Record linkage without patient identifiers: proof of concept using data from South Africa's national HIV program.

Background: Linkage between health databases typically requires identifiers such as patient names and personal identification numbers. We developed and validated a record linkage strategy to combine administrative health databases without the use of patient identifiers, with application to South Africa's public sector HIV treatment program. Methods: We linked CD4 counts and HIV viral loads from South Africa's HIV clinical monitoring database (TIER.Net) and the National Health Laboratory Service (NHLS) for patients receiving care between 2015-2019 in Ekurhuleni District (Gauteng Province). We used a combination of variables related to lab results contained in both databases (result value; specimen collection date; facility of collection; patient year and month of birth; and sex). Exact matching linked on exact linking variable values while caliper matching applied exact matching with linkage on approximate test dates (± 5 days). We then developed a sequential linkage approach utilising specimen barcode matching, then exact matching, and lastly caliper matching. Performance measures were sensitivity and positive predictive value (PPV); share of patients linked across databases; and percent increase in data points for each linkage approach. Results: We attempted to link 2,017,290 lab results from TIER.Net (representing 523,558 unique patients) and 2,414,059 lab results from the NHLS database. Linkage performance was evaluated using specimen barcodes (available for a minority of records in TIER.net) as a "gold standard". Exact matching achieved a sensitivity of 69.0% and PPV of 95.1%. Caliper-matching achieved a sensitivity of 75.7% and PPV of 94.5%. In sequential linkage, we matched 41.9% of TIER.Net labs by specimen barcodes, 51.3% by exact matching, and 6.8% by caliper matching, for a total of 71.9% of labs matched, with PPV=96.8% and Sensitivity = 85.9%. The sequential approach linked 86.0% of TIER.Net patients with at least one lab result to the NHLS database (N=1,450,087). Linkage to the NHLS Cohort increased the number of laboratory results associated with TIER.Net patients by 62.6%. Conclusions: Linkage of TIER.Net and NHLS without patient identifiers attained high accuracy and yield without compromising patient privacy. The integrated cohort provides a more complete view of patients' lab history and could yield more accurate estimates of HIV program indicators.

Assessment of facility-level antiretroviral treatment patient status utilizing a national-level laboratory cohort: Toward an understanding of system-level tracking and clinic switching in South Africa.

Background: Most estimates of HIV retention are derived at the clinic level through antiretroviral (ART) patient management systems, which capture ART clinic visit data, yet these cannot account for silent transfers across HIV treatment sites. Patient laboratory monitoring visits may also be observed in routinely collected laboratory data, which include ART monitoring tests such as CD4 count and HIV viral load, key to our work here. Methods: In this analysis, we utilized the NHLS National HIV Cohort (a system-wide viewpoint) to investigate the accuracy of facility-level estimates of retention in care for adult patients accessing care (defined using clinic visit data on patients under ART recorded in an electronic patient management system) at Themba Lethu Clinic (TLC). Furthermore, we describe patterns of facility switching among all patients and those patients classified as lost to follow-up (LTFU) at the facility level. Results: Of the 43,538 unique patients in the TLC dataset, we included 20,093 of 25,514 possible patient records (78.8%) in our analysis that were linked with the NHLS National Cohort, and we restricted the analytic sample to patients initiating ART between 1 January 2007 and 31 December 2017. Most (60%) patients were female, and the median age (IQR) at ART initiation was 37 (31-45) years. We found the laboratory records augmented retention estimates by a median of 860 additional active records (about 8% of all median active records across all years) from the facility viewpoint; this augmentation was more noticeable from the system-wide viewpoint, which added evidence of activity of about one-third of total active records in 2017. In 2017, we found 7.0% misclassification at the facility-level viewpoint, a gap which is potentially solvable through data integration/triangulation. We observed 1,134/20,093 (5.6%) silent transfers; these were noticeably more female and younger than the entire dataset. We also report the most common locations for clinic switching at a provincial level. Discussion: Integration of multiple data sources has the potential to reduce the misclassification of patients as being lost to care and help understand situations where clinic switching is common. This may help in prioritizing interventions that would assist patients moving between clinics and hopefully contribute to services that normalize formal transfers and fewer silent transfers.

In utero antiretroviral exposure and sociodemographic characteristics on neurodevelopment of HIV-exposed uninfected children versus HIV-unexposed uninfected healthy children in Malawi.

BACKGROUND: To evaluate mental development index (MDI) and psychomotor development index (PDI) scores of HIV-exposed uninfected (HEU) children by timing of in utero antiretroviral treatment (ART) initiation (Option B+) and sociodemographic characteristics compared with HIV-unexposed uninfected (HUU) children in Mzuzu, Malawi. METHODS: One hundred HEU children and 100 HUU children aged 2-30 months were recruited. The differences in MDI and PDI scores between HEU and HUU children were tested by Student's t test, analysis of variance, Mann-Whitney U test, and logistic regression analysis. RESULTS: The differences in MDI and PDI scores might be related to number of children in the family, delivery, place of residence, family income, complementary feeding, father's or mother's occupation, and degree of education. No significant difference in MDI and PDI scores between HEU and HUU children (P = 0.076 and P = 0.407) was found. Among HEU children, ART in the third trimester and beyond produced a lower PDI score compared with ART before pregnancy and in the first or second trimester (P = 0.027). CONCLUSION: The MDI and PDI scores of HEU subgroups with different timing of ART (Option B+) initiation were comparable to those of the HUU group. Early in utero ART initiation was associated with better neurodevelopmental outcomes than ART initiation in the third trimester and beyond.

The burden of oral conditions among adolescents living with HIV at a clinic in Johannesburg, South Africa.

BACKGROUND: There are inconsistent reports on the prevalence of oral conditions and their associated factors among adolescents living with HIV (ALHIV). The current inconsistencies may hinder the development of clear guidelines on the prevention and treatment of oral conditions among ALHIV. This study provides an update on oral conditions and their associated factors in a cohort of South African ALHIV and receiving routine HIV treatment services at a Johannesburg HIV wellness clinic. METHODS: Decayed Teeth (DT), Decayed Missing and Filled Teeth (DMFT) and Oral HIV/AIDS Research Alliance case definitions were used for caries examination and reporting of the Oral Mucosal Lesions (OML) respectively. Data analyses were stratified by the study main outcomes; chi-squared tests were performed to determine the associations; and multiple logistic regressions were also used to identify associated factors after adjusting for other exposure variables. In addition to fitting logistic regressions, we explored the data for potential confounders and effect modifiers. RESULTS: A total of 407 ALHIV were assessed, of which 51.0% were females. The mean age of the ALHIV was 14.75 years (SD 2.43) while the median age of their parents was 43 years (IQR 37-48 years). Regardless of sex, age group and other socio-demographic characteristics, participants had high count of dental caries (DMFT>0). The overall prevalence of dental caries was 56.76% (n = 231) with mean DT score of 2.0 (SD 2.48) and mean DMFT score of 2.65 (SD 3.01). Dental caries prevalence (DT>0) was significantly associated with the HIV clinical markers. HIV RNA viral loads more than 1000 copies/ml and CD4 cell counts less than 200 count cells/mm3, increased the likelihood of having dental decay among ALHIV (p<0.05). ALHIV at WHO staging III, IV had higher caries prevalence ranging from 70% to 75% (p<0.05). The prevalence of dental caries was directly related to the presence of oral mucosal lesions (p<0.05). The prevalence of OML was 22%, with linear gingival erythema (13.8%) accounting for most of the OML. Multiple logistic regression modelling suggested that dental caries experience (DMFT>0), age category 13-15 years, WHO staging of IV and viral load of more than 1000 copies/ml significantly predicted the outcome of oral lesions as assessed using the OHARA case definitions (p<0.05). The odds of developing dental caries was also 1.5 times more among ALHIV who brush their teeth less frequently and those who reported more frequent eating of sugar sweetened diets (p<0.05). CONCLUSIONS: There is high prevalence of dental caries and OML among ALHIV in Johannesburg. The reported prevalence was associated with high HIV RNA viral loads, shorter duration on antiretroviral treatment and high WHO staging of HIV disease on crude analysis. Additionally, caries experience contributed to the prevalence of OML. Our study acknowledges the protective effect of HIV treatment and positive oral health practices on the presence of oral conditions among ALHIV in Johannesburg.