SUNScholar - Browsing by Author "Egger, Matthias"

Browsing by Author "Egger, Matthias"

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Gender differences in survival among adult patients starting antiretroviral therapy in South Africa : a multicentre cohort study
(Public Library of Science, 2012-09-04) Cornell, Morna; Schomaker, Michael; Garone, Daniela Belen; Giddy, Janet; Hoffmann, Christopher J.; Lessells, Richard; Maskew, Mhairi; Prozesky, Hans; Wood, Robin; Johnson, Leigh F.; Egger, Matthias; Boulle, Andrew; Myer, Landon
Background: Increased mortality among men on antiretroviral therapy (ART) has been documented but remains poorly understood. We examined the magnitude of and risk factors for gender differences in mortality on ART. Methods and Findings: Analyses included 46,201 ART-naïve adults starting ART between January 2002 and December 2009 in eight ART programmes across South Africa (SA). Patients were followed from initiation of ART to outcome or analysis closure. The primary outcome was mortality; secondary outcomes were loss to follow-up (LTF), virologic suppression, and CD4+ cell count responses. Survival analyses were used to examine the hazard of death on ART by gender. Sensitivity analyses were limited to patients who were virologically suppressed and patients whose CD4+ cell count reached >200 cells/μl. We compared gender differences in mortality among HIV+ patients on ART with mortality in an age-standardised HIV-negative population. Among 46,201 adults (65% female, median age 35 years), during 77,578 person-years of follow-up, men had lower median CD4+ cell counts than women (85 versus 110 cells/μl, p <0.001), were more likely to be classified WHO stage III/IV (86 versus 77%, p <0.001), and had higher mortality in crude (8.5 versus 5.7 deaths/100 person-years, p < 0.001) and adjusted analyses (adjusted hazard ratio [AHR] 1.31, 95% CI 1.22–1.41). After 36 months on ART, men were more likely than women to be truly LTF (AHR 1.20, 95% CI 1.12–1.28) but not to die after LTF (AHR 1.04, 95% CI 0.86–1.25). Findings were consistent across all eight programmes. Virologic suppression was similar by gender; women had slightly better immunologic responses than men. Notably, the observed gender differences in mortality on ART were smaller than gender differences in age-standardised death rates in the HIV-negative South African population. Over time, non-HIV mortality appeared to account for an increasing proportion of observed mortality. The analysis was limited by missing data on baseline HIV disease characteristics, and we did not observe directly mortality in HIV-negative populations where the participating cohorts were located. Conclusions: HIV-infected men have higher mortality on ART than women in South African programmes, but these differences are only partly explained by more advanced HIV disease at the time of ART initiation, differential LTF and subsequent mortality, and differences in responses to treatment. The observed differences in mortality on ART may be best explained by background differences in mortality between men and women in the South African population unrelated to the HIV/AIDS epidemic.
Global temporal changes in the proportion of children with advanced disease at the start of combination antiretroviral therapy in an era of changing criteria for treatment initiation
(Wiley Open Access, 2018) Panayidou, Klea; Davies, Mary-Ann; Anderegg, Nanina; Egger, Matthias; The IeDEA; COHERE; PHACS; IMPAACT 219C Collaborations Writing Group
Introduction: The CD4 cell count and percent at initiation of combination antiretroviral therapy (cART) are measures of advanced HIV disease and thus are important indicators of programme performance for children living with HIV. In particular, World Health Organization (WHO) 2017 guidelines on advanced HIV disease noted that >80% of children aged <5 years started cART with WHO Stage 3 or 4 disease or severe immune suppression. We compared temporal trends in CD4 measures at cART start in children from low-, middle- and high-income countries, and examined the effect of WHO treatment initiation guidelines on reducing the proportion of children initiating cART with advanced disease. Methods: We included children aged <16 years from the International Epidemiology Databases to Evaluate acquired immunodeficiency syndrome (AIDS) (IeDEA) Collaboration (Caribbean, Central and South America, Asia-Pacific, and West, Central, East and Southern Africa), the Collaboration of Observational HIV Epidemiological Research in Europe (COHERE), the North American Pediatric HIV/AIDS Cohort Study (PHACS) and International Maternal Pediatric Adolescent AIDS Clinical Trials (IMPAACT) 219C study. Severe immunodeficiency was defined using WHO guidelines. We used generalized weighted additive mixed effect models to analyse temporal trends in CD4 measurements and piecewise regression to examine the impact of 2006 and 2010 WHO cART initiation guidelines. Results: We included 52,153 children from fourteen low-, eight lower middle-, five upper middle- and five high-income countries. From 2004 to 2013, the estimated percentage of children starting cART with severe immunodeficiency declined from 70% to 42% (low-income), 67% to 64% (lower middle-income) and 61% to 43% (upper middle-income countries). In highincome countries, severe immunodeficiency at cART initiation declined from 45% (1996) to 14% (2012). There were annual decreases in the percentage of children with severe immunodeficiency at cART initiation after the WHO guidelines revisions in 2006 (low-, lower middle- and upper middle-income countries) and 2010 (all countries). Conclusions: By 2013, less than half of children initiating cART had severe immunodeficiency worldwide. WHO treatment initiation guidelines have contributed to reducing the proportion of children and adolescents starting cART with advanced disease. However, considerable global inequity remains, in 2013, >40% of children in low- and middle-income countries started cART with severe immunodeficiency compared to <20% in high-income countries.
HIV viral load as an independent risk factor for tuberculosis in South Africa : collaborative analysis of cohort studies
(Wiley Open Access, 2017) Fenner, Lukas; Atkinson, Andrew; Boulle, Andrew; Fox, Matthew P.; Prozesky, Hans; Zurcher, Kathrin; Ballif, Marie; Furrer, Hansjakob; Zwahlen, Marcel; Davies, Mary-Ann; Egger, Matthias
Introduction: Chronic immune activation due to ongoing HIV replication may lead to impaired immune responses against opportunistic infections such as tuberculosis (TB). We studied the role of HIV replication as a risk factor for incident TB after starting antiretroviral therapy (ART). Methods: We included all HIV-positive adult patients ( 16 years) in care between 2000 and 2014 at three ART programmes in South Africa. Patients with previous TB were excluded. Missing CD4 cell counts and HIV-RNA viral loads at ART start (baseline) and during follow-up were imputed. We used parametric survival models to assess TB incidence (pulmonary and extrapulmonary) by CD4 cell and HIV-RNA levels, and estimated the rate ratios for TB by including age, sex, baseline viral loads, CD4 cell counts, and WHO clinical stage in the model. We also used Poisson general additive regression models with time-updated CD4 and HIV-RNA values, adjusting for age and sex. Results: We included 44,260 patients with a median follow-up time of 2.7 years (interquartile range [IQR] 1.0–5.0); 3,819 incident TB cases were recorded (8.6%). At baseline, the median age was 34 years (IQR 28–41); 30,675 patients (69.3%) were female. The median CD4 cell count was 156 cells/μL (IQR 79–229) and the median HIV-RNA viral load 58,000 copies/mL (IQR 6,000–240,000). Overall TB incidence was 26.2/1,000 person-years (95% confidence interval [CI] 25.3–27.0). Compared to the lowest viral load category (0–999 copies/mL), the adjusted rate ratio for TB was 1.41 (95% CI 1.15–1.75, p < 0.001) in the highest group (>10,000 copies/mL). Time-updated analyses for CD4/HIV-RNA confirmed the association of viral load with the risk for TB. Conclusions: Our results indicate that ongoing HIV replication is an important risk factor for TB, regardless of CD4 cell counts, and underline the importance of early ART start and retention on ART.
Incidence of Kaposi Sarcoma in HIV-infected patients - a prospective multi-cohort study from Southern Africa
(BioMed Central, 2012-04) Bohlius, Julia; Valeri, Fabio; Maskew, Mhairi; Prozesky, Hans; Chimbetete, Cleophas; Lumano-Mulenga, Priscilla; Garone, Daniela; Gsponer, Thomas; Egger, Matthias
Background: The incidence of Kaposi Sarcoma (KS) is high in sub-Saharan Africa. Data on KS among HIV-infected patients receiving and not yet receiving antiretroviral therapy (ART) are, however, scarce in Africa. Within the framework of a large multi-cohort project, the International epidemiologic Database to Evaluate AIDS (IeDEA), we estimate the incidence and risk factors for the development of KS in HIV-infected patients in Southern Africa.
Life expectancies of South African adults starting antiretroviral treatment : collaborative analysis of cohort studies
(Public Library of Science, 2013-04-09) Johnson, Leigh F.; Mossong, Joel; Dorrington, Rob E.; Schomaker, Michael; Hoffmann, Christopher J.; Keiser, Olivia; Fox, Matthew P.; Wood, Robin; Prozesky, Hans; Giddy, Janet; Belen Garone, Daniela; Cornell, Morna; Egger, Matthias; Boulle, Andrew
Background Few estimates exist of the life expectancy of HIV-positive adults receiving antiretroviral treatment (ART) in low- and middle-income countries. We aimed to estimate the life expectancy of patients starting ART in South Africa and compare it with that of HIV-negative adults. Methods and Findings Data were collected from six South African ART cohorts. Analysis was restricted to 37,740 HIV-positive adults starting ART for the first time. Estimates of mortality were obtained by linking patient records to the national population register. Relative survival models were used to estimate the excess mortality attributable to HIV by age, for different baseline CD4 categories and different durations. Non-HIV mortality was estimated using a South African demographic model. The average life expectancy of men starting ART varied between 27.6 y (95% CI: 25.2–30.2) at age 20 y and 10.1 y (95% CI: 9.3–10.8) at age 60 y, while estimates for women at the same ages were substantially higher, at 36.8 y (95% CI: 34.0–39.7) and 14.4 y (95% CI: 13.3–15.3), respectively. The life expectancy of a 20-y-old woman was 43.1 y (95% CI: 40.1–46.0) if her baseline CD4 count was ≥200 cells/µl, compared to 29.5 y (95% CI: 26.2–33.0) if her baseline CD4 count was <50 cells/µl. Life expectancies of patients with baseline CD4 counts ≥200 cells/µl were between 70% and 86% of those in HIV-negative adults of the same age and sex, and life expectancies were increased by 15%–20% in patients who had survived 2 y after starting ART. However, the analysis was limited by a lack of mortality data at longer durations. Conclusions South African HIV-positive adults can have a near-normal life expectancy, provided that they start ART before their CD4 count drops below 200 cells/µl. These findings demonstrate that the near-normal life expectancies of HIV-positive individuals receiving ART in high-income countries can apply to low- and middle-income countries as well.
Outcomes of the South African national antiretroviral treatment programme for children : the IeDEA southern Africa collaboration
(Health and Medical Publishing Group (HMPG), 2009-10) Davies, Mary-Ann; Keiser, Olivia; Technau, Karl; Eley, Brian; Rabie, Helena; Van Cutsem, Gilles; Giddy, Janet; Wood, Robin; Boulle, Andrew; Egger, Matthias; Moultrie, Harry
Objectives. To assess paediatric antiretroviral treatment (ART) outcomes and their associations from a collaborative cohort representing 20% of the South African national treatment programme. Design and setting. Multi-cohort study of 7 public sector paediatric ART programmes in Gauteng, Western Cape and. KwaZulu-Natal provinces. Subjects. ART-naïve children (?16 years) who commenced treatment with ≥3 antiretroviral drugs before March 2008. Outcome measures. Time to death or loss to follow-up were assessed using the Kaplan-Meier method. Associations between baseline characteristics and mortality were assessed with Cox proportional hazards models stratified by site. Immune status, virological suppression and growth were described in relation to duration of ART. Results. The median (interquartile range) age of 6 078 children with 9 368 child-years of follow-up was 43 (15 - 83) months, with 29% being <18 months. Most were severely ill at ART initiation. More than 75% of children were appropriately monitored at 6-monthly intervals with viral load suppression (<400 copies/ml) being 80% or above throughout 36 months of treatment. Mortality and retention in care at 3 years were 7.7% (95% confidence interval 7.0 - 8.6%) and 81.4% (80.1-82.6%), respectively. Together with young age, all markers of disease severity (low weight-for-age z-score, high viral load, severe immune suppression, stage 3/4 disease and anaemia) were independently associated with mortality. Conclusions. Dramatic clinical benefit for children accessing the national ART programme is demonstrated. Higher mortality in infants and those with advanced disease highlights the need for early diagnosis of HIV infection and commencement of ART.
Regression discontinuity analysis demonstrated varied effect of Treat-All on CD4 testing among Southern African countries
(Pergamon Press, 2021-12) Zaniewski, Elizabeth; Brazier, Ellen; Ostinelli, Cam Ha Dao; Wood, Robin; Osler, Meg; Technau, Karl-Günter; Van Oosterhout, Joep J; Maxwell, Nicola; Van Dijk, Janneke; Prozesky, Hans; Fox, Matthew P; Bor, Jacob; Nash, Denis; Egger, Matthias
Objective: To determine whether Treat-All policy impacted laboratory testing practices of antiretroviral therapy (ART) programs in Southern Africa. Study Design and Setting: We used HIV cohort data from Lesotho, Malawi, Mozambique, South Africa, Zambia and Zimbabwe in a regression discontinuity design to estimate changes in pre-ART CD4 testing and viral load monitoring following national Treat-all adoption that occurred during 2016–2017. This study included more than 230,000 ART-naïve people living with HIV (PLHIV) aged five years or older who started ART within two years of national Treat-All adoption. Results: We found pre-ART CD4 testing decreased following adoption of Treat-All recommendations in Malawi (−21.4 percentage points (pp), 95% CI: −26.8, −16.0) and in Mozambique (−8.8pp, 95% CI: −14.9, −2.8), but increased in Zambia (+2.7pp, 95% CI: +0.4, +5.1). Treat-All policy had no effect on viral load monitoring, except among females in South Africa (+7.1pp, 95% CI: +1.1, +13.0). Conclusion: Treat-All policy expanded ART eligibility, but led to reductions in pre-ART CD4 testing in some countries that may weaken advanced HIV disease management. Continued and expanded support of CD4 and viral load laboratory capacity is needed to further improve treatment successes and allow for uniform evaluation of ART implementation across Southern Africa.
Seasonal variations in tuberculosis diagnosis among HIV-positive individuals in Southern Africa : analysis of cohort studies at antiretroviral treatment programmes
(BMJ Publishing Group, 2018-01) Ballif, Marie; Zurcher, Kathrin; Reid, Stewart E.; Boulle, Andrew; Fox, Matthew P.; Prozesky, Hans W.; Chimbetete, Cleophas; Zwahlen, Marcel; Egger, Matthias; Fenner, Lukas
Objectives Seasonal variations in tuberculosis diagnoses have been attributed to seasonal climatic changes and indoor crowding during colder winter months. We investigated trends in pulmonary tuberculosis (PTB) diagnosis at antiretroviral therapy (ART) programmes in Southern Africa. Setting Five ART programmes participating in the International Epidemiology Database to Evaluate AIDS in South Africa, Zambia and Zimbabwe. Participants We analysed data of 331 634 HIV-positive adults (>15 years), who initiated ART between January 2004 and December 2014. Primary outcome measure We calculated aggregated averages in monthly counts of PTB diagnoses and ART initiations. To account for time trends, we compared deviations of monthly event counts to yearly averages, and calculated correlation coefficients. We used multivariable regressions to assess associations between deviations of monthly ART initiation and PTB diagnosis counts from yearly averages, adjusted for monthly air temperatures and geographical latitude. As controls, we used Kaposi sarcoma and extrapulmonary tuberculosis (EPTB) diagnoses. Results All programmes showed monthly variations in PTB diagnoses that paralleled fluctuations in ART initiations, with recurrent patterns across 2004–2014. The strongest drops in PTB diagnoses occurred in December, followed by April–May in Zimbabwe and South Africa. This corresponded to holiday seasons, when clinical activities are reduced. We observed little monthly variation in ART initiations and PTB diagnoses in Zambia. Correlation coefficients supported parallel trends in ART initiations and PTB diagnoses (correlation coefficient: 0.28, 95% CI 0.21 to 0.35, P<0.001). Monthly temperatures and latitude did not substantially change regression coefficients between ART initiations and PTB diagnoses. Trends in Kaposi sarcoma and EPTB diagnoses similarly followed changes in ART initiations throughout the year. Conclusions Monthly variations in PTB diagnosis at ART programmes in Southern Africa likely occurred regardless of seasonal variations in temperatures or latitude and reflected fluctuations in clinical activities and changes in health-seeking behaviour throughout the year, rather than climatic factors.
Twelve-year mortality in adults initiating antiretroviral therapy in South Africa
(Wiley Open Access, 2018) Cornell, Morna; Johnson, Leigh F.; Wood, Robin; Tanser, Frank; Fox, Matthew P.; Prozesky, Hans; Schomaker, Michael; Egger, Matthias; Davies, Mary-Ann; Boulle, Andrew
Introduction: South Africa has the largest number of individuals living with HIV and the largest antiretroviral therapy (ART) programme worldwide. In September 2016, ART eligibility was extended to all 7.1 million HIV-positive South Africans. To ensure that further expansion of services does not compromise quality of care, long-term outcomes must be monitored. Few studies have reported long-term mortality in resource-constrained settings, where mortality ascertainment is challenging. Combining site records with data linked to the national vital registration system, sites in the International Epidemiology Databases to Evaluate AIDS Southern Africa collaboration can identify >95% of deaths in patients with civil identification numbers (IDs). This study used linked data to explore long-term mortality and viral suppression among adults starting ART in South Africa. Methods: The study was a cohort analysis of routine data on adults with IDs starting ART 2004–2015 in five large ART cohorts. Mortality was estimated overall and by gender using the Kaplan-Meier estimator and Cox’s proportional hazards regression. Standardized mortality ratios (SMRs) were calculated by dividing observed numbers of deaths by numbers expected if patients had been HIV-negative. Viral suppression in patients with viral loads (VLs) in their last year of followup was the secondary outcome. Results: Among 72,812 adults followed for 350,376 person years (pyrs), the crude mortality rate was 3.08 (95% CI 3.02– 3.14)/100 pyrs. Patients were predominantly female (67%) and the percentage of men initiating ART did not increase. Cumulative mortality 12 years after ART initiation was 23.9% (33.4% male and 19.4% female). Mortality peaked in patients enrolling in 2007–2009 and was higher in men than women at all durations. Observed mortality rates were higher than HIVnegative mortality, decreasing with duration. By 48 months, observed mortality was close to that in the HIV-negative population, and SMRs were similar for all baseline CD4 strata. Three-quarters of patients had VLs in their last year, and 86% of these were virally suppressed. Conclusions: The South African ART programme has shown a remarkable ability to initiate and manage patients successfully over 12 years, despite rapid expansion. With further scale-up, testing and initiating men on ART must be a national priority.
When to start antiretroviral therapy in children aged 2-5 years : a collaborative causal modelling analysis of cohort studies from Southern Africa
(PLoS, 2013-11-19) Schomaker, Michael; Egger, Matthias; Ndirangu, James; Moultrie, Harri; Technau, Karl; Cox, Vivian; Giddy, Janet; Phiri, Sam; Chimbetete, Cleophas; Wood, Robin; Gsponer, Thomas; Moore, Carolyn Bolton; Rabie, Helena; Eley, Brian; Muhe, Lulu; Penazzato, Martina; Essajee, Shaffiq; Keiser, Olivia; Davies, Mary-Ann
Background There is limited evidence on the optimal timing of antiretroviral therapy (ART) initiation in children 2–5 y of age. We conducted a causal modelling analysis using the International Epidemiologic Databases to Evaluate AIDS–Southern Africa (IeDEA-SA) collaborative dataset to determine the difference in mortality when starting ART in children aged 2–5 y immediately (irrespective of CD4 criteria), as recommended in the World Health Organization (WHO) 2013 guidelines, compared to deferring to lower CD4 thresholds, for example, the WHO 2010 recommended threshold of CD4 count <750 cells/mm3 or CD4 percentage (CD4%) <25%. Methods and Findings ART-naïve children enrolling in HIV care at IeDEA-SA sites who were between 24 and 59 mo of age at first visit and with ≥1 visit prior to ART initiation and ≥1 follow-up visit were included. We estimated mortality for ART initiation at different CD4 thresholds for up to 3 y using g-computation, adjusting for measured time-dependent confounding of CD4 percent, CD4 count, and weight-for-age z-score. Confidence intervals were constructed using bootstrapping. The median (first; third quartile) age at first visit of 2,934 children (51% male) included in the analysis was 3.3 y (2.6; 4.1), with a median (first; third quartile) CD4 count of 592 cells/mm3 (356; 895) and median (first; third quartile) CD4% of 16% (10%; 23%). The estimated cumulative mortality after 3 y for ART initiation at different CD4 thresholds ranged from 3.4% (95% CI: 2.1–6.5) (no ART) to 2.1% (95% CI: 1.3%–3.5%) (ART irrespective of CD4 value). Estimated mortality was overall higher when initiating ART at lower CD4 values or not at all. There was no mortality difference between starting ART immediately, irrespective of CD4 value, and ART initiation at the WHO 2010 recommended threshold of CD4 count <750 cells/mm3 or CD4% <25%, with mortality estimates of 2.1% (95% CI: 1.3%–3.5%) and 2.2% (95% CI: 1.4%–3.5%) after 3 y, respectively. The analysis was limited by loss to follow-up and the unavailability of WHO staging data. Conclusions The results indicate no mortality difference for up to 3 y between ART initiation irrespective of CD4 value and ART initiation at a threshold of CD4 count <750 cells/mm3 or CD4% <25%, but there are overall higher point estimates for mortality when ART is initiated at lower CD4 values.

Browsing by Author "Egger, Matthias"

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