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The CIDRZ Research Repository serves as an open-access archive for peer-reviewed publications, conference papers, and other scholarly outputs from CIDRZ researchers. Our goal is to promote the dissemination of knowledge and support evidence-based public health initiatives.
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Item Acceptability and tolerability of long-acting injectable cabotegravir or rilpivirine in the first cohort of virologically suppressed adolescents living with HIV (IMPAACT 2017/MOCHA): a secondary analysis of a phase 1/2, multicentre, open-label, non-comparative dose-finding study.(2024-Apr) Lowenthal ED; Chapman J; Ohrenschall R; Calabrese K; Baltrusaitis K; Heckman B; Yin DE; Agwu AL; Harrington C; Van Solingen-Ristea RM; McCoig CC; Adeyeye A; Kneebone J; Chounta V; Smith-Anderson C; Camacho-Gonzalez A; D'Angelo J; Bearden A; Crauwels H; Huang J; Buisson S; Milligan R; Ward S; Bolton-Moore C; Gaur AH; Center for Biostatistics in AIDS Research, Harvard T.H. Chan School of Public Health, Boston, MA, USA.; National Institute of Allergy and Infectious Diseases (NIAID) Division of AIDS, National Institutes of Health (NIH), Rockville, MD, USA.; Janssen Research and Development, Beerse, Belgium.; ViiV Healthcare, Madrid, Spain.; The Children's Hospital of Philadelphia, Division of General Pediatrics and Global Health Center, Philadelphia, PA, USA.; Johns Hopkins University School of Medicine, Baltimore, MD, USA.; Emory University School of Medicine, Atlanta, GA, USA.; Northwestern University and Lurie Children's Hospital of Chicago, Chicago, IL, USA.; Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA.; St Jude Children's Research Hospital, Memphis, TN, USA.; ViiV Healthcare, Research Triangle Park, NC, USA.; Centre for Infectious Disease Research in Zambia/University of Alabama Birmingham, Lusaka, Zambia.; FHI 360 IMPAACT Operations Center, Durham, NC, USA.; Frontier Science Foundation, Amherst, NY, USA.; University of Colorado School of Medicine, Aurora, CO, USA.; The Children's Hospital of Philadelphia, Division of General Pediatrics and Global Health Center, Philadelphia, PA, USA; University of Pennsylvania Perelman School of Medicine, Departments of Pediatrics and Biostatistics, Epidemiology and Informatics, Philadelphia, PA, USA. Electronic address: lowenthale@chop.edu.; University of Pennsylvania School of Nursing, Philadelphia, PA, USA.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)BACKGROUND: Long-acting injectable cabotegravir and rilpivirine have demonstrated safety, acceptability, and efficacy in adults living with HIV-1. The IMPAACT 2017 study (MOCHA study) was the first to use these injectable formulations in adolescents (aged 12-17 years) living with HIV-1. Herein, we report acceptability and tolerability outcomes in cohort 1 of the study. METHODS: In this a secondary analysis of a phase 1/2, multicentre, open-label, non-comparative dose-finding study, with continuation of pre-study oral combination antiretroviral treatment (ART), 55 adolescents living with HIV-1 were enrolled to receive sequential doses of either long-acting cabotegravir or rilpivirine and 52 received at least two injections. Participants had a body weight greater than 35 kg and BMI less than 31·5 kg/m FINDINGS: Between March 19, 2019, and Nov 25, 2021, 55 participants were enrolled into cohort 1. Using the six-point face scale, 43 (83%) of participants at week 4 and 38 (73%) at week 8 reported that the injection caused "no hurt" or "hurts little bit", while only a single (2%) participant for each week rated the pain as one of the two highest pain levels. Quality of life was not diminished by the addition of one injectable antiretroviral. In-depth interviews revealed that parents and caregivers in the USA frequently had more hesitancy than adolescents about use of long-acting formulations, but parental acceptance was higher after their children received injections. INTERPRETATION: High acceptability and tolerability of long-acting cabotegravir or rilpivirine injections suggests that these are likely to be favoured treatment options for some adolescents living with HIV. FUNDING: National Institutes of Health and ViiV Healthcare.Item Trends in SARS-CoV-2 seroprevalence among pregnant women attending first antenatal care visits in Zambia: A repeated cross-sectional survey, 2021-2022.(2024) Heilmann E; Tembo T; Fwoloshi S; Kabamba B; Chilambe F; Kalenga K; Siwingwa M; Mulube C; Seffren V; Bolton-Moore C; Simwanza J; Yingst S; Yadav R; Rogier E; Auld AF; Agolory S; Kapina M; Gutman JR; Savory T; Kangale C; Mulenga LB; Sikazwe I; Hines JZ; Surveillance and Disease Intelligence, Zambia National Public Health Institute, Lusaka, Zambia.; Public Health Institute, Oakland, California, United States of America.; Adult Centre of Excellence, University Teaching Hospital, Lusaka, Zambia.; Division of Parasitic Diseases and Malaria, U.S. Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.; PATH, Lusaka, Zambia.; Division of Infectious Diseases, Ministry of Health, Lusaka, Zambia.; Division of Global HIV and Tuberculosis, U.S. Centers for Disease Control and Prevention, Lusaka, Zambia.; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)SARS-CoV-2 serosurveys help estimate the extent of transmission and guide the allocation of COVID-19 vaccines. We measured SARS-CoV-2 seroprevalence among women attending ANC clinics to assess exposure trends over time in Zambia. We conducted repeated cross-sectional SARS-CoV-2 seroprevalence surveys among pregnant women aged 15-49 years attending their first ANC visits in four districts of Zambia (two urban and two rural) during September 2021-September 2022. Serologic testing was done using a multiplex bead assay which detects IgG antibodies to the nucleocapsid protein and the spike protein receptor-binding domain (RBD). We calculated monthly SARS-CoV-2 seroprevalence by district. We also categorized seropositive results as infection alone, infection and vaccination, or vaccination alone based on anti-RBD and anti-nucleocapsid test results and self-reported COVID-19 vaccination status (vaccinated was having received ≥1 dose). Among 8,304 participants, 5,296 (63.8%) were cumulatively seropositive for SARS-CoV-2 antibodies from September 2021 through September 2022. SARS-CoV-2 seroprevalence primarily increased from September 2021 to September 2022 in three districts (Lusaka: 61.8-100.0%, Chongwe: 39.6-94.7%, Chipata: 56.5-95.0%), but in Chadiza, seroprevalence increased from 27.8% in September 2021 to 77.2% in April 2022 before gradually dropping to 56.6% in July 2022. Among 5,906 participants with a valid COVID-19 vaccination status, infection alone accounted for antibody responses in 77.7% (4,590) of participants. Most women attending ANC had evidence of prior SARS-CoV-2 infection and most SARS-CoV-2 seropositivity was infection-induced. Capturing COVID-19 vaccination status and using a multiplex bead assay with anti-nucleocapsid and anti-RBD targets facilitated distinguishing infection-induced versus vaccine-induced antibody responses during a period of increasing COVID-19 vaccine coverage in Zambia. Declining seroprevalence in Chadiza may indicate waning antibodies and a need for booster vaccines. ANC clinics have a potential role in ongoing SARS-CoV-2 serosurveillance and can continue to provide insights into SARS-CoV-2 antibody dynamics to inform near real-time public health responses.Item The Social Construction of Aging Among a Clinic-Based Population and Their Healthcare Workers in Zambia.(2024) Sharma A; Mwamba C; St Clair-Sullivan N; Chihota BV; Pry JM; Bolton-Moore C; Vinikoor MJ; Muula GK; Daultrey H; Gittelsohn J; Mulenga LB; Siyumbwa N; Wandeler G; Vera JH; Department of Medicine, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States.; Ministry of Health, Lusaka Zambia, Lusaka, Zambia.; Department of Preclinical Medicine, Faculty of Medicine, Institute for Social and Preventive Medicine, University of Bern, Bern, Switzerland.; Medical Faculty, Institute for Infectious Diseases, University of Bern, Bern, Switzerland.; Brighton and Sussex Medical School, Brighton, United Kingdom.; Center for Human Nutrition, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States.; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.; School of Medicine, University of California, Davis, Sacramento, CA, United States.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)OBJECTIVES: We sought to understand the social construction of aging in a clinic-based population, with and without HIV, to address gaps in care for older individuals living with HIV in Zambia. METHODS: Our exploratory qualitative study included 36 in-depth interviews with clinic clients and four focus group discussions with 36 professional and lay healthcare workers providing services to the clients. We identified themes based on social construction theory. RESULTS: At the individual level, aging was multidimensional, perceived both as an achievement in the HIV era and as a period of cognitive, physical, and economic decline. In social interactions, older individuals were often stereotyped and treated as helpless, poor, and "witches." Those living with HIV faced the additional stigma of being labeled as promiscuous. Some of the participants living without HIV refused to take daily medication for non-communicable diseases to avoid being mistaken for taking antiretroviral therapy for HIV. Older individuals wanted quality healthcare and family support to address the intersectional stigma of aging, poverty, and chronic illness. CONCLUSION: Multifaceted interventions are required to combat age-related prejudice, intersectional stigma, and discriminatory practices, particularly for people living with HIV.Item Programme science in action: lessons from an observational study of HIV prevention programming for key populations in Lusaka, Zambia.(2024-Jul) Sikazwe I; Musheke M; Chiyenu K; Ngosa B; Pry JM; Mulubwa C; Zimba M; Sakala M; Sakala M; Somwe P; Nyirenda G; Savory T; Bolton-Moore C; Herce ME; Department of Public Health Sciences, School of Medicine, University of California, Davis, California, USA.; Centre for Infectious Disease Research in Zambia (CIDRZ), Lusaka, Zambia.; Institute for Global Health and Infectious Diseases, University of North Carolina, Chapel Hill, North Carolina, USA.; Division of Infectious Diseases, Department of Medicine, University of Alabama, Birmingham, Alabama, USA.; Tithandizeni Umoyo Network, Lusaka, Zambia.; Intersex Society of Zambia, Lusaka, Zambia.; Zambia Sex Workers Alliance, Lusaka, Zambia.INTRODUCTION: Optimizing uptake of pre-exposure prophylaxis (PrEP) for individuals at risk of HIV acquisition has been challenging despite clear scientific evidence and normative guidelines, particularly for key populations (KPs) such as men who have sex with men (MSM), female sex workers (FSWs), transgender (TG) people and persons who inject drugs (PWID). Applying an iterative Programme Science cycle, building on the effective programme coverage framework, we describe the approach used by the Centre for Infectious Disease Research in Zambia (CIDRZ) to scale up PrEP delivery and address inequities in PrEP access for KP in Lusaka, Zambia. METHODS: In 2019, CIDRZ partnered with 10 local KP civil society organizations (CSOs) and the Ministry of Health (MOH) to offer HIV services within KP-designated community safe spaces. KP CSO partners led KP mobilization, managed safe spaces and delivered peer support; MOH organized clinicians and clinical commodities; and CIDRZ provided technical oversight. In December 2021, we introduced a community-based intervention focused on PrEP delivery in venues where KP socialize. We collected routine programme data from September 2019 to June 2023 using programme-specific tools and the national electronic health record. We estimated the before-after effects of our intervention on PrEP uptake, continuation and equity for KP using descriptive statistics and interrupted time series regression, and used mixed-effects regression to estimate marginal probabilities of PrEP continuity. RESULTS: Most (25,658) of the 38,307 (67.0%) Key Population Investment Fund beneficiaries were reached with HIV prevention services at community-based venues. In total, 23,527 (61.4%) received HIV testing services, with 15,508 (65.9%) testing HIV negative and found PrEP eligible, and 15,241 (98.3%) initiating PrEP. Across all programme quarters and KP types, PrEP uptake was >90%. After introducing venue-based PrEP delivery, PrEP uptake (98.7% after vs. 96.5% before, p < 0.001) and the number of initiations (p = 0.014) increased significantly. The proportion of KP with ≥1 PrEP continuation visit within 6 months of initiation was unchanged post-intervention (46.7%, 95% confidence interval [CI]: 45.7%, 47.6%) versus pre-intervention (47.2%, 95% CI: 45.4%, 49.1%). CONCLUSIONS: Applying Programme Science principles, we demonstrate how decentralizing HIV prevention services to KP venues and safe spaces in partnership with KP CSOs enabled successful community-based PrEP delivery beyond the reach of traditional facility-based services.Item Clinical outcomes and CD4 cell response in children receiving antiretroviral therapy at primary health care facilities in Zambia.(2007-Oct-24) Bolton-Moore C; Mubiana-Mbewe M; Cantrell RA; Chintu N; Stringer EM; Chi BH; Sinkala M; Kankasa C; Wilson CM; Wilfert CM; Mwango A; Levy J; Abrams EJ; Bulterys M; Stringer JS; Centre for Infectious Disease Research in Zambia, Lusaka.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)CONTEXT: The Zambian Ministry of Health provides pediatric antiretroviral therapy (ART) at primary care clinics in Lusaka, where, despite scale-up of perinatal prevention efforts, many children are already infected with the human immunodeficiency virus (HIV). OBJECTIVE: To report early clinical and immunologic outcomes of children enrolled in the pediatric treatment program. DESIGN, SETTING, AND PATIENTS: Open cohort assessment using routinely collected clinical and outcome data from an electronic medical record system in use at 18 government primary health facilities in Lusaka, Zambia. Care was provided primarily by nurses and clinical officers ("physician extenders" akin to physician assistants in the United States). Patients were children (<16 years of age) presenting for HIV care between May 1, 2004, and June 29, 2007. INTERVENTION: Three-drug ART (zidovudine or stavudine plus lamivudine plus nevirapine or efavirenz) for children who met national treatment criteria. MAIN OUTCOME MEASURES: Survival, weight gain, CD4 cell count, and hemoglobin response. RESULTS: After enrollment of 4975 children into HIV care, 2938 (59.1%) started ART. Of those initiating ART, the median age was 81 months (interquartile range, 36-125), 1531 (52.1%) were female, and 2087 (72.4%) with World Health Organization stage information were in stage III or IV. At the time of analysis, 158 children (5.4%) had withdrawn from care and 382 (13.0%) were at least 30 days late for follow-up. Of the remaining 2398 children receiving ART, 198 (8.3%) died over 3018 child-years of follow-up (mortality rate, 6.6 deaths per 100 child-years; 95% confidence interval [CI], 5.7-7.5); of these deaths, 112 (56.6%) occurred within 90 days of therapy initiation (early mortality rate, 17.4/100 child-years; post-90-day mortality rate, 2.9/100 child-years). Mortality was associated with CD4 cell depletion, lower weight-for-age, younger age, and anemia in multivariate analysis. The mean CD4 cell percentage at ART initiation among the 1561 children who had at least 1 repeat measurement was 12.9% (95% CI, 12.5%-13.3%) and increased to 23.7% (95% CI, 23.1%-24.3%) at 6 months, 27.0% (95% CI, 26.3%-27.6%) at 12 months, 28.0% (95% CI, 27.2%-28.8%) at 18 months, and 28.4% (95% CI, 27.4%-29.4%) at 24 months. CONCLUSIONS: Care provided by clinicians such as nurses and clinical officers can result in good outcomes for HIV-infected children in primary health care settings in sub-Saharan Africa. Mortality during the first 90 days of therapy is high, pointing to a need for earlier intervention.Item Causes of morbidity among HIV-infected children on antiretroviral therapy in primary care facilities in Lusaka, Zambia.(2009-Oct) Mubiana-Mbewe M; Bolton-Moore C; Banda Y; Chintu N; Nalubamba-Phiri M; Giganti M; Guffey MB; Sambo P; Stringer EM; Stringer JS; Chi BH; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)OBJECTIVES: To describe the pattern of incident illness in children after initiation of antiretroviral therapy (ART) in a large public health sector programme in Lusaka, Zambia. METHODS: Systematic chart review to retrospectively extract data from medical records of children (i.e. <15 years) initiating ART in the Lusaka, Zambia public sector. Incident conditions were listed separately and then grouped according to broad categories. Predictors for incident diagnoses were determined using univariate and multivariable analysis. RESULTS: Between May 2004 and June 2006, 1705 HIV-infected children initiated ART. Of these, 1235 (72%) had their medical records reviewed. Median age at ART initiation was 77 months and 554 (45%) were females. Eight hundred and forty-one (68%) children had an incident condition during this period, with a median time of occurrence of 64 days from ART initiation. Twenty-eight incident conditions were documented. When categorized, the most common were mucocutaneous conditions [incidence rate (IR): 70.6 per 100 child-years, 95% CI: 64.5-77.2] and upper respiratory tract infection (IR: 70.1 per 100 child-years; 95% CI: 64.0-76.7). Children with severe immunosuppression (i.e. CD4 < 10%) were more likely to develop lower respiratory tract infection (16.3%vs. 10.2%; P = 0.003) and mucocutaneous conditions (43.9% vs. 35.3%; P = 0.005) than those with CD4 > or = 10%. CONCLUSION: There is a high incidence of new illness after ART initiation, emphasizing the importance of close monitoring during this period. Early initiation of ART and use of antimicrobial prophylaxis may also help to reduce the occurrence of such co-morbidities.Item Early clinical and programmatic outcomes with tenofovir-based antiretroviral therapy in Zambia.(2010-May-01) Chi BH; Mwango A; Giganti M; Mulenga LB; Tambatamba-Chapula B; Reid SE; Bolton-Moore C; Chintu N; Mulenga PL; Stringer EM; Sheneberger R; Mwaba P; Stringer JS; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia. bchi@uab.edu; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)BACKGROUND: In July 2007, amid some controversy over cost, Zambia was the first African country to introduce tenofovir (TDF) as a component of first-line antiretroviral therapy (ART) on a wide scale. METHODS: We compared drug substitutions, mortality, and "programmatic failure" among adults starting TDF-, zidovudine (ZDV)-, and stavudine (d4T)-containing ART. Programmatic failure was defined as death, withdrawal, or loss to follow-up. RESULTS: Between July 2007 and January 2009, 10,485 adults initiated ART (66% on TDF, 23% on ZDV, 11% on d4T), with a median follow-up time of 239 (interquartile range 98, 385) days. Those starting TDF were more likely to be male and more likely to have indicators of severe disease at baseline. In adjusted Cox proportional hazards models, ZDV- (adjusted hazard ratio [AHR] = 2.74, 95% confidence interval [CI] = 2.30-3.28) and d4T-based regimens (AHR = 1.92, 95% CI = 1.55-2.38) were associated with higher risk for drug substitution when compared with TDF-based regimens. Similar hazards were noted for overall mortality (ZDV: AHR = 0 .81, 95% CI = 0.62-1.06; d4T: AHR = 1.03, 95% CI = 0.74-1.43) and programmatic failure (ZDV: AHR = 0.99, 95% CI = 0.88-1.11; d4T: AHR = 1.11, 95% CI = 0.96-1.28) when compared with TDF. CONCLUSIONS: TDF is associated with similar clinical and programmatic outcomes as ZDV and d4T but appears to be better tolerated. Although further evaluation is needed, these results are encouraging and support Zambia's policy decision.Item Causes of stillbirth, neonatal death and early childhood death in rural Zambia by verbal autopsy assessments.(2011-Jul) Turnbull E; Lembalemba MK; Guffey MB; Bolton-Moore C; Mubiana-Mbewe M; Chintu N; Giganti MJ; Nalubamba-Phiri M; Stringer EM; Stringer JS; Chi BH; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)OBJECTIVES: To describe specific causes of the high rates of stillbirth, neonatal death and early child childhood death in Zambia. METHODS: We conducted a household-based survey in rural Zambia. Socio-demographic and delivery characteristics were recorded, alongside a maternal HIV test. Verbal autopsy questionnaires were administered to elicit mortality-related information and independently reviewed by three experienced paediatricians who assigned a cause and contributing factor to death. For this secondary analysis, deaths were categorized into: stillbirths (foetal death ≥28 weeks of gestation), neonatal deaths (≤28 days) and early childhood deaths (>28 days to <2 years). RESULTS: Among 1679 households, information was collected on 148 deaths: 34% stillbirths, 26% neonatal and 40% early childhood deaths. Leading identifiable causes of stillbirth were intrauterine infection (26%) and birth asphyxia (18%). Of 32 neonatal deaths, 38 (84%) occurred within the first week of life, primarily because of infections (37%) and prematurity (34%). The majority of early childhood deaths were caused by suspected bacterial infections (82%). HIV prevalence was significantly higher in mothers who reported an early childhood death (44%) than mothers who did not (17%; P < 0.01). Factors significantly associated with mortality were lower socio-economic status (P < 0.01), inadequate water or sanitation facilities (P < 0.01), home delivery (P = 0.04) and absence of a trained delivery attendant (P < 0.01). CONCLUSION: We provide community-level data about the causes of death among children under 2 years of age. Infectious etiologies for mortality ranked highest. At a public health level, such information may have an important role in guiding prevention and treatment strategies to address perinatal and early childhood mortality.Item Opt-out provider-initiated HIV testing and counselling in primary care outpatient clinics in Zambia.(2011-May-01) Topp SM; Chipukuma JM; Chiko MM; Wamulume CS; Bolton-Moore C; Reid SE; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia. stephanie.topp@cidrz.org; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)OBJECTIVE: To increase case-finding of infection with human immunodeficiency virus (HIV) in Zambia and their referral to HIV care and treatment by supplementing existing client-initiated voluntary counselling and testing (VCT), the dominant mode of HIV testing in the country. METHODS: Lay counsellors offered provider-initiated HIV testing and counselling (PITC) to all outpatients who attended primary clinics and did not know their HIV serostatus. Data on counselling and testing were collected in registers. Outcomes of interest included HIV testing coverage, the acceptability of testing, the proportion testing HIV-positive (HIV+), the proportion enrolling in HIV care and treatment and the time between testing and enrolment. FINDINGS: After the addition of PITC to VCT, the number tested for HIV infection in the nine clinics was twice the number undergoing VCT alone. Over 30 months, 44,420 patients were counselled under PITC and 31,197 patients, 44% of them men, accepted testing. Of those tested, 21% (6572) were HIV+; 38% of these HIV+ patients (2515) enrolled in HIV care and treatment. The median time between testing and enrolment was 6 days. The acceptability of testing rose over time. CONCLUSION: The introduction of routine PITC using lay counsellors into health-care clinics in Lusaka, Zambia, dramatically increased the uptake and acceptability of HIV testing. Moreover, PITC was incorporated rapidly into primary care outpatient departments. Maximizing the number of patients who proceed to HIV care and treatment remains a challenge and warrants further research.Item Comparative outcomes of tenofovir-based and zidovudine-based antiretroviral therapy regimens in Lusaka, Zambia.(2011-Dec-15) Chi BH; Mwango A; Giganti MJ; Sikazwe I; Moyo C; Schuttner L; Mulenga LB; Bolton-Moore C; Chintu NT; Sheneberger R; Stringer EM; Stringer JS; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia. bchi@uab.edu; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)BACKGROUND: Although tenofovir (TDF) is a common component of antiretroviral therapy (ART), recent evidence suggests inferior outcomes when it is combined with nevirapine (NVP). METHODS: We compared outcomes among patients initiating TDF + emtricitabine or lamivudine (XTC) + NVP, TDF + XTC + efavirenz (EFV), zidovudine (ZDV) + lamuvidine (3TC) + NVP, and ZDV + 3TC + EFV. We categorized drug exposure by initial ART dispensation by a time-varying analysis that accounted for drug substitutions and by predominant exposure (>75% of drug dispensations) during an initial window period. Risks for death and program failure were estimated using Cox proportional hazard models. All regimens were compared with ZDV + 3TC + NVP. RESULTS: Between July 2007 and November 2010, 18,866 treatment-naive adults initiated ART: 18.2% on ZDV + 3TC + NVP, 1.8% on ZDV + 3TC + EFV, 36.2% on TDF + XTC + NVP, and 43.8% on TDF + XTC + EFV. When exposure was categorized by initial prescription, patients on TDF + XTC + NVP [adjusted hazard ratio (AHR): 1.45; 95% confidence interval (CI): 1.03 to 2.06] had a higher post-90-day mortality. TDF + XTC + NVP was also associated with an elevated risk for mortality when exposure was categorized as time-varying (AHR: 1.51; 95% CI: 1.18 to 1.95) or by predominant exposure over the first 90 days (AHR: 1.91, 95% CI: 1.09 to 3.34). However, these findings were not consistently observed across sensitivity analyses or when program failure was used as a secondary outcome. CONCLUSION: TDF + XTC + NVP was associated with higher mortality when compared with ZDV + 3TC + NVP but not consistently across sensitivity analyses. These findings may be explained in part by inherent limitations to our retrospective approach, including residual confounding. Further research is urgently needed to compare the effectiveness of ART regimens in use in resource-constrained settings.