-Bang questionnaire is an established clinical screening tool to identify the risk of having mild, moderate or severe obstructive sleep apnoea using eight variables. It is unclear whether all eight variables contribute equally to the risk of clinically significant obstructive sleep apnoea. We analysed each variable for its contribution to detecting obstructive sleep apnoea; based on the results, we investigated whether the STOP-Bang questionnaire could be abbreviated to identify patients at high risk for severe obstructive sleep apnoea. We recruited patients with suspected obstructive sleep apnoea who were referred for overnight polysomnography. We used multivariable logistic regression to investigate the association of STOP-Bang parameters with severe obstructive sleep apnoea based on clinical and polysomnography data. Regression estimates were used to select variables to create the novel B-APNEIC score. We constructed receiver operating characteristic curves for the STOP-Bang questionnaire and B-APNEIC scores to identify patients with severe obstructive sleep apnoea and compared the areas under the curve using the DeLong method. Of the 275 patients enrolled, 32% (n = 88) had severe obstructive sleep apnoea. Logistic regression demonstrated that neck circumference (OR 2.20; 95%CI 1.10-4.40, p = 0.03) was the only variable independently associated with severe obstructive sleep apnoea. Observed apnoea during sleep, blood pressure and body mass index were the three next most closely trending predictors of severe obstructive sleep apnoea and were included along with neck circumference in the B-APNEIC score. Receiver operating curves demonstrated that the areas under the curve for STOP-Bang vs. B-APNEIC were comparable for identifying patients with severe obstructive sleep apnoea (OR 0.75; 95%CI 0.68-0.81 vs. OR 0.75; 95%CI 0.68-0.81: p = 0.99, respectively). Our results suggest that the B-APNEIC score is a simplified adaptation of the STOP-Bang questionnaire with equivalent effectiveness in identifying patients with severe obstructive sleep apnoea. Further studies are needed to validate and build on our findings.

Ventral tegmental area astrocytes orchestrate avoidance and approach behavior.

The ventral tegmental area (VTA) is a heterogeneous midbrain structure, containing neurons and astrocytes, that coordinates behaviors by integrating activity from numerous afferents. Within neuron-astrocyte networks, astrocytes control signals from distinct afferents in a circuit-specific manner, but whether this capacity scales up to drive motivated behavior has been undetermined. Using genetic and optical dissection strategies we report that VTA astrocytes tune glutamatergic signaling selectively on local inhibitory neurons to drive a functional circuit for learned avoidance. In this circuit, astrocytes facilitate excitation of VTA GABA neurons to increase inhibition of dopamine neurons, eliciting real-time and learned avoidance behavior that is sufficient to impede expression of preference for reward. Loss of one glutamate transporter (GLT-1) from VTA astrocytes selectively blocks these avoidance behaviors and spares preference for reward. Thus, VTA astrocytes selectively regulate excitation of local GABA neurons to drive a distinct avoidance circuit that opposes approach behavior.

Vitamin D Status and Elevated Red Cell Distribution Width in Community-Dwelling Adults: Results from the National Health and Nutrition Examination Survey 2001-2006.

OBJECTIVES: Elevated red cell distribution width (RDW) is associated with morbidity and mortality in community-dwelling individuals. Although RDW is traditionally used to diagnose anemia, it may also be a marker of systemic inflammation. Since vitamin D is a potent modulator of inflammatory cytokines our goal was to investigate whether 25-hydroxyvitamin D levels (25OHD) are associated with RDW in non-hospitalized adults. DESIGN: To investigate this association, we conducted a cross-sectional study. Stepwise multivariable linear and logistic regression models were used to assess the independent association of 25OHD with RDW. Elevated RDW was defined as >14.5%. SETTING: Nationwide sample of non-hospitalized adults within the United States. PARTICIPANTS: Individuals from the National Health and Nutrition Examination Survey from 2001-2006. RESULTS: 15,162 individuals comprised the analytic cohort. Mean 25OHD was 24.9 ng/mL (SE 0.4) and the prevalence of elevated RDW was 6.3%. Linear regression analysis, controlling for age, sex, race, mean corpuscular volume, albumin, and neutropenia, demonstrated that 25OHD was inversely associated with RDW (ß=-0.01; 95%CI -0.01 to -0.01). Logistic regression analysis, controlling for the same covariates, also demonstrated an inverse association of 25OHD with elevated RDW (OR 0.96; 95%CI 0.94-0.99). Individuals with 25OHD <30 ng/mL were more likely to have elevated RDW (OR 1.65; 95%CI 1.13-2.40) compared to those individuals with levels ≥30ng/mL. CONCLUSIONS: In a nationwide sample of non-hospitalized adults within the United States, low 25OHD was associated with increased likelihood of elevated RDW. Further studies are needed to determine whether optimizing vitamin D status can reduce the prevalence of elevated RDW, and thereby reduce morbidity and mortality in the general population.

Clinical and microbiological outcome in septic patients with extremely low 25-hydroxyvitamin D levels at initiation of critical care.

A relationship between vitamin D status and mortality in patients in intensive care units (ICU) has been documented. The present study aims to describe the clinical profile and sepsis-related outcome of critically ill septic patients with extremely low (<7 ng/mL) vitamin D levels at ICU admission. We conducted an observational study in the ICU of a teaching hospital including all patients admitted with severe sepsis/septic shock and undergoing 25-hydroxyvitamin D (25(OH)D) testing within the first 24 hours from admission. We studied 107 patients over 12 months. At ICU admission vitamin D deficiency (≤20 ng/mL) was observed in 93.5% of the patients: 57 (53.3%) showed levels <7 ng/mL. As primary outcome, sepsis-related mortality rate was higher in patients with vitamin D levels <7 ng/mL (50.9% versus 26%). Multivariate regression analysis showed that vitamin D concentration <7 ng/mL on ICU admission (p 0.01) and higher mean SAPS II (p <0.01) score were independent predictors of sepsis-related mortality. Patients with very low vitamin D levels suffered higher rate of microbiologically confirmed infections but a lower percentage of microbiological eradication with respect to patients whose values were >7 ng/mL (80.7% versus 58%, p 0.02; 35.3% versus 68%; p 0.03, respectively). Post hoc analysis showed that, in the extremely low vitamin D group, the 52 patients with pneumonia showed a longer duration of mechanical ventilation (9 days (3.75-12.5 days) versus 4 days (2-9 days), p 0.04) and the 66 with septic shock needed vasopressor support for a longer period of time (7 days (4-10 days) versus 4 days (2-7.25 days), p 0.02). Our results suggest that in critical septic patients extremely low vitamin D levels on admission may be a major determinant of clinical outcome. Benefits of vitamin D replacement therapy in this population should be elucidated.