Abstract

Many models of infectious disease ignore the underlying contact structure through which the disease spreads. However, in order to evaluate the efficacy of certain disease control interventions, it may be important to include this network structure. We present a network modeling framework of the spread of disease and a methodology for inferring important model parameters, such as those governing network structure and network dynamics, from readily available data sources. This is a general and flexible framework with wide applicability to modeling the spread of disease through sexual or close contact networks. To illustrate, we apply this modeling framework to evaluate HIV control programs in sub-Saharan Africa, including programs aimed at concurrent partnership reduction, reductions in risky sexual behavior, and scale up of HIV treatment.

Abstract

In an era of limited healthcare budgets, mathematical models can be useful tools to identify cost-effective programs and to support policymakers in informed decision making. This paper reports results of our work carried out over several years with the Asian Liver Center at Stanford University, a nonprofit outreach and advocacy organization that is an international leader in the fight against hepatitis B and liver cancer. Hepatitis B is a vaccine-preventable viral disease that, if untreated, can lead to death from cirrhosis and liver cancer. Infection with hepatitis B is a major public health problem, particularly in Asian populations. We used new combinations of decision analysis and Markov models to analyze the cost-effectiveness of several interventions to combat hepatitis B in the United States and China. The results of our OR-based analyses have helped change United States public health policy on hepatitis B screening for millions of people and have helped encourage policymakers in China to enact legislation to provide free catch-up vaccination for hundreds of millions of children. These policies are an important step in eliminating health disparities, reducing discrimination, and ensuring that millions of people who need it can now receive hepatitis B vaccination or lifesaving treatment.

Abstract

BACKGROUND- The majority of current implantable cardioverter-defibrillator (ICD) recipients are significantly older than those in the ICD trials. Data on periprocedural complications among the elderly are insufficient. We evaluated the influence of age on perioperative complications among primary prevention ICD recipients in the United States. METHODS AND RESULTS- Using the National Cardiovascular Data's ICD Registry, we identified 150 264 primary prevention patients who received ICDs from January 2006 to December 2008. The primary end point was any adverse event or in-hospital mortality. Secondary end points included major adverse events, minor adverse events, and length of stay. Of 150 264 patients, 61% (n=91 863) were 65 years and older. A higher proportion of patients ≥65 years had diabetes, congestive heart failure, atrial fibrillation, renal disease, and coronary artery disease. Approximately 3.4% of the entire cohort had any complication, including death, after ICD implant. Any adverse event or death occurred in 2.8% of patients under 65 years old; 3.1% of 65- to 69-year-olds; 3.5% of 70- to 74-year-olds; 3.9% of 75- to 79-year-olds, 4.5% of 80- to 84-year-olds; and 4.5% of patients 85 years and older. After adjustment for clinical covariates, multivariate analysis found an increased odds of any adverse event or death among 75- to 79-year-olds (1.14 [95% confidence interval, 1.03 to 1.25], 80-to 84-year-olds (1.22 [95% confidence interval, 1.10 to 1.36], and patients 85 years and older (1.15 [95% confidence interval, 1.01 to 1.32], compared with patients under 65 years old. CONCLUSIONS- Older patients had a modestly increased-but acceptably safe-risk of periprocedural complications and in-hospital mortality, driven mostly by increased comorbidity.

Abstract

Despite the recent advances made in the care of children with sickle cell disease (SCD), premature mortality, especially among older children and young adults, remains a hallmark of this disease. The lack of survival gains highlights the translational gap of implementing innovations found efficacious in the controlled trial setting into routine clinical practice. Health services research (HSR) examines the most effective ways to finance, organize, and deliver high quality care in an equitable manner. To date, HSR has been underutilized as a means to improve the outcomes for children with SCD. Emerging national priorities in health care delivery, new sources of funding, and evolving electronic data collection systems for patients with SCD have provided a unique opportunity to overcome the translational gap in pediatric SCD. The purpose of this article is to provide a comprehensive HSR agenda to create patient-specific evidence of clinical effectiveness for interventions used in the routine care setting, understand the barriers faced by clinicians to providing high quality care, assess and improve the interactions of patients with the health care system, and measure the quality of care delivered to increase survival for all children and young adults with SCD.

The mechanism by which strictly CCR5 using HIV-1 clade C variants exacerbate disease progression in absence of coreceptor switch is not clearly known. We previously reported HIV-1 cladeC envelopes (Env) obtained from late stage Indian patients with expanded coreceptor tropism. Here we compared such Envs (having expanded coreceptor tropism) with strictly CCR5 using Envs also obtained from late stage in their capacity to utilize CD4 and CCR5 for productive entry. We found that while envelopes with low CD4 dependence tend to infect primary CD4(+) T cells better than those required optimum CD4 for entry, no significant association was found between low CD4 usage and infectivity of primary CD4(+) T cells by Env-pseudotyped viruses and theirsensitivity to CCR5 antagonist TAK-779. Interestingly, Envs that readily infected HeLa cells expressing low CD4 showed relative resistance to T20 indicating that conformational intermediates of these envelopes remained for a shorter period of time than is required for efficient inhibition by T20.

Abstract

BACKGROUND:

While studies have demonstrated higher medium-term mortality for community-acquired pneumonia (CAP), mortality and costs have not been characterized for healthcare-associated pneumonia (HCAP) over a 1-year period.

METHODS:

We conducted a retrospective cohort study to evaluate mortality rates and health system costs for patients with CAP or HCAP during initial hospitalization and for 1 year after hospital discharge. We selected 50 758 patients admitted to the Veterans Affairs (VA) healthcare system between October 2003 and May 2007. Main outcome measures included hospital, post-discharge, and cumulative mortality rates and cost during initial hospitalization and at 12 months following discharge.

RESULTS:

Hospital and 1-year HCAP mortality were nearly twice that of CAP. HCAP was an independent predictor for hospital mortality (odds ratio (OR) 1.62, 95% confidence interval (CI) 1.49-1.76) and 1-year mortality (OR 1.99, 95% CI 1.87-2.11) when controlling for demographics, comorbidities, pneumonia severity, and factors associated with multidrug-resistant infection, including immune suppression, previous antibiotic treatment, and aspiration pneumonia. HCAP patients consistently had higher mortality in each stratum of the Charlson-Deyo-Quan comorbidity index. HCAP patients incurred significantly greater cost during the initial hospital stay and in the following 12 months. Demographics and comorbid conditions, particularly aspiration pneumonia, accounted for 19-33% of this difference.

CONCLUSION:

HCAP represents a distinct category of pneumonia with particularly poor survival up to 1 year after hospital discharge. While comorbidities, pneumonia severity, and risk factors for multidrug-resistant infection may interact to produce even higher mortality compared to CAP, they alone do not explain the observed differences.

Summary

Cardiac arrhythmias during sleep are relatively common and include a diverse etiology, from benign sinus bradycardia to potentially fatal ventricular arrhythmias. Predisposing factors include obstructive sleep apnea and cardiac disease. Rapid eye movement (REM)-related bradyarrhythmia syndrome (including sinus arrest and complete atrioventricular block with ventricular asystole) in the absence of an underlying cardiac or physiologic sleep disorder was first described in the early 1980s. Although uncertain, the underlying pathophysiology likely reflects abnormal autonomic neural-cardiac inputs during REM sleep. The autonomic nervous system (ANS) is a known key modulator of heart rate fluctuations and rhythm during sleep and nocturnal heart rate reflects a balance between the sympathetic-parasympathetic systems. Whether the primary trigger for REM-related bradyarrhythmias reflects abnormal centrally mediated control of the ANS during REM sleep or anomalous baroreflex parasympathetic influences is unknown. This review focuses on the salient features of the REM-related bradyarrhythmia syndrome and explores potential mechanisms with a particular assessment of the relationship between the ANS and nocturnal heart rate fluctuations.

Author information: IOM (Institute of Medicine) and NRC (National Research Council). (Committee: Goldstein BD, DeSimone JM, Ascher MS, Buehler JW, Cook KS, Crouch NA, Doyle FJ, Foldy S, Gursky EA, Hoffman S, Johnson CB, Keim P, Kellerman AL, Kleinman KP, Layton M, Lee EK, Mayor SD, Moshier TF, Murphy FA, Murray RW, Owens DK, Pollock SM, Resnick IG, Schaudies RP, Schultz JS)

Following the attacks of September 11, 2001 and the anthrax letters, the ability to detect biological threats as quickly as possible became a top priority. In 2003 the Department of Homeland Security (DHS) introduced the BioWatch program--a federal monitoring system intended to speed detection of specific biological agents that could be released in aerosolized form during a biological attack. 

The present volume evaluates the costs and merits of both the current BioWatch program and the plans for a new generation of BioWatch devices. BioWatch and Public Health Surveillance also examines infectious disease surveillance through hospitals and public health agencies in the United States, and considers whether BioWatch and traditional infectious disease surveillance are redundant or complementary.