86 research outputs found
CD4 count at presentation for HIV care in the United States and Canada: Are those over 50 years more likely to have a delayed presentation?
We assessed CD4 count at initial presentation for HIV care among ≥50-year-olds from 1997-2007 in 13 US and Canadian clinical cohorts and compared to <50-year-olds. 44,491 HIV-infected individuals in the North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD) were included in our study. Trends in mean CD4 count (measured as cells/mm3) and 95% confidence intervals ([,]) were determined using linear regression stratified by age category and adjusted for gender, race/ethnicity, HIV transmission risk and cohort. From 1997-2007, the proportion of individuals presenting for HIV care who were ≥50-years-old increased from 17% to 27% (p-value < 0.01). The median CD4 count among ≥50 year-olds was consistently lower than younger adults. The interaction of age group and calendar year was significant (p-value <0.01) with both age groups experiencing modest annual improvements over time (< 50-year-olds: 5
[4 , 6] cells/mm3; ≥50-year-olds: 7
[5 , 9] cells/mm3), after adjusting for sex, race/ethnicity, HIV transmission risk group and cohort; however, increases in the two groups were similar after 2000. A greater proportion of older individuals had an AIDS-defining diagnosis at, or within three months prior to, first presentation for HIV care compared to younger individuals (13% vs. 10%, respectively). Due to the increasing proportion, consistently lower CD4 counts, and more advanced HIV disease in adults ≥50-year-old at first presentation for HIV care, renewed HIV testing efforts are needed
Risk Factors for Tuberculosis After Highly Active Antiretroviral Therapy Initiation in the United States and Canada: Implications for Tuberculosis Screening
Background. Screening for tuberculosis prior to highly active antiretroviral therapy (HAART) initiation is not routinely performed in low-incidence settings. Identifying factors associated with developing tuberculosis after HAART initiation could focus screening efforts
Trends in Multidrug Treatment Failure and Subsequent Mortality among Antiretroviral Therapy–Experienced Patients with HIV Infection in North America
Although combination antiretroviral therapy continues to evolve, with potentially more effective options emerging each year, the ability of therapy to prevent multiple regimen failure and mortality in clinical practice remains poorly defined
Late Presentation for HIV Care in the United States and Canada
Initiatives to improve early detection and access to HIV services have increased over time. We assessed the immune status of patients at initial presentation for HIV care from 1997-2007 in 13 US and Canadian clinical cohorts
Effect of Early versus Deferred Antiretroviral Therapy for HIV on Survival
BACKGROUND
The optimal time for the initiation of antiretroviral therapy for asymptomatic patients
with human immunodeficiency virus (HIV) infection is uncertain.
METHODS
We conducted two parallel analyses involving a total of 17,517 asymptomatic patients
with HIV infection in the United States and Canada who received medical care during
the period from 1996 through 2005. None of the patients had undergone previous
antiretroviral therapy. In each group, we stratified the patients according to the CD4+
count (351 to 500 cells per cubic millimeter or >500 cells per cubic millimeter) at the
initiation of antiretroviral therapy. In each group, we compared the relative risk of
death for patients who initiated therapy when the CD4+ count was above each of the
two thresholds of interest (early-therapy group) with that of patients who deferred
therapy until the CD4+ count fell below these thresholds (deferred-therapy group).
RESULTS
In the first analysis, which involved 8362 patients, 2084 (25%) initiated therapy at a
CD4+ count of 351 to 500 cells per cubic millimeter, and 6278 (75%) deferred therapy.
After adjustment for calendar year, cohort of patients, and demographic and clinical
characteristics, among patients in the deferred-therapy group there was an increase
in the risk of death of 69%, as compared with that in the early-therapy group (relative
risk in the deferred-therapy group, 1.69; 95% confidence interval [CI], 1.26 to 2.26;
P<0.001). In the second analysis involving 9155 patients, 2220 (24%) initiated therapy
at a CD4+ count of more than 500 cells per cubic millimeter and 6935 (76%) deferred
therapy. Among patients in the deferred-therapy group, there was an increase in the
risk of death of 94% (relative risk, 1.94; 95% CI, 1.37 to 2.79; P<0.001).
CONCLUSIONS
The early initiation of antiretroviral therapy before the CD4+ count fell below two
prespecified thresholds significantly improved survival, as compared with deferred
therapy
End-Stage Renal Disease Among HIV-Infected Adults in North America
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
Recommended from our members
Laser chirping in inverse Compton sources at high electron beam energies and high laser intensities
The onset of nonlinear effects, such as ponderomotive broadening, increases the radiation bandwidth and thereby places a stringent limitation on the laser intensity used in inverse Compton sources. Recently, we have shown that a judicious longitudinal laser frequency modulation (“chirping”) can perfectly compensate for this ponderomotive broadening and restore the narrow band property of scattered radiation in the Thomson regime, when electron recoil during the collision with the laser can be neglected. Consequently, using QED, the laser chirping has been extended to the Compton regime, where electron recoil is properly accounted for. Here we present a new, semiclassical model for computation of scattered spectra in the Compton regime. We also derive a comprehensive generalization of the expressions for chirping prescription for linearly polarized laser pulses in 1D plane-wave approximation with arbitrary shapes and arbitrary scattering angle in the Compton regime. We use these new expressions to show that the higher-order harmonics in sources with high laser fields and high electron beam energies (nonlinear Compton regime) will be nonlinearly redshifted when compared to those with lower beam energies (Thomson regime). The chirping prescription will act to correct ponderomotive broadening in very high harmonics
- …