Forecasting Daily Patient Volumes in the Emergency Department

Background: Shifts in the supply of and demand for emergency department (ED) resources make the efficient allocation of ED resources increasingly important. Forecasting is a vital activity that guides decision‐making in many areas of economic, industrial, and scientific planning, but has gained little traction in the health care industry. There are few studies that explore the use of forecasting methods to predict patient volumes in the ED. Objectives: The goals of this study are to explore and evaluate the use of several statistical forecasting methods to predict daily ED patient volumes at three diverse hospital EDs and to compare the accuracy of these methods to the accuracy of a previously proposed forecasting method. Methods: Daily patient arrivals at three hospital EDs were collected for the period January 1, 2005, through March 31, 2007. The authors evaluated the use of seasonal autoregressive integrated moving average, time series regression, exponential smoothing, and artificial neural network models to forecast daily patient volumes at each facility. Forecasts were made for horizons ranging from 1 to 30 days in advance. The forecast accuracy achieved by the various forecasting methods was compared to the forecast accuracy achieved when using a benchmark forecasting method already available in the emergency medicine literature. Results: All time series methods considered in this analysis provided improved in‐sample model goodness of fit. However, postsample analysis revealed that time series regression models that augment linear regression models by accounting for serial autocorrelation offered only small improvements in terms of postsample forecast accuracy, relative to multiple linear regression models, while seasonal autoregressive integrated moving average, exponential smoothing, and artificial neural network forecasting models did not provide consistently accurate forecasts of daily ED volumes. Conclusions: This study confirms the widely held belief that daily demand for ED services is characterized by seasonal and weekly patterns. The authors compared several time series forecasting methods to a benchmark multiple linear regression model. The results suggest that the existing methodology proposed in the literature, multiple linear regression based on calendar variables, is a reasonable approach to forecasting daily patient volumes in the ED. However, the authors conclude that regression‐based models that incorporate calendar variables, account for site‐specific special‐day effects, and allow for residual autocorrelation provide a more appropriate, informative, and consistently accurate approach to forecasting daily ED patient volumes.     

Congenital long QT syndrome: considerations for primary care physicians

Congenital long QT syndrome is an inherited disorder of cardiac repolarization that predisposes to syncope and to sudden death from polymorphic ventricular tachycardia. The disorder should be suspected when the electrocardiogram shows characteristic QT abnormalities, or when there is a family history of long QT syndrome or of an event that raises suspicion of long QT syndrome, such as sudden death, syncope, or ill-defined "seizure" disorder. We can now classify some types of congenital long QT syndrome according to their genetic mutations and their triggers, such as exercise, rest, or startle.     

新复合纤维蛋白胶可注射性磷酸钙人工骨的理学特性

目的:检测纤维蛋白胶复合β-磷酸三钙/磷酸二氢钙复合人工骨材料的物理学性能,评价纤维蛋白胶对β-磷酸三钙/磷酸二氢钙骨水泥性能的影响,以及其作为注射型复合人工骨用于修复骨缺损的可行性。方法:实验于2006-12/2007-06在南方医科大学珠江医院中心实验室和华南理工大学生物材料实验室完成。①材料:β-磷酸三钙由上海瑞邦生物材料有限公司提供,磷酸二氢钙为东泰化工赠,纤维蛋白胶购自广州倍绣生物技术有限公司。②复合材料制备:将β-磷酸三钙/磷酸二氢钙骨水泥按3∶1的比例充分混合后,与纤维蛋白胶按凝固后的体积2∶1体积比混合,制成复合人工骨材料。③观察指标:测定复合材料的凝固时间,抗压强度,抗稀散性能,并用扫描电镜观察其煅烧前后的显微结构特征,以未加纤维蛋白胶的磷酸钙水泥为对照(CPC组)。结果:复合人工骨材料的平均初凝时间长于CPC组(P<0.004),终凝时间在初凝时间后2～4 min;复合材料的抗压强度为(14.72±1.81)MPa。复合材料较CPC组有良好的抗稀散性能,扫描电镜发现,纤维蛋白胶贯穿于磷酸钙水泥晶体间,并将磷酸钙水泥晶体紧密连接。煅烧后复合材料的孔径有增大,空隙率为57.28%,并且微孔之间有空隙互相贯通。结论:该骨水泥复合材料凝固时间符合临床操作的需要;抗压强度达到松质骨强度的要求;煅烧后磷酸钙水泥的空隙率明显提高,有利于材料的降解。     

Treatment choice and quality of care for men with localized prostate cancer

BACKGROUND: Variations in patterns of care and treatment outcomes suggest differences in the quality of care for men treated for localized prostate cancer. OBJECTIVE: We sought to compare adherence with quality indicators for prostate cancer care among men treated with radical prostatectomy or external beam radiation therapy. RESEARCH DESIGN AND SUBJECTS: We sampled 5230 men diagnosed in 2000 or 2001 with early-stage prostate cancer from 984 facilities reporting to the National Cancer Data Base. Our analytic cohort includes 2604 men (from 770 facilities) treated with radical prostatectomy or external beam radiation. MAIN OUTCOME MEASURE: Subject-level compliance with the RAND quality indicators for localized prostate cancer care, stratified by treatment. We applied sampling weights to obtain national estimates of quality indicator adherence. RESULTS: The weighted samples represent 24,547 and 27,125 men treated with radical prostatectomy or external beam radiation therapy, respectively. Compliance with several quality indicators approached 100% in both treatment groups; however treatment-specific variations were noted. Men receiving radiation were less likely than those undergoing surgery to be treated in facilities with a board-certified urologist (odds ratio [OR] = 0.4, 95% confidence interval [95% CI] = 0.2-0.8). Adherence with process of care indicators was appreciably higher among radiation subjects, including documentation of clinical stage (OR = 7.5, 95% CI = 4.8-11.9), pretherapy assessment of urinary (OR = 2.8, 95% CI = 1.9-4.2) and sexual (OR = 1.6, 95% CI = 1.2-2.2) function, and discussion of treatment options (OR = 1.8, 95% CI = 1.1-2.9). CONCLUSIONS: Documented compliance with process of care quality indicators among men with localized prostate cancer appears superior for those treated with external beam radiation compared with those treated surgically.     

A clinical pathway for heart failure reduces admissions from the ED without increasing congestion in the ED

Background

A multidisciplinary team at a major academic medical center established an Acutely Decompensated Heart Failure Clinical Pathway (ADHFCP) program to reduce inpatient readmission rates among patients with heart failure which, among several interventions, included an immediate consultation from a cardiologist familiar with an ADHFCP patient when the patient presented at the Emergency Department (ED). This study analyzed how that program impacted utilization of services in the ED and its subsequent effect on rates of admission from the ED and on disposition times.

Outcome of surgical myectomy after unsuccessful alcohol septal ablation for the treatment of patients with hypertrophic obstructive cardiomyopathy.

OBJECTIVES: We sought to determine the outcome of myectomy after unsuccessful alcohol ablation. BACKGROUND: Alcohol septal ablation results in symptomatic improvement and a reduction in dynamic obstruction in most hypertrophic obstructive cardiomyopathy patients. However, a few patients remain with severe symptoms and obstruction and need surgery. The outcome of these cases is not well known. METHODS: The medical records of 375 patients who underwent alcohol ablation at our institution were reviewed. Twenty patients (5.3%, mean age 53 +/- 18 years, 17 women) subsequently needed surgical myectomy. The New York Heart Association (NYHA) functional class, angina class, exercise duration, left ventricular outflow tract (LVOT) gradient, ejection fraction, and septal thickness were tabulated. The anatomy and distribution of the septal perforator arteries were examined. RESULTS: After ablation, NYHA functional class (3 to 2.5; p < 0.05) and LVOT gradient (93 +/- 23 mm Hg to 71 +/- 26 mm Hg; p < 0.05) were slightly improved, without a change in exercise duration (171 +/- 124 s to 168 +/- 148 s; p > 0.5). Myectomy was performed at 19 +/- 15 months after ablation. There was no operative mortality, but permanent pacing was needed in 2 patients after surgery, and 3 other cases needed pacing before, or as a complication of, alcohol ablation. A significant improvement was noted, with the NYHA functional class decreasing to 1, exercise duration increasing to 423 +/- 171 s, and LVOT gradient decreasing to 6 +/- 11 mm Hg (all p < 0.05 versus post-alcohol ablation). CONCLUSIONS: Myectomy can be successfully performed after failed alcohol ablation, but with a higher incidence of heart block than in cases where only surgery is performed. Otherwise, alcohol ablation does not appear to adversely affect surgical outcome.     

Retinol binding protein 4 expression in humans: relationship to insulin resistance, inflammation, and response to pioglitazone

CONTEXT: Retinol binding protein 4 (RBP4) was recently found to be expressed and secreted by adipose tissue, and was strongly associated with insulin resistance. OBJECTIVE: The aim was to determine the relationship between RBP4 and obesity, insulin resistance, and other markers of insulin resistance in humans. DESIGN AND PATIENTS: RBP4 mRNA levels in adipose tissue and muscle of nondiabetic human subjects with either normal or impaired glucose tolerance (IGT) were studied, along with plasma RBP4. RBP4 gene expression was also measured in adipose tissue fractions, and from visceral and sc adipose tissue (SAT) from surgical patients. SETTING: The study was conducted at University Hospital and General Clinical Research Center. INTERVENTION: Insulin sensitivity (S(I)) was measured, and fat and muscle biopsies were performed. In IGT subjects, these procedures were performed before and after treatment with metformin or pioglitazone. MAIN OUTCOME MEASURES: The relationship between RBP4 expression and obesity, S(I), adipose tissue inflammation, and intramyocellular lipid level, and response to insulin sensitizers was measured. RESULTS: RBP4 was expressed predominantly from the adipocyte fraction of SAT. Although SAT RBP4 expression and the plasma RBP4 level demonstrated no significant relationship with body mass index or S(I), there was a strong positive correlation between RBP4 mRNA and adipose inflammation (monocyte chemoattractant protein-1 and CD68), and glucose transporter 4 mRNA. Treatment of IGT subjects with pioglitazone resulted in an increase in S(I) and an increase in RBP4 gene expression in both adipose tissue and muscle, but not in plasma RBP4 level, and the in vitro treatment of cultured adipocytes with pioglitazone yielded a similar increase in RBP4 mRNA. CONCLUSIONS: RBP4 gene expression in humans is associated with inflammatory markers, but not with insulin resistance. The increase in RBP4 mRNA after pioglitazone treatment is unusual, suggesting a complex regulation of this novel adipokine.     

Haemorheological, platelet and endothelial indices in relation to global measures of cardiovascular risk in hypertensive patients: a substudy of the Anglo-Scandinavian Cardiac Outcomes Trial

INTRODUCTION AND METHODS: We tested the hypothesis that there was a significant relationship between haemorheological markers [white blood cell count (WCC), plasma viscosity (PV), haematocrit (HCT) and fibrinogen], as well as plasma von Willebrand factor (vWf, an index of endothelial damage/dysfunction) and soluble P-selectin (sP-sel, an index of platelet activation), to five global measures of cardiovascular risk [i.e. Framingham coronary heart disease (CHD), stroke and cardiovascular death score, the Pocock cardiovascular risk score and the sum of individual risk factors]. RESULTS: Men with a high (> or = median, n = 156) Framingham 10-year CHD risk score had higher levels of WBC (P = 0.027), fibrinogen (P = 0.012) and vWF (P = 0.002) than 153 men with results < median. Men with a high 10-year stroke risk score had significantly higher levels of fibrinogen (P = 0.01) and vWF (P < 0.0001). In stepwise linear regression analysis in men, vWF and fibrinogen were independent predictors of the number of risk factors (P < 0.0001), whilst WCC, vWF and fibrinogen emerged as independent predictors of Framingham CHD risk (P < 0.0001), and fibrinogen and vWF predicted Framingham stroke risk (R(2) = 0.089, P < 0.0001). vWF, PV and fibrinogen were predictors of Pocock cardiovascular death risk (P < 0.0001) but vWF was the only independent predictor of Framingham cardiovascular death risk (P = 0.001). CONCLUSIONS: Abnormal haemorheological factors (particularly high plasma fibrinogen levels) and endothelial damage/dysfunction (high vWF), but not platelet activation (sP-sel), are related to established cardiovascular and death risk scores. This relationship was most evident amongst male 'high-risk' hypertensive subjects.     

Evolving resistance to obesity in an insect

Failure to adapt to a changing nutritional environment comes at a cost, as evidenced by the modern human obesity crisis. Consumption of energy-rich diets can lead to obesity and is associated with deleterious consequences not only in humans but also in many other animals, including insects. The question thus arises whether animals restricted over multiple generations to high-energy diets can evolve mechanisms to limit the deposition of adverse levels of body fat. We show that Plutella xylostella caterpillars reared for multiple generations on carbohydrate-rich foods (either a chemically defined artificial diet or a high-starch Arabidopsis mutant) progressively developed the ability to eat excess carbohydrate without laying it down as fat, providing strong evidence that excess fat storage has a fitness cost. In contrast, caterpillars reared in carbohydrate-scarce environments (a chemically defined artificial diet or a low-starch Arabidopsis mutant) had a greater propensity to store ingested carbohydrate as fat. Additionally, insects reared on the low-starch Arabidopsis mutant evolved a preference for laying their eggs on this plant, whereas those selected on the high-starch Arabidopsis mutant showed no preference. Our results provide an experimental example of metabolic adaptation in the face of changes in the nutritional environment and suggest that changes in plant macronutrient profiles may promote host-associated population divergence.