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Dive into the research topics where Stephen Boswell is active.

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Featured researches published by Stephen Boswell.


Proceedings of the National Academy of Sciences of the United States of America | 2001

Control of HIV-1 viremia and protection from AIDS are associated with HLA-Bw4 homozygosity

Pedro O. Flores-Villanueva; Edmond J. Yunis; Julio Delgado; Eric Vittinghoff; Susan Buchbinder; Jessica Y. Leung; Adele M. Uglialoro; Olga P. Clavijo; Eric S. Rosenberg; Spyros A. Kalams; James D. Braun; Stephen Boswell; Bruce D. Walker; Anne E. Goldfeld

Certain HLA-B antigens have been associated with lack of progression to AIDS. HLA-B alleles can be divided into two mutually exclusive groups based on the expression of the molecular epitopes HLA-Bw4 and HLA-Bw6. Notably, in addition to its role in presenting viral peptides for immune recognition, the HLA-Bw4, but not HLA-Bw6, motif functions as a ligand for a natural killer cell inhibitory receptor (KIR). Here, we show that profound suppression of HIV-1 viremia is significantly associated with homozygosity for HLA-B alleles that share the HLA-Bw4 epitope. Furthermore, homozygosity for HLA-Bw4 alleles was also significantly associated with the ability to remain AIDS free and to maintain a normal CD4 T cell count in a second cohort of HIV-1-infected individuals with well defined dates of seroconversion. This association was independent of the presence of a mutation in CC chemokine receptor 5 (CCR5) associated with resistance to HIV-1 infection, and it was independent of the presence of HLA alleles that could potentially confound the results. We conclude that homozygosity for HLA-Bw4-bearing B alleles is associated with a significant advantage and that the HLA-Bw4 motif is important in AIDS pathogenesis.


International Journal of Epidemiology | 2008

Cohort profile: the Centers for AIDS Research Network of Integrated Clinical Systems

Mari M. Kitahata; Benigno Rodriguez; Richard Haubrich; Stephen Boswell; W. Christopher Mathews; Michael M. Lederman; William B. Lober; Stephen E. Van Rompaey; Heidi M. Crane; Richard D. Moore; Michael J Bertram; James O. Kahn; Michael S. Saag

Highly active antiretroviral therapy (HAART) delays disease progression and death. However, the treatments incompletely control HIV replication, only partially restore immune function, have significant shortand long-term toxicities, and eventually fail in many patients with consequent development of HIV drug resistance. Thus, there is increasing need for information to guide HIV-infected patients and their providers in making decisions regarding optimal use of antiretroviral therapies. Although clinical trials provide valuable information about efficacy and side effects of antiretroviral treatment, they have limited size, duration and power to detect effects on clinical outcomes, focusing instead on surrogate endpoints such as virologic failure, treatment discontinuation or composite outcome measures. Outside the clinical trial setting, there is tremendous heterogeneity among HIV-infected patients. The prevalence and impact of important health conditions such as hepatitis C virus (HCV) co-infection, mental illness and substance abuse likely contribute to increased toxicity and decreased clinical effectiveness of HAART regimens among the broader spectrum of patients treated in routine care. Cohorts with significant diversity in HIV disease severity, comorbidities and demographic distributions are required to provide information regarding long-term outcomes and complications of HIV infection in the modern HAART era. The Centers for AIDS Research (CFAR) Network of Integrated Clinical Systems (CNICS) was created to better define the relationship between patient and treatment factors and long-term clinical outcomes among HIV-infected patients in the HAART era. The CFARs are a national network of centres of excellence for HIV care and research established by the National Institutes of Health (NIH) whose mission is to support a multi-disciplinary environment for basic, clinical, epidemiologic, behavioural and translational research in the prevention, detection and treatment of HIV infection and AIDS. There are 19 CFARs located at academic and research institutions throughout the United States. The objective of the CNICS project is to integrate clinical data from the large and diverse population of HIV-infected persons receiving care at CFAR sites to investigate questions related to HIV disease management that cannot be readily addressed through traditional randomized controlled clinical trials and other cohort studies. Investigators with expertise in basic, clinical, translational and epidemiologic research, in addition to medical informatics, are collaborating on the CNICS project. The potential to build a comprehensive clinical data repository for HIV disease was greatly advanced by the work of CFAR investigators at the participating CNICS sites who had instituted point-of-care electronic medical record systems (EMRs) with the dual purpose of providing real-time clinical information to facilitate the delivery of HIV care and capturing standardized clinical data to support populationbased HIV research. The initial four CNICS sites were Case Western Reserve University, University of * Corresponding author. Center for AIDS Research, University of Washington, 325 9th Ave, MS 359931, Seattle, WA 98104, USA. E-mail: [email protected] 1 Department of Medicine, University of Washington, Seattle, 98195, USA. 2 Department of Medicine, Case Western Reserve University, Cleveland, 44106, USA. 3 Department of Medicine, University of California, San Diego, 92110, USA. 4 Department of Medicine, Harvard University, Boston, 02115, USA. 5 Department of Medicine, Johns Hopkins University, Baltimore, 21218, USA. 6 Department of Medicine, University of Alabama, Birmingham, 35209, USA. 7 Department of Medicine, University of California, San Francisco, 94143, USA. Published by Oxford University Press on behalf of the International Epidemiological Association


Aids Care-psychological and Socio-medical Aspects of Aids\/hiv | 2005

Nonadherence to medical appointments is associated with increased plasma HIV RNA and decreased CD4 cell counts in a community-based HIV primary care clinic

Michael B. Berg; Steven A. Safren; Matthew J. Mimiaga; Chris Grasso; Stephen Boswell; Kenneth H. Mayer

Abstract This study examined the association of appointment nonadherence to markers of disease severity using one year of demographic and health information on 995 individuals with HIV in primary care at an urban community health centre. At the latest visit, 106 of 946 valid cases (11.2%) had a CD4 less than or equal to 200, and 454 of 936 valid cases (48.5%) had detectable plasma HIV RNA (greater than 50 copies/ml). Using logistic regression, appointment nonadherence (number of missed appointments) was a significant predictor (p<.03) of having an AIDS-defining CD4 count over and above the effects of number of kept appointments (p<.0001), and whether or not the patient was taking HAART (p<.002). Appointment nonadherence was also a significant predictor (p<.05) of having a detectable viral load over and above the effects of number of kept appointments (p<.003), HAART (p<.0001) and age (p<.004). Looking only at individuals with a detectable viral load at the earliest visit, the only significant unique predictor of improvement to an undetectable viral load at the latest visit was being on HAART (p<.05). Looking at those only with an undetectable viral load at the earliest visit, the only predictor of declining to a detectable viral load was number of kept appointments (p < 003), and being on HAART (p<.05).


Journal of General Internal Medicine | 1998

HIV/AIDS patients’ perspectives on adhering to regimens containing protease inhibitors

Valerie E. Stone; Jennifer G. Clarke; Joan Lovell; Kathleen A. Steger; Lisa R. Hirschhorn; Stephen Boswell; Alicia D. Monroe; Michael D. Stein; Tamra J. Tyree; Kenneth H. Mayer

AbstractOBJECTIVE: To gather qualitative data regarding HIV/AIDS patients’ perspectives about HIV-1 protease inhibitors (PIs), and about their experiences taking and adhering to regimens containing PIs. DESIGN: Six focus groups of persons under care for HIV were conducted between September and November 1996 regarding participants’ knowledge, awareness, experiences when taking, and adherence to antiretroviral regimens containing PIs. An identical discussion guide was used to facilitate all six groups. Focus group proceedings were audiotaped, transcribed, coded for themes, and analyzed qualitatively. SETTING: HIV/AIDS practices of three teaching hospitals and two community health centers. PATIENTS/PARTICIPANTS: Fifty-six patients with HIV disease: 28 men and 28 women. MEASUREMENTS AND MAIN RESULTS: Knowledge and positive impressions of PIs were prevalent among this diverse group of persons with HIV, and did not differ by race/ethnicity or gender. Most knew that these were new, potent medications for treating HIV/AIDS. Networks of persons with HIV and medical providers were the most important information sources. Those taking PIs were aware that adherence to the regimen is important, and most were using special strategies to maximize their own adherence, but expressed considerable frustration about the central role these medication regimens had assumed in their life. A subset who did not believe they would adhere to these regimens had declined treatment with them. Motivating factors for taking and adhering to these complex regimens were improving CD4 counts and viral loads and the patient-provider relationship. CONCLUSIONS: Among those with HIV/AIDS, awareness of PIs and their effectiveness is substantial, owing to the impact of informal networks and medical providers. This early positive “reputation” of PIs may enhance motivation for adherence. Those who are taking PIs invest substantial effort adhering to these complex regimens, but resent the need to make medications the focus of their lives.


Aids Care-psychological and Socio-medical Aspects of Aids\/hiv | 2003

Use of an on-line pager system to increase adherence to antiretroviral medications

Steven A. Safren; Ellen S. Hendriksen; N. Desousa; Stephen Boswell; Kenneth H. Mayer

Adherence to antiretroviral therapy is critical for treatment success. Antiretroviral therapy typically requires multiple pills at multiple dosing times. To address this, we tested the feasibility, utility, and efficacy of a customizable reminder system using pagers, which were programmed using web-based technology, to increase and maintain proper adherence in patients with pre-existing adherence problems. After a two-week monitoring period with an electronic pill-cap, participants with less than 90% adherence were randomized to continue monitoring or to receive a pager. The group who received the pagers had greater improvements in adherence from baseline to Week 2 and Week 12 than those who monitored their medications only. However, adherence in both groups at the outcome assessments points was still poor. While the provision of a reminder system helped improve adherence, it is likely that more intensive interventions are required for patients with pre-existing problems.


Clinical Infectious Diseases | 1999

Persistence of Human Immunodeficiency Virus in Semen After Adding Indinavir to Combination Antiretroviral Therapy

Kenneth H. Mayer; Stephen Boswell; Robert G. Goldstein; Wilson Lo; Chong Xu; Lynne Tucke Tucker; Maria Pia DePasquale; Richard T. D'Aquila; Deborah J. Anderson

Changes in human immunodeficiency virus (HIV) type 1 concentration and protease genotype were evaluated in semen specimens from 22 HIV-positive men before and 6 months after the addition of indinavir to dual nucleoside therapy. Seminal HIV was detected by polymerase chain reaction analysis for DNA or RNA for 59% of men before combination treatment and persisted at 6 months for 31% of the men who initially had seminal HIV detected (P = .026). The maximum levels of cell-free RNA, cell-associated RNA, and proviral DNA in semen before treatment and at 6 months were 400,000 and 10,000 copies/mL, 70,000 and 27,000 copies/mL, and 80,000 and 3,000 copies/mL, respectively. Three of the four men with persistent seminal DNA had plasma viral loads of > 10,000 copies/mL before treatment. One patient who became intolerant to indinavir had seminal HIV RNA detected by PCR analysis after 6 months. Although none of the cultures of semen specimens from the four men with PCR analysis-detectable seminal DNA after 6 months yielded HIV, indinavir resistance mutations were identified in a seminal leukocyte DNA specimen from one patient, and a second patient whose therapy was switched to saquinavir had different protease inhibitor resistance mutations in seminal and blood leukocyte DNA specimens. HIV-1 protease inhibitor resistance mutants may emerge in the semen of patients receiving combination therapy.


Clinical Infectious Diseases | 2015

End-Stage Renal Disease Among HIV-Infected Adults in North America

Alison G. Abraham; Keri N. Althoff; Yuezhou Jing; Michelle M. Estrella; Mari M. Kitahata; C. William Wester; Ronald J. Bosch; Heidi M. Crane; Joseph J. Eron; M. John Gill; Michael A. Horberg; Amy C. Justice; Marina B. Klein; Angel M. Mayor; Richard D. Moore; Frank J. Palella; Chirag R. Parikh; Michael J. Silverberg; Elizabeth T. Golub; Lisa P. Jacobson; Sonia Napravnik; Gregory M. Lucas; Gregory D. Kirk; Constance A. Benson; Ann C. Collier; Stephen Boswell; Chris Grasso; Kenneth H. Mayer; Robert S. Hogg; Richard Harrigan

BACKGROUND Human immunodeficiency virus (HIV)-infected adults, particularly those of black race, are at high-risk for end-stage renal disease (ESRD), but contributing factors are evolving. We hypothesized that improvements in HIV treatment have led to declines in risk of ESRD, particularly among HIV-infected blacks. METHODS Using data from the North American AIDS Cohort Collaboration for Research and Design from January 2000 to December 2009, we validated 286 incident ESRD cases using abstracted medical evidence of dialysis (lasting >6 months) or renal transplant. A total of 38 354 HIV-infected adults aged 18-80 years contributed 159 825 person-years (PYs). Age- and sex-standardized incidence ratios (SIRs) were estimated by race. Poisson regression was used to identify predictors of ESRD. RESULTS HIV-infected ESRD cases were more likely to be of black race, have diabetes mellitus or hypertension, inject drugs, and/or have a prior AIDS-defining illness. The overall SIR was 3.2 (95% confidence interval [CI], 2.8-3.6) but was significantly higher among black patients (4.5 [95% CI, 3.9-5.2]). ESRD incidence declined from 532 to 303 per 100 000 PYs and 138 to 34 per 100 000 PYs over the time period for blacks and nonblacks, respectively, coincident with notable increases in both the prevalence of viral suppression and the prevalence of ESRD risk factors including diabetes mellitus, hypertension, and hepatitis C virus coinfection. CONCLUSIONS The risk of ESRD remains high among HIV-infected individuals in care but is declining with improvements in virologic suppression. HIV-infected black persons continue to comprise the majority of cases, as a result of higher viral loads, comorbidities, and genetic susceptibility.


Clinical Infectious Diseases | 2014

Disparities in the Quality of HIV Care When Using US Department of Health and Human Services Indicators

Keri N. Althoff; Peter F. Rebeiro; John T. Brooks; Kate Buchacz; Kelly Gebo; Jeffrey N. Martin; Robert S. Hogg; Jennifer E. Thorne; Marina B. Klein; M. John Gill; Timothy R. Sterling; Baligh R. Yehia; Michael J. Silverberg; Heidi M. Crane; Amy C. Justice; Stephen J. Gange; Richard D. Moore; Mari M. Kitahata; Michael A. Horberg; Gregory D. Kirk; Constance A. Benson; Ronald J. Bosch; Ann C. Collier; Stephen Boswell; Chris Grasso; Kenneth H. Mayer; P. Richard Harrigan; Julio Sg Montaner; Angela Cescon; Hasina Samji

We estimated US Department of Health and Human Services (DHHS)-approved human immunodeficiency virus (HIV) indicators. Among patients, 71% were retained in care, 82% were prescribed treatment, and 78% had HIV RNA ≤200 copies/mL; younger adults, women, blacks, and injection drug users had poorer outcomes. Interventions are needed to reduce retention- and treatment-related disparities.


Journal of Acquired Immune Deficiency Syndromes | 2013

High levels of antiretroviral use and viral suppression among persons in HIV care in the United States, 2010.

Julia C. Dombrowski; Mari M. Kitahata; Stephen E. Van Rompaey; Heidi M. Crane; Michael J. Mugavero; Joseph J. Eron; Stephen Boswell; Benigno Rodriguez; W. Christopher Mathews; Jeffrey N. Martin; Richard D. Moore; Matthew R. Golden

Background:Contemporary data on patterns of antiretroviral therapy (ART) use in the United States are needed to inform efforts to improve the HIV care cascade. Methods:We conducted a cross-sectional study of patients in the Centers for AIDS Research Network of Integrated Clinical Systems cohort who were in HIV care in 2010 to assess ART use and outcomes, stratified by nadir CD4 count (⩽350, 351–500, or >500 cells/mm3), demographics, psychiatric diagnoses, substance use, and engagement in continuous care (≥2 visits ≥3 months apart in 2010). Results:Of 8633 patients at 7 sites who had ≥1 medical visit and ≥1 viral load in 2010, 94% had ever initiated ART, 89% were on ART, and 70% had an undetectable viral load at the end of 2010. Fifty percent of ART-naive patients had nadir CD4 counts >500 cells per cubic millimeter, but this group comprised just 3% of the total population. Among patients who were ART naive at the time of cohort entry (N = 4637), both ART initiation and viral suppression were strongly associated with nadir CD4 count. Comparing 2009 and 2010, the percentages of patients with viral suppression among those with nadir CD4 counts 351–500 and >500 cells per cubic millimeter were 44% vs. 57% and 25% vs. 33%, respectively. Engagement in care was the only factor consistently associated with ART use and viral suppression across nadir CD4 count strata. Conclusions:Our findings suggest that ART use and viral suppression among persons in HIV care may be more common than estimated in some previous studies and increased from 2009 to 2010.


PLOS ONE | 2015

The HIV Care Continuum: Changes over Time in Retention in Care and Viral Suppression

Baligh R. Yehia; Alisa J. Stephens-Shields; John A. Fleishman; Stephen A. Berry; Allison L. Agwu; Joshua P. Metlay; Richard D. Moore; W. Christopher Mathews; Ank E. Nijhawan; Richard M. Rutstein; Aditya H. Gaur; Kelly A. Gebo; Howard Edelstein; Roberto Corales; Jeffrey M. Jacobson; Sara Allen; Stephen Boswell; Robert Beil; Carolyn Chu; Lawrence H. Hanau; P. Todd Korthuis; Muhammad Akbar; Laura Armas-Kolostroubis; Victoria Sharp; Stephen M. Arpadi; Charurut Somboonwit; Jonathan A. Cohn; Fred J. Hellinger; Irene Fraser; Robert W. Mills

Background The HIV care continuum (diagnosis, linkage to care, retention in care, receipt of antiretroviral therapy (ART), viral suppression) has been used to identify opportunities for improving the delivery of HIV care. Continuum steps are typically calculated in a conditional manner, with the number of persons completing the prior step serving as the base population for the next step. This approach may underestimate the prevalence of viral suppression by excluding patients who are suppressed but do not meet standard definitions of retention in care. Understanding how retention in care and viral suppression interact and change over time may improve our ability to intervene on these steps in the continuum. Methods We followed 17,140 patients at 11 U.S. HIV clinics between 2010-2012. For each calendar year, patients were classified into one of five categories: (1) retained/suppressed, (2) retained/not-suppressed, (3) not-retained/suppressed, (4) not-retained/not-suppressed, and (5) lost to follow-up (for calendar years 2011 and 2012 only). Retained individuals were those completing ≥2 HIV medical visits separated by ≥90 days in the year. Persons not retained completed ≥1 HIV medical visit during the year, but did not meet the retention definition. Persons lost to follow-up had no HIV medical visits in the year. HIV viral suppression was defined as HIV-1 RNA ≤200 copies/mL at the last measure in the year. Multinomial logistic regression was used to determine the probability of patients’ transitioning between retention/suppression categories from 2010 to 2011 and 2010 to 2012, adjusting for age, sex, race/ethnicity, HIV risk factor, insurance status, CD4 count, and use of ART. Results Overall, 65.8% of patients were retained/suppressed, 17.4% retained/not-suppressed, 10.0% not-retained/suppressed, and 6.8% not-retained/not-suppressed in 2010. 59.5% of patients maintained the same status in 2011 (kappa=0.458) and 53.3% maintained the same status in 2012 (kappa=0.437). Conclusions Not counting patients not-retained/suppressed as virally suppressed, as is commonly done in the HIV care continuum, underestimated the proportion suppressed by 13%. Applying the care continuum in a longitudinal manner will enhance its utility.

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Heidi M. Crane

University of Washington

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Benigno Rodriguez

Case Western Reserve University

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Michael S. Saag

University of Alabama at Birmingham

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Joseph J. Eron

University of North Carolina at Chapel Hill

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Michael J. Mugavero

University of Alabama at Birmingham

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