Bottom Quartile (bottom + quartile)

Distribution by Scientific Domains


Selected Abstracts


Sex Differences in the Effect of Heart Rate on Mortality in the Elderly

JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 9 2003
Gila Perk MD
Objectives:, To examine the association between heart rate and mortality risk in the elderly. Design:, Longitudinal cohort. Setting:, Outpatient. Participants: Four hundred twenty-two people, aged 70 upon entry, were surveyed and followed for 6 years. Measurements: Pulse rate was measured manually, while sitting and standing, and heart rate was measured from electrocardiogram recordings. The population was divided into quartiles of heart rate, with the top quartile comprising those with heart rate greater than 77 beats per minute (bpm) and the bottom quartile those with heart rate less than 60 bpm. Results: After controlling for possible confounders, there was a clear correlation (r) between heart rate and all-cause mortality in elderly women (r=0.25, P=.0003). The correlation in women was observed using the three different methods for measuring heart rate. Heart rate was associated with all-cause and cardiovascular mortality. There was no relationship between heart rate and level of exercise or smoking status. In multiple regression analysis, the increased risk of death in the women was independent of previous cardiovascular or cerebrovascular disease, hypertension, anemia, congestive heart failure, smoking, and level of exercise or activities of daily living (relative odds ratio (ROR)=3.37, 95% confidence interval (CI)=0.96,11.8). When women using beta-blockers were excluded, this relationship became even stronger (ROR=8.5, 95% CI=1.19,60.1). Conclusion: Elevated heart rate is related to increased mortality in elderly women, thus representing a simple index of general health status in this population. Elevated heart rate did not predict mortality in elderly men. [source]


Problem-based learning: why curricula are likely to show little effect on knowledge and clinical skills

MEDICAL EDUCATION, Issue 9 2000
Mark Albanese
Objectives A recent review of problem-based learning's effect on knowledge and clinical skills updated findings reported in 1993. The author argues that effect sizes (ES) seen with PBL have not lived up to expectations (0.8,1.0) and the theoretical basis for PBL, contextual learning theory, is weak. The purposes of this study were to analyse what constitutes reasonable ES in terms of the impacts on individuals and published reports, and to elaborate upon various theories pertaining to PBL. Design Normal theory is used to demonstrate what various ESs would mean for individual change and a large meta-analysis of over 10 000 studies is referred to in identifying typical ESs. Additional theories bearing upon PBL are presented. Results Effect sizes of 0.8,1.0 would require some students to move from the bottom quartile to the top half of the class or more. The average ES reported in the literature was 0.50 and many commonly used and accepted medical procedures and therapies are based upon studies with ESs below 0.50. Conclusions Effect sizes of 0.8,1.0 are an unreasonable expectation from PBL because, firstly, the degree of changes that would be required of individuals would be excessive, secondly, leading up to medical school, students are groomed and selected for success in a traditional curriculum, expecting them to do better in a PBL curriculum than a traditional curriculum is an unreasonable expectation, and, thirdly, the average study reported in the literature and many commonly used and accepted medical procedures and therapies are based upon studies having lesser ESs. Information-processing theory, Cooperative learning, Self-determination theory and Control theory are suggested as providing better theoretical support for PBL than Contextual learning theory. Even if knowledge acquisition and clinical skills are not improved by PBL, the enhanced work environment for students and faculty that has been consistently found with PBL is a worthwhile goal. [source]


The Relationship Between the Emergent Primary Percutaneous Coronary Intervention Quality Measure and Inpatient Myocardial Infarction Mortality

ACADEMIC EMERGENCY MEDICINE, Issue 8 2010
Rahul K. Khare MD
ACADEMIC EMERGENCY MEDICINE 2010; 17:793,800 © 2010 by the Society for Academic Emergency Medicine Abstract Background:, In the setting of acute ST-segment elevation myocardial infarction (STEMI), reperfusion therapy with emergent primary percutaneous coronary intervention (PCI) significantly reduces mortality. It is unknown whether a hospital's performance on the Centers for Medicare & Medicaid Services (CMS) quality metric for time from patient arrival to angioplasty is associated with its overall hospital acute myocardial infarction (AMI) mortality rate. Objectives:, The objective of this study was to evaluate if hospitals with higher performance on the time-to-PCI quality measure are more likely to achieve lower mortality for patients admitted for any type of AMI. Methods:, Using merged 2006 data from the Nationwide Inpatient Sample (NIS), the American Hospital Association (AHA) annual survey, and CMS Hospital Compare quality indicator data, we examined 69,101 admissions with an International Classification of Diseases, Ninth Revision (ICD-9)-coded principal diagnosis of AMI in the 116 hospitals that reported more than 24 emergent primary PCI admissions in that year. Hospitals were categorized into quartiles according to percentage of admissions in 2006 that achieved the primary PCI timeliness threshold (time-to-PCI quality measure). Using a random effects logistic regression model of inpatient mortality, we examined the significance of the hospital time-to-PCI quality measure after adjustment for other hospital and individual patient sociodemographic and clinical characteristics. Results:, The unadjusted inpatient AMI mortality rate at the 27 top quartile hospitals was 4.3%, compared to 5.1% at the 32 bottom quartile (worst performing) hospitals. The risk-adjusted odds ratio (OR) of inpatient death was 0.83 (95% confidence interval [CI] = 0.72 to 0.95), or 17% lower odds of inpatient death, among patients admitted to hospitals in the top quartile for the time-to-PCI quality measure compared to the case if the hospitals were in the bottom 25th percentile. Conclusions:, Hospitals with the highest and second highest quartiles of time-to-PCI quality measure had a significantly lower overall AMI mortality rate than the lowest quartile hospitals. Despite the fact that a minority of all patients with AMI get an emergent primary PCI, hospitals that perform this more efficiently also had a significantly lower mortality rate for all their patients admitted with AMI. The time-to-PCI quality measure in 2006 was a potentially important proxy measure for overall AMI quality of care. [source]


Serum angiotensin-converting enzyme and frequency of severe hypoglycaemia in Type 1 diabetes: does a relationship exist?

DIABETIC MEDICINE, Issue 12 2007
N. N. Zammitt
Abstract Aims An association has been described between elevated serum angiotensin-converting enzyme (ACE) and an increased risk of severe hypoglycaemia (SH). To ascertain whether this reported association could be replicated in a different country, it was re-examined in 300 individuals with Type 1 diabetes. Methods People with Type 1 diabetes, none of whom was taking renin,angiotensin system blocking drugs, were recruited. Participants recorded the frequency with which they had experienced SH. Glycated haemoglobin (HbA1c) and serum ACE were measured. The difference in the incidence of SH between different quartiles of ACE activity and the relationship between serum ACE and SH were examined using non-parametric statistical tests and a negative binomial model. Results Data were obtained from 300 patients [158 male; HbA1c median (range) 8.2% (5.2,12.8%), median age 36 years (16,88); duration of diabetes 14.5 years (2,49)]. The incidence of SH was 0.93 episodes per patient year. The mean incidence of SH in the top and bottom quartiles of ACE activity was 0.5 and 1.7 episodes per patient year, respectively, but this difference was not statistically significant (P = 0.075). Spearman's test showed a very weak, although statistically significant, association between serum ACE level and SH incidence (r = 0.115, P = 0.047). The binomial model also showed a statistically significant (P = 0.002), but clinically weak, relationship between serum ACE and SH. Conclusions The present survey showed a weak relationship between serum ACE and the frequency of SH, the clinical relevance of which is unclear. This limits the proposed role for serum ACE as an index of risk for SH. [source]


Who Are Ethnic Entrepreneurs?

JOURNAL OF SMALL BUSINESS MANAGEMENT, Issue 2 2002
A Study of Entrepreneursapos; Ethnic Involvement, Business Characteristics
This article proposes that the term "ethnic entrepreneur" should be defined by the levels of personal involvement of the entrepreneur in the ethnic community instead of reported ethnic grouping. It hypothesizes that significant differences in personal and business characteristics will surface between the most community-involved and least community-involved ethnic entrepreneurs. T-tests were done on 112 Asian and Latino entrepreneurs split into top and bottom quartiles on the personal involvement scale. Results showed several significant differences between the two groups on variables relating to the entrepreneurs' background characteristics, business-related goals, cultural values, business strategies, and business performance. [source]


Self-Regulation and Its Relations to Adaptive Functioning in Low Income Youths

AMERICAN JOURNAL OF ORTHOPSYCHIATRY, Issue 1 2009
John C. Buckner PhD
Most studies of self-regulation involving children have linked it to specific outcomes within a single domain of adaptive functioning. The authors examined the association of self-regulation with a range of indices of adaptive functioning among 155 youth ages 8,18 years from families with very low income. Controlling for other explanatory variables, self-regulation was strongly associated with various outcome measures in the areas of mental health, behavior, academic achievement, and social competence. The authors also contrasted youths relatively high and low in self-regulation (the top and bottom quartiles). Youths with good self-regulation had much better indices of adaptive functioning across measures of social competence, academic achievement, grades, problem behaviors, and depression and anxiety than their counterparts with more diminished self-regulatory capacities. In addition, youths with better self-regulation skills stated more adaptive responses both in terms of how they coped with past stressful live events and how they would deal with hypothetical stressors. This study indicates that self-regulation is robustly associated with a range of important indices of adaptive functioning across many domains. Findings are discussed in light of their implications for theory and intervention for children of diverse economic backgrounds. [source]