2,290 research outputs found
Spiders can be recognized by counting their legs
Spiders are arthropods that can be distinguished from their closest
relatives, the insects, by counting their legs. Spiders have 8, insects just 6.
Spider graphs are a very restricted class of graphs that naturally appear in
the context of cograph editing. The vertex set of a spider (or its complement)
is naturally partitioned into a clique (the body), an independent set (the
legs), and a rest (serving as the head). Here we show that spiders can be
recognized directly from their degree sequences through the number of their
legs (vertices with degree 1). Furthermore, we completely characterize the
degree sequences of spiders
Comparison of performance achievement award recognition with primary stroke center certification for acute ischemic stroke care.
BackgroundHospital certification and recognition programs represent 2 independent but commonly used systems to distinguish hospitals, yet they have not been directly compared. This study assessed acute ischemic stroke quality of care measure conformity by hospitals receiving Primary Stroke Center (PSC) certification and those receiving the American Heart Association's Get With The Guidelines-Stroke (GWTG-Stroke) Performance Achievement Award (PAA) recognition.Methods and resultsThe patient and hospital characteristics as well as performance/quality measures for acute ischemic stroke from 1356 hospitals participating in the GWTG-Stroke Program 2010-2012 were compared. Hospitals were classified as PAA+/PSC+ (hospitals n = 410, patients n = 169,302), PAA+/PSC- (n = 415, n = 129,454), PAA-/PSC+ (n = 88, n = 26,386), and PAA-/PSC- (n = 443, n = 75,565). A comprehensive set of stroke measures were compared with adjustment for patient and hospital characteristics. Patient characteristics were similar by PAA and PSC status but PAA-/PSC- hospitals were more likely to be smaller and nonteaching. Measure conformity was highest for PAA+/PSC+ and PAA+/PSC- hospitals, intermediate for PAA-/PSC+ hospitals, and lowest for PAA-/PSC- hospitals (all-or-none care measure 91.2%, 91.2%, 84.3%, and 76.9%, respectively). After adjustment for patient and hospital characteristics, PAA+/PSC+, PAA+/PSC-, and PAA-/PSC+ hospitals had 3.15 (95% CIs 2.86 to 3.47); 3.23 (2.93 to 3.56) and 1.72 (1.47 to 2.00), higher odds for providing all indicated stroke performance measures to patients compared with PAA-/PSC- hospitals.ConclusionsWhile both PSC certification and GWTG-Stroke PAA recognition identified hospitals providing higher conformity with care measures for patients hospitalized with acute ischemic stroke, PAA recognition was a more robust identifier of hospitals with better performance
Relationship of national institutes of health stroke scale to 30-day mortality in medicare beneficiaries with acute ischemic stroke.
BackgroundThe National Institutes of Health Stroke Scale (NIHSS), a well-validated tool for assessing initial stroke severity, has previously been shown to be associated with mortality in acute ischemic stroke. However, the relationship, optimal categorization, and risk discrimination with the NIHSS for predicting 30-day mortality among Medicare beneficiaries with acute ischemic stroke has not been well studied.Methods and resultsWe analyzed data from 33102 fee-for-service Medicare beneficiaries treated at 404 Get With The Guidelines-Stroke hospitals between April 2003 and December 2006 with NIHSS documented. The 30-day mortality rate by NIHSS as a continuous variable and by risk-tree determined or prespecified categories were analyzed, with discrimination of risk quantified by the c-statistic. In this cohort, mean age was 79.0 years and 58% were female. The median NIHSS score was 5 (25th to 75th percentile 2 to 12). There were 4496 deaths in the first 30 days (13.6%). There was a strong graded relation between increasing NIHSS score and higher 30-day mortality. The 30-day mortality rates for acute ischemic stroke by NIHSS categories were as follows: 0 to 7, 4.2%; 8 to 13, 13.9%; 14 to 21, 31.6%; 22 to 42, 53.5%. A model with NIHSS alone provided excellent discrimination whether included as a continuous variable (c-statistic 0.82 [0.81 to 0.83]), 4 categories (c-statistic 0.80 [0.79 to 0.80]), or 3 categories (c-statistic 0.79 [0.78 to 0.79]).ConclusionsThe NIHSS provides substantial prognostic information regarding 30-day mortality risk in Medicare beneficiaries with acute ischemic stroke. This index of stroke severity is a very strong discriminator of mortality risk, even in the absence of other clinical information, whether used as a continuous or categorical risk determinant. (J Am Heart Assoc. 2012;1:42-50.)
Patterns, predictors, variations, and temporal trends in emergency medical service hospital prenotification for acute ischemic stroke.
BACKGROUND#ENTITYSTARTX02014;: Emergency medical services (EMS) hospital prenotification of an incoming stroke patient is guideline recommended as a means of increasing the timeliness with which stroke patients are evaluated and treated. Still, data are limited with regard to national use of, variations in, and temporal trends in EMS prenotification and associated predictors of its use. METHODS AND RESULTS#ENTITYSTARTX02014;: We examined 371 988 patients with acute ischemic stroke who were transported by EMS and enrolled in 1585 hospitals participating in Get With The Guidelines-Stroke from April 1, 2003, through March 31, 2011. Prenotification occurred in 249 197 EMS-transported patients (67.0%) and varied widely by hospital (range, 0% to 100%). Substantial variations by geographic regions and by state, ranging from 19.7% in Washington, DC, to 93.4% in Montana, also were noted. Patient factors associated with lower use of prenotification included older age, diabetes mellitus, and peripheral vascular disease. Prenotification was less likely for black patients than for white patients (adjusted odds ratio 0.94, 95% confidence interval 0.92-0.97, P<0.0001). Hospital factors associated with greater EMS prenotification use were absence of academic affiliation, higher annual volume of tissue plasminogen activator administration, and geographic location outside the Northeast. Temporal improvements in prenotification rates showed a modest general increase, from 58.0% in 2003 to 67.3% in 2011 (P temporal trend <0.0001). CONCLUSIONS#ENTITYSTARTX02014;: EMS hospital prenotification is guideline recommended, yet among patients transported to Get With The Guidelines-Stroke hospitals it is not provided for 1 in 3 EMS-arriving patients with acute ischemic stroke and varies substantially by hospital, state, and region. These results support the need for enhanced implementation of stroke systems of care. (J Am Heart Assoc. 2012;1:e002345 doi: 10.1161/JAHA.112.002345.)
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Use of HydralazineāIsosorbide Dinitrate Combination in African American and Other Race/Ethnic Group Patients With Heart Failure and Reduced Left Ventricular Ejection Fraction
Background: Hydralazineāisosorbide dinitrate (HāISDN) therapy is recommended for African American patients with moderate to severe heart failure with reduced ejection fraction (<40%) (HFrEF), but use, temporal trends, and clinical characteristics associated with HāISDN therapy in clinical practice are unknown. Methods and Results: An observational analysis of 54 622 patients admitted with HFrEF and discharged home from 207 hospitals participating in the Get With The GuidelinesāHeart Failure registry from April 2008 to March 2012 was conducted to assess prescription, trends, and predictors of use of HāISDN among eligible patients. Among 11 185 African American patients eligible for HāISDN therapy, only 2500 (22.4%) received HāISDN therapy at discharge. In the overall eligible population, 5115 of 43 498 (12.6%) received HāISDN at discharge. Treatment rates increased over the study period from 16% to 24% among African Americans and from 10% to 13% among the entire HFrEF population. In a multivariable model, factors associated with HāISDN use among the entire cohort included younger age; male sex; African American/Hispanic ethnicity; and history of diabetes, hypertension, anemia, renal insufficiency, higher systolic blood pressure, and lower heart rate. In African American patients, these factors were similar; in addition, being uninsured was associated with lower use. Conclusions: Overall, few potentially eligible patients with HFrEF are treated with HāISDN, and among AfricanāAmericans fewer than oneāfourth of eligible patients received guidelineārecommended HāISDN therapy. Improved ways to facilitate use of HāISDN therapy in African American patients with HFrEF are needed
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Trends in Clinical, Demographic, and Biochemical Characteristics of Patients with Acute Myocardial Infarction from 2003 to 2008: A Report from the American Heart Association Get with the Guidelines Coronary Artery Disease Program
Background: An analysis of the changes in the clinical and demographic characteristics of patients with acute myocardial infarction could identify successes and failures of risk factor identification and treatment of patients at increased risk for cardiovascular events. Methods and results: We reviewed data collected from 138 122 patients with acute myocardial infarction admitted from 2003 to 2008 to hospitals participating in the American Heart Association Get With The Guidelines Coronary Artery Disease program. Clinical, demographic, and laboratory characteristics were analyzed for each year stratified on the electrocardiogram at presentation. Patients with nonāST-segmentāelevation myocardial infarction were older, more likely to be women, and more likely to have hypertension, diabetes mellitus, and a history of past cardiovascular disease than were patients with ST-elevation myocardial infarction. In the overall patient sample, significant trends were observed of an increase over time in the proportions of nonāST-segmentāelevation myocardial infarction, patient age of 45 to 65 years, obesity, and female sex. The prevalence of diabetes mellitus decreased over time, whereas the prevalences of hypertension and smoking were substantial and unchanging. The prevalence of ālowā high-density lipoprotein increased over time, whereas that of āhighā low-density lipoprotein decreased. Stratum-specific univariate analysis revealed quantitative and qualitative differences between strata in time trends for numerous demographic, clinical, and biochemical measures. On multivariable analysis, there was concordance between strata with regard to the increase in prevalence of patients 45 to 65 years of age, obesity, and ālowā high-density lipoprotein and the decrease in prevalence of āhighā low-density lipoprotein. However, changes in trends in age distribution, sex ratio, and prevalence of smokers and the magnitude of change in diabetes mellitus prevalence differed between strata. Conclusions: There were notable differences in risk factors and patient characteristics among patients with ST-elevation myocardial infarction and those with nonāST-segmentāelevation myocardial infarction. The increasing prevalence of dysmetabolic markers in a growing proportion of patients with acute myocardial infarction suggests further opportunities for risk factor modification
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