Quantification of biological age as a determinant of age-related diseases in the Rotterdam Study: a structural equation modeling approach.

Chronological age alone is not a sufficient measure of the true physiological state of the body. The aims of the present study were to: (1) quantify biological age based on a physiological biomarker composite model; (2) and evaluate its association with death and age-related disease onset in the setting of an elderly population. Using structural equation modeling we computed biological age for 1699 individuals recruited from the first and second waves of the Rotterdam study. The algorithm included nine physiological parameters (c-reactive protein, creatinine, albumin, total cholesterol, cytomegalovirus optical density, urea nitrogen, alkaline phosphatase, forced expiratory volume and systolic blood pressure). We assessed the association between biological age, all-cause mortality, all-cause morbidity and specific age-related diseases over a median follow-up of 11 years. Biological age, compared to chronological age or the traditional biomarkers of age-related diseases, showed a stronger association with all-cause mortality (HR 1.15 vs. 1.13 and 1.10), all-cause morbidity (HR 1.06 vs. 1.05 and 1.03), stroke (HR 1.17 vs. 1.08 and 1.04), cancer (HR 1.07 vs. 1.04 and 1.02) and diabetes mellitus (HR 1.12 vs. 1.01 and 0.98). Individuals who were biologically younger exhibited a healthier life-style as reflected in their lower BMI (P < 0.001) and lower incidence of stroke (P < 0.001), cancer (P < 0.01) and diabetes mellitus (P = 0.02). Collectively, our findings suggest that biological age based on the biomarker composite model of nine physiological parameters is a useful construct to assess individuals 65 years and older at increased risk for specific age-related diseases.

Future challenges for clinical care of an ageing population infected with HIV: a modelling study.

BACKGROUND: The population infected with HIV is getting older and these people will increasingly develop age-related non-communicable diseases (NCDs). We aimed to quantify the scale of the change and the implications for HIV care in the Netherlands in the future. METHODS: We constructed an individual-based model of the ageing HIV-infected population, which followed patients on HIV treatment as they age, develop NCDs-including cardiovascular disease (hypertension, hypercholesterolaemia, myocardial infarctions, and strokes), diabetes, chronic kidney disease, osteoporosis, and non-AIDS malignancies-and start co-medication for these diseases. The model was parameterised by use of data for 10 278 patients from the national Dutch ATHENA cohort between 1996 and 2010. We made projections up to 2030. FINDINGS: Our model suggests that the median age of HIV-infected patients on combination antiretroviral therapy (ART) will increase from 43·9 years in 2010 to 56·6 in 2030, with the proportion of HIV-infected patients aged 50 years or older increasing from 28% in 2010 to 73% in 2030. In 2030, we predict that 84% of HIV-infected patients will have at least one NCD, up from 29% in 2010, with 28% of HIV-infected patients in 2030 having three or more NCDs. 54% of HIV-infected patients will be prescribed co-medications in 2030, compared with 13% in 2010, with 20% taking three or more co-medications. Most of this change will be driven by increasing prevalence of cardiovascular disease and associated drugs. Because of contraindications and drug-drug interactions, in 2030, 40% of patients could have complications with the currently recommended first-line HIV regimens. INTERPRETATION: The profile of patients in the Netherlands infected with HIV is changing, with increasing numbers of older patients with multiple morbidities. These changes mean that, in the near future, HIV care will increasingly need to draw on a wide range of medical disciplines, in addition to evidence-based screening and monitoring protocols to ensure continued high-quality care. These findings are based on a large dataset of HIV-infected patients in the Netherlands, but we believe that the overall patterns will be repeated elsewhere in Europe and North America. The implications of such a trend for care of HIV-infected patients in high-burden countries in Africa could present a particular challenge. FUNDING: Medical Research Council, Bill & Melinda Gates Foundation, Rush Foundation, and Netherlands Ministry of Health, Welfare and Sport.

Cohort profile: Antiretroviral Therapy Cohort Collaboration (ART-CC).

The advent of effective combination antiretroviral therapy (ART) in 1996 resulted in fewer patients experiencing clinical events, so that some prognostic analyses of individual cohort studies of human immunodeficiency virus-infected individuals had low statistical power. Because of this, the Antiretroviral Therapy Cohort Collaboration (ART-CC) of HIV cohort studies in Europe and North America was established in 2000, with the aim of studying the prognosis for clinical events in acquired immune deficiency syndrome (AIDS) and the mortality of adult patients treated for HIV-1 infection. In 2002, the ART-CC collected data on more than 12,000 patients in 13 cohorts who had begun combination ART between 1995 and 2001. Subsequent updates took place in 2004, 2006, 2008, and 2010. The ART-CC data base now includes data on more than 70,000 patients participating in 19 cohorts who began treatment before the end of 2009. Data are collected on patient demographics (e.g. sex, age, assumed transmission group, race/ethnicity, geographical origin), HIV biomarkers (e.g. CD4 cell count, plasma viral load of HIV-1), ART regimen, dates and types of AIDS events, and dates and causes of death. In recent years, additional data on co-infections such as hepatitis C; risk factors such as smoking, alcohol and drug use; non-HIV biomarkers such as haemoglobin and liver enzymes; and adherence to ART have been collected whenever available. The data remain the property of the contributing cohorts, whose representatives manage the ART-CC via the steering committee of the Collaboration. External collaboration is welcomed. Details of contacts are given on the ART-CC website (www.art-cohort-collaboration.org).

Prolonged decrease of CD4+ T lymphocytes in HIV-1-infected patients after radiotherapy for a solid tumor.

BACKGROUND: In HIV-negative patients, radiotherapy (RT) decreases CD4 T-cell counts. We studied the effects of RT in HIV-1 positive patients. METHODS: HIV-1 positive patients with a subsequent diagnosis of a solid tumor were selected from the Dutch national observational HIV cohort, Aids Therapy Evaluation in the Netherlands (ATHENA). The patients were grouped according to whether they had received RT or not. Primary endpoint of the study was the time from baseline to reaching CD4 cell counts higher than those at baseline. Kaplan-Meier estimates of the percentage of patients reaching the endpoint were calculated. RESULTS: Ninety patients were included of whom 36 received RT and 54 did not. Median duration of RT was 46 [interquartile range (IQR) 30-63] days. Median first CD4 cell count after stopping RT was 150 (IQR 30-270) × 10/L lower compared with baseline. In 13 of the 36 patients receiving RT, CD4 cell counts recovered to baseline, after a median of 469 (IQR 345-595) days. In 35 of the 54 patients without RT, the CD4 cell count recovered to baseline or higher, after a median of 112 (IQR 42-182) days. After 3 years, in 39% of patients who had RT compared with 71% of patients without RT, CD4 cell counts recovered to baseline or higher (P < 0.0001). In a Cox regression adjusted for potential confounders, RT was associated with a longer (hazard ratio 0.29; 95% confidence interval 0.13 to 0.63) and combination antiretroviral therapy use with a shorter time to return to baseline [hazard ratio 2.46 (95% confidence interval 1.11 to 5.48)]. CONCLUSIONS: RT resulted in a significant and prolonged decrease in CD4 cell counts.

Single nucleotide polymorphism in gene encoding transcription factor Prep1 is associated with HIV-1-associated dementia.

BACKGROUND: Infection with HIV-1 may result in severe cognitive and motor impairment, referred to as HIV-1-associated dementia (HAD). While its prevalence has dropped significantly in the era of combination antiretroviral therapy, milder neurocognitive disorders persist with a high prevalence. To identify additional therapeutic targets for treating HIV-associated neurocognitive disorders, several candidate gene polymorphisms have been evaluated, but few have been replicated across multiple studies. METHODS: We here tested 7 candidate gene polymorphisms for association with HAD in a case-control study consisting of 86 HAD cases and 246 non-HAD AIDS patients as controls. Since infected monocytes and macrophages are thought to play an important role in the infection of the brain, 5 recently identified single nucleotide polymorphisms (SNPs) affecting HIV-1 replication in macrophages in vitro were also tested. RESULTS: The CCR5 wt/Δ32 genotype was only associated with HAD in individuals who developed AIDS prior to 1991, in agreement with the observed fading effect of this genotype on viral load set point. A significant difference in genotype distribution among all cases and controls irrespective of year of AIDS diagnosis was found only for a SNP in candidate gene PREP1 (p = 1.2 × 10(-5)). Prep1 has recently been identified as a transcription factor preferentially binding the -2,518 G allele in the promoter of the gene encoding MCP-1, a protein with a well established role in the etiology of HAD. CONCLUSION: These results support previous findings suggesting an important role for MCP-1 in the onset of HIV-1-associated neurocognitive disorders.

The clinical interpretation of viral blips in HIV patients receiving antiviral treatment: are we ready to infer poor adherence?

OBJECTIVES: Viral blips may be an indication of poor adherence to antiretroviral treatment. This article studies how the variations of the definitions of viral blips and that of the choice of sampling frame in studies investigating viral blips may contribute to the uncertainty of the associations between viral blips and possible causes. DESIGN: Mathematical modeling study allows us to study the impact of different sampling frames and different definitions of blips upon study results that are usually not feasible in clinical settings. METHODS: Using a previously published mathematical model, scenarios of different drug adherence levels and viral blips, with different sampling frames, were modeled. RESULTS: In the case of viral blips as a result of nonadherence to combinational antiretroviral therapy, rather than calculating the incidence of blips directly from the number of blips observed in a given period of time, it is better to report the proportion of observations in a given period of time that are ≥50 copies per milliliter. Therefore, as the denominator, the number of observations in a given period of time is important. However, the proportion of blips is not very informative on the drug adherence level. CONCLUSIONS: We should standardize definitions of viral blips and the choice of sampling frame and to report the proportion of observations of a given sampling frame in a given period of time that are ≥50 copies per milliliter, so that comparable data can be generated across different populations.

Long-term complications in patients with poor immunological recovery despite virological successful HAART in Dutch ATHENA cohort.

OBJECTIVE: We investigated the risk of AIDS and serious non-AIDS-defining diseases (non-ADDs) according to the degree of immunological recovery after 2 years of virological successful antiretroviral therapy (HAART). DESIGN: Retrospective observational cohort study including HIV-infected patients treated with HAART resulting in viral suppression (<500 copies/ml). METHODS: Patients were grouped according to their CD4 cell count after 2 years of HAART: CD4 cell count less than 200 cells/µl (group A), 200-350 cells/µl (group B), 351-500 cells/µl (group C) or more than 500 cells/µl (group D). Analysis was done to assess predictors for poor immunological recovery and the occurrence of a composite endpoint [death, AIDS, malignancies, liver cirrhosis and cardiovascular events (CVEs)], non-ADDs, CVEs and non-AIDS-defining malignancies (non-ADMs). RESULTS: Three thousand and sixty-eight patients were included. Older age, lower CD4 cell nadir and lower plasma HIV-RNA at the start of HAART were independent predictors for a poor immunological recovery. The composite endpoint, non-ADDs and CVE were observed most frequently in group A (overall log rank, P < 0.0001, P = 0.002 and P = 0.01). In adjusted analyses, age was a strong independent predictor for all endpoints. Compared with group A, patients in group D had a lower risk for the composite endpoint [hazard ratio 0.54 (95% confidence interval [CI] 0.33-0.87]; patients in group B had a lower risk for CVEs [hazard ratio 0.34 (95% CI 0.14-0.86)]. CONCLUSION: Poor immunological recovery despite virological successful HAART is associated with a higher risk for overall morbidity and mortality and CVEs in particular. This study underlines the importance of starting HAART at higher CD4 cell counts, particularly in older patients.

Immunodeficiency as a risk factor for non-AIDS-defining malignancies in HIV-1-infected patients receiving combination antiretroviral therapy.

BACKGROUND: The aim of this study was to investigate the association between immunodeficiency, viremia, and non-AIDS-defining malignancies (NADM). METHODS: Patients starting combination antiretroviral therapy (cART) as of 1 January 1996 were selected from the AIDS Therapy Evaluation in the Netherlands (ATHENA) cohort. In Cox models, risk factors for NADM were investigated. These included age, sex, transmission route, smoking, alcohol abuse, prior AIDS diagnosis, duration of exposure to cART, and estimated duration of human immunodeficiency virus infection. CD4+ cell count and viral load (VL) were considered as time-updated variables and as measures of cumulative exposure to CD4+ cell counts of < 200, < 350, or < 500 cells/mm³ and detectable VL >50, >400, and >1000 copies/mL, respectively. RESULTS: In a cohort of 11,459 patients, 236 NADMs were diagnosed; 102 were caused by infection, and 134 were attributable to other causes. Median CD4+ cell count at NADM diagnosis was 340 cells/mm³ (range, 210-540 cells/mm³). Median time to first NADM after starting cART was 5.0 years (range, 2.2-8.2 years). In multivariate models, cumulative exposure to CD4+ cell counts < 200 cells/mm³ remained significant (hazard ratio [HR], 1.12; range, 1.03-1.22) for each additional year of exposure. In stratified analyses, cumulative exposure to CD4+ cell counts < 200 cells/mm³ was associated with malignancies possibly caused by infection (HR, 1.16; range, 1.03-1.31]) but was not associated with other types of cancers. No significant effect of viremia was seen in either type of cancer. CONCLUSIONS: Cumulative exposure to CD4+ cell counts < 200 cells/mm³ during cART was associated with an increased risk of infection-related non-AIDS-defining malignancies.

Effect of transmitted drug resistance on virological and immunological response to initial combination antiretroviral therapy for HIV (EuroCoord-CHAIN joint project): a European multicohort study.

BACKGROUND: The effect of transmitted drug resistance (TDR) on first-line combination antiretroviral therapy (cART) for HIV-1 needs further study to inform choice of optimum drug regimens. We investigated the effect of TDR on outcome in the first year of cART within a large European collaboration. METHODS: HIV-infected patients of any age were included if they started cART (at least three antiretroviral drugs) for the first time after Jan 1, 1998, and were antiretroviral naive and had at least one sample for a genotypic test taken before the start of cART. We used the WHO drug resistance list and the Stanford algorithm to classify patients into three resistance categories: no TDR, at least one mutation and fully-active cART, or at least one mutation and resistant to at least one prescribed drug. Virological failure was defined as time to the first of two consecutive viral load measurements over 500 copies per mL after 6 months of therapy. FINDINGS: Of 10,056 patients from 25 cohorts, 9102 (90·5%) had HIV without TDR, 475 (4·7%) had at least one mutation but received fully-active cART, and 479 (4·8%) had at least one mutation and resistance to at least one drug. Cumulative Kaplan-Meier estimates for virological failure at 12 months were 4·2% (95% CI 3·8-4·7) for patients in the no TDR group, 4·7% (2·9-7·5) for those in the TDR and fully-active cART group, and 15·1% (11·9-19·0) for those in the TDR and resistant group (log-rank p<0·0001). The hazard ratio for the difference in virological failure between patients with TDR and resistance to at least one drug and those without TDR was 3·13 (95% CI 2·33-4·20, p<0·0001). The hazard ratio for the difference between patients with TDR receiving fully-active cART and patients without TDR was 1·47 (95% CI 0·19-2·38, p=0·12). In stratified analysis, the hazard ratio for the risk of virological failure in patients with TDR who received fully-active cART that included a non-nucleoside reverse transcriptase inhibitor (NNRTI) compared with those without TDR was 2·0 (95% CI 0·9-4·7, p=0·093). INTERPRETATION: These findings confirm present treatment guidelines for HIV, which state that the initial treatment choice should be based on resistance testing in treatment-naive patients. FUNDING: European Community's Seventh Framework Programme FP7/2007-2013 and Gilead.

The comparison of the performance of two screening strategies identifying newly-diagnosed HIV during pregnancy.

BACKGROUND: In the Netherlands, a non-selective opt-out instead of a selective opt-in antenatal HIV screening strategy was implemented in 2004. In case of infection, screening was followed by prevention of mother-to-child-transmission (PMTCT). We compared the performance of the two strategies in terms of detection of new cases of HIV and vertical transmission. METHODS: HIV-infected pregnant women were identified retrospectively from the Dutch HIV cohort ATHENA January 2000 to January 2008. Apart from demographic, virological and immunological data, the date of HIV infection in relation to the index pregnancy was established. Separately, all infants diagnosed with HIV born following implementation of the screening program were identified by a questionnaire via the paediatric HIV centres. RESULTS: 162/481 (33.7%) HIV-positive pregnant women were diagnosed with HIV before 2004 and 172/214 (80.3%) after January 2004. Multivariate analysis showed an 8-fold (95% confidence interval 5.47-11.87) increase in the odds of HIV detection during pregnancy after the national introduction of the opt-out strategy. Still, three children born during a 5-year period after July 2004 were infected due to de novo infection in pregnancy. CONCLUSIONS: Implementation of a nation-wide screening strategy based upon non-selective opt-out screening followed by effective PMTCT appeared to detect more HIV-infected women for the first time in pregnancy and to reduce vertical transmission of HIV substantially. Nonetheless, still few children are infected because of maternal infection after the first trimester. We propose the introduction of partner screening on HIV as part of the antenatal screening strategy.

Mortality of HIV-infected patients starting potent antiretroviral therapy: comparison with the general population in nine industrialized countries.

BACKGROUND: Mortality in HIV-infected patients has declined substantially with combination antiretroviral therapy (ART), but it is unclear whether it has reached that of the general population. We compared mortality in patients starting ART in nine countries of Europe and North America with the corresponding general population, taking into account their response to ART. METHODS: Eligible patients were enrolled in prospective cohort studies participating in the ART Cohort Collaboration. We calculated the ratio of observed to expected deaths from all causes [standardized mortality ratio (SMR)], measuring time from 6 months after starting ART, according to risk group, clinical stage at the start of ART and CD4 cell count and viral load at 6 months. Expected numbers of deaths were obtained from age-, sex- and country-specific mortality rates. RESULTS: Among 29 935 eligible patients, 1134 deaths were recorded in 131 510 person-years of follow-up. The median age was 37 years, 8162 (27%) patients were females, 4400 (15%) were injecting drug users (IDUs) and 6738 (23%) had AIDS when starting ART. At 6 months, 23 539 patients (79%) had viral load measurements or=350 cells/microL and suppressed viral replication to 10 were 4, 14 and 47%. CONCLUSIONS: In industrialized countries, the mortality experience of HIV-infected patients who start ART and survive the first 6 months continues to be higher than in the general population, but for many patients excess mortality is moderate and comparable with patients having other chronic conditions. Much of the excess mortality might be prevented by earlier diagnosis of HIV followed by timely initiation of ART.

Comparison of the risks of atherosclerotic events versus death from other causes associated with antiretroviral use.

BACKGROUND: Studies considering the risk of atherosclerotic disease (AtD) associated with the use of HAART have reported inconsistent results. METHODS: Data on antiretroviral therapy (ART) use, risk factors for cardiovascular disease (CVD), AtD and death from other causes in 18 603 HIV-infected patients from two established cohorts were evaluated. The relative hazards of AtD and death from other causes were calculated using a proportional hazards competing risks framework. The impact of protease inhibitor (PI)-containing, non-nucleoside reverse transcriptase inhibitor (NNRTI)-containing or PI + NNRTI-containing regimens on these outcomes were compared to nucleoside reverse transcriptase inhibitor (NRTI)-only regimens or stopping therapy, adjusting for known CVD risk factors. RESULTS: In 77 480 person-years of follow-up (median duration 3.49 years) there were 318 AtD events including 92 myocardial infarctions and 2044 deaths. Older age, hypertension, diabetes mellitus, having smoked and HIV disease stage were significantly associated with increased risk of AtD. PI- and NNRTI-containing regimens significantly reduced the joint risk of either AtD or death from other causes compared to NRTI-only or stopping therapy [hazard ratio (HR) for PI-containing ART, 0.76, 95% confidence interval (CI), 0.73-0.78, P< 0.001; NNRTI-containing ART, 0.69, 95% CI, 0.65-0.74; P< 0.001). PI-containing ART was associated with a borderline significant increased risk of myocardial infarction (cause-specific HR for PI-containing ART 1.19, 95% CI, 1.01-1.40, P = 0.04) but not with increased risk of AtD compared to NRTI-only regimens or stopping therapy (cause-specific HR for PI-containing ART, 1.03, 95% CI, 0.95-1.13, P = 0.44). CONCLUSIONS: Overall benefits of PI- and NNRTI-based ART in reducing mortality significantly outweigh any risks of AtD in the "short-term" follow-up of this study. Traditional cardiac risk factors play an important role in determining AtD risk status.

Semi-parametric accelerated failure time regression analysis with application to interval-censored HIV/AIDS data.

This paper demonstrates a way to investigate a potentially non-linear relationship between an interval-censored response variable and a continuously distributed explanatory variable. A potentially non-linear effect of a continuous explanatory variable on the response is incorporated into an accelerated failure time model, forming a partial linear model. A sieve maximum likelihood estimator (MLE) is suggested to simultaneously estimate all the parameters. The sieve MLE is shown to be asymptotically efficient and normally distributed. Simulation studies show that the proposed estimators for the scale and regression parameters are robust and efficient, and the estimator for the non-linear function is able to capture the shape of a variety of smooth non-linear functions. The model is applied to observational HIV data, where the response variable is the time to suppression of HIV viral load after initiation of antiretroviral therapy, and baseline viral load is investigated as a potentially non-linear effect.