Long-term HIV/AIDS survival estimation in the highly active antiretroviral therapy era

Patients with human immunodeficiency virus infection do not have inferior outcomes after dialysis access creation

OBJECTIVE

Despite improvements in treating human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS), the risk of end-stage renal disease and need for long-term arteriovenous (AV) access for hemodialysis remain high in HIV-infected patients. Associations of HIV/AIDS with AV access creation complications have been conflicting. Our goal was to clarify short- and long-term outcomes of patients with HIV/AIDS undergoing AV access creation.

METHODS

The Vascular Quality Initiative registry was queried from 2011 to 2018 for all patients undergoing AV access creation. Documentation of HIV infection status with or without AIDS was recorded. Data were propensity score matched (4:1) between non-HIV-infected patients and HIV/AIDS patients. Subsequent multivariable analysis and Kaplan-Meier analysis were performed for short- and long-term outcomes.

RESULTS

There were 25,711 upper extremity AV access creations identified: 25,186 without HIV infection (98%), 424 (1.6%) with HIV infection, and 101 (.4%) with AIDS. Mean age was 61.8 years, and 55.8% were male. Patients with HIV/AIDS were more often younger, male, nonwhite, nonobese, and current smokers; they were more often on Medicaid and more likely to have a history of intravenous drug use, and they were less often diabetic and less likely to have cardiac comorbidities (P < .05 for all). There was no significant difference in autogenous or prosthetic access used in these cohorts. Wound infection requiring incision and drainage or explantation within 90 days was low for all groups (0.6% vs 1.9 vs 0%; P = .11) of non-HIV-infected patients vs HIV-infected patients vs AIDS patients. Kaplan-Meier analysis showed no significant difference in 1-year freedom from primary patency loss (43.9% vs 46.3%; P =.6), 1-year freedom from reintervention (61% vs 60.7%,; P = .81), or 3-year survival (83% vs 83.8%; P = .57) for those with and without HIV/AIDS, respectively. Multivariable analysis demonstrated that patients with HIV/AIDS were not at significantly higher risk for access reintervention (hazard ratio [HR], 0.97; 95% confidence interval [CI], 0.76-1.24; P = .81), occlusion (HR, 1.06; 95% CI, 0.86-1.29; P = .6), or mortality (HR, 1.08; 95% CI, 0.83-1.43; P = .57).

CONCLUSIONS

Patients with HIV/AIDS undergoing AV access creation have outcomes similar to those of patients without HIV infection, including long-term survival. Patients with HIV/AIDS had fewer traditional end-stage renal disease risk factors compared with non-HIV-infected patients. Our findings show that the contemporary approach for creation and management of AV access in patients with HIV/AIDS should be continued; however, further research is needed to identify risk factors in this population.

Simulation model of the relationship between cesarean section rates and labor duration

Cesarean delivery is the most common major abdominal surgery in many parts of the world, and it accounts for nearly one-third of births in the United States. For a patient who requires a C-section, allowing prolonged labor is not recommended because of the increased risk of infection. However, for a patient who is capable of a successful vaginal delivery, performing an unnecessary C-section can have a substantial adverse impact on the patient's future health. We develop two stochastic simulation models of the delivery process for women in labor; and our objectives are (i) to represent the natural progression of labor and thereby gain insights concerning the duration of labor as it depends on the dilation state for induced, augmented, and spontaneous labors; and (ii) to evaluate the Friedman curve and other labor-progression rules, including their impact on the C-section rate and on the rates of maternal and fetal complications. To use a shifted lognormal distribution for modeling the duration of labor in each dilation state and for each type of labor, we formulate a percentile-matching procedure that requires three estimated quantiles of each distribution as reported in the literature. Based on results generated by both simulation models, we concluded that for singleton births by nulliparous women with no prior complications, labor duration longer than two hours (i.e., the time limit for labor arrest based on the Friedman curve) should be allowed in each dilation state; furthermore, the allowed labor duration should be a function of dilation state.

How I treat patients with HIV-related hematological malignancies using hematopoietic cell transplantation

Hematopoietic cell transplantation (HCT) has now been shown to be safe and effective for selected HIV-infected patients with hematological malignancies. Autologous HCT is now the standard of care for patients with HIV-related lymphomas who otherwise meet standard transplant criteria. Limited data also support use of allogeneic HCT (alloHCT) in selected HIV-infected patients who meet standard transplant criteria. We recommend enrolling patients in clinical trials that offer access to CCR5Δ32 homozygous donors, if available. HIV-infected patients requiring HCT may also be considered for participation in trials evaluating the activity of gene-modified hematopoietic stem cells in conferring resistance to HIV infection. To be considered for HCT, patients must have HIV infection that is responsive to combination antiretroviral therapy (cART). Careful planning for the peri-HCT management of the cART can avoid risk of significant drug interactions and development of cART-resistant HIV. In general, we recommend against the use of boosted proteasome inhibitors and nonnucleotide reverse transcriptase inhibitors in the cART regimen, in favor of nucleoside reverse transcriptase inhibitors and integrase inhibitors (without cobicistat). After HCT, patients must be closely monitored for development of opportunistic infections (OI), such as cytomegalovirus. Prevention of OI should include prophylactic and pre-emptive antimicrobials.

Hopefulness Fosters Affective and Cognitive Constructs for Actions to Cope and Enhance Quality of Life among People Living with HIV in Dar Es Salaam, Tanzania

The aims of this study were to describe how people living with HIV (PLWH) perceive hope and illustrate implications for HIV care and treatment. This is a qualitative study done to explore perceptions and meanings of hope among PLWH attending care and treatment clinics in Dar es Salaam, Tanzania. In all, 10 focus group discussions and 9 in-depth interviews were conducted. People living with HIV described the following 3 dimensions of hope: cognitive, positive emotions, and normalization. Being cognizant of the effectiveness of antiretroviral treatment (ART) often led to positive emotions, such as feeling comforted or strengthened, which in turn was related to positive actions toward normalizing life. Improved treatment outcomes facilitated hope, while persistent health problems, such as ART side effects, were sources of negative emotions contributing to loss of hope among PLWH. Hope motivated positive health-seeking behaviors, including adherence to ART, and this may guide interventions to help PLWH cope and live positively with HIV.

Effects of Quality of Life and Coping on Depression among Adults Living with HIV/AIDS

This prospective study examined the effect of maladaptive coping strategies and psychological quality of life (QOL) on depression at two time points in a diverse sample of persons living with HIV/AIDS ( N = 85). The use of maladaptive coping strategies to deal with the stress of living with HIV/AIDS, particularly engaging in various kinds of avoidant behaviors, was significantly associated with greater depression at baseline and increased depression at three months. QOL was the single most important predictor of depression. In an effort to develop effective clinical methods aimed at decreasing depression among adults living with HIV, future studies need to focus on improving quality of life and increasing adaptive coping strategies associated with the stress of living with HIV/AIDS.

Acute myelitis as presenting symptom of HIV-HTLV-1 co-infection

A 21-year-old woman presented with acute-onset spastic paraparesis. The MRI spinal scan revealed a contrast-enhanced T2 hyperintensity between C5-T2. The most common neurotropic pathogens were excluded by first level tests. Under suspicion of an acute immune-mediated myelitis, a corticosteroid therapy was administered. However, a seropositivity for both human immunodeficiency virus (HIV) type 1 and human T-lymphotropic virus (HTLV) subsequently emerged. An antiretroviral therapy was started while steroids discontinued. Patient's clinical conditions remained unchanged. HIV-HTLV-1 co-infection should be included in the differential diagnosis of any acute myelitis, even in patients with a preserved immune status and no risk factors.

Economic impact of HIV/AIDS: a systematic review in five European countries

The HIV/AIDS disease represent a priority for all health authorities in all countries and it also represents serious added socioeconomic problems for societies over the world. The aim of this paper is to analize the economic impact associated to the HIV/AIDS in an European context. We conducted a systematic literature review for five different countries (France, Germany, Italy, Spain and United Kingdom) and searched five databases. Three types of analyses were undertaken: descriptive statistics; quantitative analysis to calculate mean costs; and comparison across countries. 26 papers were included in this study containing seventy-six cost estimates. Most of the studies analyzed the health care cost of treatment of HIV/AIDS. Only 50% of the cost estimates provided mean lymphocyte count describing the patients' disease stage. Approximately thirty percent of cost estimates did not indicate the developmental stage of the illness in the patients included. There is a high degree of variability in the estimated annual cost per patient of the treatments across countries. There is also a great disparity in total healh care costs for patients with lymphocyte counts between 200CD4+/mm3 and 500 CD4/mm3, although the reason of variation is unclear. In spite of the potential economic impact in terms of productivity losses and cost of formal and informal care, few studies have set out to estimate the non-medical costs of HIV/AIDS in the countries selected. Another important result is that, despite the low HIV/AIDS prevalence, its economic burden is very relevant in terms of the total health care costs in this five countries. This study also shows that there are relatively few studies of HIV costs in European countries compared to other diseases. Finally, we conclude that the methodology used in many of the studies carried out leaves ample room for improvement and that there is a need for these studies to reflect the economic impact of HIV/AIDS beyond health care including other components of social burden.

Clinical and immunologic outcomes of HAART-treated HIV-infected women in resource constrain settings: the Belgrade Study

We performed a study to identify factors related to favorable response to highly active-antiretroviral therapy (HAART) in HIV-infected women. A retrospective study was performed on 216 women who had initiated HAART from January 1, 1998 to December 31, 2012, at the HIV/AIDS Center, Belgrade, Serbia. Participants were followed-up for 8.2 ± 3.4 years. The mean age was 37 ± 9.7 years. During follow-up, it was found that 26 patients had died. Clinical AIDS at initiation of HAART was observed in 43.9% patients, while 64.8% had a CD4+ T-cell count below 200 cells/μL. Multivariate analyses revealed that the single factor independently related to a favorable response to HAART was good compliance (odds [OR] ratio for survival = 2.9, 95% confidence intervals [CI] = 1.0-8.6, p = 0.03), while a baseline CD4+ T-cell count below 100 cells/μL, hepatitis C virus coinfection, and aged 40 years and older were all associated with an unfavorable response to HAART (OR = 0.28, 95% CI = 0.15-0.52, p < 0.001; OR = 0.49, 95% CI = 0.22-0.8, p = 0.008; OR = 0.41, 95% CI = 0.21-0.79, p = 0.008, respectively). The estimated 14-year-survival was 100% in patients with sustained viral suppression, regardless of the CD4+ counts achieved (p = 0.6, log-rank). If women with advanced HIV-related immunodeficiency reach and maintain optimal viral suppression during HAART, regardless of the level of immune recovery, and if they continue to maintain this suppression for up to a mean 8 years of treatment, their prognosis may be fairly good, even in resource-limited settings.

Treatment outcome of HAART-treated patients in a resource-limited setting: the Belgrade Cohort Study

INTRODUCTION

We evaluated the effects of highly-active-antiretroviral-therapy (HAART) in a resource-limited settings.

METHODS

A cross-sectional study was performed in patients who had initiated HAART at the HIV/AIDS-Center, Belgrade, Serbia. Treatment response was considered favorable in case of the achievement of undetectable HIVRNA plasma-viral-load (pVL<50 copies/μL), and with the CD4+ T-cell counts increased above 350cells/μL. The treatment failure was defined as pVL over 1.7 log10 copies/mL, regardless of immunological improvement.

RESULTS

Eight hundred and forty HIV infected patients were followed-up for 8.2±3.4years. Out of 697 patients available for follow-up, 113 (16.2%) patients died, 44 (6.3%) experienced treatment failure, while 540 (77.5%) had sustained undetectable viremia. In 419 (60.1%) favorable treatment response was achieved, while the dissociation between immunological and virological responses to HAART occurred in 121 (14.4%). A baseline CD4+ T-cell counts above 200 cells/μL was the single independent predictor of a favorable treatment response (HR=2, 95%CI=1.69-2.61, P=0.001), while pre-treatment with ART, HCV co-infection and AIDS at the time of treatment initiation, were all factors preventing a favorable response (HR=0.27, 95%CI=0.19-0.36, P=0.001; HR=0.75, 95%CI=0.56-0.95, P=0.02; HR=0.73, 95%CI=0.17-0.95, P=0.018, respectively). A sustained viral suppression was an independent predictor of survival (HR=0.2, 95% CI 0.07-0.61, P=0.004). HAART treated HIV-infected patients who reach and maintain undetectable viremia, have an 80% probability of a 14-years survival (P=0.08, log-rank).

CONCLUSION

If patient with advanced HIV-related immunodeficiency reach and maintain optimal viral suppression during HAART, regardless of the level of immune recovery, and if they continue to maintain this, their prognosis may be fairly good even in the resource-limited settings.

Use of observational data in evaluating treatments: antiretroviral therapy and HIV

Observational data are increasingly used in various therapeutic areas to evaluate the use, effectiveness and side effects of new treatments. Whilst randomized clinical trials remain the gold standard for evaluating the efficacy of new agents, they have a number of limitations for HIV, including the limited number of combinations that are compared and the costs of long-term follow-up. Observational data from seroconverter and clinical cohorts have been used to compare the short- and longer-term effectiveness of different therapy combinations and to evaluate the longer-term risks associated with antiretroviral therapy. Furthermore, they provide the opportunity to evaluate the relative success of more complex patterns of therapy, such as sequencing of different regimens over time. However, because of the nature of these data, a number of potential biases may arise which can influence interpretation.

Fluorine Substituted 1,2,4-Triazinones as Potential Anti-HIV-1 and CDK2 Inhibitors

Fluorine substituted 1,2,4-triazinones have been synthesized via alkylation, amination, and/or oxidation of 6-(2-amino-5-fluorophenyl)-3-thioxo-3,4-dihydro-1,2,4-triazin-5(2H)-one1and 4-fluoro-N-(4-fluoro-2-(5-oxo-3-thioxo-2,3,4,5-tetrahydro-1,2,4-triazin-6-yl)phenyl)benzamide5as possible anti-HIV-1 and CDK2 inhibitors. Alkylation on positions 2 and 4 in 1,2,4-triazinone gave compounds6–8. Further modification was performed by selective alkylation and amination on position 3 to form compounds9–15. However oxidation of5yielded compounds16–18. Structures of the target compounds have been established by spectral analysis data. Five compounds (5, 11, 14, 16, and17) have shown very good anti-HIV activity in MT-4 cells. Similarly, five compounds (1, 3, and14–16) have exhibited very significant CDK2 inhibition activity. Compounds14and16were found to have dual anti-HIV and anticancer activities.

Closing the gap: increases in life expectancy among treated HIV-positive individuals in the United States and Canada

BACKGROUND

Combination antiretroviral therapy (ART) has significantly increased survival among HIV-positive adults in the United States (U.S.) and Canada, but gains in life expectancy for this region have not been well characterized. We aim to estimate temporal changes in life expectancy among HIV-positive adults on ART from 2000-2007 in the U.S. and Canada.

METHODS

Participants were from the North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD), aged ≥20 years and on ART. Mortality rates were calculated using participants' person-time from January 1, 2000 or ART initiation until death, loss to follow-up, or administrative censoring December 31, 2007. Life expectancy at age 20, defined as the average number of additional years that a person of a specific age will live, provided the current age-specific mortality rates remain constant, was estimated using abridged life tables.

RESULTS

The crude mortality rate was 19.8/1,000 person-years, among 22,937 individuals contributing 82,022 person-years and 1,622 deaths. Life expectancy increased from 36.1 [standard error (SE) 0.5] to 51.4 [SE 0.5] years from 2000-2002 to 2006-2007. Men and women had comparable life expectancies in all periods except the last (2006-2007). Life expectancy was lower for individuals with a history of injection drug use, non-whites, and in patients with baseline CD4 counts <350 cells/mm(3).

CONCLUSIONS

A 20-year-old HIV-positive adult on ART in the U.S. or Canada is expected to live into their early 70 s, a life expectancy approaching that of the general population. Differences by sex, race, HIV transmission risk group, and CD4 count remain.

Life expectancies of South African adults starting antiretroviral treatment: collaborative analysis of cohort studies

BACKGROUND

Few estimates exist of the life expectancy of HIV-positive adults receiving antiretroviral treatment (ART) in low- and middle-income countries. We aimed to estimate the life expectancy of patients starting ART in South Africa and compare it with that of HIV-negative adults.

METHODS AND FINDINGS

Data were collected from six South African ART cohorts. Analysis was restricted to 37,740 HIV-positive adults starting ART for the first time. Estimates of mortality were obtained by linking patient records to the national population register. Relative survival models were used to estimate the excess mortality attributable to HIV by age, for different baseline CD4 categories and different durations. Non-HIV mortality was estimated using a South African demographic model. The average life expectancy of men starting ART varied between 27.6 y (95% CI: 25.2-30.2) at age 20 y and 10.1 y (95% CI: 9.3-10.8) at age 60 y, while estimates for women at the same ages were substantially higher, at 36.8 y (95% CI: 34.0-39.7) and 14.4 y (95% CI: 13.3-15.3), respectively. The life expectancy of a 20-y-old woman was 43.1 y (95% CI: 40.1-46.0) if her baseline CD4 count was ≥ 200 cells/µl, compared to 29.5 y (95% CI: 26.2-33.0) if her baseline CD4 count was <50 cells/µl. Life expectancies of patients with baseline CD4 counts ≥ 200 cells/µl were between 70% and 86% of those in HIV-negative adults of the same age and sex, and life expectancies were increased by 15%-20% in patients who had survived 2 y after starting ART. However, the analysis was limited by a lack of mortality data at longer durations.

CONCLUSIONS

South African HIV-positive adults can have a near-normal life expectancy, provided that they start ART before their CD4 count drops below 200 cells/µl. These findings demonstrate that the near-normal life expectancies of HIV-positive individuals receiving ART in high-income countries can apply to low- and middle-income countries as well. Please see later in the article for the Editors' Summary.

Modeling of HIV-1 infection: insights to the role of monocytes/macrophages, latently infected T4 cells, and HAART regimes

A novel dynamic model covering five types of cells and three connected compartments, peripheral blood (PB), lymph nodes (LNs), and the central nervous system (CNS), is here proposed. It is based on assessment of the biological principles underlying the interactions between the human immunodeficiency virus type I (HIV-1) and the human immune system. The simulated results of this model matched the three well-documented phases of HIV-1 infection very closely and successfully described the three stages of LN destruction that occur during HIV-1 infection. The model also showed that LNs are the major location of viral replication, creating a pool of latently infected T4 cells during the latency period. A detailed discussion of the role of monocytes/macrophages is made, and the results indicated that infected monocytes/macrophages could determine the progression of HIV-1 infection. The effects of typical highly active antiretroviral therapy (HAART) drugs on HIV-1 infection were analyzed and the results showed that efficiency of each drug but not the time of the treatment start contributed to the change of the turnover of the disease greatly. An incremental count of latently infected T4 cells was made under therapeutic simulation, and patients were found to fail to respond to HAART therapy in the presence of certain stimuli, such as opportunistic infections. In general, the dynamics of the model qualitatively matched clinical observations very closely, indicating that the model may have benefits in evaluating the efficacy of different drug therapy regimens and in the discovery of new monitoring markers and therapeutic schemes for the treatment of HIV-1 infection.

Prediction of health preference values from CD4 counts in individuals with HIV

BACKGROUND

A common measure of health benefit in technology assessments is the quality-adjusted life year, which incorporates health preference or utility scores.

OBJECTIVE

To build and test a predictive model using CD4 counts to derive health preference scores.

DESIGN

Predictive modeling. Setting. Ontario HIV Treatment Network Cohort Study. Measurement. The relationship between HUI3-derived health preference score and HIV health status measured by CD4 count was examined by a regression model. Additional independent variables considered included age, time since HIV diagnosis, AIDS-defining condition, sex, and education level. A polynomial regression model was fit to predict health preference scores. The final model was established using automated backwards stepwise variable elimination using the Akaike information criterion. Tenfold cross-validation was used to assess the model.

RESULTS

Data from 841 participants were available. Mean age and time since diagnosis were 46.78 and 11.03 years, respectively. CD4 counts ranged from 2 to 995 cells per mm(3) with 267 (31.75%) individuals having less than 350 cells per mm(3). Mean HUI3 utility score was 0.72 and ranged from -0.25 to 1. The final model retained squared terms for CD4 counts, age, and time since HIV diagnosis and eliminated history of AIDS-defining condition and the nonsquared time since HIV diagnosis. Prediction error was assessed in 14 subgroups using the validation set. Two subgroups had mean prediction errors greater than 0.02. Limitations. All statistical models are limited by the data used to develop and test the model. The model estimates health utility scores primarily through CD4 counts. Therefore, the model may be inappropriate if noninfectious diseases are a significant factor.

CONCLUSIONS

Results provide a model for predicting health preference values from CD4 counts.

Projected life expectancy of people with HIV according to timing of diagnosis

BACKGROUND AND OBJECTIVES

Effective antiretroviral therapy (ART) has contributed greatly toward survival for people with HIV, yet many remain undiagnosed until very late. Our aims were to estimate the life expectancy of an HIV-infected MSM living in a developed country with extensive access to ART and healthcare, and to assess the effect of late diagnosis on life expectancy.

METHODS

A stochastic computer simulation model of HIV infection and the effect of ART was used to estimate life expectancy and determine the distribution of potential lifetime outcomes of an MSM, aged 30 years, who becomes HIV positive in 2010. The effect of altering the diagnosis rate was investigated.

RESULTS

Assuming a high rate of HIV diagnosis (median CD4 cell count at diagnosis, 432  cells/μl), projected median age at death (life expectancy) was 75.0 years. This implies 7.0 years of life were lost on average due to HIV. Cumulative risks of death by 5 and 10 years after infection were 2.3 and 5.2%, respectively. The 95% uncertainty bound for life expectancy was (68.0,77.3) years. When a low diagnosis rate was assumed (diagnosis only when symptomatic, median CD4 cell count 140  cells/μl), life expectancy was 71.5 years, implying an average 10.5 years of life lost due to HIV.

CONCLUSION

If low rates of virologic failure observed in treated patients continue, predicted life expectancy is relatively high in people with HIV who can access a wide range of antiretrovirals. The greatest risk of excess mortality is due to delays in HIV diagnosis.

Resistance evolution in HIV - modeling when to intervene

The treatment of HIV is complicated by the evolution of antiviral drug resistant virus and the limited availability of antigenically independent antiviral regimens. The consequences to the patient of successive virological failures is such that many strategies to minimize the occurrence of such failures are being investigated. In this paper, a Markov chain-based model of virological failure is introduced. This model considers sequential failure events, and differentiates between several modes of virological failure. This model is then used to evaluate the resistance- targeted interventions by means of testing the impact of a viral load preconditioning strategy on total treatment regimen longevity in HIV patients. It is shown that a proposed intervention targeting pre-existing resistance has the potential to increase the expected time to three sequential virological failures by an average of 3.3 years per patient. When combined with an intervention targeting patient compliance, the total potential increase in the time to three sequential virological failures is as high as 11.2 years. The impact on patient and public health is discussed.

Economic returns to investment in AIDS treatment in low and middle income countries

Since the early 2000s, aid organizations and developing country governments have invested heavily in AIDS treatment. By 2010, more than five million people began receiving antiretroviral therapy (ART)--yet each year, 2.7 million people are becoming newly infected and another two million are dying without ever having received treatment. As the need for treatment grows without commensurate increase in the amount of available resources, it is critical to assess the health and economic gains being realized from increasingly large investments in ART. This study estimates total program costs and compares them with selected economic benefits of ART, for the current cohort of patients whose treatment is cofinanced by the Global Fund to Fight AIDS, Tuberculosis and Malaria. At end 2011, 3.5 million patients in low and middle income countries will be receiving ART through treatment programs cofinanced by the Global Fund. Using 2009 ART prices and program costs, we estimate that the discounted resource needs required for maintaining this cohort are $14.2 billion for the period 2011-2020. This investment is expected to save 18.5 million life-years and return $12 to $34 billion through increased labor productivity, averted orphan care, and deferred medical treatment for opportunistic infections and end-of-life care. Under alternative assumptions regarding the labor productivity effects of HIV infection, AIDS disease, and ART, the monetary benefits range from 81 percent to 287 percent of program costs over the same period. These results suggest that, in addition to the large health gains generated, the economic benefits of treatment will substantially offset, and likely exceed, program costs within 10 years of investment.

Determinants of health care costs of HIV-positive patients in the Canary Islands, Spain

The aims of this study were to estimate medical expenditures on human immunodeficiency virus (HIV) treatment and to identify significant associated variables. We performed a retrospective multi-centre study in the Canary Islands using a sample of 569 patients recruited at outpatient visits. The study examined demographic and clinical variables, health-related quality of life (HRQOL), and health care resources. Clinical data was obtained from medical records and patient interviews. Several empirical models for identifying the relationship between health care costs and independent variables were developed. The greatest expense came from pharmaceutical expenditure (82.1% of direct costs), while hospital costs only represented 4.6% of total expenditure. The data showed a statistically significant association between health care costs and the CD4 count of the previous year. HRQOL was also a significant variable. Therefore, CD4 cell count can be used to predict health care costs in patients. Policymakers could use this information to help guide their decisions in allocating limited health care resources to HIV treatments.

Cost-effectiveness of strategies to improve HIV testing and receipt of results: economic analysis of a randomized controlled trial

BACKGROUND

The CDC recommends routine voluntary HIV testing of all patients 13-64 years of age. Despite this recommendation, HIV testing rates are low even among those at identifiable risk, and many patients do not return to receive their results.

OBJECTIVE

To examine the costs and benefits of strategies to improve HIV testing and receipt of results.

DESIGN

Cost-effectiveness analysis based on a Markov model. Acceptance of testing, return rates, and related costs were derived from a randomized trial of 251 patients; long-term costs and health outcomes were derived from the literature. SETTING/TARGET POPULATION: Primary-care patients with unknown HIV status.

INTERVENTIONS

Comparison of three intervention models for HIV counseling and testing: Model A = traditional HIV counseling and testing; Model B = nurse-initiated routine screening with traditional HIV testing and counseling; Model C = nurse-initiated routine screening with rapid HIV testing and streamlined counseling.

MAIN MEASURES

Life-years, quality-adjusted life-years (QALYs), costs and incremental cost-effectiveness.

KEY RESULTS

Without consideration of the benefit from reduced HIV transmission, Model A resulted in per-patient lifetime discounted costs of $48,650 and benefits of 16.271 QALYs. Model B increased lifetime costs by $53 and benefits by 0.0013 QALYs (corresponding to 0.48 quality-adjusted life days). Model C cost $66 more than Model A with an increase of 0.0018 QALYs (0.66 quality-adjusted life days) and an incremental cost-effectiveness of $36,390/QALY. When we included the benefit from reduced HIV transmission, Model C cost $10,660/QALY relative to Model A. The cost-effectiveness of Model C was robust in sensitivity analyses.

CONCLUSIONS

In a primary-care population, nurse-initiated routine screening with rapid HIV testing and streamlined counseling increased rates of testing and receipt of test results and was cost-effective compared with traditional HIV testing strategies.

Triangulating on success: innovation, public health, medical care, and cause-specific US mortality rates over a half century (1950-2000)

To identify successes in improving America's health, we identified disease categories that appeared on vital statistics lists of leading causes of death in the US adult population in either 1950 or 2000, and that experienced at least a 50% reduction in age-adjusted death rates from their peak level to their lowest point between 1950 and 2000. Of the 9 cause-of-death categories that achieved this 50% reduction, literature review suggests that 7 clearly required diffusion of new innovations through both public health and medical care channels. Our nation's health success stories are consistent with a triangulation model of innovation plus public health plus medical care, even when the 3 sectors have worked more in parallel than in partnership.

Cost effectiveness of darunavir/ritonavir 600/100 mg bid in protease inhibitor-experienced, HIV-1-infected adults in Belgium, Italy, Sweden and the UK

BACKGROUND

Two phase II trials (POWER 1 and 2) have demonstrated that darunavir co-administered with low-dose ritonavir (DRV/r) provides significant clinical benefit compared with control protease inhibitors (PIs) in highly treatment-experienced, HIV-1-infected adults, when co-administered with optimized background therapy (OBR).

OBJECTIVE

To determine whether DRV/r is cost effective compared with control PIs, from the perspective of Belgian, Italian, Swedish and UK reimbursement authorities, when used in treatment-experienced patients similar to those included in the POWER 1 and 2 trials.

METHODS

An existing Markov model containing health states defined by CD4 cell count ranges (> 500, 351-500, 201-350, 101-200, 51-100 and 0-50 cells/mm³) and death was adapted for use in four European healthcare settings. Baseline demographics, CD4 cell count distribution and antiretroviral drug usage reflected those reported in the POWER 1 and 2 trials. Virological/immunological response rates and matching transition probabilities over the patient's lifetime were based on results from the POWER trials and published data. After treatment failure, patients were assumed to switch to a tipranavir-containing regimen plus OBR. For each CD4 cell count range, utility values and HIV-related mortality rates were obtained from the published literature. National all-cause mortality data and published data on the increased risk of non HIV-related mortality in HIV-infected individuals were taken into account in the model. Data from observational studies conducted in each healthcare setting were used to determine resource-use patterns and costs associated with each CD4 cell count range. Unit costs were derived from official local sources; a lifetime horizon was taken and discount rates were selected based on local guidelines.

RESULTS

In the base-case analysis, quality-adjusted life-year (QALY) gains of up to 1.397 in Belgium, over 1.171 in Italy, 1.142 in Sweden and 1.091 in the UK were predicted when DRV/r-based therapy was used instead of control PI-based treatment. The base-case analyses predicted an incremental cost-effectiveness ratio (ICER) of €11,438/QALY in Belgium, €12,122/QALY in Italy,€10,942/QALY in Sweden and €16,438/QALY in the UK. Assuming an acceptability threshold of €30,000/QALY, DRV/r-based therapy remained cost effective over all parameter ranges tested in extensive one-way sensitivity analyses. Probabilistic sensitivity analysis revealed a 95% (Belgium), 97% (Italy), 92% (Sweden) or 78% (UK) probability of attaining an ICER below this threshold.

CONCLUSION

From four European payer perspectives, DRV/r-based antiretroviral therapy is predicted to be cost effective compared with currently available control PIs, when both are used with an OBR in treatment-experienced, HIV-1-infected adults who failed to respond to more than one PI-containing regimen.

Cost effectiveness of darunavir/ritonavir 600/100 mg bid in treatment-experienced, lopinavir-naive, protease inhibitor-resistant, HIV-infected adults in Belgium, Italy, Sweden and the UK

BACKGROUND

Using data from the phase IIb POWER trials, darunavir boosted with low-dose ritonavir (DRV/r; 600/100 mg twice daily; bid)-based highly active antiretroviral therapy (HAART) was shown to be significantly more efficacious and cost effective than other protease inhibitor (PI)-based therapy in highly treatment-experienced, HIV-1-infected adults. Furthermore, in the phase III TITAN trial (TMC114-C214), DRV/r 600/100 mg bid-based HAART generated a superior 48-week virological response rate compared with standard-of-care lopinavir/ritonavir (LPV/r; 400/100 mg bid)-based therapy in treatment-experienced, lopinavir-naive patients, and in particular those with one or more International AIDS Society - USA (IAS-USA) primary PI resistance-associated mutations at baseline. These patients had a broader degree of previous PI use/failure (0 - ≥ 2) than the POWER patients.

OBJECTIVES

To determine whether DRV/r 600/100 mg bid-based HAART is cost effective compared with LPV/r-based therapy, from the perspective of Belgian, Italian, Swedish and UK reimbursement authorities, when used in treatment-experienced patients similar to TITAN patients with one or more IAS-USA primary PI mutations at baseline.

METHODS

An existing Markov model containing health states defined by CD4 cell count ranges (>500, 351-500, 201-350, 101-200, 51-100 and 0-50 cells/mm³) and an absorbing state of death was adapted for use in the above-mentioned healthcare settings. Baseline demographics, CD4 cell count distribution, antiretroviral drug usage, virological/immunological response rates and matching transition probabilities were based on data collected during the first 48 weeks of therapy in the modelled subgroup of TITAN patients and the published literature. After treatment failure, patients were assumed to switch to a follow-on combination regimen. For each health state, utility values and mortality rates were obtained from the published literature. Data from local observational studies (Belgium, Sweden and Italy) or the published literature (UK) were used to determine resource-use patterns and costs associated with each CD4 cell count range. Unit costs were derived from official local sources; a lifetime horizon was taken and discount rates were chosen based on local guidelines.

RESULTS

The base-case analysis predicted quality-adjusted life year (QALY) gains of 0.785 in Belgium, 0.608 in Italy, 0.584 in Sweden and 0.550 in the UK when DRV/r-based therapy was used instead of LPV/r-based treatment. The estimated base-case incremental cost-effectiveness ratios (ICERs) were €6964/QALY gained in Belgium, €9277/QALY gained in Italy, €6868 (SEK69,687)/QALY gained in Sweden and €14,778 (£12 612)/QALY gained in the UK. Assuming a threshold of €30,000/QALY gained, DRV/r-based therapy remained cost effective over most parameter ranges tested in extensive one-way sensitivity analyses. The variation of immunological response rates and the time horizon were identified as important drivers of cost effectiveness. Probabilistic sensitivity analysis revealed a greater than 70% probability of achieving an ICER below this threshold in all four healthcare settings.

CONCLUSION

From the perspective of Belgian, Italian, Swedish and UK payers, DRV/r 600/100 mg bid-based HAART is predicted to be cost effective compared with LPV/r 400/100 mg bid-based therapy, when used to manage treatment experienced, lopinavir-naive, PI-resistant, HIV-infected adults with a broad range of previous PI use/failure.

Patients' perspectives on informal caregiver involvement in HIV health care appointments

HIV treatment advances have had a major impact on disease-related morbidity and mortality. However, not all HIV-positive persons are experiencing improved health outcomes. In the United States in particular, patient nonadherence and prescription bias may explain some health disparities. To address these factors, researchers and practitioners may benefit from enlisting support from an underutilized resource: patients' families and significant or supportive others. Little is known about informal caregiver involvement in treatment planning or how such involvement might affect health care delivery and receipt. The purpose of this study was to investigate patient perspectives on informal caregiver involvement in treatment planning, including the perceived consequences of others' involvement. Forty-two predominantly African American HIV-positive adults who were partnered at the time of diagnosis were recruited in 2005 from infectious disease clinics in Milwaukee, Wisconsin. Participants took part in individual semistructured interviews. They were asked questions pertaining to their diagnosis, treatment planning, and informal caregiver involvement at medical appointments. Data were recorded, transcribed, and coded for themes using NVivo 7 qualitative software. A minority of those interviewed were accompanied to medical appointments. Still, participants overwhelmingly identified more potential benefits than disadvantages to others' involvement. Benefits categories include improved information communication, the development of stronger relationships, improved family health, and successful treatment outcomes. Disadvantages of involvement included negative emotional and behavioral consequences for the patient and disrupted patient-provider communication. Recommendations for health care providers are discussed.

Modeling the population level effects of an HIV-1 vaccine in an era of highly active antiretroviral therapy

First generation HIV vaccines may have limited ability to prevent infection. Instead, they may delay the onset of AIDS or reduce the infectiousness of vaccinated individuals who become infected. To assess the population level effects of such a vaccine, we formulate a deterministic model for the spread of HIV in a homosexual population in which the use of highly active antiretroviral therapy (HAART) to treat HIV infection is incorporated. The basic reproduction number R(0) is obtained under this model. We then expand the model to include the potential effects of a prophylactic HIV vaccine. The reproduction number R(f) is derived for a population in which a fraction f of susceptible individuals is vaccinated and continues to benefit from vaccination. We define f(*) as the minimum vaccination fraction for which R(f )< or =1 and describe situations in which it equals the critical vaccination fraction necessary to eliminate disease. When R(0) is large or an HIV vaccine is only partially effective, the critical vaccination fraction may exceed one. HIV vaccination, however, may still reduce the prevalence of disease if the reduction in infectiousness is at least as great as the reduction in the rate of disease progression. In particular, a vaccine that reduces infectiousness during acute infection may have an important public health impact especially if coupled with counseling to reduce risky behavior.

HIV testing rates, testing locations, and healthcare utilization among urban African-American men

African-American men bear a disproportionate burden of HIV infection in the United States. HIV testing is essential to ensure that HIV-infected persons are aware of their HIV-positive serostatus, can benefit from early initiation of antiretroviral therapy, and can reduce their risk of transmitting the virus to sex partners. This cross-sectional study assessed HIV testing history and healthcare utilization among 352 young African-American men recruited in urban neighborhoods in a Midwestern city. The self-administered survey measured sexual risk behaviors, factors associated with HIV testing, and barriers to testing. The acceptability of community venues for HIV testing was also assessed. Of the respondents, 76% had been tested for HIV at some time in their lives, 52% during the prior 12 months. Of the participants, 70% had unprotected intercourse during the prior 12 months, 26% with two or more partners. Nearly three-quarters (72%) of participants had seen a healthcare provider during the prior year. In univariate analyses, those who had at least one healthcare provider visit during the prior 12 months and those who had a primary doctor were more likely to have been tested in the prior 12 months. In multivariate analyses, having a regular doctor who recommended HIV testing was the strongest predictor of having been tested [OR=7.38 (3.55, 15.34)]. Having been diagnosed or treated for a sexually transmitted disease also was associated with HIV testing [OR=1.83 (1.04, 3.21)]. The most commonly preferred testing locations were medical settings. However, community venues were acceptable alternatives. Having a primary doctor recommend testing was strongly associated with HIV testing and most HIV testing occurred at doctors' offices. But, a substantial proportion of persons were not tested for HIV, even if seen by a doctor. These results suggest that HIV testing could be increased within the healthcare system by increasing the number of recommendations made by physicians to patients. The use of community venues for HIV testing sites could further increase the number of persons tested for HIV.

Racial, gender and geographic disparities of antiretroviral treatment among US Medicaid enrolees in 1998

BACKGROUND

In 1998, highly active antiretroviral therapy (HAART) was widespread, but the diffusion of these life-saving treatments was not uniform. As half of all AIDS patients in the USA have Medicaid coverage, this study of a multistate Medicaid claims dataset was undertaken to assess disparities in the rates of HAART.

METHODS

Data came from 1998 Medicaid claims files from five states with varying HIV prevalence. ICD-9 codes were used to identify people with a diagnosis of HIV/AIDS or AIDS-defining illness. Multivariate analyses assessed associations between age, gender, race and state of residence for antiretroviral regimens consistent with HAART, as defined by 1998 Centers for Disease Control and Prevention (CDC) guidelines.

RESULTS

Among 7202 Medicaid enrolees with a diagnosis of HIV/AIDS or AIDS, 62% received HAART and 25% received no antiretroviral therapy. Multivariate analyses showed that age, race, gender and state were all significant predictors of receiving HAART: white, non-Hispanic patients were most likely to receive HAART (68.3%), with lower rates in Hispanic and black, non-Hispanic segments of the population (59.3% and 57.5%, respectively, p<0.001). Women were less likely to receive HAART than men (51.8% vs 69.3%, p<0.001).

CONCLUSION

Despite similar insurance coverage and drug benefits, life-saving treatments for HIV/AIDS diffused at widely varying rates in different segments of the Medicaid population. Research is needed to determine the extent to which racial, gender, interstate and region disparities currently correspond to barriers to such care.

Life expectancy of individuals on combination antiretroviral therapy in high-income countries: a collaborative analysis of 14 cohort studies

BACKGROUND

Combination antiretroviral therapy has led to significant increases in survival and quality of life, but at a population-level the effect on life expectancy is not well understood. Our objective was to compare changes in mortality and life expectancy among HIV-positive individuals on combination antiretroviral therapy.

METHODS

The Antiretroviral Therapy Cohort Collaboration is a multinational collaboration of HIV cohort studies in Europe and North America. Patients were included in this analysis if they were aged 16 years or over and antiretroviral-naive when initiating combination therapy. We constructed abridged life tables to estimate life expectancies for individuals on combination antiretroviral therapy in 1996-99, 2000-02, and 2003-05, and stratified by sex, baseline CD4 cell count, and history of injecting drug use. The average number of years remaining to be lived by those treated with combination antiretroviral therapy at 20 and 35 years of age was estimated. Potential years of life lost from 20 to 64 years of age and crude mortality rates were also calculated.

FINDINGS

18 587, 13 914, and 10 854 eligible patients initiated combination antiretroviral therapy in 1996-99, 2000-02, and 2003-05, respectively. 2056 (4.7%) deaths were observed during the study period, with crude mortality rates decreasing from 16.3 deaths per 1000 person-years in 1996-99 to 10.0 deaths per 1000 person-years in 2003-05. Potential years of life lost per 1000 person-years also decreased over the same time, from 366 to 189 years. Life expectancy at age 20 years increased from 36.1 (SE 0.6) years to 49.4 (0.5) years. Women had higher life expectancies than did men. Patients with presumed transmission via injecting drug use had lower life expectancies than did those from other transmission groups (32.6 [1.1] years vs 44.7 [0.3] years in 2003-05). Life expectancy was lower in patients with lower baseline CD4 cell counts than in those with higher baseline counts (32.4 [1.1] years for CD4 cell counts below 100 cells per muL vs 50.4 [0.4] years for counts of 200 cells per muL or more).

INTERPRETATION

Life expectancy in HIV-infected patients treated with combination antiretroviral therapy increased between 1996 and 2005, although there is considerable variability between subgroups of patients. The average number of years remaining to be lived at age 20 years was about two-thirds of that in the general population in these countries.

Costs and benefits of HAART for patients with HIV in a public hospital in Mexico

BACKGROUND

The Mexican government is currently implementing strategies to improve and expand comprehensive treatment for people living with HIV. Limited data, however, are available on the benefits obtained and costs incurred by these strategies.

OBJECTIVE

To estimate the effects of highly active antiretroviral therapy (HAART) on a cohort of people living with HIV and to estimate the cost of extending patients' lives.

METHODS

A survival analysis was used to follow a dynamic cohort of 797 people receiving AIDS treatment in Mexico from 1982 to 2006. The Kaplan-Meier method was applied to estimate the probability of survival for different lengths of time starting on the date of diagnosis. The Cox's proportional hazards regression model was used to assess differences in AIDS mortality by antiretroviral therapy regimen, age and sex.

RESULTS

The probability of survival after diagnosis without antiretroviral therapy (ART) was approximately 0.73 (95% CI 0.69-0.77) after the first year, 0.36 (95% CI 0.32-0.40) at 5 years, 0.28 (95% CI 0.24-0.33) at the tenth year, 0.26 (95% CI 0.21-0.31) at the fifteenth year and 0.22 (95% CI 0.14-0.30) thereafter. The results showed a longer life expectancy when patients took HAART (as opposed to monotherapy or dual therapy) from the beginning of their treatment. Results from the Cox model showed that those who started and continued on HAART were 7.1 (P < 0.01) times more likely to survive than those who received no treatment. Extending the length of life beyond 15 years after the initial diagnosis represents an accumulated cost of more than US$280,000.00 per individual.

Evaluating the impact of antiretroviral therapy on HIV transmission

As global efforts proceed to scale up the delivery of antiretroviral therapy (ART) to HIV-infected persons in most urgent need, it is essential to understand the potential impact of treatment expansion on the transmission of new HIV infections. In this study, we use a series of simple mathematical models to explore the direction and magnitude of treatment effects on the sexual transmission of HIV. By defining the circumstances under which ART can reduce the number of new infections transmitted by treated patients, we provide critical benchmarks to aid in prioritizing efforts to maximize the population health impact of treatment and in evaluating the performance of different treatment programmes. We find that, based on the best currently available evidence of possible treatment effects on patient infectiousness, survival and behavior, the potential remains for either positive or negative changes in overall transmission. In relation to the total number of expected secondary infections caused by each infected person, however, these net treatment effects are relatively modest, particularly if treatment is initiated at advanced stages of the disease. This finding implies that treatment alone should not be expected to alter the population-level incidence of new infections dramatically, in the absence of changes in other factors including possible behavioral responses among uninfected persons and among infected persons who are not yet treatment candidates.

Current status of HIV infection: a review for non-HIV-treating physicians

An estimated 40 million people live with human immunodeficiency virus (HIV) globally, and over four million people were newly diagnosed with HIV infection in 2006. Twenty-five million people have died as a result of HIV since its recognition in 1981. Where available, highly active antiretroviral therapy has resulted in significant decreases in HIV-associated morbidity and mortality. Nevertheless, opportunistic infections and conditions continue to occur, and their recognition and management continue to be an important component of HIV care.

When time is more than money: The allocation of time between work and leisure in HIV-infected patients

Time is a limited resource and individuals have to decide how many hours they should allocate to work and to leisure activities. Differences in wage rate or availability of non-labour income (financial support from families and savings) may influence how individuals allocate their time between work and leisure. An increase in wage rate may induce income effects (leisure time demanded increases) and substitution effects (leisure time demanded decreases) whereas an increase in non-labour income only induces income effects. We explored the effects of differences in wage rate and non-labour income on the allocation of time in HIV-infected patients. Patients enrolled in the Swiss HIV Cohort Study (SHCS) provided information on their time allocation, i.e. number of hours worked in 1998. A multinomial logistic regression model was used to test for income and substitution effects. Our results indicate that (i) the allocation of time in HIV-infected patients does not differ with level of education (i.e., wage rate), and that (ii) availability of non-labour income induces income effects, i.e. individuals demand more leisure time.

Cost-Utility Analysis of Emergency Department Thoracotomy for Trauma Victims

BACKGROUND

Our objective was to assess the cost-effectiveness of emergency department thoracotomy (EDT) performed on both penetrating and blunt trauma victims, using both published survival and outcome data and previously unaccounted for data on the cost of occupational exposure.

METHODS

Cost-utility analysis was performed using decision-analytic models constructed for both penetrating and blunt trauma scenarios. Survival and impairment data, the rates and costs of occupational exposure, and the utilities of neurologic impairment and provider seroconversion were all based on published literature. Costs of EDT were estimated using the National Inpatient Sample (NIS) from the Health Care Utilization Project database. One-way sensitivity analyses on input parameters and probabilistic sensitivity analyses using Monte Carlo simulations were performed.

RESULTS

The incremental cost-effectiveness ratio of EDT for penetrating trauma was $16,125 per quality-adjusted life year (QALY), and less than $50,000 per QALY with a 93.4% probability. The incremental cost-effectiveness ratio for blunt trauma was $163,136 per QALY, and less than $50,000 per QALY with a 37% probability. Neither model was sensitive to provider exposure. The penetrating model was insensitive to the probability of neurologically intact survival, the utility adjustment, procedure costs, and long-term care. The blunt model was sensitive to the probabilities of survival and of neurologic impairment.

CONCLUSIONS

EDT is cost-effective for penetrating trauma, and not cost-effective for blunt trauma given current rates of survival and impairment. Occupational exposure does not significantly impact the cost-effectiveness of the procedure.

EXPLORING DISPARITIES BETWEEN GLOBAL HIV/AIDS FUNDING AND RECENT TSUNAMI RELIEF EFFORTS: AN ETHICAL ANALYSIS

OBJECTIVE

To contrast relief efforts for the 26 December 2004 tsunami with current global HIV/AIDS relief efforts and analyse possible reasons for the disparity.

METHODS

Literature review and ethical analysis.

RESULTS

Just over 273,000 people died in the tsunami, resulting in relief efforts of more than US$10 bn, which is sufficient to achieve the United Nation's long-term recovery plan for South East Asia. In contrast, 14 times more people died from HIV/AIDS in 2004, with UNAIDS predicting a US$8 bn funding gap for HIV/AIDS in developing nations between now and 2007. This disparity raises two important ethical questions. First, what is it that motivates a more empathic response to the victims of the tsunami than to those affected by HIV/AIDS? Second, is there a morally relevant difference between the two tragedies that justifies the difference in the international response? The principle of justice requires that two cases similarly situated be treated similarly. For the difference in the international response to the tsunami and HIV/AIDS to be justified, the tragedies have to be shown to be dissimilar in some relevant respect. Are the tragedies of the tsunami disaster and the HIV/AIDS pandemic sufficiently different, in relevant respects, to justify the difference in scope of the response by the international community?

CONCLUSION

We detected no morally relevant distinction between the tsunami and the HIV/AIDS pandemic that justifies the disparity. Therefore, we must conclude that the international response to HIV/AIDS violates the fundamental principles of justice and fairness.

The economic burden of HIV in the United States in the era of highly active antiretroviral therapy: evidence of continuing racial and ethnic differences

BACKGROUND

Assessing the economic burden of HIV/AIDS can help to quantify the effect of the epidemic on a population and assist policy makers in allocating public health resources.

OBJECTIVE

To estimate the economic burden of HIV/AIDS in the United States and provide race/ethnicity-specific estimates.

METHODS

We conducted an incidence-based cost-of-illness analysis to estimate the lifetime cost of HIV/AIDS resulting from new infections diagnosed in 2002. Data from the HIV/AIDS Reporting System of the Centers for Disease Control and Prevention were used to determine stage of disease at diagnosis and proportion of cases by race/ethnicity. Lifetime direct medical costs and mortality-related productivity losses were estimated using data on cost, life expectancy, and antiretroviral therapy (ART) use from the literature.

RESULTS

The cost of new HIV infections in the United States in 2002 is estimated at $36.4 billion, including $6.7 billion in direct medical costs and $29.7 billion in productivity losses. Direct medical costs per case were highest for whites ($180,900) and lowest for blacks ($160,400). Productivity losses per case were lowest for whites ($661,100) and highest for Hispanics ($838,000). In a sensitivity analysis, universal use of ART and more effective ART regimens decreased the overall cost of illness.

CONCLUSION

Direct medical costs and productivity losses of HIV/AIDS resulting from infections diagnosed in 2002 are substantial. Productivity losses far surpass direct medical costs and are disproportionately borne by minority races/ethnicities. Our analysis underscores economic benefits of more effective ART regimens and universal access to ART.

Mechanisms underlying activity of antiretroviral drugs in HIV-1-infected macrophages: new therapeutic strategies

Monocyte-derived macrophages (M/M) are considered the second cellular target of HIV-1 and a crucial virus reservoir. M/M are widely distributed in all tissues and organs, including the CNS, where they represent the most common HIV-infected cells. Differently from activated CD4+ T lymphocytes, M/M are resistant to the cytopathic effect of HIV and survive HIV infection for a long time. Moreover, HIV-1 replication in M/M is a key pathogenetic event during the course of HIV-1 infection. Overall findings strongly support the clinical relevance of anti-HIV drugs in M/M. Nucleoside RT inhibitors (NRTIs) are more active against HIV in M/M than in CD4+ T lymphocytes. Their activity is further boosted by the presence of an additional monophosphate group (i.e., a phosphonate group, as in the case of Tenofovir), thus overcoming the bottleneck of the low phosphorylation ability of M/M. In contrast, the antiviral activity of non-NRTIs (not affecting the DNA chain elongation) in M/M is similar to that in CD4+ T lymphocytes. Protease inhibitors are the only clinically approved drugs acting at a late stage of the HIV lifecycle. They are able to interfere with HIV replication in HIV-1 chronically infected M/M, even if at concentrations greater than those observed in HIV-1 chronically infected CD4+ T lymphocytes. Finally, several new drugs have been shown to interfere efficiently with HIV replication in M/M, including entry inhibitors. A better understanding of the activity of the anti-HIV drugs in M/M may represent a key element for the design of effective anti-HIV chemotherapy.

Increasing survival with HIV: impact on nursing care

The introduction of highly active antiretroviral therapy (HAART) has transformed human immunodeficiency virus (HIV) infection from a rapidly progressive catastrophic illness to a chronic condition. Individuals with HIV are living longer and developing conditions usually associated with aging, as well as complications from pre-existing or subsequently acquired conditions. In addition, toxicities associated with HAART may precipitate or exacerbate comorbid conditions. As opportunistic infections account for fewer admission and lower mortality rates, new patterns of illness are emerging. Complex interactions among multiple, sometimes overlapping conditions require focused yet comprehensive attention in care and management. Nurses will encounter HIV-infected patients in an increasing range of care settings, and an understanding of the range and interaction of potential comorbidities and their treatments with HIV and its treatment will be required to provide safe and effective care.

Incorporating biological natural history in simulation models: empirical estimates of the progression of end-stage liver disease

OBJECTIVE

To develop an empiric natural-history model that can predict quantitative changes in the laboratory values and clinical characteristics of patients with end-stage liver disease (ESLD), to be used to calibrate an individual microsimulation model.

METHODS

The authors report the development of a stochastic model that uses cubic splines to interpolate between observed laboratory values over time in a cohort of 1997 patients with ESLD awaiting liver transplantation at the University of Pittsburgh Medical Center. The splines were recursively sampled to provide a stochastic, quantitative natural history of each candidate's disease.

RESULTS

The model was able to simulate the types of erratic disease trajectories that occur in individual patients and was able to preserve the statistical properties of the natural history of ESLD in cohorts of real patients. Moreover, the model was able to predict pretransplant survival rates (87% at 1 year), which were statistically similar to rates observed in the authors' local cohort (92%).

CONCLUSIONS

Cubic splines can be used to generate quantitative natural histories for individual patients with ESLD and may be useful for developing clinically robust microsimulation models of other diseases.

Economic models of antiretroviral therapy: searching for the optimal strategy

The diffusion of protease inhibitors and non-nucleoside reverse transcriptase inhibitors in the US in 1996 and 1997 reduced the number of deaths attributable to HIV disease and changed the way we think about the illness. Today, HIV disease may be deemed a fairly expensive chronic condition rather than an intolerably expensive fatal illness. Although most studies have found that patients receiving new drug therapies are hospitalised less frequently than patients who received early drug therapies, it is unclear whether the diffusion of new drug therapies has increased or decreased the annual cost of care. However, it is evident that the diffusion of new drug therapies has increased the lifetime cost of care. Analysts rely on models to simulate the course and cost of HIV disease. This study reviews the evolution of these models, paying particular attention to how these models estimate the cost of care. The primary findings of this review are that the economic data used in these models are often too imprecise to accurately identify the cost of each disease stage and are almost always outdated. Moreover, it was found that estimates of drug costs in these models may not accurately reflect actual expenditures.

Estimating the proportion of patients infected with HIV who will die of comorbid diseases

PURPOSE

Effective antiretroviral therapies have improved the prognosis for patients infected with the human immunodeficiency virus (HIV). We aimed to estimate the likelihood that HIV-infected patients would die of comorbid disease.

METHODS

A probabilistic simulation of antiretroviral-naïve HIV-infected patients in the United States was calibrated with data from an observational cohort (N = 3545) and validated with data from a separate patient cohort (N = 12574). The simulation explicitly represents the 2 main determinants of treatment failure and subsequent death from HIV-related causes: nonadherence to combination therapy and accumulation of phenotypic resistance to combination therapy. The likelihood of deaths not directly attributable to HIV was estimated from the Collaborations in HIV Outcomes Research-US (CHORUS) cohort.

RESULTS

For patients with newly diagnosed HIV infections, CD4 counts of 500 cells/mm3, and viral loads of 10000 copies/mL, the median estimated survival was 26.8 years for 30-year-olds, 24.4 years for 40-year-olds and 14.6 years for 50-year-olds. The proportion of deaths not directly attributable to HIV was 36% for 30-year-olds, 53% for 40-year-olds, and 72% for 50-year-olds. For patients with characteristics similar to CHORUS participants, the median estimated survival approached 20.4 years, the mean age at death approached 60.4 years, and 41% died of illnesses not directly attributable to HIV. These estimates of non-HIV mortality were likely conservative.

CONCLUSION

As HIV-infected patients live longer, our results suggest they will experience increasing mortality from causes not directly attributable to HIV. The projected risk from comorbid disease has clinical and policy implications for future delivery of care to HIV-infected patients.

Simulation and critical care modeling

PURPOSE OF REVIEW

Decisions made in critical care are often complicated, requiring an in-depth understanding of the relations between complex diseases, available interventions, and patients with a wide range of characteristics. Standard modeling techniques such as decision trees and statistical modeling have difficulty in capturing these interactions as the complexity of the problem increases.

RECENT FINDINGS

Recent models in the literature suggest that simulation modeling techniques such as Markov modeling, Monte Carlo simulation, and discrete-event simulation are useful tools for analyzing complex systems in critical care. These simulation techniques are reviewed briefly, and examples from the literature are presented to demonstrate their usefulness in understanding real problems in critical care.

SUMMARY

Simulation models provide useful tools for organizing and analyzing the interactions between therapies, tradeoffs, and outcomes.

AIDS-related non-Hodgkin's lymphoma: etiology, epidemiology, and impact of highly active antiretroviral therapy

Lymphoproliferative disorders (LPD) occur more frequently in the immunosuppressed host compared to those who are immunocompetent. The biological and clinical characteristics of a particular LPD are specific to the underlying immune defect, though there are clear similarities in the various tumor types that occur. Immunosuppression-related LPD are more frequently associated with gamma-herpesviruses suggesting that the immunologic environment influences tumorigenesis. Clinical outcomes may be optimized when appropriate treatment strategies are based on consideration of the underlying immunodeficiency and on the tumor biology. Consistent with this observation, in AIDS-related lymphomas (ARL), tumor biology, clinical presentations, and treatment outcomes are correlated with the CD4 cell count. This review will consider the role of immune deficiency in HIV disease on ARL pathogenesis and epidemiology, and the impact that highly active antiretroviral therapy has had in this disease.

Enfuvirtide: the first therapy to inhibit the entry of HIV-1 into host CD4 lymphocytes

Highly active antiretroviral therapy (HAART) based on combinations of drugs that target key enzymes in the life-cycle of human immunodeficiency virus (HIV) has considerably reduced morbidity and mortality from HIV infection since its introduction in the mid-1990s. However, the growing problem of the emergence of HIV strains that are resistant not only to individual drugs, but to whole drug classes, means that agents with new mechanisms of action are needed. Here, we describe the discovery and development of enfuvirtide (Fuzeon), the first drug to inhibit the entry of HIV-1 into host cells.