Simulation of Jahn-Teller-Dicke Magnetic Structural Phase Transition with Trapped Ions

We study theoretically the collective E$\otimes$e Jahn-Teller-Dicke distortion in a system of trapped ions. We focus in the limit of infinite range interactions in which an ensemble of effective spins interacts with two collective vibrational modes with U(1) symmetric couplings. Our model is exactly solvable in the thermodynamical limit and it is amenable to be solved by exact numerical diagonalization for a moderate number of ions. We show that trapped ions are ideally suited to study the emergence of spontaneous symmetry breaking of a continuous symmetry and magnetic structural phase transition in a mesoscopic system.Comment: 19 pages, 7 figure

Why Are Outcomes Different for Registry Patients Enrolled Prospectively and Retrospectively? Insights from the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF).

Background: Retrospective and prospective observational studies are designed to reflect real-world evidence on clinical practice, but can yield conflicting results. The GARFIELD-AF Registry includes both methods of enrolment and allows analysis of differences in patient characteristics and outcomes that may result. Methods and Results: Patients with atrial fibrillation (AF) and ≥1 risk factor for stroke at diagnosis of AF were recruited either retrospectively (n = 5069) or prospectively (n = 5501) from 19 countries and then followed prospectively. The retrospectively enrolled cohort comprised patients with established AF (for a least 6, and up to 24 months before enrolment), who were identified retrospectively (and baseline and partial follow-up data were collected from the emedical records) and then followed prospectively between 0-18 months (such that the total time of follow-up was 24 months; data collection Dec-2009 and Oct-2010). In the prospectively enrolled cohort, patients with newly diagnosed AF (≤6 weeks after diagnosis) were recruited between Mar-2010 and Oct-2011 and were followed for 24 months after enrolment. Differences between the cohorts were observed in clinical characteristics, including type of AF, stroke prevention strategies, and event rates. More patients in the retrospectively identified cohort received vitamin K antagonists (62.1% vs. 53.2%) and fewer received non-vitamin K oral anticoagulants (1.8% vs . 4.2%). All-cause mortality rates per 100 person-years during the prospective follow-up (starting the first study visit up to 1 year) were significantly lower in the retrospective than prospectively identified cohort (3.04 [95% CI 2.51 to 3.67] vs . 4.05 [95% CI 3.53 to 4.63]; p = 0.016). Conclusions: Interpretations of data from registries that aim to evaluate the characteristics and outcomes of patients with AF must take account of differences in registry design and the impact of recall bias and survivorship bias that is incurred with retrospective enrolment. Clinical Trial Registration: - URL: http://www.clinicaltrials.gov . Unique identifier for GARFIELD-AF (NCT01090362)

Improved risk stratification of patients with atrial fibrillation: an integrated GARFIELD-AF tool for the prediction of mortality, stroke and bleed in patients with and without anticoagulation.

OBJECTIVES: To provide an accurate, web-based tool for stratifying patients with atrial fibrillation to facilitate decisions on the potential benefits/risks of anticoagulation, based on mortality, stroke and bleeding risks. DESIGN: The new tool was developed, using stepwise regression, for all and then applied to lower risk patients. C-statistics were compared with CHA2DS2-VASc using 30-fold cross-validation to control for overfitting. External validation was undertaken in an independent dataset, Outcome Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF). PARTICIPANTS: Data from 39 898 patients enrolled in the prospective GARFIELD-AF registry provided the basis for deriving and validating an integrated risk tool to predict stroke risk, mortality and bleeding risk. RESULTS: The discriminatory value of the GARFIELD-AF risk model was superior to CHA2DS2-VASc for patients with or without anticoagulation. C-statistics (95% CI) for all-cause mortality, ischaemic stroke/systemic embolism and haemorrhagic stroke/major bleeding (treated patients) were: 0.77 (0.76 to 0.78), 0.69 (0.67 to 0.71) and 0.66 (0.62 to 0.69), respectively, for the GARFIELD-AF risk models, and 0.66 (0.64-0.67), 0.64 (0.61-0.66) and 0.64 (0.61-0.68), respectively, for CHA2DS2-VASc (or HAS-BLED for bleeding). In very low to low risk patients (CHA2DS2-VASc 0 or 1 (men) and 1 or 2 (women)), the CHA2DS2-VASc and HAS-BLED (for bleeding) scores offered weak discriminatory value for mortality, stroke/systemic embolism and major bleeding. C-statistics for the GARFIELD-AF risk tool were 0.69 (0.64 to 0.75), 0.65 (0.56 to 0.73) and 0.60 (0.47 to 0.73) for each end point, respectively, versus 0.50 (0.45 to 0.55), 0.59 (0.50 to 0.67) and 0.55 (0.53 to 0.56) for CHA2DS2-VASc (or HAS-BLED for bleeding). Upon validation in the ORBIT-AF population, C-statistics showed that the GARFIELD-AF risk tool was effective for predicting 1-year all-cause mortality using the full and simplified model for all-cause mortality: C-statistics 0.75 (0.73 to 0.77) and 0.75 (0.73 to 0.77), respectively, and for predicting for any stroke or systemic embolism over 1 year, C-statistics 0.68 (0.62 to 0.74). CONCLUSIONS: Performance of the GARFIELD-AF risk tool was superior to CHA2DS2-VASc in predicting stroke and mortality and superior to HAS-BLED for bleeding, overall and in lower risk patients. The GARFIELD-AF tool has the potential for incorporation in routine electronic systems, and for the first time, permits simultaneous evaluation of ischaemic stroke, mortality and bleeding risks. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier for GARFIELD-AF (NCT01090362) and for ORBIT-AF (NCT01165710)

Two-year outcomes of patients with newly diagnosed atrial fibrillation: results from GARFIELD-AF.

AIMS: The relationship between outcomes and time after diagnosis for patients with non-valvular atrial fibrillation (NVAF) is poorly defined, especially beyond the first year. METHODS AND RESULTS: GARFIELD-AF is an ongoing, global observational study of adults with newly diagnosed NVAF. Two-year outcomes of 17 162 patients prospectively enrolled in GARFIELD-AF were analysed in light of baseline characteristics, risk profiles for stroke/systemic embolism (SE), and antithrombotic therapy. The mean (standard deviation) age was 69.8 (11.4) years, 43.8% were women, and the mean CHA2DS2-VASc score was 3.3 (1.6); 60.8% of patients were prescribed anticoagulant therapy with/without antiplatelet (AP) therapy, 27.4% AP monotherapy, and 11.8% no antithrombotic therapy. At 2-year follow-up, all-cause mortality, stroke/SE, and major bleeding had occurred at a rate (95% confidence interval) of 3.83 (3.62; 4.05), 1.25 (1.13; 1.38), and 0.70 (0.62; 0.81) per 100 person-years, respectively. Rates for all three major events were highest during the first 4 months. Congestive heart failure, acute coronary syndromes, sudden/unwitnessed death, malignancy, respiratory failure, and infection/sepsis accounted for 65% of all known causes of death and strokes for <10%. Anticoagulant treatment was associated with a 35% lower risk of death. CONCLUSION: The most frequent of the three major outcome measures was death, whose most common causes are not known to be significantly influenced by anticoagulation. This suggests that a more comprehensive approach to the management of NVAF may be needed to improve outcome. This could include, in addition to anticoagulation, interventions targeting modifiable, cause-specific risk factors for death. CLINICAL TRIAL REGISTRATION: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

Factors associated with self-rated health after kidney transplantation: a prospective study

Background: This prospective study explores and compares the relationship between patients' self-rated health (SRH) after kidney transplantation (KT) at different follow-up periods and its medical and nonmedical predictors over time. Methods: Patients (n = 128) who completed a questionnaire (the SRH question of the SF-36 and the End-Stage Renal Disease Symptom Checklist - Transplantation Module) were enrolled. Clinical data were retrieved from medical files. The sample was stratified into early (n = 89) and late (n = 39) cohorts according to time since KT at baseline. Linear regression was used to identify predictors of SRH at follow-up. Results: In both cohorts, a change in glomerular filtration rate (GFR) over time remained a predictor of SRH; in the early cohort, age was an additional predictor; in the late cohort, a change in transplantation-associated psychological distress over time and the number of late acute rejection episodes during the observation period were additional predictors. Conclusions: Improvement in GFR over time predicted better SRH at each period after KT. Decreased transplantation-associated psychological distress and fewer late acute rejection episodes seemed to predict better SRH at a later follow-up period. Despite these observations, higher SRH was associated with better clinical outcomes. Copyright (C) 2011 S. Karger AG, Basel

Self-rated health predicts mortality and graft loss after kidney transplantation: a 10-year follow-up study

Background: This study explored whether self-rated health (SRH) shortly after kidney transplantation (KT) predicts mortality and graft loss at up to 10 years' follow-up. Methods: A total of 276 patients shortly after successful KT were interviewed. SRH was measured using the first item of the SF-36 questionnaire and divided into three tertiles: poor, average and excellent health. Clinical data were retrieved from medical records. Cox regression was used to identify whether different levels of SRH predicted mortality and graft loss in transplant recipients. The observation period was up to 10 years. Results: Poor SRH (HR 11.1, p < 0.001), average SRH (HR 4.21, p < 0.05), estimated glomerular filtration rate (HR 0.26, p < 0.05) and age (HR 1.04, p < 0.05) were significantly associated with mortality. Similarly, poor SRH (HR 6.4, p < 0.001), average SRH (HR 3.6, p < 0.05), new-onset diabetes mellitus after KT (HR 3.3, p < 0.05) and chronic renal allograft dysfunction (HR 3.7, p < 0.00) were significantly associated with graft loss. Conclusion: Poor SRH shortly after transplantation indicates an increased risk of mortality and graft loss at up to 10 years' follow-up. SRH could be an inexpensive and reliable indicator for starting diagnostic and/or treatment strategies. The usefulness of SRH compared to other global clinical measures predicting mortality and graft loss should also be studied

Differences in perceived health status between kidney transplant recipients and dialyzed patients are based mainly on the selection process

Kidney transplantation offers longer survival, less morbidity and lower costs than dialysis. It is also believed to improve quality of life. The aim of this study was to compare prospectively the perceived health status (PHS) of dialyzed patients on a waiting list with kidney transplant recipients after transplantation, matched for age, gender and comorbidity. The sample consisted of 93 dialyzed patients on a waiting list for deceased-donor kidney transplantation and 87 incident transplant recipients. A total of 62 dialyzed patients were matched for age, gender and comorbidity with 62 transplant recipients. PHS was measured using the SF-36 questionnaire. Data from baseline and after 12 months were compared between the groups. Patients on dialysis had worse physical (49 +/- 21) and mental (59 +/- 18) PHS than transplant recipients (56 +/- 21 and 64 +/- 18, p < 0.05), but when matched pairs were compared, no differences in PHS were found. After 12 months, PHS did not change significantly in either group. The PHS of patients after kidney transplantation is better than that of those on dialysis. However, this fact is significantly influenced by the selection procedure, as only some dialyzed patients are put onto the waiting list while others were actually transplanted. The differences disappear with matching