The use of C-reactive protein to predict uncomplicated appendicitis and increase uptake of laparoscopy in low resource hospitals-A retrospective cohort study.

BACKGROUND: Acute appendicitis remains the most common surgical emergency worldwide. There has been a low uptake of laparoscopic appendicectomy in the South African public sector. Preoperative identification of cases of uncomplicated appendicitis that are amenable to a laparoscopic approach may facilitate the implementation of laparoscopic appendicectomy programs in training hospitals. With limited access to preoperative imaging, alternative strategies for this preoperative prediction are needed. METHODS: A retrospective audit of patients over the age of 12 years with a histologically confirmed diagnosis of acute appendicitis over a 5-year period was performed. Patients were categorized as uncomplicated or complicated appendicitis and C-reactive protein (CRP) and white cell count (WCC) reviewed. Receiver operating characteristics curves were constructed for these blood tests and acute appendicitis severity. Youden's J statistic was used to determine optimal cut off values for diagnosing complicated appendicitis. RESULTS: 358 patients had confirmed appendicitis and complete blood results. Of these, 189 (52.79%) had complicated appendicitis with a 40.22% perforation rate. Median CRP in uncomplicated and complicated groups were 68 mg/L (IQR 19-142) and 216 mg/L (IQR 103-313) with an area under the curve (AUC) of 0.75 (95% CI: 0.70-0.80). The median WCC in the two groups were 12.6 × 109 cells/L (IQR 9.9-15.6) and 14.4 × 109 cells/L (IQR 11.5-18.28) with an AUC of 0.61 (95% CI: 0.56-0.67). The optimal cut off value for CRP was found to be 110 mg/L with a sensitivity of 74.74% and specificity of 69.23%. CONCLUSION: A cutoff value of 110 mg/dl CRP can distinguish patients with early appendicitis from those with complicated disease and when used in conjunction with clinical assessment may help identify patients in whom laparoscopic appendicectomy is appropriate.

A quantitative assessment of the consistency of projections from five mathematical models of the HIV epidemic in South Africa: a model comparison study.

BACKGROUND: Mathematical models are increasingly used to inform HIV policy and planning. Comparing estimates obtained using different mathematical models can test the robustness of estimates and highlight research gaps. As part of a larger project aiming to determine the optimal allocation of funding for HIV services, in this study we compare projections from five mathematical models of the HIV epidemic in South Africa: EMOD-HIV, Goals, HIV-Synthesis, Optima, and Thembisa. METHODS: The five modelling groups produced estimates of the total population, HIV incidence, HIV prevalence, proportion of people living with HIV who are diagnosed, ART coverage, proportion of those on ART who are virally suppressed, AIDS-related deaths, total deaths, and the proportion of adult males who are circumcised. Estimates were made under a "status quo" scenario for the period 1990 to 2040. For each output variable we assessed the consistency of model estimates by calculating the coefficient of variation and examining the trend over time. RESULTS: For most outputs there was significant inter-model variability between 1990 and 2005, when limited data was available for calibration, good consistency from 2005 to 2025, and increasing variability towards the end of the projection period. Estimates of HIV incidence, deaths in people living with HIV, and total deaths displayed the largest long-term variability, with standard deviations between 35 and 65% of the cross-model means. Despite this variability, all models predicted a gradual decline in HIV incidence in the long-term. Projections related to the UNAIDS 95-95-95 targets were more consistent, with the coefficients of variation below 0.1 for all groups except children. CONCLUSIONS: While models produced consistent estimates for several outputs, there are areas of variability that should be investigated. This is important if projections are to be used in subsequent cost-effectiveness studies.

Do increasing rates of loss to follow-up in antiretroviral treatment programs imply deteriorating patient retention?

In several studies of antiretroviral treatment (ART) programs for persons with human immunodeficiency virus infection, investigators have reported that there has been a higher rate of loss to follow-up (LTFU) among patients initiating ART in recent years than among patients who initiated ART during earlier time periods. This finding is frequently interpreted as reflecting deterioration of patient retention in the face of increasing patient loads. However, in this paper we demonstrate by simulation that transient gaps in follow-up could lead to bias when standard survival analysis techniques are applied. We created a simulated cohort of patients with different dates of ART initiation. Rates of ART interruption, ART resumption, and mortality were assumed to remain constant over time, but when we applied a standard definition of LTFU, the simulated probability of being classified LTFU at a particular ART duration was substantially higher in recently enrolled cohorts. This suggests that much of the apparent trend towards increased LTFU may be attributed to bias caused by transient interruptions in care. Alternative statistical techniques need to be used when analyzing predictors of LTFU--for example, using "prospective" definitions of LTFU in place of "retrospective" definitions. Similar considerations may apply when analyzing predictors of LTFU from treatment programs for other chronic diseases.

The effect of care interruptions on mortality in adults resuming antiretroviral therapy.

OBJECTIVE: To estimate the relative rate of all-cause mortality amongst those on antiretroviral treatment (ART) with a history of interruptions compared with those with no previous interruptions in care. DESIGN: Retrospective cohort study. METHODS: We used data from four South African cohorts participating in the International epidemiology Databases to Evaluate AIDS Southern Africa collaboration. We included adults who started ART between 2004 and 2019. We defined a care interruption as a gap in contact longer than 180 days. Observation time prior to interruption was allocated to a 'no interruption' group. Observation time after interruption was allocated to one of two groups based on whether the first interruption started before 6 months of ART ('early interruption') or later ('late interruption'). We used Cox regression to estimate hazard ratios. RESULTS: Sixty-three thousand six hundred and ninety-two participants contributed 162 916 person-years of observation. There were 3469 deaths. Most participants were female individuals (67.4%) and the median age at ART initiation was 33.3 years (interquartile range: 27.5-40.7). Seventeen thousand and eleven (26.7%) participants experienced care interruptions. Those resuming ART experienced increased mortality compared with those with no interruptions: early interrupters had a hazard ratio of 4.37 (95% confidence interval (CI) 3.87-4.95) and late interrupters had a hazard ratio of 2.74 (95% CI 2.39-3.15). In sensitivity analyses, effect sizes were found to be proportional to the length of time used to define interruptions. CONCLUSION: Our findings highlight the need to improve retention in care, regardless of treatment duration. Programmes to encourage return to care also need to be strengthened.

ART history prior to conception: trends and association with postpartum disengagement from HIV care in Khayelitsha, South Africa (2013-2019): a retrospective cohort study.

INTRODUCTION: In recent years, the expansion of HIV treatment eligibility has resulted in an increase in people with antiretroviral therapy (ART) experience prior to pregnancy but little is known about postpartum engagement in care in this population. We examined differences in disengagement from HIV care after delivery by maternal ART history before conception. METHODS: We analysed data from people living with HIV (aged 15-49) in Khayelitsha, South Africa, with ≥1 live birth between April 2013 and March 2019. We described trends over time in ART history prior to estimated conception, classifying ART history groups as: (A) on ART with no disengagement (>270 days with no evidence of HIV care); (B) returned before pregnancy following disengagement; (C) restarted ART in pregnancy after disengagement; and (D) ART new start in pregnancy. We used Kaplan-Meier curves and proportional-hazards models (adjusted for maternal age, number of pregnancy records and year of delivery) to examine the time to disengagement from delivery to 2 years postpartum. RESULTS: Among 7309 pregnancies (in 6680 individuals), the proportion on ART (A) increased from 19% in 2013 to 41% in 2019. The proportions of those who returned (B) and restarted (C) increased from 2% to 13% and from 2% to 10%, respectively. There was a corresponding decline in the proportion of new starts (D) from 77% in 2013 to 36% in 2019. In the first recorded pregnancy per person in the study period, 26% (95% CI 25-27%) had disengaged from care by 1 year and 34% (95% CI 33-36%) by 2 years postpartum. Individuals who returned (B: aHR 2.10, 95% CI 1.70-2.60), restarted (C: aHR 3.32, 95% CI 2.70-4.09) and newly started ART (D: aHR 2.41, 95% CI 2.12-2.74) had increased hazards of postpartum disengagement compared to those on ART (A). CONCLUSIONS: There is a growing population of people with ART experience prior to conception and postpartum disengagement varies substantially by ART history. Antenatal care presents an important opportunity to understand prior ART experiences and an entry into interventions for strengthened engagement in HIV care.

A tale of two waves: characteristics and outcomes of COVID-19 admissions during the Omicron-driven fourth wave in Cape Town, South Africa, and implications for the future.

Objectives: The aim of this study was to describe the pattern of admissions during the fourth wave of COVID-19 in order to inform future public health policies. Methods: This was a retrospective descriptive study of an early cohort of all adult patients with SARS-CoV-2 infection admitted to a tertiary hospital in Cape Town, South Africa, at the start of the country's fourth wave. This was compared with an early cohort from the first wave at the same institution. Results: In total, 121 SARS-CoV-2-positive admissions from the fourth wave were included. Thirty-one (25.6%) patients had COVID-19 pneumonia, while 90 (74.4%) had incidental SARS-CoV-2 infection. (In the first wave all 116 patients had COVID-19 pneumonia.) Thirty-two (26.4%) patients self-reported complete or partial COVID-19 vaccination, of whom 12 (37.5%) were admitted with COVID-19 pneumonia. Compared with the first wave, there were fewer intensive- or high-care admissions (18/121 [14.9%] vs 42/116 [36.2%]; p < 0.001) and mortality was lower (12/121 [9.9%] vs 31/116 [26.7%]; p = 0.001). Conclusion: Admissions to the COVID-19 wards during the fourth wave primarily included patients with incidental SARS-CoV-2 infection. There was a reduction in the need for critical care and in-hospital mortality. This changing epidemiology of COVID-19 admissions may be attributed to a combination of natural and/or vaccination-acquired immunity.

Progress towards the 2020 targets for HIV diagnosis and antiretroviral treatment in South Africa.

BACKGROUND: The UNAIDS targets for 2020 are to achieve a 90% rate of diagnosis in HIV-positive individuals, to provide antiretroviral treatment (ART) to 90% of HIV-diagnosed individuals and to achieve virological suppression in 90% of ART patients. OBJECTIVES: To assess South Africa's progress towards the 2020 targets and variations in performance by province. METHODS: A mathematical model was fitted to HIV data for each of South Africa's provinces, and for the country as a whole. Numbers of HIV tests performed in each province were estimated from routine data over the 2002-2015 period, and numbers of patients receiving ART in each province were estimated by fitting models to reported public and private ART enrolment statistics. RESULTS: By the middle of 2015, 85.5% (95% CI: 84.5% - 86.5%) of HIV-positive South African adults had been diagnosed, with little variation between provinces. However, only 56.9% (95% CI: 55.3% - 58.7%) of HIV-diagnosed adults were on ART, with this proportion varying between 50.8% in North West and 72.7% in Northern Cape. In addition, 78.4% of adults on ART were virally suppressed, with rates ranging from 69.7% in Limpopo to 85.9% in Western Cape. Overall, 3.39 million (95% CI: 3.26-3.52 million) South Africans were on ART by mid-2015, equivalent to 48.6% (95% CI: 46.0% - 51.2%) of the HIV-positive population. ART coverage varied between 43.0% in Gauteng and 63.0% in Northern Cape. CONCLUSION: Although South Africa is well on its way to reaching the 90% HIV diagnosis target, most provinces face challenges in reaching the remaining two 90% targets.

HIV epidemic drivers in South Africa: A model-based evaluation of factors accounting for inter-provincial differences in HIV prevalence and incidence trends.

BACKGROUND: HIV prevalence differs substantially between South Africa's provinces, but the factors accounting for this difference are poorly understood. OBJECTIVES: To estimate HIV prevalence and incidence trends by province, and to identify the epidemiological factors that account for most of the variation between provinces. METHODS: A mathematical model of the South African HIV epidemic was applied to each of the nine provinces, allowing for provincial differences in demography, sexual behaviour, male circumcision, interventions and epidemic timing. The model was calibrated to HIV prevalence data from antenatal and household surveys using a Bayesian approach. Parameters estimated for each province were substituted into the national model to assess sensitivity to provincial variations. RESULTS: HIV incidence in 15-49-year-olds peaked between 1997 and 2003 and has since declined steadily. By mid-2013, HIV prevalence in 15-49-year-olds varied between 9.4% (95% CI: 8.5%-10.2%) in Western Cape and 26.8% (95% CI: 25.8%-27.6%) in KwaZulu-Natal. When standardising parameters across provinces, this prevalence was sensitive to provincial differences in the prevalence of male circumcision (range 12.3%-21.4%) and the level of non-marital sexual activity (range 9.5%-24.1%), but not to provincial differences in condom use (range 17.7%-21.2%), sexual mixing (range 15.9%-19.2%), marriage (range 18.2%-19.4%) or assumed HIV prevalence in 1985 (range 17.0%-19.1%). CONCLUSION: The provinces of South Africa differ in the timing and magnitude of their HIV epidemics. Most of the heterogeneity in HIV prevalence between South Africa's provinces is attributable to differences in the prevalence of male circumcision and the frequency of non-marital sexual activity.

A mathematical model evaluating the timing of early diagnostic testing in HIV-exposed infants in South Africa.

BACKGROUND: Antiretroviral therapy is often initiated too late to impact early HIV-related infant mortality. Earlier treatment requires an earlier diagnosis, and the currently recommended 6-week HIV polymerase chain reaction (PCR) test needs reconsideration. This study aims to identify (1) optimal testing intervals to maximize the number of perinatal HIV infections diagnosed and (2) programmatic issues that impact diagnosis. METHODS: A mathematical model was developed to simulate antiretroviral prophylaxis uptake and health outcomes in 240,000 HIV-exposed South African infants. The model considered routine early testing with 1 PCR (at birth, 6, 10, or 14 weeks of age) and with 2 PCR tests (at birth and at 6, 10, or 14 weeks of age). RESULTS: A single 6-week test would diagnose the same number of perinatal HIV infections as birth testing (P = 0.92) but fewer infections than a 10-week test (P < 0.01). Ten-week testing identifies the highest number of perinatally infected infants (P < 0.01 compared with a single test at all other ages) but does not save additional life years compared with birth testing (P = 0.27). Performing 2 PCR tests (at birth and 10 weeks) would identify the highest number of perinatal infections (P < 0.01 versus a second 6- or 14-week test). However, 25% of perinatal HIV infections would remain undiagnosed, largely because of failure to return PCR test results to caregivers. CONCLUSIONS: Six weeks may no longer be the optimal age to diagnose perinatal HIV infections. Two early PCR tests (at birth and 10 weeks) would likely be the ideal diagnostic algorithm, but must be coupled with improved program coverage.