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Assessing the completeness and accuracy of South African National Laboratory CD4 and viral load data: a cross-sectional study.

ABSTRACT: To assess the accuracy of the South African National Health Laboratory Services (NHLS) corporate data warehouse (CDW) using a novel data cross-matching method.Adults (?18?years) on antiretroviral therapy (ART) who visited a hospital-based HIV clinic in Durban from March to June 2012 were included. We matched patient identifiers, CD4 and viral load (VL) records from the HIV clinic's electronic record with the NHLS CDW according to a set of matching criteria for patient identifiers, test values and test dates. We calculated the matching rates for patient identifiers, CD4 and VL records, and an overall matching rate.NHLS returned records for 3498 (89.6%) of the 3906 individuals requested. Using our computer algorithm, we confidently matched 3278 patients (83.9% of the total request). Considering less than confident matches as well, and then manually reviewing questionable matches using only patient identifiers, only nine (0.3% of records returned by NHLS) of the suggested matches were judged incorrect.We developed a data cross-matching method to evaluate national laboratory data and were able to match almost 9 of 10 patients with data we expected to find in the NHLS CDW. We found few questionable matches, suggesting that manual review of records returned was not essential. As the number of patients initiating ART in South Africa grows, maintaining a comprehensive and accurate national data repository is of critical importance, since it may serve as a valuable tool to evaluate the effectiveness of the country's HIV care system. This study helps validate the use of NHLS CDW data in future research on South Africa's HIV care system and may inform analyses in similar settings with national laboratory systems.

SUBMITTER: Bassett IV

PROVIDER: S-EPMC6112393 | biostudies-other | 2018 Aug

REPOSITORIES: biostudies-other

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Assessing the completeness and accuracy of South African National Laboratory CD4 and viral load data: a cross-sectional study.

Bassett Ingrid Valerie IV Huang Mingshu M Cloete Christie C Candy Sue S Giddy Janet J Frank Simone Claire SC Parker Robert A RA

BMJ open 20180823 8

<h4>Objective</h4>To assess the accuracy of the South African National Health Laboratory Services (NHLS) corporate data warehouse (CDW) using a novel data cross-matching method.<h4>Methods</h4>Adults (≥18 years) on antiretroviral therapy (ART) who visited a hospital-based HIV clinic in Durban from March to June 2012 were included. We matched patient identifiers, CD4 and viral load (VL) records from the HIV clinic's electronic record with the NHLS CDW according to a set of matching criteria for p ...[more]

PMID: 30139898

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Project description:PurposeSouth Africa's National Health Laboratory Service (NHLS) National HIV Cohort was established in 2015 to facilitate monitoring, evaluation and research on South Africa's National HIV Treatment Programme. In South Africa, 84.8% of people living with HIV know their HIV status; 70.7% who know their status are on ART; and 87.4% on ART are virologically suppressed.ParticipantsThe NHLS National HIV Cohort includes the laboratory data of nearly all patients receiving HIV care in the public sector since April 2004. Patients are included in the cohort if they have received a CD4 count or HIV RNA viral load (VL) test. Using an anonymised unique patient identifier that we have developed and validated to linked test results, we observe patients prospectively through their laboratory results as they receive HIV care and treatment. Patients in HIV care are seen for laboratory monitoring every 6-12 months. Data collected include age, sex, facility location and test results for CD4 counts, VLs and laboratory tests used to screen for potential treatment complications.Findings to dateFrom April 2004 to April 2018, 63 million CD4 count and VL tests were conducted at 5483 facilities. 12.6 million unique patients had at least one CD4 count or VL, indicating they had accessed HIV care, and 7.1 million patients had a VL test indicating they had started antiretroviral therapy. The creation of NHLS National HIV Cohort has enabled longitudinal research on all lab-monitored patients in South Africa's national HIV programme, including analyses of (1) patient health at presentation; (2) care outcomes such as 'CD4 recovery', 'retention in care' and 'viral resuppression'; (3) patterns of transfer and re-entry into care; (4) facility-level variation in care outcomes; and (5) impacts of policies and guideline changes.Future plansContinuous updating of the cohort, integration with available clinical data, and expansion to include tuberculosis and other lab-monitored comorbidities.

Project description:BackgroundWe describe CD4 count recovery among HIV positive individuals who initiated antiretroviral therapy (ART) with and without severe immune suppression using complete laboratory data from South Africa's national HIV treatment programme between 2010 and 2014 and discuss implications for CD4 count monitoring.MethodsRetrospective analysis of routinely collected laboratory data from South Africa's National Health Laboratory Service (NHLS). A probabilistic record linkage algorithm was used to create a cohort of HIV positive individuals who initiated ART between 2010 and 2014 based on timing of CD4 count and viral load measurements. A CD4 count < 50 copies/μl at ART initiation was considered severe immunosuppression. A multivariable piecewise mixed-effects linear regression model adjusting for age, gender, year of starting ART, viral suppression in follow up and province was used to predict CD4 counts during follow up.Results1,070,900 individuals had evidence of starting ART during 2010-2014 and met the criteria for inclusion in the cohort -46.6% starting ART with CD4 < 200 cells/μl and 10.1% with CD4 < 50 cells/ μl. For individuals with CD4 counts < 200 cells/μl, predicted CD4 counts > 200 cells/μl, >350 cells/μl and >500 cells/μl corresponded with mean follow up durations of 1.5 years (standard deviation [s.d] 1.1), 1.9years (s.d 1.2) and 2.1 years (s.d 1.3 years). For those with CD4 counts < 50 cells/μl, predicted CD4 count above these threshold corresponded with mean follow up durations of 2.5 years (s.d 0.9 years), 4.4 years (s.d 0.4 years) and 5.0 years (s.d 0.1years) for recovery to the same thresholds. CD4 count recovery varied mostly with duration on ART, CD4 count at the start of ART and gender.ConclusionFor individuals starting with ART with severe immunosuppression, CD4 recovery to 200cells/μl did not occur or took longer than 12 month for significant proportions. CD4 monitoring and interventions recommended for advanced HIV disease should continue until full recovery.

Project description:BACKGROUND:Despite the success of prevention of mother to child transmission (PMTCT) program in South Africa, the 30% HIV prevalence among women of childbearing age requires the PMTCT program to be maximally efficient to sustain gains in the prevention of vertical HIV transmission. We aimed to determine the immunologic and virologic status at entry into antenatal care (ANC) and at childbirth among HIV positive women who conceived under the CD4<500 cells/?l antiretroviral therapy (ART) eligibility threshold and universal test and treat (UTT) policies in the Gauteng province of South Africa. METHOD:We conducted a retrospective cohort study of 692 HIV positive adult (>18 years) postpartum women who gave birth between September 2016 and December 2017. Demographic, viral load (VL) and CD4 data at ANC start (3-9 months before delivery) and delivery (3 months before/after) were obtained from medical records of consenting women. We compared CD4?500 cell/?l and viral load (VL) suppression (<400 copes/ml) rates at ANC start and delivery among women with a pre-pregnancy ART, women known HIV positive but with in-pregnancy ART and newly diagnosed women with in-pregnancy ART. Predictors of having a high CD4 and suppressed VL were assessed by log-binomial regression. RESULTS:Of the 692 participants, 394 (57.0%) had CD4 data and 326 (47.1%) had VL data. Overall women with a pre-pregnancy ART were more likely to start ANC with CD4 count?500 cell/?l (46.3% vs 24.8%, adjusted risk ratio (aRR) = 1.9; 95% confidence interval (95% CI): 1.4-2.5), compared to newly diagnosed women. This difference was no longer apparent at the time of delivery (aRR 1.2 95% CI: 0.4-3.7). Similarly, viral suppression at delivery was higher among women with pre-pregnancy ART (87.2% vs 69.3%, aRR 1.3, 95% CI: 1.1-1.6) as compared to the newly diagnosed women. Viral suppression rate among newly diagnosed women increased substantially by the time of delivery from 43.5% to 69.3% (p = 0.001). CONCLUSION:These results show that pre-pregnancy ART improves immunologic and virologic control during pregnancy and call for renewed efforts in HIV testing, linkage to ART and viral monitoring.

Dataset Information

Assessing the completeness and accuracy of South African National Laboratory CD4 and viral load data: a cross-sectional study.

Publications

Assessing the completeness and accuracy of South African National Laboratory CD4 and viral load data: a cross-sectional study.

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