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Dive into the research topics where Alexander C. Tsai is active.

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Featured researches published by Alexander C. Tsai.


PLOS Medicine | 2013

Scaling up mHealth: where is the evidence?

Mark Tomlinson; Mary Jane Rotheram-Borus; Leslie Swartz; Alexander C. Tsai

Mark Tomlinson and colleagues question whether there is sufficient evidence on implementation and effectiveness to match the wide enthusiasm for mHealth interventions, and propose a global strategy to determine needed evidence to support mHealth scale-up.


Journal of Financial Economics | 2003

Do Equity Financing Cycles Matter?: Evidence from Biotechnology Alliances

Josh Lerner; Hilary Shane; Alexander C. Tsai

While the variability of public equity financing has been long recognized, its impact on firms has attracted little empirical scrutiny. This paper examines one setting where theory suggests that variations in financing conditions should matter, alliances between small R&D firms and major corporations: Aghion and Tirole [1994] suggest that when financial markets are weak, assigning the control rights to the small firm may be sometimes desirable but not feasible. The performance of 200 agreements entered into by biotechnology firms between 1980 and 1995 suggests that financing availability does matter. Consistent with theory, agreements signed during periods with little external equity financing that assign the bulk of the control to the corporate partner are significantly less successful than other alliances. These agreements are also disproportionately likely to be renegotiated if financial market conditions improve.


Journal of the International AIDS Society | 2013

Impact of HIV-related stigma on treatment adherence: systematic review and meta-synthesis

Ingrid T. Katz; Annemarie E Ryu; Afiachukwu G Onuegbu; Christina Psaros; Sheri D. Weiser; David R. Bangsberg; Alexander C. Tsai

Adherence to HIV antiretroviral therapy (ART) is a critical determinant of HIV‐1 RNA viral suppression and health outcomes. It is generally accepted that HIV‐related stigma is correlated with factors that may undermine ART adherence, but its relationship with ART adherence itself is not well established. We therefore undertook this review to systematically assess the relationship between HIV‐related stigma and ART adherence.


The American Journal of Clinical Nutrition | 2011

Conceptual framework for understanding the bidirectional links between food insecurity and HIV/AIDS

Sheri D. Weiser; Sera L. Young; Craig R. Cohen; Margot B. Kushel; Alexander C. Tsai; Phyllis C. Tien; Abigail M. Hatcher; Edward A. Frongillo; David R. Bangsberg

Food insecurity, which affects >1 billion people worldwide, is inextricably linked to the HIV epidemic. We present a conceptual framework of the multiple pathways through which food insecurity and HIV/AIDS may be linked at the community, household, and individual levels. Whereas the mechanisms through which HIV/AIDS can cause food insecurity have been fairly well elucidated, the ways in which food insecurity can lead to HIV are less well understood. We argue that there are nutritional, mental health, and behavioral pathways through which food insecurity leads to HIV acquisition and disease progression. Specifically, food insecurity can lead to macronutrient and micronutrient deficiencies, which can affect both vertical and horizontal transmission of HIV, and can also contribute to immunologic decline and increased morbidity and mortality among those already infected. Food insecurity can have mental health consequences, such as depression and increased drug abuse, which, in turn, contribute to HIV transmission risk and incomplete HIV viral load suppression, increased probability of AIDS-defining illness, and AIDS-related mortality among HIV-infected individuals. As a result of the inability to procure food in socially or personally acceptable ways, food insecurity also contributes to risky sexual practices and enhanced HIV transmission, as well as to antiretroviral therapy nonadherence, treatment interruptions, and missed clinic visits, which are strong determinants of worse HIV health outcomes. More research on the relative importance of each of these pathways is warranted because effective interventions to reduce food insecurity and HIV depend on a rigorous understanding of these multifaceted relationships.


BMC Medical Informatics and Decision Making | 2009

The use of mobile phones as a data collection tool: A report from a household survey in South Africa

Mark Tomlinson; Wesley Solomon; Yages Singh; Tanya Doherty; Mickey Chopra; Petrida Ijumba; Alexander C. Tsai; Debra Jackson

BackgroundTo investigate the feasibility, the ease of implementation, and the extent to which community health workers with little experience of data collection could be trained and successfully supervised to collect data using mobile phones in a large baseline surveyMethodsA web-based system was developed to allow electronic surveys or questionnaires to be designed on a word processor, sent to, and conducted on standard entry level mobile phones.ResultsThe web-based interface permitted comprehensive daily real-time supervision of CHW performance, with no data loss. The system permitted the early detection of data fabrication in combination with real-time quality control and data collector supervision.ConclusionsThe benefits of mobile technology, combined with the improvement that mobile phones offer over PDAs in terms of data loss and uploading difficulties, make mobile phones a feasible method of data collection that needs to be further explored.


Social Science & Medicine | 2012

Food Insecurity, Depression and the Modifying Role of Social Support among People Living with HIV/AIDS in Rural Uganda

Alexander C. Tsai; David R. Bangsberg; Edward A. Frongillo; Peter W. Hunt; Conrad Muzoora; Jeffrey N. Martin; Sheri D. Weiser

Depression is common among people living with HIV/AIDS and contributes to a wide range of worsened HIV-related outcomes, including AIDS-related mortality. Targeting modifiable causes of depression, either through primary or secondary prevention, may reduce suffering as well as improve HIV-related outcomes. Food insecurity is a pervasive source of uncertainty for those living in resource-limited settings, and cross-sectional studies have increasingly recognized it as a critical determinant of poor mental health. Using cohort data from 456 men and women living with HIV/AIDS initiating HIV antiretroviral therapy in rural Uganda, we sought to (a) estimate the association between food insecurity and depression symptom severity, (b) assess the extent to which social support may serve as a buffer against the adverse effects of food insecurity, and (c) determine whether the buffering effects are specific to certain types of social support. Quarterly data were collected by structured interviews and blood draws. The primary outcome was depression symptom severity, measured by a modified Hopkins Symptom Checklist for Depression. The primary explanatory variables were food insecurity, measured with the Household Food Insecurity Access Scale, and social support, measured with a modified version of the Functional Social Support Questionnaire. We found that food insecurity was associated with depression symptom severity among women but not men, and that social support buffered the impacts of food insecurity on depression. We also found that instrumental support had a greater buffering influence than emotional social support. Interventions aimed at improving food security and strengthening instrumental social support may have synergistic beneficial effects on both mental health and HIV outcomes among PLWHA in resource-limited settings.


PLOS Medicine | 2009

Setting Research Priorities to Reduce Global Mortality from Childhood Pneumonia by 2015

Olivier Fontaine; Margaret Kosek; Shinjini Bhatnagar; Cynthia Boschi-Pinto; Kit Yee Chan; Christopher Duggan; Homero Martinez; Hugo Ribeiro; Nigel C Rollins; Mohammed Abdus Salam; Mathuram Santosham; John D. Snyder; Alexander C. Tsai; Beth Vargas; Igor Rudan

Igor Rudan and colleagues report the results of their consensus building exercise that identified health research priorities to help reduce child mortality from pneumonia.


Bulletin of The World Health Organization | 2009

Setting priorities for global mental health research

Mark Tomlinson; Igor Rudan; Shekhar Saxena; Leslie Swartz; Alexander C. Tsai; Vikram Patel

OBJECTIVE To set investment priorities in global mental health research and to propose a more rational use of funds in this under-resourced and under-investigated area. METHODS Members of the Lancet Mental Health Group systematically listed and scored research investment options on four broad classes of disorders: schizophrenia and other major psychotic disorders, major depressive disorder and other common mental disorders, alcohol abuse and other substance abuse disorders, and the broad class of child and adolescent mental disorders. Using the priority-setting approach of the Child Health and Nutrition Research Initiative, the group listed various research questions and evaluated them using the criteria of answerability, effectiveness, deliverability, equity and potential impact on persisting burden of mental health disorders. Scores were then weighted according to the system of values expressed by a larger group of stakeholders. FINDINGS The research questions that scored highest were related to health policy and systems research, where and how to deliver existing cost-effective interventions in a low-resource context, and epidemiological research on the broad categories of child and adolescent mental disorders or those pertaining to alcohol and drug abuse questions. The questions that scored lowest related to the development of new interventions and new drugs or pharmacological agents, vaccines or other technologies. CONCLUSION In the context of global mental health and with a time frame of the next 10 years, it would be best to fill critical knowledge gaps by investing in research into health policy and systems, epidemiology and improved delivery of cost-effective interventions.


AIDS | 2012

Food insecurity is associated with morbidity and patterns of healthcare utilization among HIV-infected individuals in a resource-poor setting

Sheri D. Weiser; Alexander C. Tsai; Reshma Gupta; Edward A. Frongillo; Annet Kawuma; Jude Senkungu; Peter W. Hunt; Nneka Emenyonu; Jennifer E. Mattson; Jeffrey N. Martin; David R. Bangsberg

Objective:We undertook a longitudinal study in rural Uganda to understand the association of food insecurity with morbidity and patterns of healthcare utilization among HIV-infected individuals enrolled in an antiretroviral therapy program. Design:Longitudinal cohort study. Methods:Participants were enrolled from the Uganda AIDS Rural Treatment Outcomes cohort, and underwent quarterly structured interviews and blood draws. The primary predictor was food insecurity measured by the validated Household Food Insecurity Access Scale. Primary outcomes included health-related quality of life measured by the validated Medical Outcomes Study-HIV Physical Health Summary (PHS), incident self-reported opportunistic infections, number of hospitalizations, and missed clinic visits. To estimate model parameters, we used the method of generalized estimating equations, adjusting for sociodemographic and clinical variables. Explanatory variables were lagged by 3 months to strengthen causal interpretations. Results:Beginning in May 2007, 458 persons were followed for a median of 2.07 years, and 40% were severely food insecure at baseline. Severe food insecurity was associated with worse PHS, opportunistic infections, and increased hospitalizations (results were similar in concurrent and lagged models). Mild/moderate food insecurity was associated with missed clinic visits in concurrent models, whereas in lagged models, severe food insecurity was associated with reduced odds of missed clinic visits. Conclusion:Based on the negative impact of food insecurity on morbidity and patterns of healthcare utilization among HIV-infected individuals, policies and programs that address food insecurity should be a critical component of HIV treatment programs worldwide.


Clinical Infectious Diseases | 2014

Trends in CD4 Count at Presentation to Care and Treatment Initiation in Sub-Saharan Africa, 2002–2013: A Meta-analysis

Mark J. Siedner; Courtney Ng; Ingrid V. Bassett; Ingrid T. Katz; David R. Bangsberg; Alexander C. Tsai

BACKGROUND Both population- and individual-level benefits of antiretroviral therapy (ART) for human immunodeficiency virus (HIV) are contingent on early diagnosis and initiation of therapy. We estimated trends in disease status at presentation to care and at ART initiation in sub-Saharan Africa. METHODS We searched PubMed for studies published January 2002-December 2013 that reported CD4 cell count at presentation or ART initiation among adults in sub-Saharan Africa. We abstracted study sample size, year(s), and mean CD4 count. A random-effects meta-regression model was used to obtain pooled estimates during each year of the observation period. RESULTS We identified 56 articles reporting CD4 count at presentation (N = 295 455) and 71 articles reporting CD4 count at ART initiation (N = 549 702). The mean estimated CD4 count in 2002 was 251 cells/µL at presentation and 152 cells/µL at ART initiation. During 2002-2013, neither CD4 count at presentation (β = 5.8 cells/year; 95% confidence interval [CI], -10.7 to 22.4 cells/year), nor CD4 count at ART initiation (β = -1.1 cells/year; 95% CI, -8.4 to 6.2 cells/year) increased significantly. Excluding studies of opportunistic infections or prevention of mother-to-child transmission did not alter our findings. Among studies conducted in South Africa (N = 14), CD4 count at presentation increased by 39.9 cells/year (95% CI, 9.2-70.2 cells/year; P = .02), but CD4 count at ART initiation did not change. CONCLUSIONS CD4 counts at presentation to care and at ART initiation in sub-Saharan Africa have not increased over the past decade. Barriers to presentation, diagnosis, and linkage to HIV care remain major challenges that require attention to optimize population-level benefits of ART.

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Peter W. Hunt

University of California

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Bernard Kakuhikire

Mbarara University of Science and Technology

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Conrad Muzoora

Mbarara University of Science and Technology

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