Indirect markers to initiate highly active antiretroviral therapy in a rural African setting

Closer to 90-90-90. The cascade of care after 10 years of ART scale-up in rural Malawi: a population study

INTRODUCTION

The antiretroviral therapy (ART) programme supported by Médecins Sans Frontières in the rural Malawian district of Chiradzulu was one of the first in sub-Saharan Africa to scale up ART delivery in 2002. After more than a decade of continuous involvement, we conducted a population survey to evaluate the cascade of care, including population viral load, in the district.

METHODS

A cross-sectional household-based survey was conducted between February and May 2013. Using a multistage cluster sampling method, we recruited all individuals aged 15 to 59 years living in 4125 randomly selected households. Each consenting individual was interviewed and tested for HIV at home. All participants who tested positive had their CD4 count and viral load measured. The LAg-Avidity assay was used to distinguish recent from long-term infections. Viral suppression was defined as a viral load below 1000 copies/mL.

RESULTS

Of 8271 individuals eligible for the study, 7269 agreed to participate and were tested for HIV (94.1% inclusion for women and 80.3% for men). Overall HIV prevalence and incidence were 17.0% (95% CI 16.1 to 17.9) and 0.39 new cases per 100 person-years (95% CI 0.0 to 0.77), respectively. Coverage at the other steps along the HIV care cascade was as follows: 76.7% (95% CI 74.4 to 79.1) had been previously diagnosed, 71.2% (95% CI 68.6 to 73.6) were under care and 65.8% (95% CI 62.8 to 68.2) were receiving ART. Finally, the proportion of participants who were HIV positive with a viral load ≤ 1000 copies/mL reached 61.8% (95% CI 59.0 to 64.5).

CONCLUSIONS

This study demonstrates that a high level of population viral suppression and low incidence can be achieved in high HIV prevalence and resource-limited settings.

Diagnostic accuracy of the WHO clinical staging system for defining eligibility for ART in sub-Saharan Africa: a systematic review and meta-analysis

INTRODUCTION

The World Health Organization (WHO) recommends that HIV-positive adults with CD4 count ≤500 cells/mm(3) initiate antiretroviral therapy (ART). In many countries of sub-Saharan Africa, CD4 count is not widely available or consistently used and instead the WHO clinical staging system is used to determine ART eligibility. However, concerns have been raised regarding its discriminatory ability to identify patients eligible to start ART. We therefore reviewed the accuracy of WHO stage 3 or 4 assessment in identifying ART eligibility according to CD4 count thresholds for ART initiation.

METHODS

We systematically searched PubMed and Global Health databases and conference abstracts using a comprehensive strategy for studies that compared the results of WHO clinical staging with CD4 count thresholds. Studies performed in sub-Saharan Africa and published in English between 1998 and 2013 were eligible for inclusion according to our predefined study protocol. Two authors independently extracted data and assessed methodological quality and risk of bias using the Quality Assessment Tool for Diagnostic Accuracy Studies (QUADAS-2) tool. Summary estimates of sensitivity and specificity were derived for each CD4 count threshold and hierarchical summary receiver operator characteristic curves were plotted.

RESULTS

Fifteen studies met the inclusion criteria, including 25,032 participants from 14 countries. Most studies assessed individuals attending ART clinics prior to treatment initiation. WHO clinical stage 3 or 4 disease had a sensitivity of 60% (95% CI: 45-73%, Q=914.26, p<0.001) and specificity of 73% (95% CI: 60-83%, Q=1439.43, p<0.001) for a CD4 threshold of ≤200 cells/mm(3) (11 studies); sensitivity and specificity for a threshold of CD4 count ≤350 cells/mm(3) were 45% (95% CI: 26-66%, Q=1607.31, p<0.001) and 85% (95% CI: 69-93%, Q=896.70, p<0.001), respectively (six studies). For the threshold of CD4 count ≤500 cells/mm(3) sensitivity was 14% (95% CI: 13-15%) and specificity was 95% (95% CI: 94-96%) (one study).

CONCLUSIONS

When used for individual treatment decisions, WHO clinical staging misses a high proportion of individuals who are ART eligible by CD4 count, with sensitivity falling as CD4 count criteria rises. Access to accurate, accessible, robust and affordable CD4 count testing methods will be a pressing need for as long as ART initiation decisions are based on criteria other than seropositivity.

Evaluation of affordable screening markers to detect CD4+ T-cell counts below 200 cells/mul among HIV-1-infected Ugandan adults

OBJECTIVE

To evaluate validity of WHO staging, low body mass index (BMI) and anaemia in detecting HIV-infected adults with CD4+ T-cell counts < 200 cells/microl.

METHODS

Between October 1995 and April 2006, we screened Ugandans aged 16 or older at enrollment into an open cohort. We analysed highly active anti-retroviral therapy (HAART)-naïve HIV-infected patients with WHO stages 1-3 and complete data in a secondary cross-sectional study. Low BMI was a BMI < 18.5 kg/m(2). Anaemia was a haemoglobin level < 11 or 12 g/dl among women and men respectively.

RESULTS

Among 2892 HAART-naïve patients, the median age was 32 years. 71% were women, 54% had WHO stage 3 AIDS, 34% had anaemia, 16% had a low BMI and 43% had CD4+ T-cell counts < 200 cells/microl. WHO stage 3 compared to combined WHO stages 1 and 2 had a sensitivity (95% CI) of 70% (67, 72) and a specificity of 57% (55, 60) respectively to detect CD4+ T-cell counts < 200 cells/microl. Anaemia compared to normal haemoglobin had sensitivity (95% CI) of 47% (44, 50) and a specificity of 76% (74, 78). Low BMI compared to normal BMI had sensitivity (95% CI) of 23% (20, 25) and a specificity of 89% (87, 90) against CD4+ T-cell counts < 200 cells/microl.

CONCLUSION

Only WHO stage 3 had reasonably high sensitivity in detecting CD4+ T-cell counts below 200 cells/microl in this setting. Targeted low-cost CD4 testing strategies are urgently needed to detect patients eligible for HAART in rural Africa and other resource-limited settings.

Estimating the need for antiretroviral treatment and an assessment of a simplified HIV/AIDS case definition in rural Malawi

BACKGROUND

Surveillance in the era of antiretroviral therapy (ART) requires estimates of HIV prevalence as well as the proportion eligible for ART. We estimated HIV prevalence and assessed field staging of individuals to estimate the burden of HIV disease needing treatment in rural Malawi.

METHODS

Adults aged 18-59 years in a demographic surveillance system were interviewed, examined, and HIV counselled and tested. Staging that used a simplified version of the WHO criteria ('field checklist') was compared with staging by a medical assistant using a 'clinic checklist' and to CD4 cell results.

RESULTS

A total of 2129 of 2303 eligible adults (92.4%) were traced, and 2047 (96.1%) participated. Of the 1443 participants (70.5%) tested, 11.6% were HIV positive. ART eligibility classification by the field and clinic checklists were concordant in 122 of 133 HIV-positive individuals. Compared with the clinic checklist, the field checklist had a sensitivity of 50% and a specificity of 96%. Including those already known to be on ART, staging by the field and clinic checklists estimated ART eligibility at 16.3 and 17.7% of HIV-positive individuals, respectively. Using CD4 cell count under 250 cells/mul or WHO stage III/IV, the Malawi national programme criteria, 38% of HIV-positive individuals were eligible for ART, compared with 31% based on the 2006 WHO criteria of CD4 cell count under 200 cells/mul or WHO stage IV or CD4 cell count of 200-350 cells/mul and WHO stage III.

CONCLUSION

The field checklist was not a suitable tool for individual staging. Criteria for ART eligibility based on clinical staging alone missed two-thirds of those eligible by clinical staging and CD4 cell count.

Determining eligibility for antiretroviral therapy in resource-limited settings using total lymphocyte counts, hemoglobin and body mass index

BACKGROUND

CD4+ T lymphocyte (CD4) cell count testing is the standard method for determining eligibility for antiretroviral therapy (ART), but is not widely available in sub-Saharan Africa. Total lymphocyte counts (TLCs) have not proven sufficiently accurate in identifying subjects with low CD4 counts. We developed clinical algorithms using TLCs, hemoglobin (Hb), and body mass index (BMI) to identify patients who require ART.

METHODS

We conducted a cross-sectional study of HIV-infected adults in Uganda, who presented for assessment for ART-eligibility with WHO clinical stages I, II or III. Two by two tables were constructed to examine TLC thresholds, which maximized sensitivity for CD4 cell counts 350 cells microL. Hb and BMI values were then examined to try to improve model performance.

RESULTS

1787 subjects were available for analysis. Median CD4 cell counts and TLCs, were 239 cells/microL and 1830 cells/microL, respectively. Offering ART to all subjects with a TLCs 3000 cells/microL, and used Hb and/or BMI values to determine eligibility for those with TLC values between 2000 and 3000 cells/microL, marginally improved accuracy.

CONCLUSION

TLCs appear useful in predicting who would be eligible for ART based on CD4 cell count criteria. Hb and BMI values may be useful in prioritizing patients for ART, but did not improve model accuracy.