CD4 cell count variability with repeat testing in South Africa: Should reporting include both absolute counts and ranges of plausible values?

Prevalence and trends of advanced HIV disease among antiretroviral therapy-naïve and antiretroviral therapy-experienced patients in South Africa between 2010-2021: a systematic review and meta-analysis

BACKGROUND

Despite the significant progress made in South Africa in getting millions of individuals living with HIV into care, many patients still present or re-enter care with Advanced HIV Disease (AHD). We aimed to estimate the prevalence of AHD among ART-naive and ART-experienced patients in South Africa using studies published between January 2010 and May 2022.

METHODS

We searched for relevant data on PubMed, CINAHL, Scopus and other sources, with a geographical filters limited to South Africa, up to May 31, 2022. Two reviewers conducted all screening, eligibility assessment, data extraction, and critical appraisal. We synthesized the data using the inverse-variance heterogeneity model and Freeman-Tukey transformation. We assessed heterogeneity using the I2 statistic and publication bias using the Egger and Begg's test.

RESULTS

We identified 2,496 records, of which 53 met the eligibility criteria, involving 11,545,460 individuals. The pooled prevalence of AHD among ART-naive and ART-experienced patients was 43.45% (95% CI 40.1-46.8%, n = 53 studies) and 58.6% (95% CI 55.7 to 61.5%, n = 2) respectively. The time trend analysis showed a decline of 2% in the prevalence of AHD among ART-naive patients per year. However, given the high heterogeneity between studies, the pooled prevalence should be interpreted with caution.

CONCLUSION

Despite HIV's evolution to a chronic disease, our findings show that the burden of AHD remains high among both ART-naive and ART-experienced patients in South Africa. This emphasizes the importance of regular measurement of CD4 cell count as an essential component of HIV care. In addition, providing innovative adherence support and interventions to retain ART patients in effective care is a crucial priority for those on ART.

Sharing Objective Measures of Adherence to a Vaginal Microbicide Promotes Candor About Actual Use and Bolsters Motivation to Prevent HIV

Discrepancies between self-reported and actual adherence to biomedical HIV interventions is common and in clinical trials can compromise the integrity of findings. One solution is to monitor adherence biomarkers, but it is not well understood how to navigate biomarker feedback with participants. We surveyed 42 counselors and interviewed a subset of 22 to characterize their perspectives about communicating with participants about residual drug levels, an objective marker of adherence, within MTN-025/HOPE, a Phase 3b clinical trial of a vaginal ring to prevent HIV. When biomarkers indicated low drug levels that mismatched high adherence by self-report, counselors encountered barriers to acceptance and comprehension among participants. However, discrepancies between low self-report and higher drug levels generally stimulated candor. Women recollected times they had not used the product and disclosed problems that counselors thought might otherwise have remained forgotten or concealed. Navigating conversations toward HIV prevention was easier at mid-range drug levels and when women indicated motivation to prevent HIV. Ratings of residual drug level offered a somewhat objective measure of adherence and protection that counselors perceived as meaningful to participants and as a valuable catalyst for broaching conversation about HIV prevention. However, communication about drug levels required that counselors navigate emotional barriers, respond skillfully to questions about accuracy, and pivot conversations non-judgmentally away from numerical results and toward the priority of HIV prevention. Findings suggest a role for biomarker feedback in future clinical trials as well as other clinical contexts where biomarkers may be monitored, to motivate disclosure of actual adherence and movement toward HIV prevention.Clinical Trial Number NCT02858037.

Client-Centered Adherence Counseling with Adherence Measurement Feedback to Support Use of the Dapivirine Ring in MTN-025 (The HOPE Study)

Fostering adherence and open communication about adherence challenges is key to harnessing the potential of biomedical HIV prevention products. We describe the counseling intervention and objective adherence measure feedback process implemented to support adherence to the dapivirine vaginal ring among participants in four sub-Saharan countries and present findings on the counselors' likeability and acceptability of the intervention. Most counselors (N = 42; 86%) liked Options counseling "very much" and during in-depth interviews (N = 22), reported that the intervention reshaped their adherence counselling approach by emphasizing understanding participants' experiences using the ring, which facilitated open discussion of adherence challenges. Counselors found that reframing residual drug level (RDL) discussions from the "adherence" to "protection" perspective encouraged adherence among consistent users and facilitated decisions to switch to a different HIV prevention approach among infrequent users. Among counselors, 24% said participants "liked it very much" while 26% said that participants "liked it a little" possibly due to two main complaints: perceived repetitiousness of sessions and variability in the RDL assay, which at times resulted in unexpected low RDLs.

Categorizing and Establishing CD4 Service Equivalency: Testing of Residual, Archived External Quality Assessment Scheme Sample Panels Enables Accelerated Virtual Peer Laboratory Review

BACKGROUND

Testing of collated, curated residual archived external quality assessment (EQA) trial material, with pre-established true (consensus) values collated into 25-sample panels enables virtual peer review of a laboratory's proficiency. In this study, we introduce how archived EQAS samples/panels can establish equivalency of CD4 reporting across multiple laboratories in a national program.

METHODS

Curated unused trial material from archived EQAS CD4 trials were collated into 25-sample panels comprising three sets of five-sample replicates and at least three duplicate samples. Panel-samples were tested using predicate methods of participating laboratories and proficiency determined by calculating a Standard Deviation Index (SDI) for each panel-sample reported according to retrospective consensus pooled trial outcomes. All data were plotted using MS Excel and Graphpad-Prism with SDI limits between -2 and +2 SDI to define acceptable performance. Percentage similarity analysis determined agreement. Bead-count-rate data was used to determine pipetting error.

RESULTS

Tight clustering of SDI outcomes predicted acceptable laboratory proficiency with acceptable accuracy and precision as evidenced by mean SDI < 0.5 and SD of SDI < 0.5. Random pipetting error was identified with aberrant BCR. Systematic under-reading of results was noted in one lab with excellent precision but mean SDI > 1.6. Additional training requirements were evident where a respective laboratory's SD of SDI exceeded 0.7.

CONCLUSIONS

Archival panel testing undertaken across a network of CD4 laboratories using the same CD4 method to simultaneously test the same panel prior to national implementation highlighted proficient laboratories and was useful for identifying sites with service deficiencies and immediate additional training needs. © 2019 International Clinical Cytometry Society.

Performance of the BD-FACS Presto for CD4 count and hemoglobin measurement in a district hospital and rural laboratory in Ghana

INTRODUCTION

In Ghana, initiation of Antiretroviral Therapy (ART) is recommended for all patients with an HIV diagnosis, regardless of CD4+ T-cell count. However, measurement of CD4 count remains an important metric for identifying patients with advanced HIV disease, and assessing a person's overall immune status, which informs the decision to offer opportunistic infection screening and prophylaxis. Access to CD4+ T cell count in rural health facilities remains a major challenge in Ghana and other resource-limited settings. This study aimed to validate the accuracy of the BD FACSPresto near-patient device for measurement of CD4 count and hemoglobin concentration against the FACSCount (CD4) and Sysmex (hemoglobin) diagnostic machines when operated in both a district hospital and rural laboratory, serving a network of health posts in Ashanti Region, Ghana.

METHODOLOGY

In the first phase of the study, patients were recruited from a district hospital, and both venous and capillary blood samples were tested using the FACSCount and Sysmex as reference tests and compared to results of the FACSPresto performed in the clinic laboratory at the district hospital. In the second phase, patients were recruited from both the hospital and from rural health clinics, and samples were tested using the FACSPresto at a rural laboratory. Sensitivity and specificity among samples categorized into different clinically relevant CD4 count ranges were calculated, along with correlation between the Presto and the reference measurements, and mean and relative bias with limits of agreement.

RESULTS

The FACSPresto was successfully operated in both clinical settings. A total of 59 samples in the first phase and 48 samples in the second phase were included. Positive bias was observed when comparing CD4 count measured by BD FACSPresto to FACSCount in the district hospital (bias = 44, LOA -72,160) and in the rural laboratory setting (bias = 74, LOA -96, 244). In addition, capillary blood samples were shown to give higher measures when compared to venous blood samples from the same participant. All results were statistically significant (p<0.05) apart from hemoglobin measurement in venous blood in the rural laboratory. Correlation coefficients were high for CD4 count measures and lower for hemoglobin measures.

CONCLUSION

Overall, the Presto gave higher estimates of CD4 count compared to FACSCount, and hemoglobin measurements were higher than from Sysmex. Samples of capillary blood in turn gave higher results for both measurements compared to venous blood, consistent with previous analyses. These findings should be considered when selecting CD4 count machines for use at the point of care, especially in remote areas where capillary blood sampling may be preferable, but are likely balanced by device's ease of use, portability, and ability to expand access to services. These results are some of the first to demonstrate the accuracy of the FACSPresto in West Africa and show that this device can be successfully operated in a very rural lab setting and may therefore assist to provide CD4 count and hemoglobin concentration measurement to populations in need.