Neuroticism and impulsivity: Their hierarchical organization in the personality characterization of drug-dependent patients from a decision tree learning perspective

Objective

Neuroticism and impulsivity are the personality variables most consistently associated with drug-dependent patients. To date, no data mining procedures have been applied to explore the differential role of personality variables in this population.

Methods

The personality profile of 336 drug-dependent patients was compared with that of a sample of community participants in the context of a decision tree learning approach using the Alternative Five Factor Model. The resulting discriminant model was cross-validated.

Results

Neuroticism and impulsivity were the most relevant variables in the resulting model, but their association appeared to be hierarchically organized. In the personality characterization of these patients, neuroticism became the main discriminant dimension, whereas impulsivity played a differential role, explained by means of an interaction effect. Decision tree learning models appear to be a heuristic theoretical and empirical approximation to the study of relevant variables, such as personality traits, in drug-dependency research.     

Heterogeneous networks do not promote cooperation when humans play a Prisoner's Dilemma

It is not fully understood why we cooperate with strangers on a daily basis. In an increasingly global world, where interaction networks and relationships between individuals are becoming more complex, different hypotheses have been put forward to explain the foundations of human cooperation on a large scale and to account for the true motivations that are behind this phenomenon. In this context, population structure has been suggested to foster cooperation in social dilemmas, but theoretical studies of this mechanism have yielded contradictory results so far; additionally, the issue lacks a proper experimental test in large systems. We have performed the largest experiments to date with humans playing a spatial Prisoner's Dilemma on a lattice and a scale-free network (1,229 subjects). We observed that the level of cooperation reached in both networks is the same, comparable with the level of cooperation of smaller networks or unstructured populations. We have also found that subjects respond to the cooperation that they observe in a reciprocal manner, being more likely to cooperate if, in the previous round, many of their neighbors and themselves did so, which implies that humans do not consider neighbors' payoffs when making their decisions in this dilemma but only their actions. Our results, which are in agreement with recent theoretical predictions based on this behavioral rule, suggest that population structure has little relevance as a cooperation promoter or inhibitor among humans.     

¿Influyen las técnicas anestésicas en los resultados postoperatorios? Parte I

The influence of anesthetic technique on postoperative outcomes has opened a wide field of research in recent years.High-risk patients undergoing non-cardiac surgery are those who have higher incidence of postoperative complications and mortality. A proper definition of this group of patients should focus maximal efforts and resources to improve the results.In view of the significant reduction in postoperative mortality and morbidity in last 20 years, perioperative research should take into account new indicators to investigate the role of anesthetic techniques on postoperative outcomes. Studies focused on the evaluation of intermediate outcomes would probably discriminate better effectiveness differences between anesthetic techniques.We review some of the major controversies arising in the literature about the impact of anesthetic techniques on postoperative outcomes. We have grouped the impact of these techniques into 9 major investigation areas: mortality, cardiovascular complications, respiratory complications, postoperative cognitive dysfunction, chronic postoperative pain, cancer recurrence, postoperative nausea/vomiting, surgical outcomes and resources utilization.In this first part of the review, we discuss the basis on postoperative outcomes research, mortality, cardiovascular and respiratory complications.     

Prognostic power of proadrenomedullin in community-acquired pneumonia is independent of aetiology

Biomarkers are useful in community-acquired pneumonia (CAP). Recently, midregional (MR) proadrenomedullin (proADM) has been shown to be of potential prognostic use. We sought to determine whether this prognostic role depends on the cause of CAP. We conducted a prospective cohort study of immunocompetent patients with CAP. Pneumonia Severity Index (PSI) and CURB-65 score (confusion (abbreviated mental test score of ≤ 8), urea ≥ 7 mol · L(-1), respiratory rate ≥ 30 breaths · min(-1), blood pressure <90 mmHg systolic or <60 mmHg diastolic, and age ≥ 65 yrs), blood C-reactive protein, procalcitonin, MR-proADM, and microbiological studies were systematically performed. Patients were grouped as bacterial, viral/atypical and mixed CAP, and were followed up at 30, 90 and 180 days, and 1 yr. We recruited 228 CAP patients. Identification of at least one pathogen was achieved in 155 (68%) patients. MR-proADM levels closely correlated with increasing severity scores, and showed an important predictive power for complications and short- and long-term mortality (1 yr). Its addition to PSI and CURB-65 significantly improved their prognostic accuracy. A MR-proADM cut-off of 0.646 nmol · L(-1) identified 92% of patients scored as PSI classes IV and V as high risk. MR-proADM outcome prediction power was not affected by different aetiologies. MR-proADM has high short- and long-term prognostic accuracy, and increases the accuracy of clinical scores. The prognostic value of MR-proADM is not modified by different possible CAP aetiologies.     

Community-acquired pneumonia in outpatients: aetiology and outcomes

The purpose of this study was to establish the microbial aetiology and outcomes of patients with community-acquired pneumonia (CAP) treated as outpatients after presenting to a hospital emergency care unit. A prospective observational study was carried out in the Hospital Clinic of Barcelona (Barcelona, Spain). All consecutive cases of CAP treated as outpatients were included. 568 adult outpatients with CAP were studied (mean±sd age 47.2±17.6 yrs; 110 (19.4%) were aged ≥65 yrs). Aetiological diagnoses were established in 188 (33.1%) cases. Streptococcus pneumoniae was the most frequent pathogen followed by Mycoplasma pneumoniae and respiratory viruses. Legionella was detected in 13 (2.3%) cases. More than one causative agent was found in 17 (9.0%) patients. Mortality was low (three (0.5%) patients died) and other adverse events were rare (30 (5.2%) patients had complications, 13 (2.3%) were re-admitted and treatment failed in 13 (2.3%)). Complications were mostly related to pleural effusion and empyema, and re-admissions and treatment failures to comorbidities. Outpatients with CAP have a characteristic microbial pattern. Regular antipneumococcal coverage remains mandatory. Treatment failures and re-admissions are rare and may be reduced by increased attention to patients requiring short-term observation in the emergency care unit and in the presence of pleural effusion and comorbidities.     

Risk factors for the development of vertebral fractures after percutaneous vertebroplasty

We have recently observed an increased risk for vertebral fractures (VF) in a randomized controlled trial comparing the analgesic effect of vertebroplasty (VP) versus conservative treatment in symptomatic VF. The aim of the present study was to evaluate the risk factors related to the development of VF after VP in these patients. We evaluated risk factors including age, gender, bone mineral density, the number, type, and severity of vertebral deformities at baseline, the number of vertebral bodies treated, the presence and location of disk cement leakage, bone remodeling (determining bone turnover markers) and 25 hydroxyvitamin D [25(OH)D] levels at baseline in all patients. Twenty‐nine radiologically new VF were observed in 17 of 57 patients undergoing VP, 72% adjacent to the VP. Patients developing VF after VP showed an increased prevalence of 25(OH)D deficiency (<20 ng/mL) and higher P1NP values. The principal factor related to the development of VF after VP in multivariate analysis was 25(OH)D levels < 20 ng/mL (RR, 15.47; 95% CI, 2.99–79.86, p < 0.0001), whereas age >80 years (RR, 3.20; 95% CI, 1.70–6.03, p = 0.0007) and glucocorticoid therapy (RR, 3.64; 95% CI, 1.61–8.26, p = 0.0055) constituted the principal factors in the overall study population. Increased risk of VF after VP was also associated with cement leakage into the inferior disk (RR, 6.14; 95% CI, 1.65–22.78, p = 0.044) and more than one vertebral body treated during VP (RR, 4.19; 95% CI, 1.03–34.3, p = 0.044). In conclusion, nearly 30% of patients with osteoporotic VF treated with VP had a new VF after the procedure. Age, especially >80 years, the presence of inferior disk cement leakage after the procedure, the number of cemented vertebrae, and low 25(OH)D serum levels were related to the development of new VF in these patients, with the latter indicating the need to correct vitamin D deficiency prior to performing VP.