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Dive into the research topics where John Hammer is active.

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Featured researches published by John Hammer.


Sexually Transmitted Diseases | 2012

Ongoing sexually transmitted disease acquisition and risk-taking behavior among US HIV-infected patients in primary care: implications for prevention interventions.

Kenneth H. Mayer; Timothy J. Bush; Keith Henry; Edgar Turner Overton; John Hammer; Jean L. Richardson; Kathy Wood; Lois Conley; John R. Papp; Angela M. Caliendo; Pragna Patel; John T. Brooks

Background: To better understand the factors associated with HIV- and sexually transmitted disease (STD)-transmitting behavior among HIV-infected persons, we estimated STD prevalence and incidence and associated risk factors among a diverse sample of HIV-infected patients in primary care. Methods: We analyzed data from 557 participants in the SUN Study, a prospective observational cohort of HIV-infected adults in primary care in 4 US cities. At enrollment and 6 months thereafter, participants completed an audio computer-assisted self-interview about their sexual behavior, and were screened for genitourinary, rectal, and pharyngeal Neisseria gonorrhoeae and Chlamydia trachomatis infections by nucleic acid amplification testing, and for serologic evidence of syphilis. Women provided cervicovaginal samples and men provided urine to screen for Trichomonas vaginalis by polymerase chain reaction. Results: Thirteen percent of participants had a prevalent STD at enrollment and 7% an incident STD 6 months later. The most commonly diagnosed infections were rectal chlamydia, oropharyngeal gonorrhea, and chlamydial urethritis among the men and trichomoniasis among the women. Other than trichomoniasis, 94% of incident STDs were identified in men who have sex with men. Polysubstance abuse other than marijuana, and having ≥4 sex partners in the 6 months before testing were associated with diagnosis of an incident STD. Conclusions: STDs were commonly diagnosed among contemporary HIV-infected patients receiving routine outpatient care, particularly among sexually active men who have sex with men who used recreational drugs. These findings underscore the need for frequent STD screening, prevention counseling, and substance abuse treatment for HIV-infected persons in care.


Sexually Transmitted Diseases | 2010

Human papillomavirus infection and cytologic abnormalities of the anus and cervix among HIV-infected women in the study to understand the natural history of HIV/AIDS in the era of effective therapy (the SUN study).

Erna M. Kojic; Susan Cu-Uvin; Lois Conley; Tim Bush; Juanita Onyekwuluje; David C. Swan; Elizabeth R. Unger; Keith Henry; John Hammer; Edgar Turner Overton; Teresa M. Darragh; Joel M. Palefsky; Claudia Vellozzi; Pragna Patel; John T. Brooks

Background: Human papillomavirus (HPV) infection of the cervix and related abnormal cervical cytology in HIV-infected women has been well described. Little is known about anal HPV infection in HIV-infected women. Methods: The SUN Study is a prospective cohort study of 700 HIV-infected patients including 167 women. At baseline, patients completed a behavioral questionnaire and provided, among other samples, cervical and anal swabs for HPV detection and genotyping and for cytologic examination. Here, we present the available baseline data on the 167 women in the SUN study. Results: Baseline results were available for 120 women (median age: 38 years, 57% non-Hispanic black, median CD4 cell count 444.5 cells/mm3), of whom, 77% were taking antiretroviral therapy. The prevalences in the anus and cervix of any HPV were 90% and 83%, respectively (P = 0.039), and of high-risk (HR) types 85% and 70%, respectively, (P = 0.001). There was no significant difference in the prevalences of abnormal cytology between the anus and cervix: 38% and 33%, respectively (P = 0.217). Although the presence of abnormal cervical cytology was associated with the presence of abnormal anal cytology (relative risk: 1.7, P = 0.024), its sensitivity (52.5%) and positive predictive value positive (45.6%) for identifying women with abnormal anal cytology were poor. A history of anal sex was not associated with anal HPV infection or abnormal anal cytology. Conclusions: In this cohort of HIV-infected women, anal HPV infection was more prevalent and diverse than cervical HPV infection. Anal cytologic abnormalities were as prevalent as cervical cytologic abnormalities, and although abnormal cervical cytology was predictive of abnormal anal cytology, results were not highly concordant. These data support the need for studies of anal cytologic screening of HIV-infected women.


The Journal of Infectious Diseases | 2010

Factors Associated with Prevalent Abnormal Anal Cytology in a Large Cohort of HIV-Infected Adults in the United States

Lois Conley; Timothy J. Bush; Teresa M. Darragh; Joel M. Palefsky; Elizabeth R. Unger; Pragna Patel; Erna Kojic; Susan Cu-Uvin; Harold L. Martin; Edgar Turner Overton; John Hammer; Keith Henry; Claudia Vellozzi; Kathleen C. Wood; John T. Brooks

BACKGROUND The prevalence of and risk factors for abnormal anal cytology among men and women with human immunodeficiency virus (HIV) infection have not been extensively investigated. METHODS The Study to Understand the Natural History of HIV and AIDS in the Era of Effective Therapy (SUN study) is a prospective cohort study of HIV-infected patients in 4 US cities. Baseline questionnaires were administered and anal samples for cytology and human papillomavirus (HPV) detection and genotyping were collected. RESULTS Among 471 men and 150 women (median age, 41 years), 78% of participants were receiving combination antiretroviral therapy, 41% had a CD4(+) cell count of ≥500 cells/μL, and 71% had an HIV RNA viral load of <400 copies/mL. The anal cytology results were as follows: 336 participants (54%) had negative results, 96 participants (15%) had atypical squamous cells, 149 participants (24%) had low-grade squamous intraepithelial lesions, and 40 participants (6%) had high-grade squamous intraepithelial lesions. In a multivariate analysis, abnormal anal cytology was associated with number of high-risk and low-risk HPV types (adjusted odds ratio [AOR] for both, 1.28; P < .001), nadir CD4(+) cell count of <50 cells/μL (AOR, 2.38; P = .001), baseline CD4(+) cell count of <500 cells/μL (AOR, 1.75; P = .004), and ever having receptive anal intercourse (AOR, 2.51; P < .001). CONCLUSION HIV-infected persons with multiple anal HPV types or a nadir CD4(+) cell count of <50 cells/μL have an increased risk for abnormal anal cytology.


Clinical Infectious Diseases | 2011

Progression of Carotid Intima-Media Thickness in a Contemporary Human Immunodeficiency Virus Cohort

Jason V. Baker; W. Keith Henry; Pragna Patel; Timothy J. Bush; Lois Conley; Wendy J. Mack; E. Turner Overton; Matthew J. Budoff; John Hammer; Charles C. Carpenter; Howard N. Hodis; John T. Brooks

BACKGROUND Persons with human immunodeficiency virus (HIV) infection are at risk for premature cardiovascular disease (CVD). Predictors of atherosclerotic disease progression in contemporary patients have not been well described. METHODS Using data from a prospective observational cohort of adults infected with HIV (Study to Understand the Natural History of HIV/AIDS in the Era of Effective Therapy), we assessed common carotid artery intima-media thickness (CIMT) at baseline and year 2 by ultrasound. We examined HIV-associated predictors of CIMT progression after adjusting for age, sex, race/ethnicity, body mass index, smoking, hypertension, diabetes, low-density lipoprotein cholesterol level, and baseline CIMT using linear regression. RESULTS Among 389 participants (median age at baseline, 42 years; male sex, 77%; median CD4+ cell count at baseline, 485 cells/mm³; 78% receiving antiretroviral therapy), the median 2-year CIMT change was 0.016 mm (interquartile range, -0.003 to 0.033 mm; P < .001). Lesser CIMT progression was associated with a suppressed viral load at baseline (-0.009 mm change; P = .015) and remaining virologically suppressed throughout follow-up (-0.011 mm change; P < .001). After adjusting for additional risk factors and a suppressed viral load during follow-up, nonnucleoside reverse transcriptase inhibitor versus protease inhibitor exposure was associated with lesser CIMT progression (-0.011 mm change; P = .02). CONCLUSIONS Suppressing HIV replication below clinical thresholds was associated with less progression of atherosclerosis. The proatherogenic mechanisms of HIV replication and the net CVD benefit of different antiretroviral drugs should be a focus of future research.


Aids Care-psychological and Socio-medical Aspects of Aids\/hiv | 2011

Factors associated with non-adherence to antiretroviral therapy in the SUN study

Melanie Kyser; Kate Buchacz; Timothy J. Bush; Lois Conley; John Hammer; Keith Henry; Erna M. Kojic; Joel Milam; E. Turner Overton; Kathy Wood; John T. Brooks

Abstract Background. Adherence of 95% or greater to highly active combination antiretroviral therapy is generally considered necessary to achieve optimal virologic suppression in HIV-infected patients. Understanding factors associated with poor adherence is essential to improve patient compliance, maximize virologic suppression, and reduce morbidity and mortality. Methods. We evaluated baseline data from 528 patients taking antiretrovirals, enrolled from March 2004 to June 2006, in a multicenter, longitudinal, prospective cohort study (the SUN study). Using multiple logistic regression, we examined independent risk factors for non-adherence, defined as reporting having missed one or more antiretroviral doses in the past three days on the baseline questionnaire. Results. Of 528 participants (22% female, 28% black, median age 41 years, and median CD4 cell count 486 cells/mm3), 85 (16%) were non-adherent. In the final parsimonious multivariate model, factors independently associated with non-adherence included black race (adjusted odds ratio (aOR): 2.08, 95% confidence interval (CI): 1.20–3.60 vs. white race), being unemployed and looking for work (aOR: 2.03, 95% CI: 1.14–3.61 vs. all other employment categories), having been diagnosed with HIV ≥5 years ago (aOR: 1.95, 95% CI: 1.18–3.24 vs. being HIV-diagnosed <5 years ago), drinking three or more drinks per day (aOR: 1.73, 95% CI: 1.02–2.91 vs. drinking <3 drinks per day), and having not engaged in any aerobic exercise in the last 30 days (aOR: 2.13, 95% CI: 1.25–3.57). Conclusion. Although the above factors may not be causally related to non-adherence, they might serve as proxies for identifying HIV-infected patients at greatest risk for non-adherence who may benefit from additional adherence support.


Sexually Transmitted Diseases | 2012

Prevalence and risk factors associated with herpes simplex virus-2 infection in a contemporary cohort of HIV-infected persons in the united states

Pragna Patel; Tim Bush; Kenneth H. Mayer; Sheila Desai; Keith Henry; Edgar Turner Overton; Lois Conley; John Hammer; John T. Brooks

Background: We compared the herpes simplex virus type 2 (HSV-2) seroprevalence in a contemporary HIV cohort with the general US population and determined risk factors for HSV-2 infection among HIV-infected persons. Methods: The Study to Understand the Natural History of HIV and AIDS in the Era of Effective Therapy (SUN) Study is a prospective observational cohort of 700 HIV-infected adults enrolled in 4 US cities between 2004 and 2006. At baseline, participants completed a behavioral risk questionnaire and provided specimens for HSV-2 serology. We calculated HSV-2 seroprevalence, standardized by age, gender, and race among HIV-infected persons compared with the general US adult population, using data from the National Health and Nutrition Examination Survey from 2003 to 2006. We examined risk factors associated with HSV-2 infection among HIV-infected persons using multivariate logistic regression. Results: Among 660 (94%) SUN participants with adequate specimens for HSV-2 serologic testing, 548 (83%) were 20 to 49 years old (median age, 39 years; 77% male; 59% non-Hispanic white; median CD4 count, 470 cells/mm3; 74% with HIV RNA viral loads <400 copies/mL). HSV-2 seroprevalence was significantly higher among HIV-infected adults (59.7%, 95% confidence interval: 55.8–63.6) compared with the general US population (19.2%, 95% confidence interval: 17.5–21.1). In multivariate analysis, we found that older age, female gender, black non-Hispanic race/ethnicity, being currently unemployed, high-risk anal HPV infection, and longer duration since HIV diagnosis were associated with significantly higher odds of HSV-2 infection. Conclusion: HSV-2 seroprevalence is 3 times as high among HIV-infected adults as in the general US population. Clinicians should be aware that increased risk for HSV-2 infection was distributed broadly among HIV-infected persons and not limited to those with high-risk sexual behaviors.


AIDS Research and Human Retroviruses | 2016

High Prevalence of Low Bone Mineral Density and Substantial Bone Loss over 4 Years Among HIV-Infected Persons in the Era of Modern Antiretroviral Therapy

Gerome Escota; Kristin Mondy; Tim Bush; Lois Conley; John T. Brooks; Nur F. Önen; Pragna Patel; Erna M. Kojic; Keith Henry; John Hammer; Kathy Wood; Kenneth A. Lichtenstein; Edgar Turner Overton

HIV-infected persons are living longer on combination antiretroviral therapy (cART) but experiencing more comorbidities including low bone mineral density (BMD). Using data from the Study to Understand the Natural History of HIV and AIDS in the Era of Effective Therapy (SUN Study), we determined the prevalence of low BMD (T-score below one standard deviation of the reference mean) and compared it with matched controls from the National Health and Nutrition Examination Survey (NHANES). We also assessed 4-year longitudinal BMD changes among participants virologically suppressed on cART. Of 653 participants included in this analysis (77% male, 29% black, median age 41 years, median CD4(+) cell count 464 cells/mm(3), 89% with HIV RNA <400 copies/ml), 51% and 10% had baseline osteopenia and osteoporosis, respectively. Low BMD at the femoral neck was significantly more prevalent than for the NHANES controls (47% versus 29%, p<0.001). Lower body mass index, nonwhite race, longer tenofovir exposure, older age, being unemployed or retired, and lower apolipoprotein E were independently associated with baseline osteoporosis. Among 170 participants virologically suppressed on cART and with longitudinal BMD data, 31% experienced substantial bone loss (≥5% BMD decline from baseline) over 4 years. Female sex, current smoking, and longer stavudine use were more common among participants who had substantial bone loss, although these variables failed to reach statistical significance. Low BMD was highly prevalent among HIV-infected persons. One-third of participants experienced substantial bone loss despite cART, suggesting the need for monitoring and potential clinical interventions.


Aids Patient Care and Stds | 2012

Sadness in the SUN: Using Computerized Screening to Analyze Correlates of Depression and Adherence in HIV-Infected Adults in the United States

Ellen Tedaldi; Mary van den Berg-Wolf; James T. Richardson; Pragna Patel; Marcus D. Durham; John Hammer; Keith Henry; Sara Metzler; Nur F. Önen; Lois Conley; Kathy Wood; John T. Brooks; Kate Buchacz

We used a standardized screening tool to examine frequency of depression and its relation to antiretroviral medication adherence among HIV-infected persons on highly active antiretroviral therapy (HAART) in the Study to Understand the Natural History of HIV/AIDS in the Era of Effective Therapy (SUN Study). This is a prospective observational cohort of 700 HIV-infected patients enrolled between March 2004 and June 2006 in four U.S. cities, who completed a confidential audio computer-assisted self-interview [ACASI] with behavioral risk and health-related questions at baseline and 6-month follow-up visits, including the nine-question PRIME-MD depression screener and a validated 3-day antiretroviral adherence question. Among 539 eligible participants receiving HAART, 14% had depression at baseline (22% women, 12% men). In multivariable analysis using generalized estimating equations (GEE) to account for repeated measurements through 24 months of follow-up, persons who reported depression on a given ACASI were twice as likely to report nonadherence to antiretrovirals on the same ACASI (Odds ratio [OR] 2.02, 95% CI: 1.15, 3.57] for mild/moderate depression versus none); such persons were also less likely to have HIV viral load<400 copies/mL. Self-administered computerized standardized screening tools can identify at-risk individuals with depression who may benefit from interventions to improve antiretroviral adherence.


Antiviral Therapy | 2015

Low bone mineral density and risk of incident fracture in HIV-infected adults

Linda Ann Battalora; Kate Buchacz; Carl Armon; Edgar Turner Overton; John Hammer; Pragna Patel; Joan S. Chmiel; Kathy Wood; Timothy J. Bush; John R. Spear; John T. Brooks; Benjamin Young

BACKGROUND Prevalence rates of low bone mineral density (BMD) and bone fractures are higher among HIV-infected adults compared with the general United States (US) population, but the relationship between BMD and incident fractures in HIV-infected persons has not been well described. METHODS Dual energy X-ray absorptiometry (DXA) results of the femoral neck of the hip and clinical data were obtained prospectively during 2004-2012 from participants in two HIV cohort studies. Low BMD was defined by a T-score in the interval >-2.5 to <-1.0 (osteopenia) or ≤-2.5 (osteoporosis). We analysed the association of low BMD with risk of subsequent incident fractures, adjusted for sociodemographics, other risk factors and covariables, using multivariable proportional hazards regression. RESULTS Among 1,006 participants analysed (median age 43 years [IQR 36-49], 83% male, 67% non-Hispanic white, median CD4(+) T-cell count 461 cells/mm(3) [IQR 311-658]), 36% (n=358) had osteopenia and 4% (n=37) osteoporosis; 67 had a prior fracture documented. During 4,068 person-years of observation after DXA scanning, 85 incident fractures occurred, predominantly rib/sternum (n=18), hand (n=14), foot (n=13) and wrist (n=11). In multivariable analyses, osteoporosis (adjusted hazard ratio [aHR] 4.02, 95% CI 2.02, 8.01) and current/prior tobacco use (aHR 1.59, 95% CI 1.02, 2.50) were associated with incident fracture. CONCLUSIONS In this large sample of HIV-infected adults in the US, low baseline BMD was significantly associated with elevated risk of incident fracture. There is potential value of DXA screening in this population.


Journal of Acquired Immune Deficiency Syndromes | 2015

Elevated Soluble CD14 and Lower D-Dimer Are Associated With Cigarette Smoking and Heavy Episodic Alcohol Use in Persons Living With HIV.

Patricia A. Cioe; Jason V. Baker; Erna M. Kojic; Nur F. Önen; John Hammer; Pragna Patel; Christopher W. Kahler

Background:Persons living with HIV are at increased risk for cardiovascular disease in part because of persistent inflammation and coagulation activation. Methods:We examined whether smoking and heavy episodic alcohol use (defined as 5 or more drinks on one occasion) were associated with greater monocyte activation (soluble CD14) and coagulation (D-dimer) in participants in the Study to Understand the Natural History of HIV and AIDS in the Era of Effective Therapy (the “SUN” Study), a prospective observational cohort. Results:Using regression analysis (n = 689), current smoking compared with nonsmoking was associated with significantly elevated soluble CD14 (B = 135.57, 95% confidence interval: 84.95 to 186.19, P < 0.001), whereas heavy alcohol use compared with nonheavy use was associated with significantly lower D-dimer levels (B = −0.059, 95% confidence interval: −0.102 to −0.016, P = 0.007). Conclusions:Smoking cessation should be encouraged by HIV care providers to improve mortality outcomes from all causes of death, particularly cardiovascular disease.

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John T. Brooks

Centers for Disease Control and Prevention

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Pragna Patel

Centers for Disease Control and Prevention

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Lois Conley

Centers for Disease Control and Prevention

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Keith Henry

Hennepin County Medical Center

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Edgar Turner Overton

University of Alabama at Birmingham

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Kate Buchacz

Centers for Disease Control and Prevention

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Timothy J. Bush

Centers for Disease Control and Prevention

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Tim Bush

Centers for Disease Control and Prevention

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