Ahmed M. Bayoumi

State-Transition Modeling A Report of the ISPOR-SMDM Modeling Good Research Practices Task Force–3

State-transition modeling (STM) is an intuitive, flexible, and transparent approach of computer-based decision-analytic modeling, including both Markov model cohort simulation as well as individual-based (first-order Monte Carlo) microsimulation. Conceptualizing a decision problem in terms of a set of (health) states and transitions among these states, STM is one of the most widespread modeling techniques in clinical decision analysis, health technology assessment, and health-economic evaluation. STMs have been used in many different populations and diseases, and their applications range from personalized health care strategies to public health programs. Most frequently, state-transition models are used in the evaluation of risk factor interventions, screening, diagnostic procedures, treatment strategies, and disease management programs.

Employment status is associated with both physical and mental health quality of life in people living with HIV

Abstract To evaluate the relationship between employment status and health-related quality of life (HRQOL) in HIV/AIDS. A total of 361 participants provided baseline data in the context of an ongoing cohort study examining the natural history of neurobehavioral functioning and its effects on HRQOL. We administered tests and collected laboratory data to determine demographic status, HIV disease markers, psychosocial symptom burden, neurocognitive function and HRQOL (MOS-HIV). We performed regression analyses to evaluate the contribution of employment status to the physical and mental health components of quality of life (QOL). Multivariate analyses showed that employment status was strongly related to better physical and mental health QOL after controlling for potential confounders. We found, however, that employment status had a greater impact on physical health than mental health QOL [physical health (β = 6.8, 95% CI 4.6 to 9.1) and mental health QOL (β = 3.3, 95% CI 0.93 to 5.7)]. The effect of employment for physical health QOL was stronger than that observed for ethnicity, social support, or having an AIDS diagnosis and was comparable to that observed with having many HIV-related symptoms. This cross-sectional study suggests that there may be physical and mental health benefits associated with obtaining or keeping employment, or more likely that both selection and causation mechanisms comprise an interactional and reinforcing process.

Cost-Effectiveness of HIV Monitoring Strategies in Resource-Limited Settings – A Southern African Analysis

BACKGROUND Although the number of infected persons receiving highly active antiretroviral therapy (HAART) in low- and middle-income countries has increased dramatically, optimal disease management is not well defined. METHODS We developed a model to compare the costs and benefits of 3 types of human immunodeficiency virus monitoring strategies: symptom-based strategies, CD4-based strategies, and CD4 counts plus viral load strategies for starting, switching, and stopping HAART. We used clinical and cost data from southern Africa and performed a cost-effectiveness analysis. All assumptions were tested in sensitivity analyses. RESULTS Compared with the symptom-based approaches, monitoring CD4 counts every 6 months and starting treatment at a threshold of 200/muL was associated with a gain in life expectancy of 6.5 months (61.9 months vs 68.4 months) and a discounted lifetime cost savings of US

Exploring disability from the perspective of adults living with HIV/AIDS: Development of a conceptual framework

464 per person (US

The cost-effectiveness of Vancouver's supervised injection facility

4069 vs US

The Measurement of Contingent Valuation for Health Economics

3605, discounted 2007 dollars). The CD4-based strategies in which treatment was started at the higher threshold of 350/microL provided an additional gain in life expectancy of 5.3 months at a cost-effectiveness of US

Payments for care at private for-profit and private not-for-profit hospitals: a systematic review and meta-analysis

107 per life-year gained compared with a threshold of 200/microL. Monitoring viral load with CD4 was more expensive than monitoring CD4 counts alone, added 2.0 months of life, and had an incremental cost-effectiveness ratio of US

Association of returning to work with better health in working-aged adults: a systematic review.

5414 per life-year gained relative to monitoring of CD4 counts. In sensitivity analyses, the cost savings from CD4 count monitoring compared with the symptom-based approaches was sensitive to cost of inpatient care, and the cost-effectiveness of viral load monitoring was influenced by the per test costs and rates of virologic failure. CONCLUSIONS Use of CD4 monitoring and early initiation of HAART in southern Africa provides large health benefits relative to symptom-based approaches for HAART management. In southern African countries with relatively high costs of hospitalization, CD4 monitoring would likely reduce total health care expenditures. The cost-effectiveness of viral load monitoring depends on test prices and rates of virologic failure.

Improving the diagnosis of acute heart failure using a validated prediction model.

BackgroundSince the advent of combination antiretroviral therapy, in developed countries HIV increasingly is perceived as a long-term illness. Individuals may experience health-related consequences of HIV and its associated treatments, a concept that may be termed disability. To date, a comprehensive framework for understanding the health-related consequences experienced by people living with HIV has not been developed. The purpose of this research was to develop a conceptual framework of disability from the perspective of adults living with HIV.MethodsWe conducted four focus groups and 15 face-to-face interviews with 38 adults living with HIV. We asked participants to describe their health-related challenges, their physical, social and psychological areas of life affected, and impact on their overall health. We analyzed data using grounded theory techniques. We also conducted two validity check focus groups with seven returning participants.ResultsDisability was conceptualized by participants as multi-dimensional and episodic characterized by unpredictable periods of wellness and illness. The Episodic Disability Framework consisted of three main components: a) dimensions of disability that included symptoms and impairments, difficulties carrying out day-to-day activities, challenges to social inclusion, and uncertainty that may fluctuate on a daily basis and over the course of living with HIV, b) contextual factors that included extrinsic factors (social support and stigma) and intrinsic factors (living strategies and personal attributes) that may exacerbate or alleviate disability, and c) triggers that initiate momentous or major episodes of disability such as receiving an HIV diagnosis, starting or changing medications, experiencing a serious illness, and suffering a loss of others.ConclusionThe Episodic Disability Framework considers the variable nature of disability, acknowledges uncertainty as a key component, describes contextual factors that influence experiences of disability, and considers life events that may initiate a major or momentous episode. This framework presents a new way to conceptualize disability based on the experience of living with HIV.

The impact of neuropsychological impairment and depression on health-related quality of life in HIV-infection.

Background: The cost-effectiveness of Canadas only supervised injection facility has not been rigorously evaluated. We estimated the impact of the facility on survival, rates of HIV and hepatitis C virus infection, referral to methadone maintenance treatment and associated costs. Methods: We simulated the population of Vancouver, British Columbia, including injection drug users and persons infected with HIV and hepatitis C virus. The model used a time horizon of 10 years and the perspective of the health care system. We compared the situation of the supervised injection facility with one that had no facility but that had other interventions, such as needle-exchange programs. The effects considered were decreased needle sharing, increased use of safe injection practices and increased referral to methadone maintenance treatment. Outcomes included life-years gained, costs, and incremental cost-effectiveness ratios discounted at 5% per year. Results: Focusing on the base assumption of decreased needle sharing as the only effect of the supervised injection facility, we found that the facility was associated with an incremental net savings of almost