Dataset Information

CD4 Variability in Malawi: Implications for Use of a CD4 Threshold of 500 Cells/mm³ Versus Universal Eligibility for Antiretroviral Therapy.

ABSTRACT: Background. ?Given the uncertainty about the ability of a single CD4 count to accurately classify a patient as antiretroviral therapy (ART) eligible, we sought to understand the extent to which CD4 variability results in misclassification at a CD4 threshold of 500 cells/mm³. Methods. ?We performed a prospective study of CD4 variability in Malawian human immunodeficiency virus-infected, ART-naive, World Health Organization (WHO) stage 1 or 2, nonpregnant adults. CD4 counts were performed daily for 8 days. We fit a Bayesian linear mixed-effects model of log-transformed CD4 cell counts to the data. We used Monte Carlo approximations to estimate misclassification rates for different observed values of CD4. The misclassification rate was calculated based on the conditional probability of true CD4 given the geometric mean of observed CD4 measurements. Results. ?Fifty patients were enrolled from 2 sites. The median age was 33.5 years (interquartile range, 27.5-40.0) and 34 (68%) were female. Misclassification rates were <1% when the observed CD4 counts were ?250 or ?750 cells/mm³. Rates of misclassification were high at observed CD4 counts between 350 and 650 cells/mm³, particularly when a single measurement was used (up to 46.7%). Conclusions. ?Our data show that ART eligibility based on a single CD4 count results in highest risk of misclassification when observed CD4 counts are in the range of 350-650 cells/mm³. Given the benefits of early ART, countries should weigh the costs and complexity of CD4 testing using a 500 cell/mm³ threshold against the cost savings and public health benefits of universal eligibility.

SUBMITTER: Schooley AL

PROVIDER: S-EPMC5047419 | biostudies-literature | 2016 Sep

REPOSITORIES: biostudies-literature

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CD4 Variability in Malawi: Implications for Use of a CD4 Threshold of 500 Cells/mm3 Versus Universal Eligibility for Antiretroviral Therapy.

Schooley Alan L AL Kamudumuli Pocha Samuel PS Vangala Sitaram S Tseng Chi-Hong CH Soko Chifundo C Parent Julie J Phiri Khumbo K Jahn Andreas A Namarika Dan D Hoffman Risa M RM

Open forum infectious diseases 20160829 3

Background. Given the uncertainty about the ability of a single CD4 count to accurately classify a patient as antiretroviral therapy (ART) eligible, we sought to understand the extent to which CD4 variability results in misclassification at a CD4 threshold of 500 cells/mm3. Methods. We performed a prospective study of CD4 variability in Malawian human immunodeficiency virus-infected, ART-naive, World Health Organization (WHO) stage 1 or 2, nonpregnant adu ...[more]

PMID: 27704028

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Project description:BackgroundMeasurement of CD4+ T-lymphocytes (CD4) is a crucial parameter in the management of HIV patients, particularly in determining eligibility to initiate antiretroviral treatment (ART). A number of technologies exist for CD4 enumeration, with considerable variation in cost, complexity, and operational requirements. We conducted a systematic review of the performance of technologies for CD4 enumeration.Methods and findingsStudies were identified by searching electronic databases MEDLINE and EMBASE using a pre-defined search strategy. Data on test accuracy and precision included bias and limits of agreement with a reference standard, and misclassification probabilities around CD4 thresholds of 200 and 350 cells/μl over a clinically relevant range. The secondary outcome measure was test imprecision, expressed as % coefficient of variation. Thirty-two studies evaluating 15 CD4 technologies were included, of which less than half presented data on bias and misclassification compared to the same reference technology. At CD4 counts <350 cells/μl, bias ranged from -35.2 to +13.1 cells/μl while at counts >350 cells/μl, bias ranged from -70.7 to +47 cells/μl, compared to the BD FACSCount as a reference technology. Misclassification around the threshold of 350 cells/μl ranged from 1-29% for upward classification, resulting in under-treatment, and 7-68% for downward classification resulting in overtreatment. Less than half of these studies reported within laboratory precision or reproducibility of the CD4 values obtained.ConclusionsA wide range of bias and percent misclassification around treatment thresholds were reported on the CD4 enumeration technologies included in this review, with few studies reporting assay precision. The lack of standardised methodology on test evaluation, including the use of different reference standards, is a barrier to assessing relative assay performance and could hinder the introduction of new point-of-care assays in countries where they are most needed.

Project description:BackgroundComplete recovery of the CD4 T cell count is uncommon among chronically HIV-infected individuals with very low pre-treatment CD4 count. We studied the prevalence of chronically immune recovery and its associated factors including immune characteristics chronic HIV-infected Thais.MethodsTreatment-naïve participants (n = 375) from the HIV-NAT 006 cohort with a pre-treatment CD4 T cell count after initiating antiretroviral therapy (ART) and having achieved a suppressed viremia (HIV-RNA level < 400 copies/mL) were retrospectively followed at the Thai Red Cross AIDS Research Centre, Bangkok, Thailand. Suboptimal immune recovery (SIR) was defined as having a CD4+ T cell count <200 cells/mm3 for 3 years after ART initiation. A case-control sub-study matched for age, sex and pre-ART CD4 T cell count was conducted to compare immunological characteristics between SIR (n = 17) and non-SIR (n = 24) participants. Immunological biomarkers such as interleukin-7 (IL-7) and soluble CD14 (sCD14) and other covariates including cytomegalovirus (CMV) DNA level, baseline hemoglobin level, hepatitis B and C co-infections, and T cell subsets associated with immune activation and exhaustion were evaluated.ResultsAmong 375 participants with pre-ART CD4 T cell counts < 200 cells/mm3, the prevalence of SIR was 39.7%, 19.7% and 7.7% at years 1, 2 and 3 after starting ART, respectively. In a multivariate analysis, a pre-ART CD4 T cell count ≤100 cells/mm3 (adjusted odds ratio [aOR] 9.45, 95% CI 2.92-30.61, p < 0.001), older age (aOR 1.07, 95% CI 1.01-1.13, p = 0.029) and baseline HIV-RNA level (aOR 0.36, 95% CI 0.21-0.59, p < 0.001) were independently associated with SIR at year 3 after ART initiation. In the matched case-control sub-study (cases = 17, controls = 24), there was a higher prevalence of hepatitis C co-infection (18.8% vs. 0%, p = 0.05), lower sCD14 levels (mean, 6.23 vs. 6.27 log10 pg/mL, p = 0.04), lower CD8 T cell counts (mean, 514 vs. 876, p = 0.0003), lower CD4/CD8 T cell ratio (mean, 0.27 vs. 0.41, p = 0.01) and higher expression of PD1 on CD8+ T cells (74.2% vs. 65.1%, p = 0.02) observed in SIR participants compared to their non-SIR counterparts at year 3 after ART initiation.ConclusionsNearly 10% of the study participants who had achieved virological suppression failed to recover a CD4 T cell count > 200 cells/mm3 after 3 years of ART which was with a very low pre-ART CD4 T cell count and older age. The long-term clinical outcomes of SIR participants need to be further explored.

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Dataset Information

CD4 Variability in Malawi: Implications for Use of a CD4 Threshold of 500 Cells/mm³ Versus Universal Eligibility for Antiretroviral Therapy.

Publications

CD4 Variability in Malawi: Implications for Use of a CD4 Threshold of 500 Cells/mm<sup>3</sup> Versus Universal Eligibility for Antiretroviral Therapy.

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