A comparison of Australian chronic disease prevalence estimates using administrative pharmaceutical dispensing data with international and community survey data

Introduction

Chronic disease (CD) is a leading cause of population mortality, illness and disability. Identification of CD using administrative data is increasingly used and may have utility in monitoring population health. Pharmaceutical administrative data using World Health Organization, Anatomic Therapeutic Chemical Codification (ATC) assigned to prescribed medicines may offer an improved method to define persons with certain CD and enable the calculation of population prevalence.

Objective

To assess the feasibility of Australian Pharmaceutical Benefits Scheme (PBS) dispensing data, to provide realistic measures of chronic disease prevalence using ATC codification, and compare values with international data using similar ATC methods and Australian community surveys.

Methods

Twenty-two chronic diseases were identified using World Health Organization (WHO) formulated ATC codes assigned to treatments received and recorded in a PBS database. Distinct treatment episodes prescribed to individuals were counted annually for prevalence estimates. Comparisons were then made with estimates from international studies using pharmaceutical data and published Australian community surveys.

Results

PBS prevalence estimates for a range of chronic diseases listed in European studies and Australian community surveys demonstrated good correlation. PBS estimates of the prevalence of diabetes, cardiovascular disease and hypertension, dyslipidemia, and respiratory disease with comparable Australian National Health Survey in older adults showed correlations of between (r = 0.82 - 0.99) and a range of percentage error of -11% to 59%. However, other conditions such as psychological disease and migraine showed greater disparity and correlated less well.

Conclusions

Although not without limitations, Australian administrative pharmaceutical dispensing data may provide an alternative perspective on population health and a useful resource to estimate the prevalence of a number of chronic diseases within the Australian population.

The 2016 HIV diagnosis and care cascade in New South Wales, Australia: meeting the UNAIDS 90-90-90 targets

Introduction

The HIV Strategy in New South Wales (NSW) Australia aims to virtually eliminate HIV transmission by 2020. We estimated the 2016 HIV diagnosis and care cascade for the state of NSW, with a focus on introducing population‐based data to improve data quality and assess progress towards the UNAIDS 90‐90‐90 targets.

Methods

To estimate the number of people living with diagnosed HIV (PLDHIV) we used NSW data from the Australian National HIV Registry, enhanced by surveillance among people recently diagnosed with HIV to improve migration estimates. The number of undiagnosed PLHIV was estimated using back‐projection modelling by CD4 count at diagnosis. De‐duplicated prescription claims data were obtained from the Australian Pharmaceutical Benefits Scheme (PBS), and were combined with an estimate for those ineligible, to determine the number of PLDHIV on antiretroviral therapy (ART). Data from a clinic network with 87% coverage of PLDHIV in NSW enabled the estimation of the number on ART who had HIV suppression.

Results and discussion

We estimated that 10,110 PLHIV resided in NSW in 2016 (range 8400 to 11,720), among whom 9230 (91.3%) were diagnosed, and 8490 (92.0% of those diagnosed) were receiving ART. Among PLDHIV receiving ART, 8020 (94.5%) had suppressed viral load (<200 HIV‐1 RNA copies/mL). Overall, 79.3% of all PLHIV had HIV virological suppression.

Conclusion

NSW has met each of the UNAIDS 90‐90‐90 targets. The enhanced surveillance methods and data collection systems improved data quality. Measuring and meeting the 90‐90‐90 targets is feasible and could be achieved in comparable parts of the world.

Clinicopathological characteristics and management of prostate cancer in the human immunodeficiency virus (HIV)-positive population: experience in an Australian major HIV centre

OBJECTIVES

To characterise clinicopathological characteristics of prostate cancer among human immunodeficiency virus (HIV)-positive men and to evaluate the current practice patterns in the management of prostate cancer in these men.

PATIENTS AND METHODS

We retrospectively reviewed all patients with HIV in the State-wide HIV referral centre in Victoria, who were diagnosed with prostate cancer from 2000 onwards. In all, 12 patients were identified, and the medical records were reviewed to collect data on HIV parameters at the time of prostate cancer diagnosis, as well as prostate cancer clinicopathological characteristics, treatment details and outcomes.

RESULTS

At the time of prostate cancer diagnosis, eight patients had undetectable viral load, and the median cluster of differentiation 4 (CD4) count was 485 cells/μL. The average age at diagnosis of prostate cancer was 63 years and the median prostate-specific antigen (PSA) level of 11.1 ng/mL. Four patients had Gleason 6 prostate cancer, four Gleason 7, one Gleason 8 and three Gleason 9. Seven of the 12 patients had a positive family history for prostate cancer. Of the patients with clinically localised prostate cancer (10), most were treated with radiotherapy (RT): one permanent seed brachytherapy (BT), five external beam RT (EBRT), two open radical prostatectomies (RP), one active surveillance (AS), and one on watchful waiting (WW). For the two patients with metastatic disease, one had androgen-deprivation therapy and EBRT, while the other had a combination of EBRT and chemo-hormonal therapy with doxetacel. All patients were followed for a median of 46 months, with three deaths reported, none of which was a prostate cancer-specific death.

CONCLUSIONS

This is the first Australasian series on prostate cancer management in a HIV population. With the prolonged survival among HIV-positive men in the highly active anti-retroviral therapy era, PSA testing should be offered to this group of patients, especially those with a positive family history. HIV-positive men should also be offered all treatment options in the same manner as men in the general population.

Loss to follow-up in the Australian HIV Observational Database

BACKGROUND

Loss to follow-up (LTFU) in HIV-positive cohorts is an important surrogate for interrupted clinical care, which can potentially influence the assessment of HIV disease status and outcomes. After preliminary evaluation of LTFU rates and patient characteristics, we evaluated the risk of mortality by LTFU status in a high-resource setting.

METHODS

Rates of LTFU were measured in the Australian HIV Observational Database for a range of patient characteristics. Multivariate repeated measures regression methods were used to identify determinants of LTFU. Mortality by LTFU status was ascertained using linkage to the National Death Index. Survival following combination antiretroviral therapy initiation was investigated using the Kaplan-Meier (KM) method and Cox proportional hazards models.

RESULTS

Of 3,413 patients included in this analysis, 1,632 (47.8%) had at least one episode of LTFU after enrolment. Multivariate predictors of LTFU included viral load (VL)>10,000 copies/ml (rate ratio [RR] 1.63; 95% CI 1.45, 1.84; ref ≤400), time under follow-up (per year; RR 1.03; 95% CI 1.02, 1.04) and prior LTFU (per episode; RR 1.15; 95% CI 1.06, 1.24). KM curves for survival were similar by LTFU status (P=0.484). LTFU was not associated with mortality in Cox proportional hazards models (univariate hazard ratio [HR] 0.93; 95% CI 0.69, 1.26) and multivariate HR 1.04 (95% CI 0.77, 1.43).

CONCLUSIONS

Increased risk of LTFU was identified amongst patients with potentially higher infectiousness. We did not find significant mortality risk associated with LTFU. This is consistent with timely re-engagement with treatment, possibly via high levels of unreported linkage to other health-care providers.

The Opposites Attract Study of viral load, HIV treatment and HIV transmission in serodiscordant homosexual male couples: design and methods

BACKGROUND

Studies in heterosexual HIV serodiscordant couples have provided critical evidence on the role of HIV treatments and undetectable viral load in reducing the risk of HIV transmission. There is very limited data on the risk of transmission from anal sex in homosexual male serodiscordant couples.

METHODS/DESIGN

The Opposites Attract Study is an observational prospective longitudinal cohort study of male homosexual serodiscordant partnerships running from 2012 to 2015 and conducted in clinics throughout Australia, Brazil and Thailand. Couples attend two or more clinic visits per year. The HIV-positive partner's viral load is tested and the HIV-negative partner is tested for HIV antibodies at every clinic visit. Results from any tests for sexually transmitted infections are also collected. Detailed behavioural questionnaires are completed by both partners at the time of each visit. The primary research question is whether HIV incidence is lower in those couples where the HIV-positive partner is receiving HIV treatment compared to couples where he is not receiving treatment. A voluntary semen sub-study will examine semen plasma viral load in a subsample of HIV-positive partners in Sydney, Rio de Janeiro and Bangkok. In cases of seroconversion of the initially HIV-negative partner, phylogenetic analysis will be conducted at the end of the study on virus from stored blood samples from both partners to determine if the infection came from the HIV-positive study partner. Men in new serodiscordant relationships will specifically be targeted for recruitment.

DISCUSSION

This study will provide critical data on the reduction in HIV transmission risk associated with being on HIV treatment in homosexual male serodiscordant couples in different regions of the world. Data from men in new relationships will be particularly valuable given that the highest transmission risk is in the first year of serodiscordant relationships. Furthermore, the detailed behavioural and attitudinal data from the participant questionnaires will allow exploration of many contextual factors associated with HIV risk, condom use and the negotiation of sexual practice within couples.

Recent trends in early stage response to combination antiretroviral therapy in Australia

BACKGROUND

There have been improvements in combination antiretroviral therapy (cART) over the past 15 years. The aim of this analysis was to assess whether improvements in ART have resulted in improvements in surrogates of HIV outcome.

METHODS

Patients in the Australian HIV Observational Database who initiated treatment using mono/duo therapy prior to 1996, or using cART from 1996 onwards, were included in the analysis. Patients were stratified by era of ART initiation. Median changes in CD4(+) T-cell count and the proportion of patients with detectable HIV viral load (>400 copies/ml) were calculated over the first 4 years of treatment. Probabilities of treatment switch were estimated using the Kaplan-Meier method.

RESULTS

A total of 2,753 patients were included in the analysis: 28% initiated treatment <1996 using mono/duo therapy and 72% initiated treatment ≥1996 using cART (30% 1996-1999, 12% 2000-2003, 11% 2004-2007 and 19% ≥2008). Overall CD4(+) T-cell count response improved by later era of initiation (P<0.001), although 2000-2003 CD4(+) T-cell count response was less than that for 1996-1999 (P=0.007). The average proportion with detectable viral load from 2 to 4 years post-treatment commencement by era was: <1996 mono/duo 0.69 (0.67-0.71), 1996-1999 cART 0.29 (0.28-0.30), 2000-2003 cART 0.22 (0.20-0.24), 2004-2007 cART 0.09 (0.07-0.10) and ≥2008 cART 0.04 (0.03-0.05). Probability of treatment switch at 4 years after initiation decreased from 53% in 1996-1999 to 29% after 2008 (P<0.001).

CONCLUSIONS

Across the five time-periods examined, there have been incremental improvements for patients initiated on cART, as measured by overall response (viral load and CD4(+) T-cell count) and also increased durability of first-line ART regimens.

Recently diagnosed gay men talk about HIV treatment decisions

Background In recent years, there has been increasing evidence that early initiation of antiretroviral therapy (ART) may provide health benefits for those infected with HIV. There has also been significant discussion about the role of HIV treatment in preventing onward transmission of the virus. Early provision and uptake of ART to people recently diagnosed with HIV could achieve both individual and public health outcomes. The success of such an initiative relies, in part, on the preparedness of those recently diagnosed with HIV to engage with the therapy. Methods: The HIV Seroconversion Study collects both quantitative and qualitative data from people in Australia who have recently been diagnosed with HIV. During 2011–2012, 53 gay or bisexual men recruited across Australia took part in semistructured interviews as part of the study. The men were asked about their knowledge and experience of, and their decisions about whether or not to commence, HIV treatment. Results: The interviews identified differing levels of knowledge about HIV treatments and divergent views about the health and prevention benefits of ART. For some, treatments provided a sense of control over the virus; others were apprehensive and distrustful, and preferred to resist commencing treatments for as long as possible. Conclusions: If early initiation of treatment is to be encouraged, appropriate measures must be in place to ensure recently diagnosed individuals have access to the appropriate information and the support they need to enable them to make informed choices and, if necessary, to address their fears.

Predicting the population impact of increased HIV testing and treatment in Australia

Introduction The treatment as prevention strategy has gained popularity as a way to reduce the incidence of HIV by suppressing viral load such that transmission risk is decreased. The effectiveness of the strategy also requires early diagnosis.

METHODS

Informed by data on the influence of diagnosis and treatment on reducing transmission risk, a model simulated the impact of increasing testing and treatment rates on the expected incidence of HIV in Australia under varying assumptions of treatment efficacy and risk compensation. The model utilises Australia's National HIV Registry data, and simulates disease progression, testing, treatment, transmission and mortality.

RESULTS

Decreasing the average time between infection and diagnosis by 30% is expected to reduce population incidence by 12% (~126 cases per year, 95% confidence interval (CI): 82-198). Treatment of all people living with HIV with CD4 counts <500cellsμL(-1) is expected to reduce new infections by 30.9% (95% CI: 15.9-37.6%) at 96% efficacy if no risk compensation occurs. The number of infections could increase up to 12.9% (95% CI: 20.1-7.4%) at 26% efficacy if a return to prediagnosis risk levels occur.

CONCLUSION

Treatment as prevention has the potential to prevent HIV infections but its effectiveness depends on the efficacy outside trial settings among men who have sex with men and the level of risk compensation. If antiretroviral therapy has high efficacy, risk compensation will not greatly change the number of infections. If the efficacy of antiretroviral therapy is low, risk compensation could lead to increased infections.

Australian prescribers' perspectives on ART initiation in the era of "treatment as prevention"

This study explores Australian prescribers' attitudes towards Treatment as Prevention (TasP) and their practices around initiating combination antiretroviral treatment (cART) for HIV. A brief online survey was conducted nationally amongst antiretroviral treatment (ART) prescribers in Australia. The sample broadly represented ART prescribers in Australia (N = 108), with 40.7% general practitioners (GPs), 25.9% sexual health clinic-based physicians and 21.3% hospital-based infectious diseases physicians. About 60% of respondents had been treating HIV-positive patients for more than 10 years. Respondents estimated that about 70-80% of all their HIV-positive patients were receiving ART. Over half of the prescribers agreed very strongly that their primary concern in recommending cART initiation was clinical benefit to individual patients rather than any population benefit. A majority of the prescribers (68.5%) strongly endorsed cART initiation before CD4+ T-cell count drops below 350 cells/mm(3), and a further 22.2% strongly endorsed cART initiation before CD4+ T-cell count drops below 500 cells/mm(3). Regarding the optimal timing of cART initiation, this study shows that prescribers in Australia in 2012 focus primarily on the benefits for their individual patients. Prescribers may need more convincing evidence of individual health benefits or increased knowledge about the population health benefits for a TasP approach to be effective in Australia.

HIV treatment as prevention: natural experiments highlight limits of antiretroviral treatment as HIV prevention

There is growing enthusiasm for increasing coverage of antiretroviral treatment among HIV-infected people for the purposes of preventing ongoing transmission. Treatment as prevention will face a number of barriers when implemented in real world populations, which will likely lead to the effectiveness of this strategy being lower than proposed by optimistic modelling scenarios or ideal clinical trial settings. Some settings, as part of their prevention and treatment strategies, have already attained rates of HIV testing and use of antiretroviral therapy--with high levels of viral suppression--that many countries would aspire to as targets for a treatment-as-prevention strategy. This review examines a number of these "natural experiments", namely, British Columbia, San Francisco, France, and Australia, to provide commentary on whether treatment as prevention has worked in real world populations. This review suggests that the population-level impact of this strategy is likely to be considerably less than as inferred from ideal conditions.

Triple class experience after initiation of combination antiretroviral treatment in Australia: survival and projections

BACKGROUND

Patients who have become triple class experienced (TCE) are at a high risk of exhausting available treatment options. This study aims to investigate factors associated with becoming TCE and to explore the effect of becoming TCE on survival. We also project the prevalence of TCE in Australia to 2012.

METHODS

Patients were defined as TCE when they stopped a combination antiretroviral treatment (cART) that introduced the third of the three major antiretroviral classes. Cox proportional hazards models were used to investigate factors associated with TCE and the effect of TCE on survival. To project TCE prevalence, we used predicted rates of TCE by fitting a Poisson regression model, together with the estimated number of patients who started cART in each year in Australia, assuming a mortality rate of 1.5 per 100 person-years.

RESULTS

Of the 1498 eligible patients, 526 became TCE. Independent predictors of a higher risk of TCE included current CD4 counts below 200cellsμL(-1) and earlier calendar periods. No significant difference in survival was observed between those who were TCE and those who were not yet TCE. An increasing number of patients are using cART in Australia and if current trends continue, the number of patients who are TCE is estimated to increase from 2800 in 2003 to 5000 in 2012.

CONCLUSION

Our results suggest that the prevalence of TCE in Australia is estimated to plateau after 2003. However, as an increasing number of patients are becoming TCE, it is necessary to develop new drugs that come from new classes or do not have overlapping resistance.

Antiretroviral therapy: a key component of a comprehensive HIV prevention strategy

Transmission of HIV is critically dependent on the level of HIV viral load within blood and genital secretions. Antiretroviral therapy results in sustained reductions in viral load to undetectable levels. Thus, antiretroviral therapy has long been postulated as a potential means to curb HIV transmission. Observational data have now confirmed that antiretroviral therapy is associated with a decrease in transmission among heterosexual serodiscordant couples, injection-drug users, and in population-based studies. Mathematical models suggest that further expansion of antiretroviral coverage within current guidelines can play a major role in controlling the spread of HIV. Concerns regarding the potential for transmission during acute HIV infection, behavioral disinhibition, and resistance to overcome the impact of treatment on prevention have not materialized to date. The Joint United Nations AIDS (UNAIDS) program has called for the inclusion of antiretroviral treatment as a key pillar in the global strategy to control the spread of HIV infection.

Activation of NK cells by ADCC responses during early HIV infection

Partial control of HIV occurs during acute infection, although the mechanisms responsible are poorly understood. We studied the ability of antibody-dependent cellular cytotoxicity (ADCC) antibodies in serum to activate natural killer (NK) cells in longitudinal samples from 8 subjects with well-defined early HIV infection who controlled viremia to low levels. NK cell activation by ADCC antibodies to gp140 Env proteins was detected in half of the subjects at the first time point studied, a mean of 111 d after the estimated time of infection. In contrast, ADCC-mediated NK cell activation in response to linear HIV peptides evolved more slowly, over the first 2 y of infection. Our studies suggest that HIV-specific ADCC responses to conformational epitopes occur early during acute HIV infection, and broaden to include linear epitopes over time. These findings have implications for the immune control of HIV.

Using population attributable risk to choose HIV prevention strategies in men who have sex with men

Background

In Australia, HIV is concentrated in men who have sex with men (MSM) and rates have increased steadily over the past ten years. Health promotion strategies should ideally be informed by an understanding of both the prevalence of the factors being modified, as well as the size of the risk that they confer. We undertook an analysis of the potential population impact and cost saving that would likely result from modifying key HIV risk factors among men who have sex with men (MSM) in Sydney, Australia.

Methods

Proportional hazard analyses were used to examine the association between sexual behaviours in the last six months and sexually transmissible infections on HIV incidence in a cohort of 1426 HIV-negative MSM who were recruited primarily from community-based sources between 2001 and 2004 and followed to mid-2007. We then estimated the proportion of HIV infections that would be prevented if specific factors were no longer present in the population, using a population attributable risk (PAR) method which controls for confounding among factors. We also calculated the average lifetime healthcare costs incurred by the HIV infections associated with specific factors by estimating costs associated with clinical care and treatment following infection and discounting at 3% (1% and 5% sensitivity) to present value.

Results

Unprotected anal intercourse (UAI) with a known HIV-positive partner was reported by 5% of men, the hazard ratio (HR) was 16.1 (95%CI:6.4-40.5), the PAR was 34% (95%CI:24-44%) and the average lifetime HIV-related healthcare costs attributable to UAI with HIV-positive partners were $AUD102 million (uncertainty range: $93-114 m). UAI with unknown HIV status partners was reported by 25% of men, the HR was 4.4 (95%CI:1.8-11.2), the PAR was 33% (95%CI:26-42%) and the lifetime incurred costs were $AUD99 million. Anal warts prevalence was 4%, the HR was 5.2 (95%CI:2.4-11.2), the PAR was 13% (95%CI:9-19%) and the lifetime incurred costs were $AUD39 million.

Conclusions

Our analysis has found that although UAI with an HIV-positive sexual partner is a relatively low-prevalence behaviour (reported by 5% of men), if this behaviour was not present in the population, the number of infections would be reduced by one third. No other single behaviour or sexually transmissible infections contributes to a greater proportion of infections and HIV-related healthcare costs.

Trends in detectable viral load by calendar year in the Australian HIV observational database

Background

Recent papers have suggested that expanded combination antiretroviral treatment (cART) through lower viral load may be a strategy to reduce HIV transmission at a population level. We assessed calendar trends in detectable viral load in patients recruited to the Australian HIV Observational Database who were receiving cART.

Methods

Patients were included in analyses if they had started cART (defined as three or more antiretrovirals) and had at least one viral load assessment after 1 January 1997. We analyzed detectable viral load (>400 copies/ml) in the first and second six months of each calendar year while receiving cART. Repeated measures logistic regression methods were used to account for within and between patient variability. Rates of detectable viral load were predicted allowing for patients lost to follow up.

Results

Analyses were based on 2439 patients and 31,339 viral load assessments between 1 January 1997 and 31 March 2009. Observed detectable viral load in patients receiving cART declined to 5.3% in the first half of 2009. Predicted detectable viral load based on multivariate models, allowing for patient loss to follow up, also declined over time, but at higher levels, to 13.8% in 2009.

Conclusions

Predicted detectable viral load in Australian HIV Observational Database patients receiving cART declined over calendar time, albeit at higher levels than observed. However, over this period, HIV diagnoses and estimated HIV incidence increased in Australia.

High viral fitness during acute HIV-1 infection

Several clinical studies have shown that, relative to disease progression, HIV-1 isolates that are less fit are also less pathogenic. The aim of the present study was to investigate the relationship between viral fitness and control of viral load (VL) in acute and early HIV-1 infection. Samples were obtained from subjects participating in two clinical studies. In the PULSE study, antiretroviral therapy (ART) was initiated before, or no later than six months following seroconversion. Subjects then underwent multiple structured treatment interruptions (STIs). The PHAEDRA study enrolled and monitored a cohort of individuals with documented evidence of primary infection. The subset chosen were individuals identified no later than 12 months following seroconversion to HIV-1, who were not receiving ART. The relative fitness of primary isolates obtained from study participants was investigated ex vivo. Viral DNA production was quantified using a novel real time PCR assay. Following intermittent ART, the fitness of isolates obtained from 5 of 6 PULSE subjects decreased over time. In contrast, in the absence of ART the fitness of paired isolates obtained from 7 of 9 PHAEDRA subjects increased over time. However, viral fitness did not correlate with plasma VL. Most unexpected was the high relative fitness of isolates obtained at Baseline from PULSE subjects, before initiating ART. It is widely thought that the fitness of strains present during the acute phase is low relative to strains present during chronic HIV-1 infection, due to the bottleneck imposed upon transmission. The results of this study provide evidence that the relative fitness of strains present during acute HIV-1 infection may be higher than previously thought. Furthermore, that viral fitness may represent an important clinical parameter to be considered when deciding whether to initiate ART during early HIV-1 infection.

Per-contact probability of HIV transmission in homosexual men in Sydney in the era of HAART

OBJECTIVE

The objective of this study is to estimate per-contact probability of HIV transmission in homosexual men due to unprotected anal intercourse (UAI) in the era of HAART.

DESIGN

Data were collected from a longitudinal cohort study of community-based HIV-negative homosexual men in Sydney, Australia.

METHODS

A total of 1427 participants were recruited from June 2001 to December 2004. They were followed up with 6-monthly detailed behavioral interviews and annual testing for HIV till June 2007. Data were used in a bootstrapping method, coupled with a statistical analysis that optimized a likelihood function for estimating the per-exposure risks of HIV transmission due to various forms of UAI.

RESULTS

During the study, 53 HIV seroconversion cases were identified. The estimated per-contact probability of HIV transmission for receptive UAI was 1.43% [95% confidence interval (CI) 0.48-2.85] if ejaculation occurred inside the rectum, and it was 0.65% (95% CI 0.15-1.53) if withdrawal prior to ejaculation was involved. The estimated transmission rate for insertive UAI in participants who were circumcised was 0.11% (95% CI 0.02-0.24), and it was 0.62% (95% CI 0.07-1.68) in uncircumcised men. Thus, receptive UAI with ejaculation was found to be approximately twice as risky as receptive UAI with withdrawal or insertive UAI for uncircumcised men and over 10 times as risky as insertive UAI for circumcised men.

CONCLUSION

Despite the fact that a high proportion of HIV-infected men are on antiretroviral treatment and have undetectable viral load, the per-contact probability of HIV transmission due to UAI is similar to estimates reported from developed country settings in the pre-HAART era.

Continuing declines in some but not all HIV-associated cancers in Australia after widespread use of antiretroviral therapy

OBJECTIVE

To describe changes in cancer incidence in people with HIV in Australia since the introduction of highly active antiretroviral therapy (HAART).

DESIGN

Population-based, retrospective cohort study of people with HIV (n = 20 232) using data linkage between national registers of HIV/AIDS and cancer in 1982-2004.

METHODS

Age-adjusted and sex-adjusted incidence rate ratios with 95% confidence intervals were calculated to compare site-specific cancer incidence during the early (1996-1999) and late (2000-2004) HAART periods with that prior to HAART (1982-1995). Five-year age-specific, sex-specific, calendar year-specific, and state-specific standardized incidence ratios with 95% confidence interval were also calculated for each period.

RESULTS

Incidence of Kaposi sarcoma and non-Hodgkin lymphoma declined significantly (Ptrend < 0.001). Incidence of Hodgkin lymphoma was significantly higher during the early-HAART period (incidence rate ratio 2.34, 95% confidence interval 1.19-4.63) but declined thereafter (Pdiff = 0.014). Incidence of anal cancer was unchanged (Ptrend = 0.451) and remained raised more than 30-fold. Incidence declined significantly for melanoma (Ptrend = 0.041) and prostate cancer (Ptrend = 0.026), and, during the late-HAART period, was lower than in the general population for both cancers. Incidence of colorectal cancer was consistently lower than in the general population.

CONCLUSION

Incidence of Kaposi sarcoma and non-Hodgkin lymphoma has continued to decline among people with HIV in Australia, though it remains very substantially elevated. Incidence of Hodgkin lymphoma may now also be declining. Incidence of anal cancer has remained stable, and it is now the third most common cancer in HIV-infected Australians. Reasons for the reduced incidence of colorectal and prostate cancer, and more recently of melanoma, are unclear.

Use of viral load to negotiate condom use among gay men in Sydney, Australia

Using two cohort studies (Health in men-HIM and positive health-PH) and repeated large cross-sectional surveys (Gay Community Periodic Survey-GCPS) of gay men in Sydney, Australia, we examined the association between viral load and unprotected anal intercourse (UAI) between HIV sero-discordant regular partners. Between 2001 and 2007, we conducted 243 interviews with 102 HIV-negative gay men in HIM and 148 interviews with 99 HIV-positive gay men in PH who were in regular relationships with HIV sero-discordant partners. During the same time period, 437 HIV positive men with HIV sero-discordant regular partners completed questionnaires for the GCPS. All completed interviews or questionnaires during that time period were used for these analyses. Amongst the HIV-negative respondents, sero-discordant UAI was more likely to be reported when the men believed their HIV-positive regular partner had an undetectable rather than a detectable viral load (P = 0.002). Amongst the HIV-positive respondents, sero-discordant UAI was as likely to be reported when they themselves reported having an undetectable or a detectable viral load. Use of viral load in negotiating condom use between sero-discordant gay couples may be understood very differently by the HIV-negative and HIV-positive men within those partnerships.

Antiretroviral treatment in pregnancy: a six-year perspective on recent trends in prescription patterns, viral load suppression, and pregnancy outcomes

The aim of the study was to describe the recent trends in antiretroviral treatment in late pregnancy and the sociodemographic changes among pregnant women with HIV over the last 6 years. Data from the National Program on Surveillance on Antiretroviral Treatment in Pregnancy in Italy were grouped per calendar year, and changes in antiretroviral treatment, population characteristics, maternal immunovirologic status and newborn clinical parameters were analyzed. A total of 981 HIV-infected mothers who delivered between 2002 and 2008 were evaluated. The proportion of women receiving at least three antiretroviral drugs at delivery increased significantly from 63.0% in 2002 to 95.5% in 2007-2008, paralleled by a similar upward trend in the proportion of women who achieved complete viral suppression at third trimester (from 37.3 in 2002 to 80.9 in 2007-2008; p < 0.001). The co-formulation of zidovudine plus lamivudine remained the most common nucleoside backbone in pregnancy, even if a significant increase in the use of tenofovir plus emtricitabine was observed in more recent years. Starting from 2003, nevirapine prescription declined, paralleled by a significant rise in the use of protease inhibitors (PI), which were present in more than 60% of regimens administered in 2007-2008. Nelfinavir was progressively replaced by ritonavir-boosted PIs, mainly lopinavir. No significant changes in preterm delivery, Apgar score, birth weight, and birth defects were observed during the study period, and the rate of HIV transmission remained below 2%. These data demonstrate a significant evolution in the treatment of HIV in pregnancy. Constant improvements in the rates of HIV suppression were observed, probably driven by the adoption of stronger and more effective regimens and by the increasing options available for combination treatment.

Importance of promoting HIV testing for preventing secondary transmissions: modelling the Australian HIV epidemic among men who have sex with men

BACKGROUND

We address the research questions: (i) what proportion of new HIV infections is transmitted from people who are (a) undiagnosed, (b) in primary HIV infection (PHI), (c) on antiretroviral therapy?; and (ii) what is the expected epidemiological impact of (a) increasing the proportion of newly acquired HIV infections receiving early treatment, and (b) increasing HIV testing rates?

METHODS

We used a mathematical model to simulate HIV transmission in the population of men who have sex with men (MSM) in Australia. We calibrated the model using established biological and clinical data and a wide range of Australian MSM epidemiological and behavioural data sources.

RESULTS

We estimate that ~19% of all new HIV infections are transmitted from the ~3% of Australian HIV-infected MSM who are in PHI; ~31% of new HIV infections are estimated to be transmitted from the ~9% of MSM with undiagnosed HIV. We estimate that the average number of infections caused per HIV-infected MSM through the duration of PHI is ~0.14-0.28.

CONCLUSIONS

The epidemiological impact of increasing treatment in PHI would be modest due to insufficient detection of newly-infected individuals. In contrast, increases in HIV testing rates could have substantial epidemiological consequences. The benefit of testing will also increase over time. Promoting increases in the coverage and frequency of testing for HIV could be a highly-effective public health intervention, but the population-level impact of interventions based on promoting early treatment of patients diagnosed in PHI is likely to be small. Treating PHI requires further evaluation of its long-term effects on HIV-infected individuals.

Using mathematical modelling to help explain the differential increase in HIV incidence in New South Wales, Victoria and Queensland: importance of other sexually transmissible infections

Background: Since 1999 there has been an increase in the number of HIV diagnoses in Australia, predominantly among men who have sex with men (MSM), but the magnitude of increase differs between states: ~7% rise in New South Wales, ~96% rise in Victoria, and ~68% rise in Queensland. Methods: Epidemiological, clinical, behavioural and biological data were collated into a mechanistic mathematical model to explore possible reasons for this increase in HIV notifications in MSM. The model was then used to make projections to 2015 under various scenarios. Results: The model suggests that trends in clinical and behavioural parameters, including increases in unprotected anal intercourse, cannot explain the magnitude of the observed rise in HIV notifications, without a substantial increase in a ‘transmission-increasing’ factor. We suggest that a highly plausible biological factor is an increase in the prevalence of other sexually transmissible infections (STI). It was found that New South Wales required an ~2-fold increase in other STI to match the data, Victoria needed an ~11-fold increase, and Queensland required an ~9-fold increase. This is consistent with observed trends in Australia for some STI in recent years. Future projections also indicate that the best way to control the current rise in HIV notifications is to reduce the prevalence of other STI and to promote condom use, testing for HIV, and initiation of early treatment in MSM diagnosed during primary infection. Conclusions: Our model can explain the recent rise in HIV notifications with an increase in the prevalence of other STI. This analysis highlights that further investigation into the causes and impact of other STI is warranted in Australia, particularly in Victoria.

Sexually transmissible infection and HIV management among men who have sex with men with and without HIV: survey of medical practitioners who are members of the Australasian Society for HIV Medicine

Background: Rates of HIV in New South Wales (NSW) have been stable, but have increased significantly in other Australian states. The reasons for this are unknown and may be associated with differences in the management of sexually transmissible infections (STI) and HIV in different states in Australia. Our aim was to determine if the use of suppressive treatment for genital herpes, the treatment of HIV or STI screening practices were different between states in Australia. Methods: This study was a cross-sectional survey of medical practitioners who are S100 prescribers and members of the Australian Society for HIV Medicine. Results: In general, there were no differences between the clinical practices of practitioners in NSW and other states except that in NSW fewer practitioners tested HIV-positive men who have sex with men (MSM) for syphilis annually (NSW 78% v. others 87%, P = 0.04) or treated MSM with advanced HIV disease (CD4 < 150 × 106 cells L–1) with acicylovir in the absence of herpes simplex virus (HSV) (NSW 4% v. others 13%, P = 0.03), and more practitioners in NSW tested HIV-negative MSM for HSV type-specific serology (NSW 21% v. others 11%, P = 0.02). Conclusions: It is unlikely that the minor differences in HSV and HIV treatment or STI screening practices among practitioners in NSW and other Australian states explains the differences in HIV notifications between these two areas.