Analyzing continuous measures in HIV prevention research using semiparametric regression and parametric regression models: how to use data to get the (right) answer?

Semiparametric regression models based on smoothing splines were used to examine the associations between the risk of HIV seropositivity and a continuous covariate. For example, in the fully parametric logistic regression model, age was associated with a decreased risk of HIV seropositivity [Odds ratio (OR): 0.94 per 5 year increase, 95% Confidence Interval (CI): 0.

The effects of injectable hormonal contraceptives on HIV seroconversion and on sexually transmitted infections.

Objectives: To investigate the association between hormonal contraceptives and risk of HIV-1 seroconversion and prevalence of other sexually transmitted infections.

Design: Prospective cohort.

Methods: The study population was 2,236 HIV-negative women who were screened in a biomedical intervention trial in Durban, South Africa.

How effective are short message service reminders at increasing clinic attendance? A meta-analysis and systematic review.

Background And Objectives: In the last few years there has been a steady uptake of mobile phone short message service (SMS) reminders to increase medical attendance rates. We undertook a review of studies that assessed the effectiveness of SMS reminders at increasing the uptake of appointments in health care settings.

Methods: We reviewed studies which involved a comparison of appointment attendance rates between patients who did and did not receive SMS reminders published prior to June 2010.

Individual-level syringe coverage among Needle and Syringe Program attendees in Australia.

Background: Harm associated with injecting drug use is a significant public health issue and a major cause of morbidity and mortality, with global estimates of 3 million injectors infected with HIV and 8 million living with chronic hepatitis C virus (HCV) infection. Estimates of program coverage are widely used in the context of HIV prevention and are critical in determining the effectiveness of interventions such as Needle and Syringe Programs (NSPs).

Methods: Data from a national cross-sectional study of NSP attendees in Australia were used to estimate individual-level syringe coverage as a proportion of monthly injections covered by a new syringe.

Developing and validating a risk scoring tool for chlamydia infection among sexual health clinic attendees in Australia: a simple algorithm to identify those at high risk of chlamydia infection.

Objective: To develop and validate a risk scoring tool to identify those who are at increased risk of chlamydia infection.

Methods: We used demographic data, sexual behaviour information and chlamydia positivity results from more than 45,000 individuals who attended Sydney Sexual Health Centre between 1998 and 2009. Participants were randomly allocated to either the development or internal validation data set.

Population attributable risk for chlamydia infection in a cohort of young international travellers (backpackers) and residents in Australia.

Aim: To estimate the population attributable risk (PAR) for Chlamydia trachomatis infection in young men and women in Sydney, Australia.

Method: Multivariate logistic regression was used to examine the association between demographic, sexual behaviour and other potential risk factors and chlamydia positivity in young (≤ 30 years) heterosexual international travellers (backpackers) and Australian residents attending a sexual health clinic. Point and interval estimates of PAR were calculated to quantify the proportion of chlamydia infections that can theoretically be prevented if a combination of risk factors is eliminated from a target population.

Higher HCV antibody prevalence among Indigenous clients of needle and syringe programs.

Objective: To compare prevalence of hepatitis C virus (HCV) antibody and associated risk behaviours among Indigenous and non-Indigenous participants in the Australian Needle and Syringe Program Survey.

Methods: During 1 or 2 weeks each October from 1998 to 2008, clients of participating needle and syringe programs (NSPs) completed a self-administered questionnaire on demographics and risk behaviour and provided a capillary blood sample for HIV and HCV antibody testing. After de-duplication, 16,132 individuals participated during the 11 years, of whom 1,380 (8.

HIV incidence among non-pregnant women living in selected rural, semi-rural and urban areas in KwaZulu-Natal, South Africa.

The province of KwaZulu-Natal has the highest prevalence of HIV in South Africa, particularly among young women. In order to more closely examine the HIV prevalence and incidence in non-pregnant women from rural, semi-rural and urban areas, data from 5,753 women screened for enrolment into three HIV prevention studies were combined and analysed. The prevalence of HIV infection was 43% at screening.

Is azithromycin adequate treatment for asymptomatic rectal chlamydia?

Rectal chlamydia is a common sexually transmissible infection (STI) in men who have sex with men (MSM) that is predominantly asymptomatic. The recommended treatment of azithromycin 1 g as a single oral dose has not been subject to randomized trials and so its efficacy is unknown. We conducted a retrospective case-note review of all MSM diagnosed at the Sydney Sexual Health Centre with asymptomatic rectal chlamydia in 2009.

Improving surveillance for acute hepatitis C.

Understanding patterns of newly acquired hepatitis C virus (HCV) infection is fundamental to assessing the impact of prevention and treatment interventions. However, identifying newly acquired cases is difficult, usually requiring documented testing before and after exposure. As the proportion of cases identified as newly acquired by current New South Wales surveillance methodologies is significantly lower than that identified nationally, the impact on the identification of newly acquired cases of systematic reporting of past negative HCV test results from notifying laboratories was assessed.

Epidemiology of syphilis in Australia: moving toward elimination of infectious syphilis from remote Aboriginal and Torres Strait Islander communities?

Objective: To describe the epidemiology of infectious syphilis among Aboriginal and Torres Strait Islander (Indigenous) people in Australia.

Design And Setting: We assessed trends in national infectious syphilis notification rates from 2005 to 2009 using Poisson regression, with a focus on geographic and demographic differences by Indigenous status. We compared Indigenous and non-Indigenous rate ratios over the study period and summarised the annual changes (summary rate ratio).

Disproportionate impact of combination antiretroviral therapy on AIDS incidence in Australia: results from a modified back-projection model.

The objective of the current study is to describe the impact of Combination antiretroviral therapy (cART) on trends in AIDS incidence over time for selected population groups in Australia, specifically, men who have sex with men (MSM) and injecting drug users (IDUs). A modified back-projection modeling technique was used to predict the number of AIDS diagnoses without cART based on Australia's HIV/AIDS surveillance system database. Modelled estimates indicate that since 1996, the effective cART has reduced overall AIDS cases by ~70 and ~10% among MSM and IDUs respectively.

Re-testing for chlamydia at sexual health services in Australia, 2004-08.

Objective: To describe the frequency of the 3-month test for re-infection among sexual health service patients in Australia.

Methods: We assessed the re-testing rates at 30-120 days after chlamydia infection in men who have sex with men (MSM), heterosexual males and females attending sexual health services across Australia between 2004 and 2008. A χ(2)-test was used to determine significant differences in re-testing rates according to demographic characteristics and trends over time.

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.

Geoadditive models to assess spatial variation of HIV infections among women in local communities of Durban, South Africa.

Background: The severity of the HIV/AIDS epidemic in South Africa varies between and within provinces, with differences noted even at the suburban scale. We investigated the geographical variability of HIV infection in rural areas of the eThekwini Metropolitan Municipality in KwaZulu-Natal province, South Africa.

Method: We used geoadditive models to assess nonlinear geographical variation in HIV prevalence while simultaneously controlling for important demographic and sexual risk factors.

Short message service reminder intervention doubles sexually transmitted infection/HIV re-testing rates among men who have sex with men.

Objectives: To evaluate the impact of a short message service (SMS) reminder system on HIV/sexually transmitted infection (STI) re-testing rates among men who have sex with men (MSM).

Methods: The SMS reminder programme started in late 2008 at a large Australian sexual health clinic. SMS reminders were recommended 3-6 monthly for MSM considered high-risk based on self-reported sexual behaviour.

Plasma levels of soluble CD14 independently predict mortality in HIV infection.

Background: Chronic human immunodeficiency virus (HIV) infection is associated with intestinal permeability and microbial translocation that contributes to systemic immune activation, which is an independent predictor of HIV disease progression. The association of microbial translocation with clinical outcome remains unknown.

Methods: This nested case-control study included 74 subjects who died, 120 of whom developed cardiovascular disease and 81 of whom developed AIDS during the Strategies for Management of Anti-Retroviral Therapy (SMART) study with matched control subjects.

Chlamydia trends in men who have sex with men attending sexual health services in Australia, 2004-2008.

Background: In most Australian settings, chlamydia notifications do not contain information on the gender of sexual partners. We assessed trends and predictors of chlamydia testing and positivity among men who have sex with men (MSM), attending sexual health services in Australia.

Methods: The Australian Collaboration for Chlamydia Enhanced Sentinel Surveillance (ACCESS) program was established in 2008 to collate demographic and chlamydia testing information from 25 sexual health services.

Fifteen years of HIV surveillance among people who inject drugs: the Australian Needle and Syringe Program Survey 1995-2009.

Objectives: Following bipartisan political support in Australia for the timely introduction of needle and syringe programs (NSPs), HIV prevalence among people who inject drugs (PWID) remains low. This study aimed to determine the correlates of HIV infection among PWID; and to examine these correlates over time.

Design: Annual cross-sectional seroprevalence studies among attendees of sentinel NSP sites.

Quadrivalent human papillomavirus vaccination and trends in genital warts in Australia: analysis of national sentinel surveillance data.

Background: Quadrivalent human papillomavirus (HPV) vaccine has high efficacy in clinical trials but no reports describe its effects at a population level. From July, 2007, Australia was the first country to fund a vaccination programme for all women aged 12-26 years. We established a national surveillance network in Australia and aimed to identify trends in diagnoses of genital warts in 2004-09.

Development of a clinical algorithm to prioritise HIV testing of hospitalised paediatric patients in a low resource moderate prevalence setting.

Objective: To develop a clinical algorithm to identify paediatric patients who should be offered HIV testing in a setting of moderate HIV prevalence and limited resources.

Methods: In a prospective cross-sectional study at Port Moresby General Hospital, Papua New Guinea, carers of inpatients were offered HIV testing and counselling for their children. Recruited children were tested for HIV antibodies and DNA.

The decriminalization of prostitution is associated with better coverage of health promotion programs for sex workers.

Objective: In order to assess whether the law has an impact on the delivery of health promotion services to sex workers, we compared health promotion programs in three Australian cities with different prostitution laws. The cities were Melbourne (brothels legalized if licensed, unlicensed brothels criminalized), Perth (criminalization of all forms of sex work) and Sydney (sex work largely decriminalized, without licensing).

Methods: We interviewed key informants and gave questionnaires to representative samples of female sex workers in urban brothels.

Combined impact of sexual risk behaviors for HIV seroconversion among women in Durban, South Africa: implications for prevention policy and planning.

The objective of this study was to estimate the joint impact of demographic and sexual risk behaviors on HIV acquisition. A total of 2,523 HIV seronegative women were recruited through three community based studies in Durban, South Africa. Point and interval estimates of partial population attributable risk (PAR) were used to quantify the proportion of HIV seroconversions which can be prevented if a combination of risk factors is eliminated from a target population.

Targeting the hotspots: investigating spatial and demographic variations in HIV infection in small communities in South Africa.

Background: In South Africa, the severity of the HIV/AIDS epidemic varies according to geographical location; hence, localized monitoring of the epidemic would enable more effective prevention strategies. Our objectives were to assess the core areas of HIV infection in KwaZulu-Natal, South Africa, using epidemiological data among sexually active women from localized communities.

Methods: A total of 5753 women from urban, peri-rural and rural communities in KwaZulu-Natal were screened from 2002 to 2005.

Hospitalizations in a cohort of HIV patients in Australia, 1999-2007.

Objectives: To describe hospitalization rates, risk factors and associated diagnoses in people with HIV in Australia between 1999 and 2007.

Design: Retrospective cohort study of people with HIV (n = 842) using data linkage between the Australian HIV Observational Database and administrative hospital morbidity data collections.

Methods: Incidence rate ratios with 95% confidence intervals were estimated using Poisson regression models to assess risk factors for hospitalization.