Reduced Bayesian Hierarchical Models: Estimating Health Effects of Simultaneous Exposure to Multiple Pollutants

Quantifying the health effects associated with simultaneous exposure to many air pollutants is now a research priority of the US EPA. Bayesian hierarchical models (BHM) have been extensively used in multisite time series studies of air pollution and health to estimate health effects of a single pollutant adjusted for potential confounding of other pollutants and other time-varying factors. However, when the scientific goal is to estimate the impacts of many pollutants jointly, a straightforward application of BHM is challenged by the need to specify a random-effect distribution on a high-dimensional vector of nuisance parameters, which often do not have an easy interpretation. In this paper we introduce a new BHM formulation, which we call "reduced BHM", aimed at analyzing clustered data sets in the presence of a large number of random effects that are not of primary scientific interest. At the first stage of the reduced BHM, we calculate the integrated likelihood of the parameter of interest (e.g. excess number of deaths attributed to simultaneous exposure to high levels of many pollutants). At the second stage, we specify a flexible random-effect distribution directly on the parameter of interest. The reduced BHM overcomes many of the challenges in the specification and implementation of full BHM in the context of a large number of nuisance parameters. In simulation studies we show that the reduced BHM performs comparably to the full BHM in many scenarios, and even performs better in some cases. Methods are applied to estimate location-specific and overall relative risks of cardiovascular hospital admissions associated with simultaneous exposure to elevated levels of particulate matter and ozone in 51 US counties during the period 1999-2005.

On Time Series Analysis of Public Health and Biomedical Data

A time series is a sequence of observations made over time. Examples in public health include daily ozone concentrations, weekly admissions to an emergency department or annual expenditures on health care in the United States. Time series models are used to describe the dependence of the response at each time on predictor variables including covariates and possibly previous values in the series. Time series methods are necessary to account for the correlation among repeated responses over time. This paper gives an overview of time series ideas and methods used in public health research.

Wheeze and asthma prevalence and related health-service use in white and south Asian pre-schoolchildren in the United Kingdom

BACKGROUND: Epidemiological data for south Asian children in the United Kingdom are contradictory, showing a lower prevalence of wheeze, but a higher rate of medical consultations and admissions for asthma compared with white children. These studies have not distinguished different asthma phenotypes or controlled for varying environmental exposures. OBJECTIVE: To compare the prevalence of wheeze and related health-service use in south Asian and white pre-schoolchildren in the United Kingdom, taking into account wheeze phenotype (viral and multiple wheeze) and environmental exposures. METHODS: A postal questionnaire was completed by parents of a population-based sample of 4366 white and 1714 south Asian children aged 1-4 years in Leicestershire, UK. Children were classified as having viral wheeze or multiple trigger wheeze. RESULTS: The prevalence of current wheeze was 35.6% in white and 25.5% in south Asian 1-year-olds (P<0.001), and 21.9% and 20.9%, respectively, in children aged 2-4 years. Odds ratios (ORs) (95% confidence interval) for multiple wheeze and for viral wheeze, comparing south Asian with white children, were 2.21 (1.19-4.09) and 1.43 (0.77-2.65) in 2-4-year-olds after controlling for socio-economic conditions, environmental exposures and family history. In 1-year-olds, the respective ORs for multiple and viral wheeze were 0.66 (0.47-0.92) and 0.81 (0.64-1.03). Reported GP consultation rates for wheeze and hospital admissions were greater in south Asian children aged 2-4 years, even after adjustment for severity, but the use of inhaled corticosteroids was lower. CONCLUSIONS: South Asian 2-4-year-olds are more likely than white children to have multiple wheeze (a condition with many features of chronic atopic asthma), after taking into account ethnic differences in exposure to some environmental agents. Undertreatment with inhaled corticosteroids might partly explain their greater use of health services.

[Pneumonia: what's new?]

Pneumonia continues to be one of the most important infectious diseases which often leads to hospital admissions and is occasionally fatal. The spectrum of causative organisms, their sensitivity pattern to antibiotics, diagnostic tools, and available antibiotics are continually changing. Currently, the most disquieting trend is the increasing development of resistance to commonly used antibiotics by the pneumococcus. Although this trend has thus far been observed primarily in other countries, it will most likely not spare Switzerland. Rational empiric therapy must include careful clinical assessment of the patient, knowledge of the spectrum of organisms locally causing pneumonias, including their resistance patterns, as well as a prognostic assessment of the patient. Using these factors, possible antibiotic schemes for empiric therapy of community-acquired pneumonia are reviewed.

Associations with multiple pituitary hormone deficiency in patients with an ectopic posterior pituitary gland

INTRODUCTION: The presence of an ectopic posterior pituitary gland (EPP) on magnetic resonance imaging (MRI) is associated with hypopituitarism with one or more hormone deficiencies. We aimed to identify risk factors for having multiple pituitary hormone deficiency (MPHD) compared to isolated growth hormone deficiency (IGHD) in patients with an EPP. METHODS: In 67 patients (45 male) with an EPP on MRI, the site (hypothalamic vs. stalk) and surface area (SA) [ x (maximum diameter/2) x (maximum height/2), mm(2)] of the EPP were recorded and compared in patients with IGHD and MPHD in relation to clinical characteristics. RESULTS: In MPHD (n = 32) compared to IGHD (n = 35) patients: age of presentation was younger (1.4 [0.1-10.7]vs. 4.0 [0.1-11.3] years, P = 0.005), major incidents during pregnancy were increased (47%vs. 20%, P = 0.02) as were admissions to a neonatal intensive care unit (NICU) (60%vs. 26%, P = 0.04), whilst EPP SA was lower (12.3 [2.4-34.6]vs. 25.7 [6.9-48.2] mm(2), P < 0.001). In patients with a hypothalamic (n = 56) compared to a stalk sited EPP (n = 11): prevalence of MPHD was greater (55%vs. 9%,P = 0.05) and EPP surface area was smaller (17.3 [2.4-48.2]vs. 25.3 [11.8-38.5] mm(2), P < 0.001). In regression analysis, after adjusting for age, presence of MPHD was associated with: major incidents during pregnancy (RR 6.8 [95%CI 1.2-37.7]), hypothalamic EPP site (RR 10.9 [1.0-123.9]) and small EPP SA (RR 2.5 [1.0-5.0] for tertiles of SA). CONCLUSION: In patients with an EPP, adverse antenatal events, size (small) and position (hypothalamic) of the posterior pituitary gland on MRI were associated with MPHD. These findings suggest that adverse factors during pregnancy may be important for the development of an EPP.

Multidimensional preventive home visit programs for community-dwelling older adults: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND: Multidimensional preventive home visit programs aim at maintaining health and autonomy of older adults and preventing disability and subsequent nursing home admission, but results of randomized controlled trials (RCTs) have been inconsistent. Our objective was to systematically review RCTs examining the effect of home visit programs on mortality, nursing home admissions, and functional status decline. METHODS: Data sources were MEDLINE, EMBASE, Cochrane CENTRAL database, and references. Studies were reviewed to identify RCTs that compared outcome data of older participants in preventive home visit programs with control group outcome data. Publications reporting 21 trials were included. Data on study population, intervention characteristics, outcomes, and trial quality were double-extracted. We conducted random effects meta-analyses. RESULTS: Pooled effects estimates revealed statistically nonsignificant favorable, and heterogeneous effects on mortality (odds ratio [OR] 0.92, 95% confidence interval [CI], 0.80-1.05), functional status decline (OR 0.89, 95% CI, 0.77-1.03), and nursing home admission (OR 0.86, 95% CI, 0.68-1.10). A beneficial effect on mortality was seen in younger study populations (OR 0.74, 95% CI, 0.58-0.94) but not in older populations (OR 1.14, 95% CI, 0.90-1.43). Functional decline was reduced in programs including a clinical examination in the initial assessment (OR 0.64, 95% CI, 0.48-0.87) but not in other trials (OR 1.00, 95% CI, 0.88-1.14). There was no single factor explaining the heterogenous effects of trials on nursing home admissions. CONCLUSION: Multidimensional preventive home visits have the potential to reduce disability burden among older adults when based on multidimensional assessment with clinical examination. Effects on nursing home admissions are heterogeneous and likely depend on multiple factors including population factors, program characteristics, and health care setting.

Resource use and outcome in critically ill patients with hematological malignancy: a retrospective cohort study

INTRODUCTION: The paucity of data on resource use in critically ill patients with hematological malignancy and on these patients' perceived poor outcome can lead to uncertainty over the extent to which intensive care treatment is appropriate. The aim of the present study was to assess the amount of intensive care resources needed for, and the effect of treatment of, hemato-oncological patients in the intensive care unit (ICU) in comparison with a nononcological patient population with a similar degree of organ dysfunction. METHODS: A retrospective cohort study of 101 ICU admissions of 84 consecutive hemato-oncological patients and 3,808 ICU admissions of 3,478 nononcological patients over a period of 4 years was performed. RESULTS: As assessed by Therapeutic Intervention Scoring System points, resource use was higher in hemato-oncological patients than in nononcological patients (median (interquartile range), 214 (102 to 642) versus 95 (54 to 224), P < 0.0001). Severity of disease at ICU admission was a less important predictor of ICU resource use than necessity for specific treatment modalities. Hemato-oncological patients and nononcological patients with similar admission Simplified Acute Physiology Score scores had the same ICU mortality. In hemato-oncological patients, improvement of organ function within the first 48 hours of the ICU stay was the best predictor of 28-day survival. CONCLUSION: The presence of a hemato-oncological disease per se is associated with higher ICU resource use, but not with increased mortality. If withdrawal of treatment is considered, this decision should not be based on admission parameters but rather on the evolutional changes in organ dysfunctions.

Affirmative Action Endures Three Decades of Challenges: The Pursuit of Diversity on Campus

Race and affirmative action are among the most contentious issues in higher education. This talk will explore the constitutionality of affirmative action in college admissions. What principles and technicalities are dominating the discussion, and what strategies show the most promise?

Epidemiology and direct medical costs of osteoporotic fractures in men and women in Switzerland

The aim of this study was to estimate the hospitalization incidence and the total number of hospital days related to all fractures and osteoporotic fractures in the year 2000 in Switzerland and to compare these with data from other frequent disorders in men and women. The official administrative and medical statistics database of the Swiss Federal Office of Statistics (SFOS) from the year 2000 was used. It covered 81.2% of all registered patient admissions and was considered to be representative of the entire population. We included the ICD-10 codes of 84 diagnoses that were compatible with an underlying osteoporosis and applied the best matching age-specific osteoporosis attribution rates published for the ICD-9 diagnosis codes to the individual ICD-10 codes. To preserve comparability with previously published data from 1992, we grouped the data related to the ICD-10 fracture codes into seven diagnosis pools (fractures of the axial skeleton, fractures of the proximal upper limbs, fractures of the distal upper limbs, fractures of the proximal lower limbs, fractures of the distal lower limbs, multiple fractures, and osteoporosis) and analyzed them separately for women and men by age group. Incidences of hospitalization due to fractures were calculated, and the direct medical costs related to hospitalization were estimated. In addition, we compared the results with those from chronic pulmonary obstructive disease (COPD), stroke, acute myocardial infarction, heart failure, diabetes and breast carcinoma from the same database. In Switzerland during 2000, 62,535 hospitalizations for fractures (35,586 women and 26,949 men) were registered. Fifty-one percent of all fractures in women and 24% in men were considered as osteoporotic. The overall incidences of hospitalization due to fractures were 969 and 768 per 100,000 in women and men, respectively. The hospitalization incidences for fractures of the proximal lower limbs and the axial skeleton increased exponentially after the age of 65 years. The direct medical cost of hospitalization of patients with osteoporosis and/or related fractures was 357 million CHF. Hip fractures accounted for approximately half of these costs in women and men. Among other common diseases in women and men, osteoporosis ranked number 1 in women and number 2 (behind COPD) in men. When compared with data from 1992, the average length of stay had shortened by 8.4 days for women and 4.7 days for men, leading to a decrease of almost 40% in direct medical costs related to acute hospitalizations. This apparent decrease in cost might result from a shift into the ambulatory cost segment, for which the assessment and management tools need to be developed. We conclude that, in 2000, osteoporosis continued to be a heavy burden on the Swiss healthcare system. Lack of awareness of the disease and its consequences prevents widespread use of drugs with anti-fracture efficacy. This limits their potential to reduce costs.

[Community-integrated acute psychiatric care. Options and limitations]

The shift of psychiatric care from the hospital to the community has been accompanied by a reduction of hospital beds and shortened durations of inpatient treatment, but also by an increase in admissions. This evolution may be largely attributed to the prime focus of community mental health institutions on rehabilitation. The continued implementation of reforms in psychiatric care is contingent upon effectively halting the "revolving door phenomenon" by incorporating community-integrated treatment approaches into the care of acutely ill patients. Since the mid-1960s, a series of studies have established the efficacy of two community-integrated modalities for the treatment of acute psychiatric illness, i.e. home-based and day hospital treatment. In general, these approaches not only seem to be as effective as inpatient care for certain groups of patients but also reduce their need of hospitalisation, thereby contributing towards a cost effective, comprehensive psychiatric care system.

Maternal and neonatal outcomes by labor onset type and gestational age.

OBJECTIVE: We sought to determine maternal and neonatal outcomes by labor onset type and gestational age. STUDY DESIGN: We used electronic medical records data from 10 US institutions in the Consortium on Safe Labor on 115,528 deliveries from 2002 through 2008. Deliveries were divided by labor onset type (spontaneous, elective induction, indicated induction, unlabored cesarean). Neonatal and maternal outcomes were calculated by labor onset type and gestational age. RESULTS: Neonatal intensive care unit admissions and sepsis improved with each week of gestational age until 39 weeks (P < .001). After adjusting for complications, elective induction of labor was associated with a lower risk of ventilator use (odds ratio [OR], 0.38; 95% confidence interval [CI], 0.28-0.53), sepsis (OR, 0.36; 95% CI, 0.26-0.49), and neonatal intensive care unit admissions (OR, 0.52; 95% CI, 0.48-0.57) compared to spontaneous labor. The relative risk of hysterectomy at term was 3.21 (95% CI, 1.08-9.54) with elective induction, 1.16 (95% CI, 0.24-5.58) with indicated induction, and 6.57 (95% CI, 1.78-24.30) with cesarean without labor compared to spontaneous labor. CONCLUSION: Some neonatal outcomes improved until 39 weeks. Babies born with elective induction are associated with better neonatal outcomes compared to spontaneous labor. Elective induction may be associated with an increased hysterectomy risk.

Modern approaches to pediatric brain injury therapy.

Each year, pediatric traumatic brain injury (TBI) accounts for 435,000 emergency department visits, 37,000 hospital admissions, and approximately 2,500 deaths in the United States. TBI results in immediate injury from direct mechanical force and shear. Secondary injury results from the release of biochemical or inflammatory factors that alter the loco-regional milieu in the acute, subacute, and delayed intervals after a mechanical insult. Preliminary preclinical and clinical research is underway to evaluate the benefit from progenitor cell therapeutics, hypertonic saline infusion, and controlled hypothermia. However, all phase III clinical trials investigating pharmacologic monotherapy for TBI have shown no benefit. A recent National Institutes of Health consensus statement recommends research into multimodality treatments for TBI. This article will review the complex pathophysiology of TBI as well as the possible therapeutic mechanisms of progenitor cell transplantation, hypertonic saline infusion, and controlled hypothermia for possible utilization in multimodality clinical trials.

Riding the Escalator: How Dangerous is it Really?

INTRODUCTION About 10,000 escalator-related injuries per year result in emergency department treatment in the United States. Since the 1990s, a steady increase has been reported, but few statistics on escalator-related injuries have been published worldwide. We have therefore analyzed escalator accident statistics in admissions to our hospital in Switzerland since 2000. METHODS Using retrospective electronic patient chart analysis, we included in our study patients >16 years treated over an 11-year period. We categorized patients in terms of gender, age and associated risk factors, and classified accidents according to day, time, location and cause. Resulting trauma was categorized according to type and location. We divided post-admission treatment into surgical and conservative, and into treatment as an outpatient, in a short-stay unit, or as a hospital admission. Women and men were compared using Fisher's exact test. RESULTS We identified 173 patients with 285 discrete injuries. Of these, 87 patients (50%) were women. Fifty-three (61%) of the women and 38 (44%) of the men were >60 years old (P = 0.033). Fifty percent of the men (43/86) of the men, but only 7% (6/87) of the women showed signs of alcohol intoxication (P < 0.0001). Accidents in women occurred predominantly on Tuesdays (19/87; 22%) between 12pm and 6pm (35/87; 40%), and in men on Saturdays (16/86; 19%) between 6pm and 12am (29/86; 34%; P = 0.0097). Sixty-two percent (44/71) of the accidents were in public transport facilities and 30% (21/71) in shopping centers. The majority of injuries in women were to the lower extremities (49/87; 56%), while most accidents in men were to the head and neck (51/86; 59%; P = 0.0052). About half (90; 52%) of the patients were treated conservatively. Almost half of all patients (76, 44%) required hospital admission. Of those, 45% left the hospital within 24 hours of admission (short stay unit) and 55% stayed longer than 24 hours. CONCLUSION Escalator accidents can result in severe trauma. Significant gender differences in escalator accidents have been observed. Alcohol intoxication and age are significant risk factors in escalator-related accidents and might be possible targets for preventive measures.

Integrated care programmes for adults with chronic conditions: a meta-review.

OBJECTIVE To review systematic reviews and meta-analyses of integrated care programmes in chronically ill patients, with a focus on methodological quality, elements of integration assessed and effects reported. DESIGN Meta-review of systematic reviews and meta-analyses identified in Medline (1946-March 2012), Embase (1980-March 2012), CINHAL (1981-March 2012) and the Cochrane Library of Systematic Reviews (issue 1, 2012). MAIN OUTCOME MEASURES Methodological quality assessed by the 11-item Assessment of Multiple Systematic Reviews (AMSTAR) checklist; elements of integration assessed using a published list of 10 key principles of integration; effects on patient-centred outcomes, process quality, use of healthcare and costs. RESULTS Twenty-seven systematic reviews were identified; conditions included chronic heart failure (CHF; 12 reviews), diabetes mellitus (DM; seven reviews), chronic obstructive pulmonary disease (COPD; seven reviews) and asthma (five reviews). The median number of AMSTAR checklist items met was five: few reviewers searched for unpublished literature or described the primary studies and interventions in detail. Most reviews covered comprehensive services across the care continuum or standardization of care through inter-professional teams, but organizational culture, governance structure or financial management were rarely assessed. A majority of reviews found beneficial effects of integration, including reduced hospital admissions and re-admissions (in CHF and DM), improved adherence to treatment guidelines (DM, COPD and asthma) or quality of life (DM). Few reviews showed reductions in costs. CONCLUSIONS Systematic reviews of integrated care programmes were of mixed quality, assessed only some components of integration of care, and showed consistent benefits for some outcomes but not others.

Avoidable hospitalizations in Switzerland: a small area analysis on regional variation, density of physicians, hospital supply and rurality.

BACKGROUND Avoidable hospitalizations (AH) are hospital admissions for diseases and conditions that could have been prevented by appropriate ambulatory care. We examine regional variation of AH in Switzerland and the factors that determine AH. METHODS We used hospital service areas, and data from 2008-2010 hospital discharges in Switzerland to examine regional variation in AH. Age and sex standardized AH were the outcome variable, and year of admission, primary care physician density, medical specialist density, rurality, hospital bed density and type of hospital reimbursement system were explanatory variables in our multilevel poisson regression. RESULTS Regional differences in AH were as high as 12-fold. Poisson regression showed significant increase of all AH over time. There was a significantly lower rate of all AH in areas with more primary care physicians. Rates increased in areas with more specialists. Rates of all AH also increased where the proportion of residences in rural communities increased. Regional hospital capacity and type of hospital reimbursement did not have significant associations. Inconsistent patterns of significant determinants were found for disease specific analyses. CONCLUSION The identification of regions with high and low AH rates is a starting point for future studies on unwarranted medical procedures, and may help to reduce their incidence. AH have complex multifactorial origins and this study demonstrates that rurality and physician density are relevant determinants. The results are helpful to improve the performance of the outpatient sector with emphasis on local context. Rural and urban differences in health care delivery remain a cause of concern in Switzerland.