Holly Rawizza

Immunologic Criteria Are Poor Predictors of Virologic Outcome: Implications for HIV Treatment Monitoring in Resource-Limited Settings

BACKGROUND Viral load (VL) quantification is considered essential for determining antiretroviral treatment (ART) success in resource-rich countries. However, it is not widely available in resource-limited settings where the burden of human immunodeficiency virus infection is greatest. In the absence of VL monitoring, switches to second-line ART are based on World Health Organization (WHO) clinical or immunologic failure criteria. METHODS We assessed the performance of CD4 cell criteria to predict virologic outcomes in a large ART program in Nigeria. Laboratory monitoring consists of CD4 cell count and VL at baseline, then every 6 months. Failure was defined as 2 consecutive VLs >1000 copies/mL after at least 6 months of ART. Virologic outcomes were compared with the 3 WHO-defined immunologic failure criteria. RESULTS A total of 9690 patients were included in the analysis (median follow-up, 33.2 months). A total of 1225 patients experienced failure by both immunologic and virologic criteria, 872 by virologic criteria only, and 1897 by immunologic criteria only. The sensitivity of CD4 cell criteria to detect viral failure was 58%, specificity was 75%, and the positive-predictive value was 39%. For patients with both virologic and immunologic failure, VL criteria identified failure significantly earlier than CD4 cell criteria (median, 10.4 vs 15.6 months; P < .0001). CONCLUSIONS Because of the low sensitivity of immunologic criteria, a substantial number of failures are missed, potentially resulting in accumulation of resistance mutations. In addition, specificity and predictive values are low, which may result in large numbers of unnecessary ART switches. Monitoring solely by immunologic criteria may result in increased costs because of excess switches to more expensive ART and development of drug-resistant virus.

Time-Dependent Predictors of Loss to Follow-up in a Large HIV Treatment Cohort in Nigeria

Evaluation of time-dependent predictors of loss to follow-up in a large HIV treatment program revealed that early adherence patterns, in addition to CD4 count and viral load, predicted loss to follow-up and should be used as measures in devising targeted interventions to increase program retention.

Accumulation of Protease Mutations among Patients Failing Second-Line Antiretroviral Therapy and Response to Salvage Therapy in Nigeria

Background To date, antiretroviral therapy (ART) guidelines and programs in resource-limited settings (RLS) have focused on 1st- and 2nd-line (2 L) therapy. As programs approach a decade of implementation, policy regarding access to 3rd-line (3 L) ART is needed. We aimed to examine the impact of maintaining patients on failing 2 L ART on the accumulation of protease (PR) mutations. Methods and Findings From 2004–2011, the Harvard/APIN PEPFAR Program provided ART to >100,000 people in Nigeria. Genotypic resistance testing was performed on a subset of patients experiencing 2 L failure, defined as 2 consecutive viral loads (VL)>1000 copies/mL after ≥6 months on 2 L. Of 6714 patients who received protease inhibitor (PI)-based ART, 673 (10.0%) met virologic failure criteria. Genotypes were performed on 61 samples. Patients on non-suppressive 2 L therapy for <12 months prior to genotyping had a median of 2 (IQR: 0–5) International AIDS Society (IAS) PR mutations compared with 5 (IQR: 0–6) among patients failing for >24 months. Patients developed a median of 0.6 (IQR: 0–1.4) IAS PR mutations per 6 months on failing 2 L therapy. In 38% of failing patients no PR mutations were present. For patients failing >24 months, high- or intermediate-level resistance to lopinavir and atazanavir was present in 63%, with 5% to darunavir. Conclusions This is the first report assessing the impact of duration of non-suppressive 2 L therapy on the accumulation of PR resistance in a RLS. This information provides insight into the resistance cost of failing to switch non-suppressive 2 L regimens and highlights the issue of 3 L access.

Loss to Follow-up within the Prevention of Mother-to-Child Transmission Care Cascade in a Large ART Program in Nigeria

BACKGROUND The 2013 WHO guidelines incorporated simplified and more effective antiretroviral regimens for the purposes of preventing mother-to-child transmission of HIV. With ideal implementation of these recommendations, perinatal HIV transmission could be reduced to less than 2%. However, loss to follow-up (LTFU) has the potential to erode the success of programs and a number of studies report high rates of LTFU within the prevention of mother-to-child transmission (PMTCT) care cascade. We evaluated the timing and magnitude of LTFU in a large programmatic PMTCT cohort in Nigeria in order to focus future efforts to reduce loss in this high burden setting. METHODS From 2004-2014, the APIN/Harvard PEPFAR program supported antenatal HIV screening for nearly one million pregnant women and provided PMTCT care to over 30,000 women. The care cascade for women enrolling in the PMTCT program includes antenatal, delivery, and infant follow-up services through 12-18 months of life. In this retrospective cohort analysis, we examined data collected between 2004-2014 from 31 clinical sites in Nigeria and assessed the numbers of mothers and infants enrolled and LTFU at various points along the care cascade. RESULTS Among 31,504 women (median age 30, IQR: 27-34) entering PMTCT care during the antenatal period, 20,679 (66%) completed the entire cascade of services including antenatal, delivery, and at least one infant follow-up visit. The median gestational age at presentation for antenatal care services was 23 weeks (IQR: 17-29). The median infant age at last follow-up visit was 12 months (IQR: 5-18). The greatest loss in the PMTCT care cascade occurred prior to delivery care (21%), with a further 16% lost prior to first infant visit. Of the 38,223 women who entered at any point along the PMTCT cascade, an HIV DNA PCR was available for 20,202 (53%) of their infants. Among infants for whom DNA PCR results were available, the rate of HIV transmission for infants whose mothers received any antenatal and/or delivery care was 2.8% versus 20.0% if their mother received none. CONCLUSION In this large cohort analysis, the proportion of women LTFU in the PMTCT care cascade was lower than that reported in previous cohort analyses. Nevertheless, this proportion remains unacceptably high and inhibits the program from maximally achieving the goals of PMTCT care. We also provide the largest analysis to date on rates of perinatal HIV transmission, with low rates among women receiving NNRTI- or PI-based regimens, approaching that reported in clinical trials. However, among mothers who received any antenatal care, infant outcomes were unknown for 48%, and women presented later in pregnancy than that recommended by current guidelines. Implementation research to evaluate ways to improve integration of services, particularly transitions from antenatal to delivery and pediatric care, are critically needed to reduce LTFU within PMTCT programs and achieve the ultimate goal of eliminating pediatric HIV infection.

Superior Effectiveness of Zidovudine Compared With Tenofovir When Combined With Nevirapine-based Antiretroviral Therapy in a Large Nigerian Cohort.

While tenofovir-containing antiretroviral therapy is generally considered superior to zidovudine, our analysis demonstrates a higher rate of virologic failure when tenofovir, as compared with zidovudine, was combined with nevirapine-based first-line antiretroviral therapy in a Nigerian human immunodeficiency virus treatment program.

Tuberculosis Incidence and Risk Factors Among Human Immunodeficiency Virus (HIV)-Infected Adults Receiving Antiretroviral Therapy in a Large HIV Program in Nigeria

Background. Despite the benefits of antiretroviral therapy (ART), tuberculosis (TB) is the leading cause of mortality among human immunodeficiency virus (HIV)-infected persons in Africa. Nigeria bears the highest TB burden in Africa and second highest HIV burden globally. This long-term multicenter study aimed to determine the incidence rate and predictors of TB in adults in the Harvard/AIDS Prevention Initiative in Nigeria (APIN) and Presidents Emergency Plan for AIDS Relief (PEPFAR) Nigeria ART program. Methods. This retrospective evaluation used data collected from 2004 to 2012 through the Harvard/APIN PEPFAR program. Risk factors for incident TB were determined using multivariate Cox proportional hazards regression with time-dependent covariates. Results. Of 50 320 adults enrolled from 2005 to 2010, 11 092 (22%) had laboratory-confirmed active TB disease at ART initiation, and 2021 (4%) developed active TB after commencing ART. During 78 228 total person-years (PY) of follow-up, the TB incidence rate was 25.8 cases per 1000 PY (95% confidence interval [CI], 24.7–27.0) overall, and it decreased significantly both with duration on ART and calendar year. Risk factors at ART initiation for incident TB included the following: earlier ART enrollment year, tenofovir-containing initial ART regimen, and World Health Organization clinical stage above 1. Time-updated risk factors included the following: low body mass index, low CD4+ cell count, unsuppressed viral load, anemia, and ART adherence below 80%. Conclusions. The rate of incident TB decreased with longer duration on ART and over the program years. The strongest TB risk factors were time-updated clinical markers, reinforcing the importance of consistent clinical and laboratory monitoring of ART patients in prompt diagnosis and treatment of TB and other coinfections.

Sputum smear concentration may misidentify acid-fast bacilli as Mycobacterium tuberculosis in HIV-infected patients.

Background:Tuberculosis (TB) diagnosis in most resource-limited settings still depends on smear microscopy for identification of acid-fast bacilli (AFB). However, recently developed molecular diagnostics that test for the presence of Mycobacterium tuberculosis (Mtb) DNA have been shown to be superior for confirmation of TB diagnosis. Methods:At regular clinical visits over a 12-month period, we collected sputa from HIV-infected patients presenting with signs or symptoms of TB at 2 Nigerian clinics. Sputa were stained for AFB and tested using the Genotype MTBDRplus to confirm the presence of Mtb. Other species were identified using 16S rRNA sequence. Results:In 56% (233/415) of AFB-positive patients, Mtb was confirmed. The patients on antiretroviral therapy were less likely than those not on antiretroviral therapy to be infected with Mtb [odds ratio (OR) = 0.25, P = 0.003]. In a multivariate logistic regression model using clinical features and diagnostic results, abnormal respiratory findings on auscultation (OR = 3.28, P = 0.03) and a direct sputum smear grade >3/100 (OR = 6.4, 4.6, P < 0.02) were significant predictors of Mtb infection. Concentrated sputum smear was predictive of Mtb infection only at the highest grades (2+, 3+). Interestingly, among 65 samples that could not be confirmed for Mtb, 32 (49%) were found to contain other, possibly novel, actinomycetes, including atypical Mycobacteria, Rhodococcus spp, Nocardia spp, and Corynebacterium spp. Conclusions:We conclude that concentrated sputum smears may misidentify other bacteria as Mtb in HIV-infected patients. The use of molecular diagnostics could reduce unnecessary or inappropriate treatment and improve identification of pathogens in resource-limited settings with high HIV burden.

On the Cusp

A 27-year-old man presented to the emergency department with a 5-day history of fevers. Test your diagnostic and therapeutic skills at NEJM.org.

Treatment Failure in Children with HIV

Maintaining durable virologic suppression is critical for all HIV-infected patients, but particularly so for children, who require lifelong

Implication of First-Line Antiretroviral Therapy Choice on Second-Line Options

Abstract Background Although there are a number of studies comparing the currently recommended preferred and alternative first-line (1L) antiretroviral therapy (ART) regimens on clinical outcomes, there are limited data examining the impact of 1L regimen choice and duration of virologic failure (VF) on accumulation of drug resistance mutations (DRM). The patterns of DRM from patients failing zidovudine (AZT)-containing versus tenofovir (TDF)-containing ART were assessed to evaluate the predicted susceptibility to second-line (2L) nucleoside reverse-transcriptase inhibitor (NRTI) backbone options in the context of an ongoing programmatic setting that uses viral load (VL) monitoring. Methods Paired samples from Nigerian ART patients who experienced VF and switched to 2L ART were retrospectively identified. For each sample, the human immunodeficiency virus (HIV)-1 polymerase gene was sequenced at 2 time points, and DRM was analyzed using Stanford University’s HIVdb program. Results Sequences were generated for 191 patients. At time of 2L switch, 28.2% of patients on AZT-containing regimens developed resistance to TDF, whereas only 6.8% of patients on TDF-containing 1L had mutations compromising susceptibility to AZT. In a stratified evaluation, patients with 0–6 months between tested VL samples had no difference in proportion compromised to 2L, whereas those with >6 months between samples had a statistically significant difference in proportion with compromised 2L NRTI. In multivariate analyses, patients on 1L AZT had 9.90 times higher odds of having a compromised 2L NRTI option than patients on 1L TDF. Conclusions In the context of constrained resources, where VL monitoring is limited, we present further evidence to support use of TDF as the preferred 1L NRTI because it allows for preservation of the recommended 2L NRTI option.