Immunological Failure Criteria Research Articles

HIV treatment outcomes following antiretroviral therapy initiation and monitoring: A workplace program in Papua, Indonesia.

BackgroundPapua Province, Indonesia is experiencing an on-going epidemic of Human Immunodeficiency Virus (HIV) infection, with an estimated 9-fold greater prevalence than the overall national rate. This study reviewed the treatment outcomes of an HIV-infected cohort on Antiretroviral Therapy (ART) and the predictors in terms of immunological recovery and virological response.MethodsART-naïve individuals in a workplace HIV program in southern Papua were retrospectively analyzed. Patients were assessed at 6, 12 and 36 months after ART initiation for treatment outcomes, and risk factors for virological suppression (viral load (VL) <1,000 copies/ml), poor immune response (CD4 <200 cells/mm3) and immunological failure (CD4 <100 cells/ mm3) after at least 6 months on ART, using a longitudinal Generalized Estimating Equations multivariate model.ResultsAssessment of 105 patients were included in the final analysis with a median age of 34 years, 88% male, median baseline CD4 236 cells/ mm3, and VL 179,000 copies/ml. There were 74, 73, and 39 patients at 6, 12, and 36 months follow-up, respectively, with 5 deaths over the entire period. For the three observation periods, 68, 80, and 75% of patents achieved virological suppression, poor immune responders decreased from 15, 16 to 10%, whilst 15, 16, 10% met the immunological failure criteria, respectively. Using multivariate analysis, the independent predictor for viral suppression at 12 and 36 months was ≥1 log decrease in VL at 6 months (OR 19.25, p<0.001). Higher baseline CD4 was significantly correlated with better immunological outcomes, and lower likelihood of experiencing immunological failure (p <0.001).ConclusionVirological response at six months after beginning ART is the strongest predictor of viral suppression at 12 and 36 months, and may help in identifying patients needing additional adherence therapy support. Higher baseline CD4 positively affects the immunological outcomes of patients. The findings indicate HIV control programs should prioritize the availability of VL testing and begin ART regardless of CD4 counts in infected patients.

Upward trends of acquired drug resistances in Ethiopian HIV-1C isolates: A decade longitudinal study.

BackgroundThe emergence, accumulation and spread of HIV-1 drug resistance strains in Africa could compromise the effectiveness of HIV treatment programs. This study was aimed at determining the incidence of virological failure and acquired drug resistance mutations overtime and identifying the most common mutational pathways of resistance in a well characterized HIV-1C infected Ethiopian cohort.MethodsA total of 320 patients (220 ART naïve and 100 on first lines ART) were included and followed. ART initiation and patients’ monitoring was based on the WHO clinical and immunological parameters. HIV viral load measurement and genotypic drug resistance testing were done at baseline (T0-2008) and after on average at a median time of 30 months on ART at three time points (T1-2011, T2-2013, T3-2015).FindingsThe incidence of virological failure has increased overtime from 11 at T1 to 17 at T2 and then to 30% at T3. At all time point’s almost all of the patients with virological failure and accumulated drug resistance mutations had not met the WHO clinical and immunologic failure criteria and continued the failing regimen. A steep increase in the incidence and accumulation of major acquired NRTI and NNRTI drug resistance mutations have been observed (from 40% at T1 to 64% at T2 and then to 66% at T3). The most frequent NRTIs drug resistance associated mutations are mainly the lamivudine-induced mutation M184V which was detected in 4 patients at T1 and showed a 2 fold increase in the following time points (T2: n = 8) and at (T3: n = 12) and the thymidine analogue mutations (such as D67N, K70R and K219E) which were not-detected at baseline T0 and T1 but were increased progressively to 10 at T2 and to 17 at T3. The most frequent NNRTIs associated mutations were K103N, V106M and Y188C.ConclusionsAn upward trend in the incidence of virological failure and accumulation of NRTI and NNRTI associated acquired antiretroviral drug resistance mutations are observed. The data suggest the need for virological monitoring, resistance testing for early detection of failure and access for TDF and PI containing drugs. Population-level and patient targeted interventions to prevent the spread of mutant variants is warranted.

Switching to second-line ART in relation to mortality in a large Tanzanian HIV cohort.

In a large cohort of HIV-infected Tanzanians, we assessed: (i) rates of first-line treatment failure and switches to second-line ART; (ii) the effect of switching to second-line ART on death and loss to follow-up; and (iii) treatment outcomes on second-line ART by regimen. HIV-1-infected adults (≥15 years) initiated on first-line ART between November 2004 and September 2012, and who remained on initial therapy for at least 24 weeks before switching, were studied. Survival analyses were conducted to examine the effect of second-line ART on mortality and loss to follow-up in: (i) the whole cohort; (ii) all patients eligible for second-line ART by immunological failure (IF) and/or virological failure (VF) criteria; and (iii) patients eligible by VF criteria. In total, 47 296 HIV-infected patients [mean age 37.5 (SD 9.5) years, CD4 175 (SD 158) cells/mm 3 , 71% female] were included in the analyses. Of these, 1760 (3.7%) patients switched to second-line ART (incidence rate = 1.7/100 person-years). Higher rates of mortality were observed in switchers versus non-switchers in all patients and patients with ART failure using IF/VF criteria. Switching only protected against mortality in patients with ART failure defined virologically and with the highest level of adherence [switching versus non-switching; >95% adherence; adjusted HR = 0.50 (95% CI = 0.26-0.93); P = 0.03]. Switching patients to second-line ART may only be beneficial in a select group of patients who are virologically monitored and demonstrate good adherence. Our data emphasize the need for routine viral load monitoring and aggressive adherence interventions in HIV programmes in sub-Saharan Africa.

The Effect of Switching to Second-Line Antiretroviral Therapy on the Risk of Opportunistic Infections Among Patients Infected With Human Immunodeficiency Virus in Northern Tanzania.

Background. Due to the unintended potential misclassifications of the World Health Organization (WHO) immunological failure criteria in predicting virological failure, limited availability of treatment options, poor laboratory infrastructure, and healthcare providers' confidence in making switches, physicians delay switching patients to second-line antiretroviral therapy (ART). Evaluating whether timely switching and delayed switching are associated with the risk of opportunistic infections (OI) among patients with unrecognized treatment failure is critical to improve patient outcomes. Methods. A retrospective review of 637 adolescents and adults meeting WHO immunological failure criteria was conducted. Timely and delayed switching to second-line ART were defined when switching happened at <3 and ≥3 months, respectively, after failure diagnosis was made. Cox proportional hazard marginal structural models were used to assess the effect of switching to second-line ART on the risk of developing OI. Results. Of 637 patients meeting WHO immunological failure criteria, 396 (62.2%) switched to second-line ART. Of those switched, 230 (58.1%) were delayed. Switching to second-line ART reduced the risk of OI (adjusted hazards ratio [AHR], 0.4; 95% CI, .2-.6). Compared with patients who received timely switch after failure diagnosis was made, those who delayed switching were more likely to develop OI (AHR, 2.2; 95% CI, 1.1-4.3). Conclusion. Delayed switching to second-line ART after failure diagnosis may increase the risk of OI. Serial immunological assessment for switching patients to second-line ART is critical to improve their outcomes.

CD4 count-based failure criteria combined with viral load monitoring may trigger worse switch decisions than viral load monitoring alone.

CD4 count decline often triggers antiretroviral regimen switches in resource-limited settings, even when viral load testing is available. We therefore compared CD4 failure and CD4 trends in patients with viraemia with or without antiretroviral resistance. Retrospective cohort study investigating the association of HIV drug resistance with CD4 failure or CD4 trends in patients on first-line antiretroviral regimens during viraemia. Patients with viraemia (HIV RNA >1000 copies/ml) from two HIV treatment programmes in South Africa (n = 350) were included. We investigated the association of M184V and NNRTI resistance with WHO immunological failure criteria and CD4 count trends, using chi-square tests and linear mixed models. Fewer patients with the M184V mutation reached immunologic failure criteria than those without: 51 of 151(34%) vs. 90 of 199 (45%) (P = 0.03). Similarly, 79 of 220 (36%) patients, who had major NNRTI resistance, had immunological failure, whereas 62 of 130 (48%) without (chi-square P = 0.03) did. The CD4 count decline among patients with the M184V mutation was 2.5 cells/mm(3) /year, whereas in those without M184V it was 14 cells/mm(3) /year (P = 0.1), but the difference in CD4 count decline with and without NNRTI resistance was marginal. Our data suggest that CD4 count monitoring may lead to inappropriate delayed therapy switches for patients with HIV drug resistance. Conversely, patients with viraemia but no drug resistance are more likely to have a CD4 count decline and thus may be more likely to be switched to a second-line regimen.

Low Incidence of HIV-1C Acquired Drug Resistance 10 Years after Roll-Out of Antiretroviral Therapy in Ethiopia: A Prospective Cohort Study.

The emergence of HIV-1 drug resistance mutations has mainly been linked to the duration and composition of antiretroviral treatment (ART), as well as the level of adherence. This study reports the incidence and pattern of acquired antiretroviral drug resistance mutations and long-term outcomes of ART in a prospective cohort from Northwest Ethiopia. Two hundred and twenty HIV-1C infected treatment naïve patients were enrolled and 127 were followed-up for up to 38 months on ART. ART initiation and patients’ monitoring was based on the WHO clinical and immunological parameters. HIV viral RNA measurement and drug resistance genotyping were done at baseline (N = 160) and after a median time of 30 (IQR, 27–38) months on ART (N = 127). Viral suppression rate (HIV RNA levels ≤ 400 copies/ml) after a median time of 30 months on ART was found to be 88.2% (112/127), which is in the range for HIV drug resistance prevention suggested by WHO. Of those 15 patients with viral load >400 copies/ml, six harboured one or more drug resistant associated mutations in the reverse transcriptase (RT) region. Observed NRTIs resistance associated mutations were the lamivudine-induced mutation M184V (n = 4) and tenofovir associated mutation K65R (n = 1). The NNRTIs resistance associated mutations were K103N (n = 2), V106M, Y181S, Y188L, V90I, K101E and G190A (n = 1 each). Thymidine analogue mutations and major drug resistance mutations in the protease (PR) region were not detected. Most of the patients (13/15) with virologic failure and accumulated drug resistance mutations had not met the WHO clinical and/or immunological failure criteria and continued the failing regimen. The incidence and pattern of acquired antiretroviral drug resistance mutations is lower and less complex than previous reports from sub Saharan Africa countries. Nevertheless, the data suggest the need for virological monitoring and resistance testing for early detection of failure. Moreover, adherence reinforcement will contribute to improving overall treatment outcomes.

The vulnerability of men to virologic failure during antiretroviral therapy in a public routine clinic in Burkina Faso

IntroductionGender differences in antiretroviral therapy (ART) outcomes are critical in sub-Saharan Africa. We assessed the association between gender and virologic failure among adult patients treated in a public routine clinic (one of the largest in West Africa) in Burkina Faso.MethodsWe performed a case-control study between July and October 2012 among patients who had received ART at the Bobo Dioulasso Day Care Unit. Patients were eligible if they were 15 years or older, positive for HIV-1 or HIV-1+2, and on first-line ART for at least six months. Cases were all patients with two consecutive HIV loads >1000 copies/mL (Biocentric Generic or Abbott Real Time assays), or one HIV load >1000 copies/mL associated with immunologic or clinical failure criteria. Controls were all patients who only had HIV loads <300 copies/mL. The association between gender and virologic failure was assessed using a multivariate logistic regression, adjusted on age, level of education, baseline CD4+ T cell count, first and current antiretroviral regimens and time on ART.ResultsOf 2303 patients (74.2% women; median age: 40 years; median time on ART: 34 months), 172 had virologic failure and 2131 had virologic success. Among the former, 130 (75.6%) had confirmed virologic failure, 38 (22.1%) had viro-immunologic failure, and four (2.3%) had viro-clinical failure. The proportion of men was significantly higher among the cases than among the controls (37.2% vs. 24.9%; p<0.001). Compared to controls, cases were also younger, more immunodeficient at ART initiation, less likely to receive a protease inhibitor-based antiretroviral regimen and had spent a longer period of time on ART. After adjustment, male gender remained strongly associated with virologic failure (odds ratio 2.52, 95% CI: 1.77–3.60; p<0.001).ConclusionsMen on ART appeared more vulnerable to virologic failure than women. Additional studies are needed to confirm the poorer prognosis of men in this setting and to determine the causes for their vulnerability in order to optimize HIV care. From now on, efforts should be made to support the adherence of men to ART in the African setting.

Prediction of HIV Drug Resistance Based on Virologic, Immunologic, Clinical, and/or Adherence Criteria in the Stratall ANRS 12110/ESTHER Trial in Cameroon

Our study in Cameroonian rural district hospitals showed that the immunologic and clinical failure criteria had poor performance to identify human immunodeficiency virus drug resistance in a timely manner. Switching to second-line antiretroviral therapy after 2 consecutive viral loads ≥5000 copies/mL, as recommended by the World Health Organization, appeared to be the most appropriate strategy.

Evaluation of Clinical and Immunological Markers for Predicting Virological Failure in a HIV/AIDS Treatment Cohort in Busia, Kenya

BackgroundIn resource-limited settings where viral load (VL) monitoring is scarce or unavailable, clinicians must use immunological and clinical criteria to define HIV virological treatment failure. This study examined the performance of World Health Organization (WHO) clinical and immunological failure criteria in predicting virological failure in HIV patients receiving antiretroviral therapy (ART).MethodsIn a HIV/AIDS program in Busia District Hospital, Kenya, a retrospective, cross-sectional cohort analysis was performed in April 2008 for all adult patients (>18 years old) on ART for ≥12 months, treatment-naive at ART start, attending the clinic at least once in last 6 months, and who had given informed consent. Treatment failure was assessed per WHO clinical (disease stage 3 or 4) and immunological (CD4 cell count) criteria, and compared with virological failure (VL >5,000 copies/mL).ResultsOf 926 patients, 123 (13.3%) had clinically defined treatment failure, 53 (5.7%) immunologically defined failure, and 55 (6.0%) virological failure. Sensitivity, specificity, positive predictive value, and negative predictive value of both clinical and immunological criteria (combined) in predicting virological failure were 36.4%, 83.5%, 12.3%, and 95.4%, respectively.ConclusionsIn this analysis, clinical and immunological criteria were found to perform relatively poorly in predicting virological failure of ART. VL monitoring and new algorithms for assessing clinical or immunological treatment failure, as well as improved adherence strategies, are required in ART programs in resource-limited settings.

The role of targeted viral load testing in diagnosing virological failure in children on antiretroviral therapy with immunological failure

To determine the improvement in positive predictive value of immunological failure criteria for identifying virological failure in HIV-infected children on antiretroviral therapy (ART) when a single targeted viral load measurement is performed in children identified as having immunological failure. Analysis of data from children (<16 years at ART initiation) at South African ART sites at which CD4 count/per cent and HIV-RNA monitoring are performed 6-monthly. Immunological failure was defined according to both WHO 2010 and United States Department of Health and Human Services (DHHS) 2008 criteria. Confirmed virological failure was defined as HIV-RNA >5000 copies/ml on two consecutive occasions <365 days apart in a child on ART for ≥18 months. Among 2798 children on ART for ≥18 months [median (IQR) age 50 (21-84) months at ART initiation], the cumulative probability of confirmed virological failure by 42 months on ART was 6.3%. Using targeted viral load after meeting DHHS immunological failure criteria rather than DHHS immunological failure criteria alone increased positive predictive value from 28% to 82%. Targeted viral load improved the positive predictive value of WHO 2010 criteria for identifying confirmed virological failure from 49% to 82%. The addition of a single viral load measurement in children identified as failing immunologically will prevent most switches to second-line treatment in virologically suppressed children.

The causal effect of switching to second-line ART in programmes without access to routine viral load monitoring

We examined the effect of switching to second-line antiretroviral therapy (ART) on mortality in patients who experienced immunological failure in ART programmes without access to routine viral load monitoring in sub-Saharan Africa. Collaborative analysis of two ART programmes in Lusaka, Zambia and Lilongwe, Malawi. We included all adult patients experiencing immunological failure based on WHO criteria. We used Cox proportional hazards models weighted by the inverse probability of switching to compare mortality between patients who switched and patients who did not; and between patients who switched immediately and patients who switched later. Results are expressed as hazard ratios with 95% credible intervals (95% CI). Among 2411 patients with immunological failure 324 patients (13.4%) switched to second-line ART during 3932 person-years of follow-up. The median CD4 cell count at start of ART and failure was lower in patients who switched compared to patients who did not: 80 versus 155 cells/μl (P < 0.001) and 77 versus 146 cells/μl (P < 0.001), respectively. Adjusting for baseline and time-dependent confounders, mortality was lower among patients who switched compared to patients remaining on failing first-line ART: hazard ratio 0.25 (95% CI 0.09-0.72). Mortality was also lower among patients who remained on failing first-line ART for shorter periods: hazard ratio 0.70 (95% CI 0.44-1.09) per 6 months shorter exposure. In ART programmes switching patients to second-line regimens based on WHO immunological failure criteria appears to reduce mortality, with the greatest benefit in patients switching immediately after immunological failure is diagnosed.

Factors Associated with First-Line Antiretroviral Therapy Failure amongst HIV-Infected African Patients: A Case-Control Study

Background: Since 2001, anti-retroviral therapy (ART) has been provided to over 75,000 HIV-infected patients at the USAID-Academic Model Providing Access to Healthcare (AMPATH) Partnership in western Kenya. Over 1000 of these patients have switched to second-line ART. We therefore set out to determine factors associated with first-line ART failure amongst these patients. Methods: This case controlled study matched patients (in the ratio 1:2) from the electronic AMPATH Medical Record System on the basis of age, gender, and ART initiation date. Cases were adults (≥18 years) who initiated second-line ART between January 1, 2007 and July 31, 2011 after at least one viral load measurement >5000 copies/ml or satisfying the WHO immunological or clinical failure criteria. Controls were those on non-failing first-line ART with a CD4 count > 400 /ml within the last 12 months, at the time of case incidence. Conditional logistic regression for paired data was used to assess association. We evaluated the strength of association of risk factors using stratified Cox model. Results: Of the 1084 cases and 2149 controls included in the analysis, 62% were female. Median age was 36.5 years (IQR = 30.7 - 43.1); median baseline CD4 cell count was 161 /ml (IQR = 72 - 277); Median time to ART failure was 37 months (IQR = 24 - 47). Low baseline CD4 count < 50 /ml (H.R = 7.07, (95% CI = 4.92 - 10.15); Zidovudine based ART (H.R 1.76, 95% CI = 1.25 - 2.48) and imperfect ART adherence (H.R = 2.77, 95% CI = 2.20 - 3.49) were independently associated with treatment failure. Conclusion: In this setting, low baseline CD4 count, zidovudine-based ART and imperfect adherence are associated with first-line ART treatment failure.

Benefit of viral load testing for confirmation of immunological failure in HIV patients treated in rural Malawi

Viral load testing is used in the HIV programme of Chiradzulu, Malawi, to confirm the diagnosis of immunological failure to prevent unnecessary switching to second-line therapy. Our objective was to quantify the benefit of this strategy for management of treatment failure in a large decentralized HIV programme in Africa. Retrospective analysis of monitoring data from adults treated with first-line antiretroviral regimens for >1 year and meeting the WHO immunological failure criteria in an HIV programme in rural Malawi. The positive predictive value of using immunological failure criteria to diagnose virological failure (viral load >5000 copies/ml) was estimated. Of the 227 patients with immunological failure (185 confirmed with a repeat CD4 measurement), 155 (68.2%) had confirmatory viral load testing. Forty-four (28.4%) had viral load >5000 copies/ml and 57 (36.8%) >1000 copies/ml. Positive predictive value was 28.4% (95% CI 21.4-36.2%). Repeat CD4 count testing showed that 41% of patients initially diagnosed with immunological failure did no longer meet failure criteria. Our results support the need for confirming all cases of immunological failure with viral load testing before switching to second-line ART to optimize the use of resources in developing countries.

Short Communication: Three Years Follow-Up of First-Line Antiretroviral Therapy in Cambodia: Negative Impact of Prior Antiretroviral Treatment

There are few long-term data on ART-experienced patients in resource-limited settings. We performed a cross-sectional study of HIV-infected patients included in the ESTHER program in Calmette hospital, Phnom Penh, Cambodia, after 36 ± 3 months of cART. Therapeutic, clinical, and immunovirological outcomes were compared between patients who stated they were ART-naive (naive group), dual nucleoside reverse-transcriptase inhibitor (two-NRTI group), or fixed-dose combination of stavudine/lamivudine/nevirapine experienced (three-drug group) at entry to the program. A logistic regression model was used to evaluate the factors associated with virological failure (PCR HIV > 250 copies/ml). Among the 256 patients included in the analysis, 148 (58%) were ART naive while 50 (20%) had previously received two NRTIs and 58 (22%) three drugs. At entry to the program, all the patients received two NRTIs and one nonnucleoside reverse-transcriptase inhibitor (NNRTI). At evaluation, 46 patients (18%) were switched to a protease inhibitor-based regimen (9%, 32%, and 29% of the naive, two-NRTI, and three-drug groups; p < 0.0001). The median CD4 cell count increase was 180/μl overall (IQR: 96-276) and was higher in ART-naive than ART-experienced patients. In the intent-to-treat analysis, virological success was achieved in 83.5%, 67%, and 69% of the naive, two-NRTI, and three-drug groups, respectively (p = 0.002). Factors associated with virological failure were suboptimal previous ART exposure and WHO immunological failure criteria. The long-term efficacy of first-line cART is maintained in Cambodia. In ART-experienced patients, viral load monitoring needs to be available to establish early virological failure and preserve the potency of second line regimens.

Immunological response to highly active antiretroviral therapy following treatment for prevention of mother to child transmission of HIV‐1: a study in Côte d'Ivoire

BackgroundInformation is currently limited on the long-term follow up of HIV-1 infected women who are on highly active antiretroviral therapy (HAART) that contains nevirapine and lamivudine and who were previously exposed to antiretroviral drugs for the prevention of mother to child transmission (PMTCT) of HIV.MethodsWe studied the 36-month immunological response to HAART in HIV-1 infected women in Côte d'Ivoire. The women were previously exposed to antiretroviral drug regimens for PMTCT, including single-dose nevirapine and/or short-course zidovudine with or without lamivudine. All HAART regimens included a non-nucleoside reverse transcriptase inhibitor.ResultsAt 36 months: the median absolute increase in CD4+ T cell count was +359 cells/mm3 (IQR: 210-466) in 200 women who had undergone 36-month follow-up visits; +359 cells/mm3 (IQR: 222-491) in 88 women not exposed to PMTCT antiretrovirals; and +363 cells/mm3 (IQR: 200-464) in 112 women exposed to at least one antiretroviral PMTCT regimen. Overall, 49 (19.8%) of the 247 women who initiated HAART met the immunological failure criteria at least once during follow up. The overall probability of immunological failure was 0.08 (95% CI: 0.12-0.15) at 12 months, and 0.21 (95% CI: 0.16-0.27) at 36 months. No difference was observed according to the presence or absence of resistance mutations to nevirapine or lamivudine in women tested at four weeks postpartum. In addition, at 36 months, 23% of women were lost to follow up, dead or had stopped their treatment.ConclusionsA non-nucleoside reverse transcriptase inhibitor-based antiretroviral regimen, initiated a year or more after PMTCT exposure and that includes nevirapine, remains a good option for at least the first 36 months of treatment.

Diagnosis of antiretroviral therapy failure in Malawi: poor performance of clinical and immunological WHO criteria

In antiretroviral therapy (ART) scale-up programmes in sub-Saharan Africa viral load monitoring is not recommended. We wanted to study the impact of only using clinical and immunological monitoring on the diagnosis of virological ART failure under routine circumstances. Clinicians in two urban ART clinics in Malawi used clinical and immunological monitoring to identify adult patients for switching to second-line ART. If patients met clinical and/or immunological failure criteria of WHO guidelines and had a viral load <400 copies/ml there was misclassification of virological ART failure. Between January 2006 and July 2007, we identified 155 patients with WHO criteria for immunological and/or clinical failure. Virological ART failure had been misclassified in 66 (43%) patients. Misclassification was significantly higher in patients meeting clinical failure criteria (57%) than in those with immunological criteria (30%). On multivariate analysis, misclassification was associated with being on ART <2 years [OR = 7.42 (2.63, 20.95)] and CD4 > 200 cells/microl [OR = 5.03 (2.05, 12.34)]. Active tuberculosis and Kaposi's sarcoma were the most common conditions causing misclassification of virological ART failure. Misclassification of virological ART failure occurs frequently using WHO clinical and immunological criteria of ART failure for poor settings. A viral load test confirming virological ART failure is therefore advised to avoid unnecessary switching to second-line regimens.

Failure of immunologic criteria to appropriately identify antiretroviral treatment failure in Uganda

Most antiretroviral treatment program in resource-limited settings use immunologic or clinical monitoring to measure response to therapy and to decide when to change to a second-line regimen. Our objective was to evaluate immunologic failure criteria against gold standard virologic monitoring. Observational cohort. Participants enrolled in an antiretroviral treatment program in rural Uganda who had at least 6 months of follow-up were included in this analysis. Immunologic monitoring was performed by CD4 cell counts every 3 months during the first year, and every 6 months thereafter. HIV-1 viral loads were performed every 6 months. A total of 1133 participants enrolled in the Rakai Health Sciences Program antiretroviral treatment program between June 2004 and September 2007 were followed for up to 44.4 months (median follow-up 20.2 months; IQR 12.4-29.5 months). WHO immunologic failure criteria were reached by 125 (11.0%) participants. A virologic failure endpoint defined as HIV-1 viral load more than 400 copies/ml on two measurements was reached by 112 participants (9.9%). Only 26 participants (2.3%) experienced both an immunologic and virologic failure endpoint (2 viral load > 400 copies/ml) during follow-up. Immunologic failure criteria performed poorly in our setting and would have resulted in a substantial proportion of participants with suppressed HIV-1 viral load being switched unnecessarily. These criteria also lacked sensitivity to identify participants failing virologically. Periodic viral load measurements may be a better marker for treatment failure in our setting.