Cost-effectiveness analysis of coronary artery disease screening in HIV-infected men.

BACKGROUND: HIV-infected patients are at increased risk of coronary artery disease (CAD). We evaluated the cost-effectiveness of cardiac screening for HIV-positive men at intermediate or greater CAD risk. DESIGN: We developed a lifetime microsimulation model of CAD incidence and progression in HIV-infected men. METHODS: Input parameters were derived from two HIV cohort studies and the literature. We compared no CAD screening with stress testing and coronary computed tomography angiography (CCTA)-based strategies. Patients with test results indicating 3-vessel/left main CAD underwent invasive coronary angiography (ICA) and received coronary artery bypass graft surgery. In the stress testing + medication and CCTA + medication strategies, patients with 1-2-vessel CAD results received lifetime medical treatment without further diagnostics whereas in the stress testing + intervention and CCTA + intervention strategies, patients with these results underwent ICA and received percutaneous coronary intervention. RESULTS: Compared to no screening, the stress testing + medication, stress testing + intervention, CCTA + medication, and CCTA + intervention strategies resulted in 14, 11, 19, and 14 quality-adjusted life days per patient and incremental cost-effectiveness ratios of 49,261, 57,817, 34,887 and 56,518 Euros per quality-adjusted life year (QALY), respectively. Screening only at higher CAD risk thresholds was more cost-effective. Repeated screening was clinically beneficial compared to one-time screening, but only stress testing + medication every 5 years remained cost-effective. At a willingness-to-pay threshold of 83,000 €/QALY (∼ 100,000 US$/QALY), implementing any CAD screening was cost-effective with a probability of 75-95%. CONCLUSIONS: Screening HIV-positive men for CAD would be clinically beneficial and comes at a cost-effectiveness ratio comparable to other accepted interventions in HIV care.

Barriers to treatment access for Chagas disease in Mexico.

BACKGROUND: According to World Health Organization (WHO) prevalence estimates, 1.1 million people in Mexico are infected with Trypanosoma cruzi, the etiologic agent of Chagas disease (CD). However, limited information is available about access to antitrypanosomal treatment. This study assesses the extent of access in Mexico, analyzes the barriers to access, and suggests strategies to overcome them. METHODS AND FINDINGS: Semi-structured in-depth interviews were conducted with 18 key informants and policymakers at the national level in Mexico. Data on CD cases, relevant policy documents and interview data were analyzed using the Flagship Framework for Pharmaceutical Policy Reform policy interventions: regulation, financing, payment, organization, and persuasion. Data showed that 3,013 cases were registered nationally from 2007-2011, representing 0.41% of total expected cases based on Mexico's national prevalence estimate. In four of five years, new registered cases were below national targets by 11-36%. Of 1,329 cases registered nationally in 2010-2011, 834 received treatment, 120 were pending treatment as of January 2012, and the treatment status of 375 was unknown. The analysis revealed that the national program mainly coordinated donation of nifurtimox and that important obstacles to access include the exclusion of antitrypanosomal medicines from the national formulary (regulation), historical exclusion of CD from the social insurance package (organization), absence of national clinical guidelines (organization), and limited provider awareness (persuasion). CONCLUSIONS: Efforts to treat CD in Mexico indicate an increased commitment to addressing this disease. Access to treatment could be advanced by improving the importation process for antitrypanosomal medicines and adding them to the national formulary, increasing education for healthcare providers, and strengthening clinical guidelines. These recommendations have important implications for other countries in the region with similar problems in access to treatment for CD.

The effects of city streets on an urban disease vector.

With increasing urbanization vector-borne diseases are quickly developing in cities, and urban control strategies are needed. If streets are shown to be barriers to disease vectors, city blocks could be used as a convenient and relevant spatial unit of study and control. Unfortunately, existing spatial analysis tools do not allow for assessment of the impact of an urban grid on the presence of disease agents. Here, we first propose a method to test for the significance of the impact of streets on vector infestation based on a decomposition of Moran's spatial autocorrelation index; and second, develop a Gaussian Field Latent Class model to finely describe the effect of streets while controlling for cofactors and imperfect detection of vectors. We apply these methods to cross-sectional data of infestation by the Chagas disease vector Triatoma infestans in the city of Arequipa, Peru. Our Moran's decomposition test reveals that the distribution of T. infestans in this urban environment is significantly constrained by streets (p<0.05). With the Gaussian Field Latent Class model we confirm that streets provide a barrier against infestation and further show that greater than 90% of the spatial component of the probability of vector presence is explained by the correlation among houses within city blocks. The city block is thus likely to be an appropriate spatial unit to describe and control T. infestans in an urban context. Characteristics of the urban grid can influence the spatial dynamics of vector borne disease and should be considered when designing public health policies.

Decision-analytic models to simulate health outcomes and costs in heart failure: a systematic review.

Chronic heart failure (CHF) is a critical public health issue with increasing effect on the healthcare budgets of developed countries. Various decision-analytic modelling approaches exist to estimate the cost effectiveness of health technologies for CHF. We sought to systematically identify these models and describe their structures. We performed a systematic literature review in MEDLINE/PreMEDLINE, EMBASE, EconLit and the Cost-Effectiveness Analysis Registry using a combination of search terms for CHF and decision-analytic models. The inclusion criterion required 'use of a mathematical model evaluating both costs and health consequences for CHF management strategies'. Studies that were only economic evaluations alongside a clinical trial or that were purely descriptive studies were excluded. We identified 34 modelling studies investigating different interventions including screening (n = 1), diagnostics (n = 1), pharmaceuticals (n = 15), devices (n = 13), disease management programmes (n = 3) and cardiac transplantation (n = 1) in CHF. The identified models primarily focused on middle-aged to elderly patients with stable but progressed heart failure with systolic left ventricular dysfunction. Modelling approaches varied substantially and included 27 Markov models, three discrete-event simulation models and four mathematical equation sets models; 19 studies reported QALYs. Three models were externally validated. In addition to a detailed description of study characteristics, the model structure and output, the manuscript also contains a synthesis and critical appraisal for each of the modelling approaches. Well designed decision models are available for the evaluation of different CHF health technologies. Most models depend on New York Heart Association (NYHA) classes or number of hospitalizations as proxy for disease severity and progression. As the diagnostics and biomarkers evolve, there is the hope for better intermediate endpoints for modelling disease progression as those that are currently in use all have limitations.

Utility estimates for decision-analytic modeling in chronic heart failure--health states based on New York Heart Association classes and number of rehospitalizations.

OBJECTIVES: For economic evaluations of chronic heart failure (CHF) management strategies, utilities are not currently available for disease proxies commonly used in Markov models. Our objective was to estimate utilities for New York Heart Association (NYHA) classification and number of cardiovascular rehospitalizations. METHODS: EuroQol 5D data from the Eplerenone Post-acute Myocardial Infarction Heart Failure Efficacy and Survival Study trial were used to estimate utilities as a function of NYHA classification and number of cardiovascular rehospitalizations. RESULTS: In multivariate regression analyses adjusted for age (60 years), female sex and absence of further comorbidities, utilities for NYHA classes I-IV were 0.90, 0.83, 0.74, and 0.60 (P-value < 0.001 for trend). For cardiovascular rehospitalizations 0, 1, 2 and >or=3, the associated utilities were 0.88, 0.85, 0.84, and 0.82 (P-value < 0.001 for trend). CONCLUSIONS: NYHA class and number of cardiovascular rehospitalizations are established proxies for CHF progression and can be linked to utilities when used as health states in a Markov model. NYHA class should be used when feasible.