Purpose of review
It is unknown whether biomarkers simply correlate with or are causal for HIV-associated outcomes. Mendelian randomization (MR), is a genetic epidemiologic approach used to disentangle causation from association. Here, we discuss the potential use of MR for differentiating whether biomarkers are correlating with or causal for HIV-associated outcomes.
MR refers to the random allocation of alleles at the time of gamete formation. In observational epidemiology, this refers to the use of genetic variants to estimate a causal effect between a modifiable risk factor and an outcome of interest. A formal MR study using a genetic marker as a proxy for the biomarker has not been conducted in the HIV field. However, in the post-genomic era this approach is being used increasingly. Examples are evidence for the causal role of body mass index on blood pressure and non-causal role of CRP in coronary heart disease. We discuss the conceptual framework, uses and limitations of MR in the context of HIV infection as well as specific biomarkers (IL-6, CRP) and genetic determinants (e.g., in CCR5, chemokine, and DARC genes) that associate with HIV-related outcomes.
Making the distinction between correlation and causality has particular relevance when a biomarker (e.g. IL-6) is potentially modifiable, in which case a biomarker-guided targeted treatment strategy may be feasible. Although the tenets of MR rest on strong assumptions, and conducting an MR study in HIV infection presents many challenges, it may offer the potential to identify causal biomarkers for HIV-associated outcomes.
Mendelian randomization; gene; chemokine; HIV; biomarker
Life expectancy has increased in HIV-positive individuals receiving combination antiretroviral therapy (cART); however, they still experience increased mortality due to ageing-associated comorbidities compared with HIV-negative individuals.
A retrospective study of 314 Queensland HIV-infected males on cART was conducted. The negative impact of ageing was assessed by estimating the probability of 5-year mortality; comparisons were made between an HIV-specific predictive tool (VACS index) and the Australian Bureau of Statistics (ABS) life-tables to examine potential differences attributed to HIV. The negative impact of ageing was also assessed by the prevalence of comorbidities. Associations between comorbidity and estimates of predicted mortality by regression analysis were assessed.
The mean predicted 5-year mortality rate was 6% using the VACS index compared with 2.1% using the ABS life-table (p<0.001). The proportion of patients at predicted high risk of mortality (>9%) using the VACS index or ABS life-table were 17% and 1.8% respectively. Comorbidities were also more prevalent in this cohort compared with rates of comorbidities in age-matched Australian men from the general population. Metabolic disease (38.2%) was the most prevalent comorbidity followed by renal (33.1%) and cardiovascular disease (23.9%). Multivariate analysis demonstrated that patients with a history of cardiovascular disease had a higher predicted risk of mortality (OR=1.69;95%CI:1.17-2.45) whereas ex-smokers had a lower predicted risk of mortality (OR=0.61;95%CI:0.41-0.92).
Using the VACS Index there is an increased predicted risk of mortality in cART-treated HIV infected Australian men compared with age-matched men using the ABS data. This increased predicted mortality risk is associated with cardiovascular disease and the number of comorbidities per subject; which suggests that the VACS Index may discriminate between high and low predicted mortality risks in this population. However, until the VACS Index is validated in Australia this data may suggest the VACS Index overestimates predicted mortality risk in this country.
The relationship between CD4+ T-cell counts determined soon after seroconversion with HIV-1 (baseline CD4), nadir CD4, and CD4 levels attained during highly active antiretroviral therapy (HAART) is unknown.
Longitudinal, including baseline (at or soon after HIV diagnosis), intermediate (nadir), and distal (post-HAART) CD4+ T-cell counts were assessed in 1085 seroconverting subjects who achieved viral load suppression from a large well-characterized cohort. The association of baseline with post-HAART CD4+ T-cell count was determined after adjustment for other relevant covariates.
A higher baseline CD4+ T-cell count predicted a greater post- HAART CD4+ T-cell count, independent of the nadir and other explanatory variables. Together, baseline and nadir strongly predicted the post-HAART CD4+ count such that a high baseline and lower nadir were associated with a maximal immune recovery after HAART. Likelihood of recovery of the baseline count after HAART was significantly higher when the nadir/baseline count ratio was consistently ≥0.6.
Among viral load suppressing seroconverters, the absolute CD4+ T-cell count attained post-HAART is highly dependent on both baseline and nadir CD4+ T-cell counts. These associations further support the early diagnosis and initiation of HAART among HIV-infected persons.
CD4 count; highly active antiretroviral therapy; outcomes; predictors; treatment response
The relationship between the timing of the initiation of antiretroviral therapy (ART) after infection with human immunodeficiency virus type 1 (HIV-1) and the recovery of CD4+ T-cell counts is unknown.
In a prospective, observational cohort of persons with acute or early HIV-1 infection, we determined the trajectory of CD4+ counts over a 48-month period in partially overlapping study sets: study set 1 included 384 participants during the time window in which they were not receiving ART and study set 2 included 213 participants who received ART soon after study entry or sometime thereafter and had a suppressed plasma HIV viral load. We investigated the likelihood and rate of CD4+ T-cell recovery to 900 or more cells per cubic millimeter within 48 months while the participants were receiving viral-load–suppressive ART.
Among the participants who were not receiving ART, CD4+ counts increased spontaneously, soon after HIV-1 infection, from the level at study entry (median, 495 cells per cubic millimeter; interquartile range, 383 to 622), reached a peak value (median, 763 cells per cubic millimeter; interquartile range, 573 to 987) within approximately 4 months after the estimated date of infection, and declined progressively thereafter. Recovery of CD4+ counts to 900 or more cells per cubic millimeter was seen in approximately 64% of the participants who initiated ART earlier (≤4 months after the estimated date of HIV infection) as compared with approximately 34% of participants who initiated ART later (>4 months) (P<0.001). After adjustment for whether ART was initiated when the CD4+ count was 500 or more cells per cubic millimeter or less than 500 cells per cubic millimeter, the likelihood that the count would increase to 900 or more cells per cubic millimeter was lower by 65% (odds ratio, 0.35), and the rate of recovery was slower by 56% (rate ratio, 0.44), if ART was initiated later rather than earlier. There was no association between the plasma HIV RNA level at the time of initiation of ART and CD4+ T-cell recovery.
A transient, spontaneous restoration of CD4+ T-cell counts occurs in the 4-month time window after HIV-1 infection. Initiation of ART during this period is associated with an enhanced likelihood of recovery of CD4+ counts. (Funded by the National Institute of Allergy and Infectious Diseases and others.)
To evaluate whether elevated CD8 counts are associated with increased risk of virologic treatment failure in HIV-infected individuals.
Retrospective cohort study.
U.S. Military HIV Natural History Study participants who initiated HAART in 1996-2008, had 6- and 12-month post-HAART HIV RNA <400 c/ml, ≥2 subsequent HIV viral loads and a baseline CD8 count were eligible (n=817). Baseline was 12 months after HAART start, virologic failure was defined as confirmed HIV RNA ≥400 c/ml, and CD8 counts ≥1200 cells/mm3 were considered elevated. Cox models were used to examine the effect of baseline and time-updated CD8 counts on virologic failure.
There were 216 failures for a rate of 5.6 per 100 person-years (95% confidence interval [CI] 4.9-6.4). Among those initiating HAART in 2000-2008, participants with elevated baseline CD8 counts had significantly greater risk of virologic failure compared to those with baseline CD8 counts ≤600 cells/mm3 (hazard ratio [HR] = 2.68, 95% CI 1.13 – 6.35). Participants with elevated CD8 counts at >20% of prior 6-month follow-up visits had greater risk of failure at the current visit than those who did not (HR = 1.53, 95% CI 1.14 - 2.06). Those with CD8 counts that increased after HAART start had greater risk of failure than those with CD8 counts that decreased or remained the same (HR = 1.59, 95% CI 1.19 – 2.13).
Initial or serial elevated CD8 counts while on HAART or an increase in CD8 counts from HAART initiation may be early warnings for future treatment failure.
Human immunodeficiency virus; CD8 count; antiretroviral therapy; HIV viral load suppression; HIV virologic failure
Delayed-type hypersensitivity (DTH) testing, an in vivo assessment of cell-mediated immunity, is a predictor of HIV disease progression beyond CD4 cell count. We investigated whether preserved DTH responsiveness was characteristic of HIV controllers compared to non-controllers and individuals on suppressive HAART.
DTH testing consisted of ≥ 3 recall antigens applied approximately every 6 months. DTH responses were classified by the number of positive skin tests: anergic (0), partial anergic (1), or non-anergic (≥ 2). HIV controllers were compared to treatment naïve non-controllers (n = 3822) and a subgroup of non-controllers with VL < 400 copies/mL on their initial HAART regimen (n = 491). The proportion of non-anergic results at first DTH testing was similar for HIV controllers compared to non-controllers (81.9% vs. 77.6%; P = 0.22), but tended to be greater in HIV controllers compared to the HAART subgroup (81.9% vs. 74.5%; P = 0.07). Complete anergy was observed in 14 (10.1%) HIV controllers with CD4 counts ≥ 400 cells/uL. For longitudinal testing, the average percentage of non-anergic DTH determinations per participant was higher in HIV controllers compared to non-controllers (81.2 ± 31.9% vs. 70.7 ± 36.8%; P = 0.0002), however this difference was eliminated with stratification by CD4 count: 200-399 (83.4 ± 35.6% vs. 71.9 ± 40.9%; P = 0.15) and > 400 cells/uL (81.2 ± 31.5% vs. 80.4 ± 32.7%; P = 0.76).
Spontaneous virologic control was not associated with DTH responsiveness, and several HIV controllers were anergic despite having elevated CD4 counts. These findings suggest that cellular immunity assessed by DTH is not a principal factor contributing to spontaneous virologic suppression in HIV controllers.
HIV; Elite controllers; HIV controllers; Delayed-type hypersensitivity test; HAART
Whether seroresponse to a vaccine such as hepatitis B virus (HBV) vaccine can provide a measure of the functional immune status of HIV-infected persons is unknown.This study evaluated the relationship between HBV vaccine seroresponses and progression to clinical AIDS or death.
Methods and Findings
From a large HIV cohort, we evaluated those who received HBV vaccine only after HIV diagnosis and had anti-HBs determination 1–12 months after the last vaccine dose. Non-response and positive response were defined as anti-HBs <10 and ≥10 IU/L, respectively. Participants were followed from date of last vaccination to clinical AIDS, death, or last visit. Univariate and multivariable risk of progression to clinical AIDS or death were evaluated with Cox regression models. A total of 795 participants vaccinated from 1986–2010 were included, of which 41% were responders. During 3,872 person-years of observation, 122 AIDS or death events occurred (53% after 1995). Twenty-two percent of non-responders experienced clinical AIDS or death compared with 5% of responders (p<0.001). Non-response to HBV vaccine was associated with a greater than 2-fold increased risk of clinical AIDS or death (HR 2.47; 95% CI, 1.38–4.43) compared with a positive response, after adjusting for CD4 count, HIV viral load, HAART use, and delayed type hypersensitivity skin test responses (an in vivo marker of cell-mediated immunity). This association remained evident among those with CD4 count ≥500 cells/mm3 (HR 3.40; 95% CI, 1.39–8.32).
HBV vaccine responses may have utility in assessing functional immune status and risk stratificating HIV-infected individuals, including those with CD4 count ≥500 cells/mm3.
We evaluated longitudinal rates of Kaposi sarcoma (KS) and trends in CD4 counts at the time of KS diagnosis during the HIV epidemic (1985–2008). Although rates of KS have decreased, cases are now occurring at higher CD4 counts over time, with more than a third of cases diagnosed in 2002–2008 occurring at CD4 counts ≥350 cells/mm3. These data support future studies evaluating the impact of HAART initiation at higher CD4 counts to further reduce KS.
The impact of viral load (VL) decay and cumulative VL on CD4 recovery and AIDS after highly-active antiretroviral therapy (HAART) is unknown.
Methods and Findings
Three virologic kinetic parameters (first year and overall exponential VL decay constants, and first year VL slope) and cumulative VL during HAART were estimated for 2,278 patients who initiated HAART in the U.S. Military HIV Natural History Study. CD4 and VL trajectories were computed using linear and nonlinear Generalized Estimating Equations models. Multivariate Poisson and linear regression models were used to determine associations of VL parameters with CD4 recovery, adjusted for factors known to correlate with immune recovery. Cumulative VL higher than the sample median was independently associated with an increased risk of AIDS (relative risk 2.38, 95% confidence interval 1.56–3.62, p<0.001). Among patients with VL suppression, first year VL decay and slope were independent predictors of early CD4 recovery (p = 0.001) and overall gain (p<0.05). Despite VL suppression, those with slow decay during the first year of HAART as well as during the entire therapy period (overall), in general, gained less CD4 cells compared to the other subjects (133 vs. 195.4 cells/µL; p = 0.001) even after adjusting for potential confounders.
In a cohort with free access to healthcare, independent of established predictors of AIDS and CD4 recovery during HAART, cumulative VL and virologic decay patterns were associated with AIDS and distinct aspects of CD4 reconstitution.
To evaluate the efficacy of highly-active antiretroviral therapy (HAART) in individuals taking cytochrome P450 enzyme-inducing antiepileptics (EI-EADs), we evaluated the virologic response to HAART with or without concurrent antiepileptic use.
Participants in the US Military HIV Natural History Study were included if taking HAART for ≥6 months with concurrent use of EI-AEDs phenytoin, carbamazepine, or phenobarbital for ≥28 days. Virologic outcomes were compared to HAART-treated participants taking AEDs that are not CYP450 enzyme-inducing (NEI-AED group) as well as to a matched group of individuals not taking AEDs (non-AED group). For participants with multiple HAART regimens with AED overlap, the first 3 overlaps were studied.
EI-AED participants (n = 19) had greater virologic failure (62.5%) compared to NEI-AED participants (n = 85; 26.7%) for the first HAART/AED overlap period (OR 4.58 [1.47-14.25]; P = 0.009). Analysis of multiple overlap periods yielded consistent results (OR 4.29 [1.51-12.21]; P = 0.006). Virologic failure was also greater in the EI-AED versus NEI-AED group with multiple HAART/AED overlaps when adjusted for both year of and viral load at HAART initiation (OR 4.19 [1.54-11.44]; P = 0.005). Compared to the non-AED group (n = 190), EI-AED participants had greater virologic failure (62.5% vs. 42.5%; P = 0.134), however this result was only significant when adjusted for viral load at HAART initiation (OR 4.30 [1.02-18.07]; P = 0.046).
Consistent with data from pharmacokinetic studies demonstrating that EI-AED use may result in subtherapeutic levels of HAART, EI-AED use is associated with greater risk of virologic failure compared to NEI-AEDs when co-administered with HAART. Concurrent use of EI-AEDs and HAART should be avoided when possible.
U.S. state AIDS Drug Assistance Programs (ADAPs) are federally funded to provide antiretroviral therapy (ART) as the payer of last resort to eligible persons with HIV infection. States differ regarding their financial contributions to and ways of implementing these programs, and it remains unclear how this interstate variability affects HIV treatment outcomes.
We analyzed data from HIV-infected individuals who were clinically-eligible for ART between 2001 and 2009 (i.e., a first reported CD4+ <350 cells/uL or AIDS-defining illness) from 14 U.S. cohorts of the North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD). Using propensity score matching and Cox regression, we assessed ART initiation (within 6 months following eligibility) and virologic suppression (within 1 year) based on differences in two state ADAP features: the amount of state funding in annual ADAP budgets and the implementation of waiting lists. We performed an a priori subgroup analysis in persons with a history of injection drug use (IDU).
Among 8,874 persons, 56% initiated ART within six months following eligibility. Persons living in states with no additional state contribution to the ADAP budget initiated ART on a less timely basis (hazard ratio [HR] 0.73, 95% CI 0.60–0.88). Living in a state with an ADAP waiting list was not associated with less timely initiation (HR 1.12, 95% CI 0.87–1.45). Neither additional state contributions nor waiting lists were significantly associated with virologic suppression. Persons with an IDU history initiated ART on a less timely basis (HR 0.67, 95% CI 0.47–0.95).
We found that living in states that did not contribute additionally to the ADAP budget was associated with delayed ART initiation when treatment was clinically indicated. Given the changing healthcare environment, continued assessment of the role of ADAPs and their features that facilitate prompt treatment is needed.
Patients who are lost to follow-up (LTFU) while on antiretroviral therapy (ART) pose challenges to the long-term success of ART programs. We describe the extent to which patients considered LTFU are misclassified as true disengagement from care when they are still alive on ART and explain reasons for ART discontinuation using our active tracing program to further improve ART retention programs and policies.
We identified adult ART patients who missed clinic appointment by more than 3 weeks between January 2006 and December 2010, assuming that such patients would miss their doses of antiretroviral drugs. Patients considered LTFU who consented during ART registration were traced by phone or home visits; true ART status after tracing was documented. Reasons for ART discontinuation were also recorded for those who stopped ART.
Of the 4,560 suspected LTFU cases, 1,384 (30%) could not be traced. Of the 3,176 successfully traced patients, 952 (30%) were dead and 2,224 (70%) were alive, of which 2,183 (99.5%) started ART according to phone-based self-reports or physical verification during in-person interviews. Of those who started ART, 957 (44%) stopped ART and 1,226 (56%) reported still taking ART at the time of interview by sourcing drugs from another clinic, using alternative ART sources or making brief ART interruptions. Among 940 cases with reasons for ART discontinuations, failure to remember (17%), too weak/sick (12%), travel (46%), and lack of transport to the clinic (16%) were frequently cited; reasons differed by gender.
The LTFU category comprises sizeable proportions of patients still taking ART that may potentially bias retention estimates and misdirect resources at the clinic and national levels if not properly accounted for. Clinics should consider further decentralization efforts, increasing drug allocations for frequent travels, and improving communication on patient transfers between clinics to increase retention and adherence.
At the end of 2009, a total of 501 AIDS patients were receiving antiretroviral therapy (ART) in Fujian Province in China, yet there were no assessments to determine treatment efficacy and HIV-1 preventive potency under the current health care delivery system.
During the period of 2005–2009, we assessed the outcomes of initial ART by following up 381 patients for 12 months in Fujian Province. CD4+ T-lymphocyte (CD4) count, plasma viral load (VL), and patient characteristics were analysed. The results were compared between 4 groups divided by the baseline CD4 values at the 25, 50 (median), and 75 percentiles.
Over three-quarters of the subjects reported heterosexual contact as the probable route of transmission. After 12 months of ART, CD4 recovery varied between the 4 groups (P < 0.001), but VL sharply declined regardless of the baseline CD4 count (P = 0.136). Although this VL decline indicates the potency of ART as an HIV-1 prevention tool, the time between positive diagnosis and ART initiation suggests serious delay in both diagnosis and treatment; the medians of periods for the lowest and highest baseline CD4 quartiles were 1.2 and 9.6 months, respectively.
Current limitations in VL determination make it difficult to assess the efficacy of initial ART, and delays in diagnosis and treatment suggest that subjects contributed to HIV-1 transmission while they were not receiving ART. The current National Free ART scheme does not provide free treatment for sexually transmitted infection (STI), and there is no link between ART and the STI care delivery system. This may interfere with the HIV-1 preventive potency of ART. We highly recommend establishing a collaborating mechanism with STI care, strengthening the VL determination system, and promoting HIV tests and early ART initiation.
To prepare for future HIV prevention trials, we conducted prospective cohort studies among women working in food and recreational facilities in northern Tanzania. We examined the prevalence and incidence of HIV and HSV-2, and associated risk factors.
Women aged 18–44 years working in food and recreational facilities were screened to determine their eligibility for the studies. Between 2008–2010, HIV-negative women were enrolled and followed for 12 months. At enrolment and 3-monthly, we collected socio-demographic and behavioural data, and performed clinical examinations for collection of biological specimens that were tested for reproductive tract infections. Risk factors for HIV and HSV-2 incidence were investigated using Poisson regression models.
We screened 2,229 and enrolled 1,378 women. The median age was 27 years (interquartile range, IQR 22, 33), and median duration working at current facility was 2 years. The prevalences of HIV at screening and HSV-2 at enrolment were 16% and 67%, respectively. Attendance at the 12-month visit was 86%. HIV and HSV-2 incidence rates were 3.7 (95% confidence interval, CI: 2.8,5.1) and 28.6 (95% CI: 23.5,35.0)/100 person-years, respectively. Women who were separated, divorced, or widowed were at increased risk of HIV (adjusted incidence rate ratio, aRR = 6.63; 95% CI: 1.97,22.2) and HSV-2 (aRR = 2.00; 95% CI: 1.15,3.47) compared with married women. Women reporting ≥3 partners in the past 3 months were at higher HIV risk compared with women with 0–1 partner (aRR = 4.75; 95% CI: 2.10,10.8), while those who had reached secondary education or above were at lower risk of HSV-2 compared with women with incomplete primary education (aRR = 0.42; 95% CI: 0.22,0.82).
HIV and HSV-2 rates remain substantially higher in this cohort than in the general population, indicating urgent need for effective interventions. These studies demonstrate the feasibility of conducting trials to test new interventions in this highly-mobile population.
Anemia is the main concern among patients using a zidovudine (AZT)-based antiretroviral treatment (ART). Some studies suggested weight-adjusted AZT dosing as a way to reduce toxicity. We analyzed the risk factors associated with AZT-induced anemia in a cohort using AZT as substitution for stavudine (D4T).
We retrospectively studied HIV-infected patients in a referral hospital in Phnom Penh, Cambodia between 2003 and 2011. Factors associated with AZT-related anemia requiring AZT-discontinuation within the first year after AZT initiation were analyzed using Cox regression.
Overall, 1180 patients, 60.5% female, were included. At AZT initiation, the median hemoglobin was 12.7 g/dL (IQR 11.7–13.9), the median weight: 51 kg (IQR 45–58) and the median time on ART prior to AZT substitution: 1.4 years (IQR 1.0–2.0). Within one year follow-up, 139 patients (11.8%) developed anemia requiring AZT discontinuation. Overall, there was no independent association of body weight with AZT discontinuation. AZT discontinuation was associated with lower hemoglobin level when starting AZT; older age and taking D4T-based ART less than one year prior to AZT. In exploratory analysis, a linear increase in risk of grade 2–4 anemia with lower body weight was seen if starting AZT substitution within less than one year of D4T-based ART.
Our findings argue against the need of weight-based dosing of AZT to reduce anemia among patients using AZT as substitution for D4T. Whether this also applies to ART-naïve individuals remains to be assessed. Future studies with AZT dose reduction should assess efficacy and overall tolerance of AZT.
Little is known about the treatment outcomes of undocumented Hispanic immigrants with HIV infection. We sought to compare the treatment outcomes of undocumented and documented patients 12-months after entering HIV care.
We conducted a retrospective cohort study of antiretroviral-naive patients 18 years and older attending their first visit at Thomas Street Health Center in Houston, Texas, between 1/1/2003 and 6/30/2008. The study population of 1,620 HIV-infected adults included 186 undocumented Hispanic, 278 documented Hispanic, 986 Black, and 170 White patients. The main outcome measures were retention in care (quarter years with at least one completed HIV primary care provider visit) and HIV suppression (HIV RNA <400 copies/mL), both measured 12-months after entering HIV care.
Undocumented Hispanic patients had lower median initial CD4 cell count (132 cells/mm3) than documented Hispanic patients (166 cells/mm3; P = 0.186), Black patients (226 cells/mm3; P<0.001), and White patients (264 cells/mm3; P = 0.001). However, once in care, undocumented Hispanic patients did as well or better than their documented counterparts. One year after entering HIV care, undocumented Hispanics achieved similar rates of retention in care and HIV suppression as documented Hispanic and White patients. Of note, black patients were significantly less likely to have optimal retention in care (adjusted odds ratio [aOR] 0.65, CI = 0.45–0.94) or achieve HIV suppression (aOR 0.32, CI = 0.17–0.61) than undocumented Hispanics.
Undocumented Hispanic persons with HIV infection enter care with more advanced disease than documented persons, suggesting testing and/or linkage to care efforts for this difficult-to-reach population need intensification. Once diagnosed, however, undocumented Hispanics have outcomes as good as or better than other racial/ethnic groups. Safety net providers for undocumented immigrants are vital for maintaining individual and public health.
To review the incidence of respiratory conditions and their effect on mortality in HIV-infected and uninfected individuals prior to and during the era of highly active antiretroviral therapy (HAART).
Two large observational cohorts of HIV-infected and HIV-uninfected men (Multicenter AIDS Cohort Study [MACS]) and women (Women’s Interagency HIV Study [WIHS]), followed since 1984 and 1994, respectively.
Adjusted odds or hazards ratios for incident respiratory infections or non-infectious respiratory diagnoses, respectively, in HIV-infected compared to HIV-uninfected individuals in both the pre-HAART (MACS only) and HAART eras; and adjusted Cox proportional hazard ratios for mortality in HIV-infected persons with lung disease during the HAART era.
Compared to HIV-uninfected participants, HIV-infected individuals had more incident respiratory infections both pre-HAART (MACS, odds ratio [adjusted-OR], 2.4; 95% confidence interval [CI], 2.2–2.7; p<0.001) and after HAART availability (MACS, adjusted-OR, 1.5; 95%CI 1.3–1.7; p<0.001; WIHS adjusted-OR, 2.2; 95%CI 1.8–2.7; p<0.001). Chronic obstructive pulmonary disease was more common in MACS HIV-infected vs. HIV-uninfected participants pre-HAART (hazard ratio [adjusted-HR] 2.9; 95%CI, 1.02–8.4; p = 0.046). After HAART availability, non-infectious lung diseases were not significantly more common in HIV-infected participants in either MACS or WIHS participants. HIV-infected participants in the HAART era with respiratory infections had an increased risk of death compared to those without infections (MACS adjusted-HR, 1.5; 95%CI, 1.3–1.7; p<0.001; WIHS adjusted-HR, 1.9; 95%CI, 1.5–2.4; p<0.001).
HIV infection remained a significant risk for infectious respiratory diseases after the introduction of HAART, and infectious respiratory diseases were associated with an increased risk of mortality.
The magnitude of HIV viral rebound following ART cessation has consequences for clinical outcome and onward transmission. We compared plasma viral load (pVL) rebound after stopping ART initiated in primary (PHI) and chronic HIV infection (CHI).
Two populations with protocol-indicated ART cessation from SPARTAC (PHI, n = 182) and SMART (CHI, n = 1450) trials.
Time for pVL to reach pre-ART levels after stopping ART was assessed in PHI using survival analysis. Differences in pVL between PHI and CHI populations 4 weeks after stopping ART were examined using linear and logistic regression. Differences in pVL slopes up to 48 weeks were examined using linear mixed models and viral burden was estimated through a time-averaged area-under-pVL curve. CHI participants were categorised by nadir CD4 at ART stop.
Of 171 PHI participants, 71 (41.5%) rebounded to pre-ART pVL levels, at a median of 50 (95% CI 48–51) weeks after stopping ART. Four weeks after stopping treatment, although the proportion with pVL≥400 copies/ml was similar (78% PHI versus 79% CHI), levels were 0.45 (95% CI 0.26–0.64) log10 copies/ml lower for PHI versus CHI, and remained lower up to 48 weeks. Lower CD4 nadir in CHI was associated with higher pVL after ART stop. Rebound for CHI participants with CD4 nadir >500 cells/mm3 was comparable to that experienced by PHI participants.
Stopping ART initiated in PHI and CHI was associated with viral rebound to levels conferring increased transmission risk, although the level of rebound was significantly lower and sustained in PHI compared to CHI.
Although highly active antiretroviral therapy (HAART) has improved HIV survival, some patients receiving therapy are still dying. This analysis was conducted to identify factors associated with increased risk of post-HAART mortality.
We evaluated baseline (prior to HAART initiation) clinical, demographic and laboratory factors (including CD4+ count and HIV RNA level) for associations with subsequent mortality in 1,600 patients who began HAART in a prospective observational cohort of HIV-infected U.S. military personnel.
Cumulative mortality was 5%, 10% and 18% at 4, 8 and 12 years post-HAART. Mortality was highest (6.23 deaths/100 person-years [PY]) in those with ≤ 50 CD4+ cells/mm3 before HAART initiation, and became progressively lower as CD4+ counts increased (0.70/100 PY with ≥ 500 CD4+ cells/mm3). In multivariate analysis, factors significantly (p < 0.05) associated with post-HAART mortality included: increasing age among those ≥ 40 years (Hazard ratio [HR] = 1.32 per 5 year increase), clinical AIDS events before HAART (HR = 1.93), ≤ 50 CD4+ cells/mm3 (vs. CD4+ ≥ 500, HR = 2.97), greater HIV RNA level (HR = 1.36 per one log10 increase), hepatitis C antibody or chronic hepatitis B (HR = 1.96), and HIV diagnosis before 1996 (HR = 2.44). Baseline CD4+ = 51-200 cells (HR = 1.74, p = 0.06), and hemoglobin < 12 gm/dL for women or < 13.5 for men (HR = 1.36, p = 0.07) were borderline significant.
Although treatment has improved HIV survival, defining those at greatest risk for death after HAART initiation, including demographic, clinical and laboratory correlates of poorer prognoses, can help identify a subset of patients for whom more intensive monitoring, counseling, and care interventions may improve clinical outcomes and post-HAART survival.
Highly active antiretroviral therapy; mortality; CD4+ lymphocyte count
To examine the outcomes of highly-active antiretroviral therapy (HAART) for individuals with free access to healthcare, we evaluated 2327 patients in a cohort study composed of military personnel and beneficiaries with HIV infection who initiated HAART from 1996 to the end of 2007.
Outcomes analyzed were virologic suppression (VS) and failure (VF), CD4 count changes, AIDS and death. VF was defined as never suppressing or having at least one rebound event. Multivariate (MV) analyses stratified by the HAART initiation year (before or after 2000) were performed to identify risk factors associated with these outcomes.
Among patients who started HAART after 2000, 81% had VS at 1 year (N = 1,759), 85% at 5 years (N = 1,061), and 82% at 8 years (N = 735). Five years post-HAART, the median CD4 increase was 247 cells/ml and 34% experienced VF. AIDS and mortality rates at 5 years were 2% and 0.3%, respectively. In a MV model adjusted for known risk factors associated with treatment response, being on active duty (versus retired) at HAART initiation was associated with a decreased risk of AIDS (HR = 0.6, 95% CI 0.4-1.0) and mortality (0.6, 0.3-0.9), an increased probability of CD4 increase ≥ 50% (1.2, 1.0-1.4), but was not significant for VF.
In this observational cohort, VS rates approach those described in clinical trials. Initiating HAART on active duty was associated with even better outcomes. These findings support the notion that free access to healthcare likely improves the response to HAART thereby reducing HIV-related morbidity and mortality.