Gerald van Belle

Explicit Calculation of the Rarefaction Diversity Measurement and the Determination of Sufficient Sample Size

An explicit means of calculating the expected number of species [E(Sn)] and the variance of (Sn) in a random sample of n individuals from a collection containing N individuals and S species is presented. An example illustrates a new use of E(Sn): determination of the sample size required for any desired degree of accuracy in collecting species known to occur in a particular area.

Transfusion of Plasma, Platelets, and Red Blood Cells in a 1:1:1 vs a 1:1:2 Ratio and Mortality in Patients With Severe Trauma: The PROPPR Randomized Clinical Trial

IMPORTANCE Severely injured patients experiencing hemorrhagic shock often require massive transfusion. Earlier transfusion with higher blood product ratios (plasma, platelets, and red blood cells), defined as damage control resuscitation, has been associated with improved outcomes; however, there have been no large multicenter clinical trials. OBJECTIVE To determine the effectiveness and safety of transfusing patients with severe trauma and major bleeding using plasma, platelets, and red blood cells in a 1:1:1 ratio compared with a 1:1:2 ratio. DESIGN, SETTING, AND PARTICIPANTS Pragmatic, phase 3, multisite, randomized clinical trial of 680 severely injured patients who arrived at 1 of 12 level I trauma centers in North America directly from the scene and were predicted to require massive transfusion between August 2012 and December 2013. INTERVENTIONS Blood product ratios of 1:1:1 (338 patients) vs 1:1:2 (342 patients) during active resuscitation in addition to all local standard-of-care interventions (uncontrolled). MAIN OUTCOMES AND MEASURES Primary outcomes were 24-hour and 30-day all-cause mortality. Prespecified ancillary outcomes included time to hemostasis, blood product volumes transfused, complications, incidence of surgical procedures, and functional status. RESULTS No significant differences were detected in mortality at 24 hours (12.7% in 1:1:1 group vs 17.0% in 1:1:2 group; difference, -4.2% [95% CI, -9.6% to 1.1%]; P = .12) or at 30 days (22.4% vs 26.1%, respectively; difference, -3.7% [95% CI, -10.2% to 2.7%]; P = .26). Exsanguination, which was the predominant cause of death within the first 24 hours, was significantly decreased in the 1:1:1 group (9.2% vs 14.6% in 1:1:2 group; difference, -5.4% [95% CI, -10.4% to -0.5%]; P = .03). More patients in the 1:1:1 group achieved hemostasis than in the 1:1:2 group (86% vs 78%, respectively; P = .006). Despite the 1:1:1 group receiving more plasma (median of 7 U vs 5 U, P < .001) and platelets (12 U vs 6 U, P < .001) and similar amounts of red blood cells (9 U) over the first 24 hours, no differences between the 2 groups were found for the 23 prespecified complications, including acute respiratory distress syndrome, multiple organ failure, venous thromboembolism, sepsis, and transfusion-related complications. CONCLUSIONS AND RELEVANCE Among patients with severe trauma and major bleeding, early administration of plasma, platelets, and red blood cells in a 1:1:1 ratio compared with a 1:1:2 ratio did not result in significant differences in mortality at 24 hours or at 30 days. However, more patients in the 1:1:1 group achieved hemostasis and fewer experienced death due to exsanguination by 24 hours. Even though there was an increased use of plasma and platelets transfused in the 1:1:1 group, no other safety differences were identified between the 2 groups. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01545232.

Prevention of antibiotic-associated diarrhea by Saccharomyces boulardii: A prospective study

Saccharomyces boulardii, a nonpathogenic yeast, has been widely used in Europe to prevent antibiotic-associated diarrhea (AAD). We performed a prospective double-blind controlled study to investigate AAD in hospitalized patients and to evaluate the effect of S. boulardii, a living yeast, given in capsule form concurrently with antibiotics. Over 23 mo, 180 patients completed the study. Of the patients receiving placebo, 22% experienced diarrhea compared with 9.5% of patients receiving S. boulardii (p = 0.038). Risk factors found to be associated with AAD were multiple antibiotic combinations (containing clindamycin, cephalosporins, or trimethoprim-sulfamethoxazole) and tube feeding. Clostridium difficile, an anaerobe found in the stools of most patients with pseudomembranous colitis, was variably associated with AAD. We evaluated the role of C. difficile in AAD in the study population and found no significant association between the presence of C. difficile or cytotoxin with AAD. Approximately 33% of the patients without diarrhea harbored at least one C. difficile-positive stool and nearly 50% of these patients had detectable cytotoxin. Similar values were obtained in patients with diarrhea. Of C. difficile-positive patients, 31% (5/16) on placebo developed diarrhea compared with 9.4% (3/32) on S. boulardii; this difference was not statistically significant (p = 0.07). There were no discernable adverse effects of yeast administration. We conclude that S. boulardii reduces the incidence of antibiotic-associated diarrhea in hospitalized patients.

Predictors of Functional Change: A Longitudinal Study of Nondemented People Aged 65 and Older

OBJECTIVES: To identify factors associated with functional change in an older population and investigate interactions among selected potential risk factors.

Clinical course of spontaneous subarachnoid hemorrhage: A population‐based study in King County, Washington

Over 2 years, we identified 171 patients in King County, Washington, experiencing an incident subarachnoid hemorrhage and characterized their clinical course and outcome. Most (65%) were women and most (68%) were under age sixty-five. Only five died without medical attention. The remaining 166 patients were hospitalized and had CTs of the head. Of these, 103 underwent aneurysm surgery, 40 developed acute hydrocephalus, 32 had symptomatic vasospasm, and 30 re-bled. Sixty-eight percent (68%) survived to 1 month after the bleed and 62% to 1 year. Independent predictors of good recovery by 1 month after the bleed included youth, a high score on the admission Glasgow Coma Scale, and absence of blood on the first CT. In this population-based series, at 1 month after the bleed, approximately one-third of patients were dead, one-third had neurologic deficits, and one-third were doing well.

Subjective memory deterioration and future dementia in people aged 65 and older

Objectives: To study whether subjective memory deterioration is associated with future dementia in older people.

Differential item functioning analysis with ordinal logistic regression techniques. DIFdetect and difwithpar.

Introduction:We present an ordinal logistic regression model for identification of items with differential item functioning (DIF) and apply this model to a Mini-Mental State Examination (MMSE) dataset. We employ item response theory ability estimation in our models. Three nested ordinal logistic regression models are applied to each item. Model testing begins with examination of the statistical significance of the interaction term between ability and the group indicator, consistent with nonuniform DIF. Then we turn our attention to the coefficient of the ability term in models with and without the group term. If including the group term has a marked effect on that coefficient, we declare that it has uniform DIF. We examined DIF related to language of test administration in addition to self-reported race, Hispanic ethnicity, age, years of education, and sex. Methods:We used PARSCALE for IRT analyses and STATA for ordinal logistic regression approaches. We used an iterative technique for adjusting IRT ability estimates on the basis of DIF findings. Results:Five items were found to have DIF related to language. These same items also had DIF related to other covariates. Discussion:The ordinal logistic regression approach to DIF detection, when combined with IRT ability estimates, provides a reasonable alternative for DIF detection. There appear to be several items with significant DIF related to language of test administration in the MMSE. More attention needs to be paid to the specific criteria used to determine whether an item has DIF, not just the technique used to identify DIF.

Effects of Electronic Fetal-Heart-Rate Monitoring, as Compared with Periodic Auscultation, on the Neurologic Development of Premature Infants

In a multicenter, randomized clinical trial, we assessed the early neurologic development of 93 children born prematurely whose heart rates were monitored electronically during delivery and compared it with that of 96 children born prematurely whose heart rates were periodically monitored by auscultation. All the children were singletons with cephalic presentation, and all weighed less than or equal to 1750 g at birth. The mental and psychomotor indexes of the Bayley Scales of Infant Development (standardized mean score +/- SD, 100 +/- 16) and a formal neurologic examination were administered at three follow-up visits (at 4, 8, and 18 months of age, corrected for gestational age). At 18 months, the mean mental-development scores in the groups receiving electronic fetal monitoring and periodic auscultation were 100.5 +/- 2.4 and 104.9 +/- 1.8, respectively (P greater than 0.1). The mean psychomotor-development scores in the two groups at 18 months were 94.0 +/- 2.4 and 98.3 +/- 1.8, respectively (P greater than 0.1). The incidence of cerebral palsy was higher in the electronically monitored group--20 percent as compared with 8 percent in the group that was monitored by auscultation (P less than 0.03). In the electronic-fetal-monitoring group (but not in the periodic-auscultation group), the risk of cerebral palsy increased with the duration of abnormal fetal-heart-rate patterns, as assessed by retrospective review (chi 2 trend = 12.71, P less than 0.001). The median time to delivery after the diagnosis of abnormal fetal-heart-rate patterns was 104 minutes with electronic fetal monitoring, as compared with 60 minutes with periodic auscultation. We conclude that as compared with a structured program of periodic auscultation, electronic fetal monitoring does not result in improved neurologic development in children born prematurely.

Incidence of amyotrophic lateral sclerosis in three counties in western Washington state

We conducted a population-based study of amyotrophic lateral sclerosis (ALS) in King, Pierce, and Snohomish counties in western Washington state. Between April 1, 1990 and March 31, 1995, neurologists diagnosed 235 patients with ALS, including 127 men (54%) and 108 women (46%). The incidence rate, age-adjusted to the 1990 total U.S. population, was higher for men at 2.1 per 100,000 per year (95% CI, 1.3 to 2.9) than for women at 1.9 (95% CI, 1.1, 2.7) and increased with age for both men and women. These incidence rates are consistent with other studies from northern latitudes. NEUROLOGY 1996;47: 571-573

Consortium to Establish a Registry for Alzheimer's Disease (CERAD): the first twenty years.

The Consortium to Establish a Registry for Alzheimers Disease (CERAD) was funded by the National Institute on Aging in 1986 to develop standardized, validated measures for the assessment of Alzheimers disease (AD). The present report describes the measures that CERAD developed during its first decade and their continued use in their original and translated forms. These measures include clinical, neuropsychological, neuropathologic, and behavioral assessments of AD and also assessment of family history and parkinsonism in AD. An approach to evaluating neuroimages did not meet the standards desired. Further evaluations that could not be completed because of lack of funding (but where some materials are available) include evaluation of very severe AD and of service use and need by patient and caregiver. The information that was developed in the U.S. and abroad permits standardized assessment of AD in clinical practice, facilitates epidemiologic studies, and provides information valuable for individual and public health planning. CERAD materials and data remain available for those wishing to use them.