CIDRZ Research
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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 Association between weight gain and clinical outcomes among malnourished adults initiating antiretroviral therapy in Lusaka, Zambia.(2010-Apr-01) Koethe JR; Lukusa A; Giganti MJ; Chi BH; Nyirenda CK; Limbada MI; Banda Y; Stringer JS; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia. john.r.koethe@vanderbilt.edu; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)OBJECTIVE: To describe the association between 6-month weight gain on antiretroviral therapy (ART) and subsequent clinical outcomes. DESIGN: A retrospective analysis of a large programmatic cohort in Lusaka, Zambia. METHODS: Using Kaplan-Meier analysis and Cox proportional hazards models, we examined the association between 6-month weight gain and the risk of subsequent death and clinical treatment failure. Because it is a known effect modifier, we stratified our analysis according to body mass index (BMI). RESULTS: Twenty-seven thousand nine hundred fifteen adults initiating ART were included in the analysis. Patients in the lower BMI categories demonstrated greater weight gain. In the post 6-month analysis, absolute weight loss was strongly associated with mortality across all BMI strata, with the highest risk observed among those with BMI <16 kg/m (adjusted hazard ratio 9.7; 95% CI: 4.7 to 20.0). There seemed to be an inverse relationship between weight gain and mortality among patients with BMI <16 kg/m. Similar trends were observed with clinical treatment failure. CONCLUSIONS: Weight gain after ART initiation is associated with improved survival and decreased risk for clinical failure, especially in the lower BMI strata. Prospective trials to promote weight gain after ART initiation among malnourished patients in resource-constrained settings are warranted.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 Implementation of cervical cancer prevention services for HIV-infected women in Zambia: measuring program effectiveness.(2010) Parham GP; Mwanahamuntu MH; Sahasrabuddhe VV; Westfall AO; King KE; Chibwesha C; Pfaendler KS; Mkumba G; Mudenda V; Kapambwe S; Vermund SH; Hicks ML; Stringer JS; Chi BH; University of Cincinnati, OH, USA.; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia ; University Teaching Hospital, Lusaka, Zambia.; University of Alabama at Birmingham, AL, USA ; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia ; University Teaching Hospital, Lusaka, Zambia.; Vanderbilt University, TN, USA.; Michigan Cancer Institute, MI, USA.; University of Michigan, MI, USA.; University Teaching Hospital, Lusaka, Zambia.; University of Alabama at Birmingham, AL, USA ; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.; Vanderbilt University, TN, USA ; National Cancer Institute, MD, USA.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)BACKGROUND: Cervical cancer kills more women in low-income nations than any other malignancy. A variety of research and demonstration efforts have proven the efficacy and effectiveness of low-cost cervical cancer prevention methods but none in routine program implementation settings of the developing world, particularly in HIV-infected women. METHODS: In our public sector cervical cancer prevention program in Zambia, nurses conduct screening using visual inspection with acetic acid aided by digital cervicography. Women with visible lesions are offered same-visit cryotherapy or referred for histologic evaluation and clinical management. We analyzed clinical outcomes and modeled program effectiveness among HIV-infected women by estimating the total number of cervical cancer deaths prevented through screening and treatment. RESULTS: Between 2006 and 2008, 6572 HIV-infected women were screened, 53.6% (3523) had visible lesions, 58.5% (2062) were eligible for cryotherapy and 41.5% (1461) were referred for histologic evaluation. A total of 75% (1095 out of 1462) of patients who were referred for evaluation complied. Pathology results from 65% (715 out of 1095) of women revealed benign abnormalities in 21% (151), cervical intraepithelial neoplasia (CIN) I in 30% (214), CIN 2/3 in 33% (235) and invasive cervical cancer in 16.1% (115, of which 69% were early stage). Using a conditional probability model, we estimated that our program prevented 142 cervical cancer deaths (high/low range: 238-96) among the 6572 HIV-infected women screened, or one cervical cancer death prevented per 46 (corresponding range: 28-68) HIV-infected women screened. CONCLUSION: Our prevention efforts using setting-appropriate human resources and technology have reduced morbidity and mortality from cervical cancer among HIV-infected women in Zambia. Financial support for implementing cervical cancer prevention programs integrated within HIV/AIDS care programs is warranted. Our prevention model can serve as the implementation platform for future low-cost HPV-based screening methods, and our results may provide the basis for comparison of programmatic effectiveness of future prevention efforts.Item An empirical approach to defining loss to follow-up among patients enrolled in antiretroviral treatment programs.(2010-Apr-15) Chi BH; Cantrell RA; Mwango A; Westfall AO; Mutale W; Limbada M; Mulenga LB; Vermund SH; Stringer JS; Centre for Infectious Disease Research in Zambia, Box 34681, 1275 Lubuto Road, Lusaka, Zambia. bchi@cidrz.org; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)In many programs providing antiretroviral therapy (ART), clinicians report substantial patient attrition; however, there are no consensus criteria for defining patient loss to follow-up (LTFU). Data on a multisite human immunodeficiency virus (HIV) treatment cohort in Lusaka, Zambia, were used to determine an empirical "days-late" definition of LTFU among patients on ART. Cohort members were classified as either "in care" or LTFU as of December 31, 2007, according to a range of days-late intervals. The authors then looked forward in the database to determine which patients actually returned to care at any point over the following year. The interval that best minimized LTFU misclassification was described as "best-performing." Overall, 33,704 HIV-infected adults on ART were included. Nearly one-third (n = 10,196) were at least 1 day late for an appointment. The best-performing LTFU definition was 56 days after a missed visit, which had a sensitivity of 84.1% (95% confidence interval (CI): 83.2, 85.0), specificity of 97.5% (95% CI: 97.3, 97.7), and misclassification of 5.1% (95% CI: 4.8, 5.3). The 60-day threshold performed similarly well, with only a marginal difference (<0.1%) in misclassification. This analysis suggests that > or =60 days since the last appointment is a reasonable definition of LTFU. Standardization to empirically derived definitions of LTFU will permit more reliable comparisons within and across programs.Item A cluster randomized trial of routine HIV-1 viral load monitoring in Zambia: study design, implementation, and baseline cohort characteristics.(2010-Mar-12) Koethe JR; Westfall AO; Luhanga DK; Clark GM; Goldman JD; Mulenga PL; Cantrell RA; Chi BH; Zulu I; Saag MS; Stringer JS; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)BACKGROUND: The benefit of routine HIV-1 viral load (VL) monitoring of patients on antiretroviral therapy (ART) in resource-constrained settings is uncertain because of the high costs associated with the test and the limited treatment options. We designed a cluster randomized controlled trial to compare the use of routine VL testing at ART-initiation and at 3, 6, 12, and 18 months, versus our local standard of care (which uses immunological and clinical criteria to diagnose treatment failure, with discretionary VL testing when the two do not agree). METHODOLOGY: Dedicated study personnel were integrated into public-sector ART clinics. We collected participant information in a dedicated research database. Twelve ART clinics in Lusaka, Zambia constituted the units of randomization. Study clinics were stratified into pairs according to matching criteria (historical mortality rate, size, and duration of operation) to limit the effect of clustering, and independently randomized to the intervention and control arms. The study was powered to detect a 36% reduction in mortality at 18 months. PRINCIPAL FINDINGS: From December 2006 to May 2008, we completed enrollment of 1973 participants. Measured baseline characteristics did not differ significantly between the study arms. Enrollment was staggered by clinic pair and truncated at two matched sites. CONCLUSIONS: A large clinical trial of routing VL monitoring was successfully implemented in a dynamic and rapidly growing national ART program. Close collaboration with local health authorities and adequate reserve staff were critical to success. Randomized controlled trials such as this will likely prove valuable in determining long-term outcomes in resource-constrained settings. TRIAL REGISTRATION: Clinicaltrials.gov NCT00929604.Item Methods and baseline results of a repeated cross-sectional survey to assess the public health impact of antiretroviral therapy in Lusaka, Zambia.(2010-May) Giganti MJ; Levy JW; Banda Y; Kusanthan T; Sinkala M; Stringer JS; Chi BH; Centre for Infectious Disease Research in Zambia, Box 34681, Plot 1275, Lubuto Road, Lusaka, Zambia. mark.giganti@cidrz.org; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)Although the individual-level impact of antiretroviral therapy (ART) is well documented, there are few available data describing the public health impact of services for persons infected with human immunodeficiency virus in resource-constrained settings. We describe the methods and baseline results of a household survey that assessed the population-level impact of the national program for HIV care in Zambia and treatment in the city of Lusaka. The survey was timed with the staggered expansion of services and repeated cross-sectional surveys planned for pre-implementation and post-implementation comparisons made by community. In the initial survey round, which was performed during the early phases of the program (November-December 2004), 18,110 persons were enumerated from 3,600 households surveyed. Respondents were asked questions designed to evaluate community-level mortality and respondent knowledge and attitudes towards HIV. These findings will serve as a reliable reference in the future analysis of the population-level impact of this HIV treatment and care program in Zambia.Item Peripartum nevirapine exposure and subsequent clinical outcomes among HIV-infected women receiving antiretroviral therapy for at least 12 months.(2010-Jul) Chintu N; Giganti MJ; Putta NB; Sinkala M; Sadoki E; Stringer EM; Stringer JS; Chi BH; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)OBJECTIVE: Prior exposure to intrapartum/neonatal nevirapine (NVP) is associated with compromised virologic treatment outcomes once non-nucleoside reverse transcriptase inhibitor (NNRTI)-based antiretroviral therapy (ART) is initiated. We examined the longer-term clinical outcomes in a programmatic setting. METHODS: We compared post-12 month mortality and clinical treatment failure (defined by WHO clinical and immunologic criteria) among women with and without prior NVP exposure in Lusaka, Zambia. RESULTS: Between April 2004 and July 2006, 6740 women initiated an NNRTI-containing regimen. At 12 months, 5172 (78%) remained active and were included in this analysis. Of these, 596 (12%) reported prior NVP exposure, whose time from exposure to ART initiation was: <6 months for 11%, 6-12 months for 13%, >12 months for 37%, unknown for 39%. Overall, women with prior NVP exposure trended towards increased survival (adjusted hazard ratio [AHR]: 0.53; 95% confidence interval [CI]: 0.27-1.06, P = 0.07) and towards increased hazard of clinical treatment failure (AHR: 1.18; 95% CI: 0.95-1.47, P = 0.14), particularly those with exposure for <6 months (AHR: 1.52; 95% CI: 0.94-2.45, P = 0.09). CONCLUSIONS: Prior NVP exposure appeared to increase risk for clinical treatment failure after 12 months of follow-up, but this finding did not reach statistical significance. With growing evidence linking recent NVP exposure to virologic failure, optimized monitoring algorithms should be considered for women with starting NNRTI-based ART. The association between prior NVP exposure and improved survival has not been previously shown and may be a result of residual confounding around health-seeking behaviours.Item Early immunologic response and subsequent survival among malnourished adults receiving antiretroviral therapy in Urban Zambia.(2010-Aug-24) Koethe JR; Limbada MI; Giganti MJ; Nyirenda CK; Mulenga L; Wester CW; Chi BH; Stringer JS; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia. john.r.koethe@vanderbilt.edu; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)OBJECTIVE: To evaluate the relationship between early CD4(+) lymphocyte recovery on antiretroviral therapy (ART) and subsequent survival among low body mass index (BMI) HIV-1-infected adults. DESIGN: Retrospective analysis of a large programmatic cohort in Lusaka, Zambia. METHODS: We evaluated ART-treated adults enrolled in care for more than 6 months. We stratified this study population according to World Health Organization (WHO) malnutrition criteria: normal (BMI >or=18.5 kg/m(2)), mild (17.00-18.49), moderate (16.00-16.99), and severe (<16.0). We used Cox proportional hazards regression to estimate the subsequent risk of death associated with absolute CD4(+) cell count change over the first 6 months on ART. To account for effect modification associated with baseline CD4(+) cell count, a weighted summary measure was calculated. RESULTS: From May 2004 to February 2009, 56,612 patients initiated ART at Lusaka district clinics; of these, 33 097 (58%) were included in this analysis. The median change in 0-6 month CD4(+) cell count in each baseline BMI strata varied from 127 to 131 cells/microl. There was a statistically significant, inverse association between baseline BMI and the post 6-month hazard for mortality only among those patients with less than 100 cells/microl increase in the first 6 months of ART. A CD4(+) cell count increase of at least 100 cells/microl over the first 6 months of ART was not associated with a higher hazard for mortality, regardless of baseline BMI. CONCLUSIONS: Low baseline BMI and attenuated CD4(+) cell count response at 6 months had a compounding, negative impact on post 6-month survival. Specific guidelines for monitoring ART response using immunologic criteria may be warranted for low BMI patients.Item Serum phosphate predicts early mortality in adults starting antiretroviral therapy in Lusaka, Zambia: a prospective cohort study.(2010-May-18) Heimburger DC; Koethe JR; Nyirenda C; Bosire C; Chiasera JM; Blevins M; Munoz AJ; Shepherd BE; Potter D; Zulu I; Chisembele-Taylor A; Chi BH; Stringer JS; Kabagambe EK; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia. douglas.heimburger@vanderbilt.edu; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)BACKGROUND: Patients starting antiretroviral therapy (ART) for acquired immunodeficiency syndrome (AIDS) in sub-Saharan Africa have high rates of mortality in the initial weeks of treatment. We assessed the association of serum phosphate with early mortality among HIV-infected adults with severe malnutrition and/or advanced immunosuppression. METHODOLOGY/PRINCIPAL FINDINGS: An observational cohort of 142 HIV-infected adults initiating ART in Lusaka, Zambia with body mass index (BMI) <16 kg/m(2) or CD4(+) lymphocyte count <50 cells/microL, or both, was followed prospectively during the first 12 weeks of ART. Detailed health and dietary intake history, review of systems, physical examination, serum metabolic panel including phosphate, and serum ferritin and high-sensitivity C-reactive protein (hsCRP) were monitored. The primary outcome was mortality. Baseline serum phosphate was a significant predictor of mortality; participants alive at 12 weeks had a median value of 1.30 mmol/L (interquartile range [IQR]: 1.04, 1.43), compared to 1.06 mmol/L (IQR: 0.89, 1.27) among those who died (p<0.01). Each 0.1 mmol/L increase in baseline phosphate was associated with an incremental decrease in mortality (AHR 0.83; 95% CI 0.72 to 0.95). The association was independent of other metabolic parameters and known risk factors for early ART-associated mortality in sub-Saharan Africa. While participant attrition represented a limitation, it was consistent with local program experience. CONCLUSIONS/SIGNIFICANCE: Low serum phosphate at ART initiation was an independent predictor of early mortality among HIV patients starting ART with severe malnutrition or advanced immunosuppression. This may represent a physiologic phenomenon similar to refeeding syndrome, and may lead to therapeutic interventions that could reduce mortality.Item Coverage of nevirapine-based services to prevent mother-to-child HIV transmission in 4 African countries.(2010-Jul-21) Stringer EM; Ekouevi DK; Coetzee D; Tih PM; Creek TL; Stinson K; Giganti MJ; Welty TK; Chintu N; Chi BH; Wilfert CM; Shaffer N; Dabis F; Stringer JS; Centre for Infectious Disease Research in Zambia, Plot 1275 Lubutu Rd, PO Box 34681, Lusaka, Zambia.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)CONTEXT: Few studies have objectively evaluated the coverage of services to prevent transmission of human immunodeficiency virus (HIV) from mother to child. OBJECTIVE: To measure the coverage of services to prevent mother-to-child HIV transmission in 4 African countries. DESIGN, SETTING, AND PATIENTS: Cross-sectional surveillance study of mother-infant pairs using umbilical cord blood samples collected between June 10, 2007, and October 30, 2008, from 43 randomly selected facilities (grouped as 25 service clusters) providing delivery services in Cameroon, Côte d'Ivoire, South Africa, and Zambia. All sites used at least single-dose nevirapine to prevent mother-to-child HIV transmission and some sites used additional prophylaxis drugs. MAIN OUTCOME MEASURE: Population nevirapine coverage, defined as the proportion of HIV-exposed infants in the sample with both maternal nevirapine ingestion (confirmed by cord blood chromatography) and infant nevirapine ingestion (confirmed by direct observation). RESULTS: A total of 27,893 cord blood specimens were tested, of which 3324 were HIV seropositive (12%). Complete data for cord blood nevirapine results were available on 3196 HIV-seropositive mother-infant pairs. Nevirapine coverage varied significantly by site (range: 0%-82%). Adjusted for country, the overall coverage estimate was 51% (95% confidence interval [CI], 49%-53%). In multivariable analysis, failed coverage of nevirapine-based services was significantly associated with maternal age younger than 20 years (adjusted odds ratio [AOR], 1.44; 95% CI, 1.18-1.76) and maternal age between 20 and 25 years (AOR, 1.28; 95% CI, 1.07-1.54) vs maternal age of older than 30 years; 1 or fewer antenatal care visits (AOR, 2.91; 95% CI, 2.40-3.54), 2 or 3 antenatal care visits (AOR, 1.93; 95% CI, 1.60-2.33), and 4 or 5 antenatal care visits (AOR, 1.56; 95% CI, 1.34-1.80) vs 6 or more antenatal care visits; vaginal delivery (AOR, 1.22; 95% CI, 1.03-1.44) vs cesarean delivery; and infant birth weight of less than 2500 g (AOR, 1.34; 95% CI, 1.11-1.62) vs birth weight of 3500 g or greater. CONCLUSION: In this random sampling of sites with services to prevent mother-to-child HIV transmission, only 51% of HIV-exposed infants received the minimal regimen of single-dose nevirapine.