To estimate the association of antiretroviral therapy initiation with incident acquired immunodeficiency syndrome (AIDS) or death while accounting for time-varying confounding in a cost-efficient manner, the authors combined a case-cohort study design with inverse probability-weighted estimation of a marginal structural Cox proportional hazards model. A total of 950 adults who were positive for human immunodeficiency virus type 1 were followed in 2 US cohort studies between 1995 and 2007. In the full cohort, 211 AIDS cases or deaths occurred during 4,456 person-years. In an illustrative 20% random subcohort of 190 participants, 41 AIDS cases or deaths occurred during 861 person-years. Accounting for measured confounders and determinants of dropout by inverse probability weighting, the full cohort hazard ratio was 0.41 (95% confidence interval: 0.26, 0.65) and the case-cohort hazard ratio was 0.47 (95% confidence interval: 0.26, 0.83). Standard multivariable-adjusted hazard ratios were closer to the null, regardless of study design. The precision lost with the case-cohort design was modest given the cost savings. Results from Monte Carlo simulations demonstrated that the proposed approach yields approximately unbiased estimates of the hazard ratio with appropriate confidence interval coverage. Marginal structural model analysis of case-cohort study designs provides a cost-efficient design coupled with an accurate analytic method for research settings in which there is time-varying confounding.

Purpose

To compare liver ADC obtained with breath-hold and free-breathing diffusion weighted imaging (DWI) in healthy volunteers and patients with liver disease.

Materials and Methods

Twenty-eight subjects, 12 healthy volunteers and 16 patients (9 NAFLD, 7 chronic active HCV), underwent breath-hold (BH) and free-breathing (FB) DWI MRI at 1.5T. Pearson’s correlation coefficient was used to determine correlation while paired t-tests assessed differences between BH and FB ADC. Estimated bias was calculated using the Bland-Altman method.

Results

Liver ADC (×10−3 mm2/sec) was lower on BH for all groups (mean difference 0.36±0.20; p<0.01). ADC was higher in healthy volunteers (BH 1.80±0.18; FB 2.24±0.20) compared to NAFLD patients (BH 1.43±0.27; FB 1.78±0.28) (p<0.001) and HCV patients (BH 1.63±0.191; FB 1.88±0.12). Overall correlation between BH and FB ADC was (r =0.75), greatest in NAFLD (r =0.90) compared to the correlation in HCV (r =0.24) and healthy subjects (r =0.34). Bland-Altman plots did not show agreement in mean absolute difference and estimated bias between subjects.

Conclusion

Correlation between BH and FB liver ADC is moderate indicating that BH and FB should not be used interchangeably. Additionally, the lower ADC values in BH versus FB should be accounted for when comparing different liver DWI studies.

Background

Coinfection with hepatitis C virus (HCV) is common among HIV-infected women.

Objective

To further our understanding of the risk factors for HCV viremia and the predictors of HCV viral load among women.

Study design

We investigated sociodemographic, immunologic, and virologic factors associated with presence and level of HCV viremia among 882 HIV-infected and 167 HIV-uninfected HCV-seropositive women at entry into the Women's Interagency HIV Study.

Results

Plasma HCV RNA was detected in 852 (81%) of these 1,049 women (range: 1.2–7.8 log10 copies/ml). HCV-viremic women were more likely to have an HIV RNA level >100,000 copies/ml (P =0.0004), have reported smoking (P =0.01), or to be Black (P =0.005). They were less likely to have current or resolved hepatitis B infection. HCV RNA levels were higher in women who were >35 years old, or HIV-infected. Current smoking and history of drug use (crack/freebase cocaine, marijuana, amphetamines, or heroin) were each associated with both presence and level of viremia.

Conclusions

Substance abuse counseling aimed at eliminating ongoing use of illicit drugs and tobacco may reduce clinical progression, improve response to treatment, and decrease HCV transmission by lowering levels of HCV viremia in women.

Background.

Skeletal muscle (SM) mass decreases with advanced age and with disease in HIV infection. It is unknown whether age-related muscle loss is accelerated in the current era of antiretroviral therapy and which factors might contribute to muscle loss among HIV-infected adults. We hypothesized that muscle mass would be lower and decline faster in HIV-infected adults than in similar-aged controls.

Methods.

Whole-body 1H-magnetic resonance imaging was used to quantify regional and total SM in 399 HIV-infected and 204 control men and women at baseline and 5 years later. Multivariable regression identified associated factors.

Results.

At baseline and Year 5, total SM was lower in HIV-infected than control men. HIV-infected women were similar to control women at both time points. After adjusting for demographics, lifestyle factors, and total adipose tissue, HIV infection was associated with lower Year 5 SM in men and higher SM in women compared with controls. Average overall 5-year change in total SM was small and age related, but rate of change was similar in HIV-infected and control men and women. CD4 count and efavirenz use in HIV-infected participants were associated with increasing SM, whereas age and stavudine use were associated with decreasing SM.

Conclusions.

Muscle mass was lower in HIV-infected men compared with controls, whereas HIV-infected women had slightly higher SM than control women after multivariable adjustment. We found evidence against substantially faster SM decline in HIV infected versus similar-aged controls. SM gain was associated with increasing CD4 count, whereas stavudine use may contribute to SM loss.

Background

We previously reported an increased risk of all-cause and AIDS mortality among HIV-infected women with albuminuria (proteinuria or microalbuminuria) enrolled in the Women’s Interagency HIV Study (WIHS) prior to the introduction of highly active antiretroviral therapy (HAART).

Methods

The current analysis includes 1,073 WIHS participants who subsequently initiated HAART. Urinalysis for proteinuria and semi-quantitative testing for microalbuminuria from two consecutive study visits prior to HAART initiation were categorized as follows: confirmed proteinuria (both specimens positive for protein), confirmed microalbuminuria (both specimens positive with at least one microalbuminuria), unconfirmed albuminuria (one specimen positive for proteinuria or microalbuminuria), or negative (both specimens negative). Time from HAART initiation to death was modeled using proportional hazards analysis.

Results

Compared to the reference group of women with two negative specimens, the hazard ratio (HR) for all-cause mortality was significantly elevated for women with confirmed microalbuminuria (HR 1.9; 95% CI 1.2–2.9). Confirmed microalbuminuria was also independently associated with AIDS death (HR 2.3; 95% CI 1.3–4.3), while women with confirmed proteinuria were at increased risk for non-AIDS death (HR 2.4; 95% CI 1.2–4.6).

Conclusions

In women initiating HAART, pre-existing microalbuminuria independently predicted increased AIDS mortality, while pre-existing proteinuria predicted increased risk of non-AIDS death. Urine testing may identify HIV-infected individuals at increased risk for mortality even after the initiation of HAART. Future studies should consider whether these widely available tests can identify individuals who would benefit from more aggressive management of HIV infection and comorbid conditions associated with mortality in this population.

Background

Previous research has demonstrated an increase in carotid intima–media thickness (cIMT) in HIV-infected individuals compared to controls. However, the reason for this increased level of subclinical vascular disease is unknown.

Objective

To identify HIV-related risk factors for increased cIMT.

Methods

We evaluated the relationship between HIV-related characteristics (including markers of HIV disease severity and use of antiretroviral therapy) and cIMT measurements in the internal/bulb and common carotid regions among 538 HIV-infected participants from the Study of Fat Redistribution and Metabolic Change in HIV Infection (FRAM). We used Bayesian model averaging to estimate the posterior probability of candidate HIV and non-HIV-related risk factors being true predictors of increased cIMT. Variables with a posterior probability of more than 50% were used to develop a selected regression model for each of the anatomic regions.

Results

For common cIMT, the Bayesian model selection process identified age, African-American race, and systolic and diastolic blood pressure with probability more than 95%, HDL cholesterol with probability 85% and Hispanic ethnicity with probability 51%. Among the HIV-related factors included in the analysis, only tenofovir use was selected (51% probability). In the selected model, duration of tenofovir use was associated with lower common cIMT (−0.0094 mm/year of use; 95% confidence interval: −0.0177 to −0.0010). For internal cIMT, no HIV-related risk factors were above the 50% posterior probability threshold.

Conclusion

We observed an inverse association between duration of tenofovir use and common carotid cIMT. Whether this association is causal or due to confounding by indication needs further investigation.

Background

The clinical importance of the association of HIV infection and antiretroviral therapy (ART) with low bone mineral density (BMD) in premenopausal women is uncertain because BMD stabilizes on established ART and fracture data are limited.

Methods

We measured time to first new fracture at any site with median follow-up of 5.4 years in 2391 (1728 HIV-infected, 663 HIV-uninfected) participants in the Women’s Interagency HIV Study (WIHS). Self-report of fracture was recorded at semiannual visits. Proportional hazard models assessed predictors of incident fracture.

Results

At baseline, HIV-infected women were older (40 ± 9 vs. 36 ± 10 years, P <0.0001), more likely to report postmenopausal status and be hepatitis C virus-infected, and weighed less than HIV-uninfected women. Among HIV-infected women, mean CD4+ cell count was 482 cells/μl; 66% were taking ART. Unadjusted incidence of fracture did not differ between HIV-infected and uninfected women (1.8 vs. 1.4/100 person-years, respectively, P = 0.18). In multivariate models, white (vs. African-American) race, hepatitis C virus infection, and higher serum creatinine, but not HIV serostatus, were statistically significant predictors of incident fracture. Among HIV-infected women, older age, white race, current cigarette use, and history of AIDS-defining illness were associated with incidence of new fracture.

Conclusion

Among predominantly premenopausal women, there was little difference in fracture incidence rates by HIV status, rather traditional risk factors were important predictors. Further research is necessary to characterize fracture risk in HIV-infected women during and after the menopausal transition.

Objective

To determine the association of inflammatory markers, fibrinogen and C-reactive protein (CRP), with 5-year mortality risk.

Methods

Vital status was ascertained in 922 HIV-infected participants from the Study of Fat Redistribution and Metabolic Change in HIV infection. Multivariable logistic regression estimated odds ratios (OR) after adjustment for demographic, cardiovascular and HIV-related factors.

Results

Over a 5-year period, HIV-infected participants with fibrinogen levels in the highest tertile(>406mg/dL) had 2.6-fold higher adjusted odds of death than those with fibrinogen in the lowest tertile(<319mg/dL). Those with high CRP(>3mg/L) had 2.7-fold higher adjusted odds of death than those with CRP<1mg/L. When stratified by CD4 count category, fibrinogen (as a linear variable) remained independently associated [OR(95% confidence intervals) per 100mg/dL increase in fibrinogen: 1.93(1.57,2.37);1.43(1.14,1.79);1.43(1.14,1.81);and 1.30(1.04,1.63) for CD4 <200,200–350,>350–500, and >500cells/μL, respectively. Higher CRP also remained associated with higher odds of death overall and within each CD4 subgroup.

Conclusion

Fibrinogen and CRP are strong and independent predictors of mortality in HIV-infected adults. Our findings suggest that even in those with relatively preserved CD4 counts >500cells/μL, inflammation remains an important risk factor for mortality. Further investigation should determine whether interventions to reduce inflammation might decrease mortality risk in HIV-infected individuals.

Background

Compared with controls, HIV-infected persons have a greater prevalence of kidney disease as assessed by high levels of cystatin C and albuminuria, but not as assessed by creatinine level. However, the clinical importance of elevated cystatin C and albuminuria in the HIV-infected population has not been studied.

Study Design

We conducted an observational cohort study to determine the association of kidney disease (measured by albuminuria, cystatin C, and serum creatinine) with mortality.

Setting & Participants

922 HIV-infected persons enrolled in the FRAM (Fat Redistribution and Metabolic Change in HIV infection) study.

Predictor

Serum cystatin C and serum creatinine were used to estimate glomerular filtration rate (eGFR). Albuminuria was defined as a positive urine dipstick (≥1+) or a urine albumin-creatinine ratio > 30 mg/g.

Outcome

5-year mortality

Results

At baseline, reduced kidney function (eGFRSCysC <60 mL/min/1.73m2) or albuminuria was present in 28% of participants. After five years of follow-up, mortality was 48% among those with both eGFRSCysC <60 mL/min/1.73m2 and albuminuria, 23% in those with eGFRSCysC <60 mL/min/1.73m2 alone, 20% in those with albuminuria alone, and 9% in those with neither condition. After multivariable adjustment for demographics, cardiovascular risk factors, HIV-related factors, and inflammatory markers, eGFRSCysC <60 mL/min/1.73m2 and albuminuria were associated with nearly a twofold increase in mortality, whereas eGFRSCr <60 mL/min/1.73m2 did not appear to have any substantial association with mortality. Together, eGFRSCysC <60 mL/min/1.73m2 and albuminuria accounted for 17% of the population-level attributable risk for mortality.

Limitations

Vital status was unknown in 261 participants from the original cohort.

Conclusions

Kidney disease marked by albuminuria or increased cystatin C levels appears to be an important risk factor for mortality in HIV-infected individuals. A substantial proportion of this risk may be unrecognized because of the current reliance on serum creatinine to estimate kidney function in clinical practice.

Objective

To determine the prevalence of illicit drug use and the impact on HIV treatment.

Design

Multivariable regression of cross-sectional data from 1163 HIV-infected and 294 controls from the Study of Fat Redistribution and Metabolic Change in HIV Infection (FRAM).

Methods

An analysis of (1) prevalence of specific illicit drug use (ever, current), (2) being on HAART among those with an indication and (3) current HIV RNA and CD4 cell count among HAART users.

Results

Median age was 42 years, approximately 50% were non-Caucasian and 33% were women. Eighty-six percent of HIV-infected and 67% of controls reported ever using illicit drugs (P <0.0001); 28% of HIV-infected and 16% of controls reported current use (P = 0.0001). In adjusted models, current cocaine use and past heroin use were associated with not currently being on HAART. Among HAART users, those reporting past heroin use were as likely to have an undetectable HIV viral load as those who had never used heroin. Current and past cocaine use and current heroin use was associated with lower odds of undetectable HIV RNA. Past amphetamine use was associated with having an undetectable HIV. Similar results were seen for CD4 lymphocyte counts.

Conclusion

Illicit drug use in the US is common, although far fewer report current use than past use. Among HIV-infected patients, understanding of the type of illicit drugs used and whether drug use was in the past or ongoing is important, because of their differential effects on HIV treatment outcomes.

Background

Hepatic steatosis is common in persons with HIV and hepatitis C virus (HCV); yet biopsy measurement of steatosis is prone to sampling error. We compared magnetic resonance spectroscopy (MRS) measurement of steatosis to histology in HIV/HCV-coinfected patients, and explored the associated adipose tissue and metabolic factors.

Methods

Cross-sectional analysis of 42 HIV/HCV-coinfected men and women. Logistic regression analysis identified factors [MRI-measured visceral adipose tissue (VAT) and abdominal subcutaneous adipose tissue (SAT) and Homeostasis Model Assessment (HOMA) estimated insulin resistance] associated with histologic steatosis (≥5% of hepatocytes with fat) and MRS steatosis (≥5% of hepatic fat).

Results

MRS steatosis was strongly associated with histologic steatosis, when measured continuously [odds ratio: 10.2 per doubling of MRS-measured hepatic fat; 95% confidence interval (CI):2.9, 69.3] and dichotomously (Kappa coefficient=0.52; p=0.0007). Four of the 10 with MRS-measured steatosis did not have histologic steatosis; 3 of 9 with histologic steatosis did not have MRS-measured steatosis (67% sensitivity; 88% specificity). Associations of VAT and abdominal SAT were associated with both histologic and MRS-measured steatosis. Insulin resistance was also associated with both.

Conclusions

When compared to histology, MRS was similarly associated with adipose tissue and metabolic factors. MRS is a useful non-invasive alternative to biopsy in HIV/HCV coinfection.

The Study of Fat Redistribution and Metabolic Change in HIV Infection (FRAM), initiated in 2000, investigates the prevalence and correlates of changes in fat distribution, insulin resistance, and dyslipidemia among human immunodeficiency virus (HIV)-infected men and women compared with a population-based group of control men and women. Between June 2000 and September 2002, 1,480 participants (1,183 HIV-infected persons and 297 controls) were enrolled in FRAM. Measurements taken included whole-body magnetic resonance imaging for quantification of regional fat, anthropometric measurements, central laboratory analysis of metabolites, and assessment of symptoms, sociodemographic factors, and lifestyle. Similar measurements were repeated among FRAM participants 4 years later (FRAM 2) for investigation of the progression of fat distribution changes, insulin resistance, and hyperlipidemia. In FRAM 2, which is ongoing, investigators are also determining the associations of subclinical cardiovascular disease, as measured by carotid intimal-medial wall thickness, with HIV infection, fat distribution changes, insulin resistance, and other proatherogenic changes in serum lipid levels. The demographic characteristics of HIV-infected FRAM men and women were comparable to those reported from a national random sampling of HIV-infected men and women receiving medical care in the United States. The representativeness of the FRAM sample increases its value as a resource for studies on fat distribution, metabolic changes, and atherosclerosis in HIV infection.

Background

Chronic seronegative hepatitis C virus (HCV) infection is defined as being HCV antibody (anti-HCV) negative, but HCV RNA positivity occurs in individuals infected with human immunodeficiency virus (HIV). However, associated factors are not well established because of the small number of reported cases.

Methods

Multivariate logistic regression analysis of HIV-infected subjects from 4 cohorts (Tien et al., 2006; Bonacini et al., 2001; George et al., 2002; and Hall et al., 2004) determined factors associated with HCV RNA positivity in anti-HCV–negative subjects. HCV enzyme immunoassay 2.0 was used to determine anti-HCV status.

Results

Among 1174 anti-HCV–negative, HIV-infected subjects, the prevalence of seronegative HCV infection was 3.2% (95% confidence interval [CI], 2.2%–4.3%). History of injection drug use (IDU; OR, 5.8; 95% CI, 2.7–12.8), higher alanine aminotransferase (ALT) level (OR, 2.0 per doubling; 95% CI, 1.3–3.2), and CD4 cell count <200 cells/μL (OR, 2.3; 95% CI, 1.1–4.8) were associated with HCV RNA positivity in anti-HCV–negative subjects. Among those with a history of IDU who had either a CD4 cell count <200 cells/μL or an ALT level greater than the upper limit of normal, the prevalence of seronegative HCV infection was 24% (95% CI, 13%–39%).

Conclusions

Detectable HCV RNA in the context of a negative HCV enzyme immunoassay 2.0 result in HIV-infected patients is low, but higher than the reported prevalence in HIV-uninfected patients. Our findings suggest that HCV RNA testing should be performed in anti-HCV–negative, HIV-infected patients, especially those with a history of IDU and either a CD4 cell count <200 cells/μL or an abnormal ALT level.

Objective

Coinfection with hepatitis C virus (HCV) is reported to be associated with a higher prevalence of lipodystrophy than HIV infection alone. We examine the association between HCV and adipose tissue volume in HIV-infected men and women.

Methods

Cross-sectional analysis of HIV-infected subjects from the study of Fat Redistribution and Metabolic Change in HIV Infection. MRI measured regional adipose tissue volume. Detectable HCV RNA defined HCV infection.

Results

Twenty percent of 792 men and 26% of 329 women were HIV/HCV-coinfected. HIV/HCV-coinfected and HIV-monoinfected women had similar amounts of subcutaneous adipose tissue (SAT) in the leg, lower trunk, upper trunk, and arm and similar amounts of visceral adipose tissue (VAT). Similar findings were seen in men, except in the leg and VAT. After adjustment, HCV infection remained associated with more leg fat in men (12.2%, 95% confidence interval [CI]: 0.3 to 25.3; P = 0.043). Among those on stavudine, HIV-monoinfected men had less leg fat (−7% effect per year of stavudine use, 95% CI: −9 to −5; P < 0.001); a weaker association was seen in HIV/HCV-coinfected men (−2% effect, 95% CI: −7 to 3; P = 0.45). Indinavir was associated with less leg fat (−4% in HIV-monoinfected men, 95% CI: −6 to −1; P = 0.002; −5% in HIV/HCV-coinfected men, 95% CI: −11 to 2; P = 0.14).

Conclusions

Our findings suggest that HIV/HCV coinfection is not associated with less SAT in men and women. HCV infection seems to mitigate the loss of leg fat seen in HIV-infected men on stavudine.

Prevalence of microalbuminuria is increased in patients with HIV. Microalbuminuria is associated with increased mortality in other populations, including diabetics, for whom microalbuminuria testing is standard of care. We investigated whether microalbuminuria is associated with mortality in HIV-infected women not receiving antiretroviral therapy.

Methods

Urinalysis for proteinuria and semi-quantitative testing for microalbuminuria were performed in specimens from two consecutive visits in 1,547 HIV-infected women enrolled in the Women’s Interagency HIV Study in 1994–1995. Time to death was modeled using proportional hazards analysis.

Results

Compared to women without albuminuria, the hazard ratio (HR) for all-cause mortality was increased in women with one (HR 3.4; 95% CI 2.2–5.2) or two specimens positive for either proteinuria or microalbuminuria (HR 3.9; 95% CI 2.1–7.0). The highest risk was observed in women with both specimens positive for proteinuria (HR 5.8; 95% CI 3.4–9.8). The association between albuminuria and all-cause mortality risk remained significant after adjustment for demographics, HIV disease severity, and related comorbidities. Similar results were obtained for AIDS death.

Conclusions

We identified a graded relationship between albuminuria and the risk of all-cause and AIDS mortality.

We previously demonstrated that HIV infection is associated with peripheral and central lipoatrophy in women. We now describe the association of specific antiretroviral drugs (ARV) with body fat changes over a four-year period from 1999 to 2003. 775 HIV-positive and 205 HIV-negative women in the Women’s Interagency HIV Study with anthropometric measurements, weight, bioelectric impedance analysis and ARV collected semiannually were included in analysis. Exposure to ARV was defined as report of use for 3 consecutive semiannual study visits. The average 6–month change in weight, percent total body fat, and circumference measurements (i.e., hip, waist, chest, arm, and thigh) was compared between those exposed and those unexposed to the specific ARV for any of the same three consecutive visits. Weight, percent total body fat, and hip, waist, thigh, chest, and arm circumferences decreased in HIV-positive women, but increased in HIV-negative women on average for every six-month interval over the 4-year study period. Among the HIV-positive women, didanosine was the only ARV associated with decreases in circumference measures in the hip (−0.65 cm, 95% confidence interval [CI]: −1.18, −0.12), waist (−0.71 cm, 95% CI: −1.37, −0.04), chest (−0.71 cm, 95% CI: −1.17, −0.26), and arm (−0.23 cm, 95% CI: −0.48, 0.03; p = 0.08). These prospective data suggest that fat loss continues to predominate in HIV-positive women and exposure to didanosine for at least 12 months may further worsen fat loss.

To characterize predictors of isolated hepatitis B core antibody (anti-HBc) among human immunodeficiency virus (HIV)–infected and HIV-uninfected women, we compared 702 women with anti-HBc and hepatitis B surface antibody (anti-HBs) with 490 women with isolated anti-HBc (1.8% of whom had detectable hepatitis B virus [HBV] DNA). Factors independently associated with isolated anti-HBc without viremia were detectable hepatitis C virus (HCV) RNA, HIV positivity, history of injection drug use, >10 lifetime sex partners, and HIV RNA level >100,000 copies/mL. Anti-HBs levels were lower among anti-HCV–positive women. Isolated anti-HBc was rarely explained by occult HBV in this cohort but may be explained by the influence of viral coinfections on anti-HBs level or durability.

Background

Liver disease is a leading cause of death in human immunodeficiency virus (HIV)–infected women; however, risk factors for hepatitis B virus (HBV) infection in this population have not been well studied.

Methods

We describe the seroprevalence and predictors of HBV infection in a cross-sectional analysis of 2132 women with and at risk for HIV infection enrolled in the Women’s Interagency HIV Study during the periods 1994–95 and 2001–02. Any test result positive for antibody to hepatitis B core antigen defined infection; those women with serological evidence of vaccine immunity were excluded from analysis. Women were stratified into those with a history of injection drug use (IDU), those with a history of noninjection drug use (non-IDU), and those with no history of illicit drug use.

Results

Of 1606 HIV-infected and 526 HIV-uninfected women, 7% and 12%, respectively, appeared to be vaccine immune. After exclusion of these women, 43% of 1500 HIV-infected and 22% of 461 HIV-uninfected women had HBV infection. HBV infection prevalence differed among the IDU, non-IDU, and no illicit drug use groups (76%, 30%, and 17%, respectively; P < .0001). HBV infection was strongly associated with herpes simplex virus 2 (HSV-2) seropositivity in the IDU group (odds ratio [OR], 2.9; 95% confidence interval [CI], 1.6–5.4) and with a history of syphilis in the non-IDU group (OR, 2.7; 95% CI, 1.4–5.0).

Discussion

We found a high prevalence of HBV infection in our cohort of women with and at risk for HIV infection. HSV-2 seropositivity and a history of syphilis appeared to be important correlates of HBV infection. Sexual transmission of HBV, particularly in those with a history of genital ulcer disease, should be a major focus of education in all high-risk groups.

We assessed the prevalence and predictors of latent Toxoplasma infection in a large group of human immunodeficiency virus (HIV)–infected and HIV-uninfected at-risk US women. The prevalence of latent Toxoplasma infection was 15% (380 of 2525 persons) and did not differ by HIV infection status. HIV-infected women aged ≥50 years and those born outside of the United States were more likely to have latent Toxoplasma infection, with prevalences of 32% and 41%, respectively.

Background

Because activation of T cells is associated with human immunodeficiency virus (HIV) pathogenesis, CD4 and CD8 activation levels in patients coinfected with HIV and hepatitis C virus (HCV) may explain conflicting reports regarding effects of HCV on HIV disease progression.

Methods

Kaplan-Meier and multivariate Cox regression models were used to study the risk of incident clinical AIDS and AIDS-related deaths among 813 HCV-negative women with HIV infection, 87 HCV-positive nonviremic women with HIV coinfection, and 407 HCV-positive viremic women with HIV coinfection (median follow-up time, 5.2 years). For 592 women, the percentages of activated CD4 and CD8 T cells expressing HLA-DR (DR) and/or CD38 were evaluated.

Results

HCV-positive viremic women had a statistically significantly higher percentage of activated CD8 T cells (P < .001) and a statistically significantly higher incidence of AIDS compared with HCV-negative women (P < .001 [log-rank test]). The AIDS risk was greater among HCV-positive viremic women in the highest tertile compared with the lowest tertile (>43% vs <26%) of CD8+CD38+DR+ T cells (hazard ratio, 2.94 [95% confidence interval, 1.50–5.77]; P =.001). This difference was not observed in the HCV-negative women (hazard ratio, 1.87 [95% confidence interval, 0.80–4.35]; P =.16). In contrast, CD4 activation predicted AIDS in both groups similarly. Increased percentages of CD8+CD38−DR+, CD4+CD38−DR−, and CD8+CD38−DR− T cells were associated with a >60% decreased risk of AIDS for HCV-positive viremic women and HCV-negative women.

Conclusion

HCV-positive viremic women with HIV coinfection who have high levels of T cell activation may have increased risk of AIDS. Earlier treatment of HIV and HCV infection may be beneficial.

Typical applications of marginal structural time-to-event (e.g., Cox) models have used time on study as the time scale. Here, the authors illustrate use of time on treatment as an alternative time scale. In addition, a method is provided for estimating Kaplan-Meier–type survival curves for marginal structural models. For illustration, the authors estimate the total effect of highly active antiretroviral therapy on time to acquired immunodeficiency syndrome (AIDS) or death in 1,498 US men and women infected with human immunodeficiency virus and followed for 6,556 person-years between 1995 and 2002; 323 incident cases of clinical AIDS and 59 deaths occurred. Of the remaining 1,116 participants, 77% were still under observation at the end of follow-up. By using time on study, the hazard ratio for AIDS or death comparing always with never using highly active antiretroviral therapy from the marginal structural model was 0.52 (95% confidence interval: 0.35, 0.76). By using time on treatment, the analogous hazard ratio was 0.44 (95% confidence interval: 0.32, 0.60). In time-to-event analyses, the choice of time scale may have a meaningful impact on estimates of association and precision. In the present example, use of time on treatment yielded a hazard ratio further from the null and more precise than use of time on study as the time scale.

Background

Low bone mineral density (BMD) has been reported in HIV + women, but less is known about the longitudinal evolution of BMD and fracture incidence.

Methods

In 100 HIV+ and 68 HIV− premenopausal women in the Women’s Interagency HIV Study (WIHS), BMD was measured by dual energy x-ray absorptiometry at the femoral neck (FN) and lumbar spine (LS) at index visit and after a median of 2.5 years.

Results

In HIV+ women, BMD at index visit was normal but 5% lower at the LS and FN than in HIV− women. Annual percent decrease in BMD did not differ between HIV+ and HIV− women at the LS (−0.8±0.2% vs −0.4±0.2%, p=0.20) or FN (−0.8±0.3% vs −0.6±0.3%, p=0.56), and remained similar after adjustment for age, weight, and BMD at index visit. Among HIV+ women, bone loss was associated with vitamin D deficiency and opiate use but not with use or class of antiretrovirals. Incidence of self-reported fracture was 0.74/100 person-years in HIV+ women, and similar in HIV− women.

Conclusions

In premenopausal HIV+ women, index BMD was lower than comparable HIV− women; however, rates of bone loss at the LS and FN were similar over 2.5 years of observation, irrespective of ART.

Objective

To determine the relationship of HIV infection, demographic and cardiovascular disease (CVD) risk factors with mortality in the recent HAART era.

Methods

Vital status was ascertained from 2004–2007 in 922 HIV-infected and 280 controls in the Study of Fat Redistribution and Metabolic Change in HIV infection; 469 HIV-infected were included in analysis comparing HIV to similar age controls. Multivariable exponential survival regression (adjusting for demographic and CVD factors) estimated hazard ratios (HR) for death.

Results

After 5 years of follow-up, the overall adjusted mortality HR was 3.4[95% confidence interval (CI):1.35,8.5]; HR was 6.3 among HIV-infected with CD4<200(95% CI:2.2,18.2), 4.3 with CD4 200–350(95% CI:1.14,16.0), and 2.3 with CD4>350(95% CI:0.78,6.9). Among HIV-infected, current smoking (HR=2.73 vs. never smokers, 95% CI:1.64,4.5) and older age (HR=1.61 per decade, 95% CI:1.27,2.1) were independent risk factors for death; higher baseline CD4 count was associated with lower risk (HR=0.65 per CD4 doubling, 95% CI:0.58,0.73).

Conclusion

HIV infection was associated with a 3-fold mortality risk compared to controls after adjustment for demographic and CVD risk factors. In addition to low baseline CD4 count, older age and current smoking were strong and independent predictors of mortality in a US cohort of HIV-infected participants in clinical care.