The integration of independent national HIV surveillance datasets and application of statistical methods to enhance their public health utility

The aims of this thesis were two-fold. Firstly, to develop a robust method to create a fully integrated, national surveillance dataset for human immunodeficiency virus (HIV) infections by linking records from three independent, national HIV case reporting systems. Secondly, to apply statistical techniques, more commonly used in cohort study research, to the integrated dataset to yield more of the potential from the constituent information and increase the public health utility of the data. This demonstrated that an integrated dataset can reduce missing information in each surveillance system and improve information use by combining different data that was previously available only in separate databases. Using the integrated dataset, I achieved the following: accounted for missing information; described the frequency of CD4 count measurements and associated factors; determined characteristics associated with late diagnosis and consequent mortality; estimated the national incidence of acquired immunodeficiency syndrome (AIDS) and death and the influencing factors; assessed information about the date of starting therapy for each individual; and assessed factors associated with immune defence recovery after the start of treatment. These analyses will be/have been integrated into national surveillance processes as appropriate and used to publish academic papers. Lessons have been learnt for surveillance methodology with regards sharing information and ensuring that data are representative of the whole population. The large size, wide coverage and prospective nature of the integrated dataset mean that national (and local) policy decisions can be based on information that reflects the national picture rather than unrepresentative and time-bound studies. The dataset also has the power to unpick differences within small population groups. For example, evidence about late diagnoses and mortality has been used to promote the need for earlier HIV diagnosis and is updated annually and used to target local needs and to monitor improvements

The Cost-Effectiveness of Early Access to HIV Services and Starting cART in the UK 1996–2008

To calculate use, cost and cost-effectiveness of people living with HIV (PLHIV) starting routine treatment and care before starting combination antiretroviral therapy (cART) and PLHIV starting first-line 2NRTIs+NNRTI or 2NRTIs+PI(boosted), comparing PLHIV with CD4≤200 cells/mm3 and CD4>200 cells/mm3. Few studies have calculated the use, cost and cost-effectiveness of routine treatment and care before starting cART and starting cART above and below CD4 200 cells/mm3.Use, costs and cost-effectiveness were calculated for PLHIV in routine pre-cART and starting first-line cART, comparing CD4≤200 cells/mm3 with CD4>200 cells/mm3 (2008 UK prices).cART naïve patients CD4≤200 cells/mm3 had an annual cost of £6,407 (95%CI £6,382 to £6,425) PPY compared with £2,758 (95%CI £2,752 to £2,761) PPY for those with CD4>200 cells/mm3; cost per life year gained of pre-cART treatment and care for those with CD4>200 cells/mm3 was £1,776 (cost-saving to £2,752). Annual cost for starting 2NRTIs+NNRTI or 2NRTIs+PI(boosted) with CD4≤200 cells/mm3 was £12,812 (95%CI £12,685-£12,937) compared with £10,478 (95%CI £10,376-£10,581) for PLHIV with CD4>200 cells/mm3. Cost per additional life-year gained on first-line therapy for those with CD4>200 cells/mm3 was £4639 (£3,967 to £2,960).PLHIV starting to use HIV services before CD4≤200 cells/mm3 is cost-effective and enables them to be monitored so they start cART with a CD4>200 cells/mm3, which results in better outcomes and is cost-effective. However, 25% of PLHIV accessing services continue to present with CD4≤200 cells/mm3. This highlights the need to investigate the cost-effectiveness of testing and early treatment programs for key populations in the UK

Cross-Sectional Analysis of Late HAART Initiation in Latin America and the Caribbean: Late Testers and Late Presenters

Background: Starting HAART in a very advanced stage of disease is assumed to be the most prevalent form of initiation in HIV-infected subjects in developing countries. Data from Latin America and the Caribbean is still lacking. Our main objective was to determine the frequency, risk factors and trends in time for being late HAART initiator (LHI) in this region. Methodology: Cross-sectional analysis from 9817 HIV-infected treatment-naive patients initiating HAART at 6 sites (Argentina, Chile, Haiti, Honduras, Peru and Mexico) from October 1999 to July 2010. LHI had CD4$^+$ count $\leq$200cells/mm$^3$ prior to HAART. Late testers (LT) were those LHI who initiated HAART within 6 months of HIV diagnosis. Late presenters (LP) initiated after 6 months of diagnosis. Prevalence, risk factors and trends over time were analyzed. Principal Findings: Among subjects starting HAART (n = 9817) who had baseline CD4$^+$ available (n = 8515), 76% were LHI: Argentina (56%[95%CI:52–59]), Chile (80%[95%CI:77–82]), Haiti (76%[95%CI:74–77]), Honduras (91%[95%CI:87–94]), Mexico (79%[95%CI:75–83]), Peru (86%[95%CI:84–88]). The proportion of LHI statistically changed over time (except in Honduras) ($p\leq0.02$; Honduras p = 0.7), with a tendency towards lower rates in recent years. Males had increased risk of LHI in Chile, Haiti, Peru, and in the combined site analyses (CSA). Older patients were more likely LHI in Argentina and Peru (OR 1.21 per +10-year of age, 95%CI:1.02–1.45; OR 1.20, 95%CI:1.02–1.43; respectively), but not in CSA (OR 1.07, 95%CI:0.94–1.21). Higher education was associated with decreased risk for LHI in Chile (OR 0.92 per +1-year of education, 95%CI:0.87–0.98) (similar trends in Mexico, Peru, and CSA). LHI with date of HIV-diagnosis available, 55% were LT and 45% LP. Conclusion: LHI was highly prevalent in CCASAnet sites, mostly due to LT; the main risk factors associated were being male and older age. Earlier HIV-diagnosis and earlier treatment initiation are needed to maximize benefits from HAART in the region

HIV Testing Practices by Clinical Service before and after Revised Testing Guidelines in a Swiss University Hospital

OBJECTIVES: To determine 1) HIV testing practices in a 1400-bed university hospital where local HIV prevalence is 0.4% and 2) the effect on testing practices of national HIV testing guidelines, revised in March 2010, recommending Physician-Initiated Counselling and Testing (PICT). METHODS: Using 2 hospital databases, we determined the number of HIV tests performed by selected clinical services, and the number of patients tested as a percentage of the number seen per service ('testing rate'). To explore the effect of the revised national guidelines, we examined testing rates for two years pre- and two years post-PICT guideline publication. RESULTS: Combining the clinical services, 253,178 patients were seen and 9,183 tests were performed (of which 80 tested positive, 0.9%) in the four-year study period. The emergency department (ED) performed the second highest number of tests, but had the lowest testing rates (0.9-1.1%). Of inpatient services, neurology and psychiatry had higher testing rates than internal medicine (19.7% and 9.6% versus 8%, respectively). There was no significant increase in testing rates, either globally or in the majority of the clinical services examined, and no increase in new HIV diagnoses post-PICT recommendations. CONCLUSIONS: Using a simple two-database tool, we observe no global improvement in HIV testing rates in our hospital following new national guidelines but do identify services where testing practices merit improvement. This study may show the limit of PICT strategies based on physician risk assessment, compared to the opt-out approach

Morbidity and Risk of Subsequent Diagnosis of HIV: A Population Based Case Control Study Identifying Indicator Diseases for HIV Infection

BACKGROUND: Early identification of persons with undiagnosed HIV infection is an important health care issue. We examined associations between diseases diagnosed in hospitals and risk of subsequent HIV diagnosis. METHODS: In this population-based case control study, cases were persons with incident HIV infection diagnosed in Denmark between 1 January 1995 and 1 June 2008. Risk-set sampling was used to identify 19 age- and gender-matched population controls for each HIV case, using the HIV diagnosis date as the index date for both cases and controls. Prior hospital diagnoses obtained from Danish medical databases were first categorized into 22 major disease categories (excluding AIDS-defining diseases except tuberculosis) and then subdivided into 161 subcategories, allowing us to examine specific diseases as potential HIV indicators by conditional logistic regression. RESULTS: The study included 2,036 HIV cases and 35,718 controls. Persons with the following disease categories had a high risk of HIV diagnosis during the subsequent 5-year period: sexually transmitted infections and viral hepatitis (adjusted odds ratio [aOR] = 12.3, 95% CI: 9.60-15.7), hematological diseases (aOR = 4.28, 3.13-5.85), lower respiratory tract infections (aOR = 3.98, 3.14-5.04)), CNS infections (aOR = 3.44, 1.74-6.80), skin infections (aOR = 3.05, 2.47-3.75), other infections (aOR = 4.64, 3.89-5.54), and substance abuse (aOR = 2.60, 2.06-3.29). Several specific diseases were associated with aORs >20 including syphilis, hepatitis A, non "A" viral hepatitis, herpes zoster, candida infection, endocarditis, thrombocytopenia, and opioid abuse. CONCLUSIONS: Targeted testing for HIV in patients diagnosed with diseases associated with HIV may lead to earlier treatment and thereby reduced morbidity, mortality and HIV transmission

Feasibility and effectiveness of indicator condition-guided testing for HIV: results from HIDES I (HIV indicator diseases across Europe study)

Improved methods for targeting HIV testing among patients most likely to be infected are required; HIDES I aimed to define the methodology of a European wide study of HIV prevalence in individuals presenting with one of eight indicator conditions/diseases (ID); sexually transmitted infection, lymphoma, cervical or anal cancer/dysplasia, herpes zoster, hepatitis B/C, mononucleosis-like illness, unexplained leukocytopenia/thrombocytopenia and seborrheic dermatitis/exanthema, and to identify those with an HIV prevalence of >0.1%, a level determined to be cost effective. A staff questionnaire was performed. From October 2009- February 2011, individuals, not known to be HIV positive, presenting with one of the ID were offered an HIV test; additional information was collected on previous HIV testing behaviour and recent medical history. A total of 3588 individuals from 16 centres were included. Sixty-six tested positive for HIV, giving an HIV prevalence of 1.8% [95% CI: 1.42-2.34]; all eight ID exceeded 0.1% prevalence. Of those testing HIV positive, 83% were male, 58% identified as MSM and 9% were injecting drug users. Twenty percent reported previously having potentially HIV-related symptoms and 52% had previously tested HIV negative (median time since last test: 1.58 years); which together with the median CD4 count at diagnosis (400 cell/uL) adds weight to this strategy being effective in diagnosing HIV at an earlier stage. A positive test was more likely for non-white individuals, MSM, injecting drug users and those testing in non-Northern regions. HIDES I describes an effective strategy to detect undiagnosed HIV infection. All eight ID fulfilled the >0.1% criterion for cost effectiveness. All individuals presenting to any health care setting with one of these ID should be strongly recommended an HIV test. A strategy is being developed in collaboration with ECDC and WHO Europe to guide the implementation of this novel public health initiative across Europe

The impact in the UK of the Central and Eastern European HIV epidemics.

Despite increasing migration, the impact of HIV epidemics from Central and Eastern Europe (C&EE) on the UK HIV epidemic remains small. C&EE-born adults comprised 1.2% of adults newly diagnosed with HIV in the UK between 2000 and 2007. Most C&EE-born women probably acquired their infection heterosexually in C&EE. In contrast, 59% of C&EE-born men reported sex with men, half of whom probably acquired their infection in the UK. Previously undiagnosed HIV prevalence in C&EE-born sexual-health-clinic attendees was low (2007, 0.5%) as was overall HIV prevalence in C&EE-born women giving birth in England (2007, <0.1%). The high proportion of men who have sex with men (MSM) suggests under-reporting of this group in C&EE HIV statistics and/or migration of MSM to the UK. In addition to reducing HIV transmission in injecting drug users, preventative efforts aimed at C&EE-born MSM both within their country of origin and the UK are required