Impact of Obesity on Outcomes in a Multiethnic Cohort of Medical Intensive Care Unit Patients.

PURPOSE: To examine the association of obesity with in-hospital mortality and complications during critical illness. METHODS: We performed a retrospective analysis of a multiethnic cohort of 699 patients admitted to medical intensive care unit between January 2010 and May 2011 at Mount Sinai St. Luke's and Mount Sinai West Hospitals, tertiary care centers in New York City. Multivariate logistic regression analysis was used to evaluate the association between obesity (body mass index [BMI] ≥ 30] and in-hospital mortality. Subgroup analysis was performed in elderly patients (age ≥65 years). RESULTS: Compared to normal BMI, obese patients had lower in-hospital mortality (24.4% vs 17.6%, P = .04). On multivariate analysis, obesity was independently associated with lower in-hospital mortality (odds ratio [OR]: 0.49, 95% confidence interval [CI]: 0.27-0.89, P = .018). There was no significant difference in rates of mechanical ventilation, reintubation, and vasopressor requirement across BMI categories. In subgroup analysis, elderly obese patients did not display lower in-hospital mortality (adjusted OR: 0.85, 95% CI: 0.40-1.82, P = .68). CONCLUSION: Our study supports the hypothesis that obesity is associated with decreased mortality during critical illness. However, this finding was not observed among elderly obese patients. Further studies should explore the interaction between age, obesity, and outcomes in critical illness.

Cocaine cues drive opposing context-dependent shifts in reward processing and emotional state.

BACKGROUND: Prominent neurobiological theories of addiction posit a central role for aberrant mesolimbic dopamine release but disagree as to whether repeated drug experience blunts or enhances this system. Although drug withdrawal diminishes dopamine release, drug sensitization augments mesolimbic function, and both processes have been linked to drug seeking. One possibility is that the dopamine system can rapidly switch from dampened to enhanced release depending on the specific drug-predictive environment. To test this, we examined dopamine release when cues signaled delayed cocaine delivery versus imminent cocaine self-administration. METHODS: Fast-scan cyclic voltammetry was used to examine real-time dopamine release while simultaneously monitoring behavioral indexes of aversion as rats experienced a sweet taste cue that predicted delayed cocaine availability and during self-administration. Furthermore, the impact of cues signaling delayed drug availability on intracranial self-stimulation, a broad measure of reward function, was assessed. RESULTS: We observed decreased mesolimbic dopamine concentrations, decreased reward sensitivity, and negative affect in response to the cocaine-predictive taste cue that signaled delayed cocaine availability. Importantly, dopamine concentration rapidly switched to elevated levels to cues signaling imminent cocaine delivery in the subsequent self-administration session. CONCLUSIONS: These findings show rapid, bivalent contextual control over brain reward processing, affect, and motivated behavior and have implications for mechanisms mediating substance abuse.