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UFS PhD study focuses on improving life expectancy of HIV/Aids patients

11 December 2019 | Story Leonie Bolleurs

According to Global Statistics, there were approximately 37,9 million people across the globe with HIV/Aids in 2018. They also state that in 2018, an estimated 1,7 million individuals worldwide became newly infected with HIV.

In the city of Masvingo, Zimbabwe, Claris Shoko is a Statistics lecturer at the Great Zimbabwe University. In her PhD thesis at the University of the Free State (UFS) in the Department of Mathematical Statistics and Actuarial Sciences, she presented the argument that the inclusion of both the CD4 cell count and the viral-load counts in the monitoring and management of HIV+ patients on antiretroviral therapy (ART), is helping in reducing mortality rates, leading to improved life expectancy for HIV/Aids patients.

She received her doctoral degree at the December UFS Graduation Ceremonies, with her thesis: Continuous-time Markov modelling of the effects of treatment regimens on HIV/Aids immunology and virology.

CD4 cell count and viral-load count

Dr Shoko explains: “When the human immunodeficiency virus (HIV) enters the human body, the virus attacks the CD4 cells in their blood. This process damages CD4 cells, causing the number of white blood cells in the body to drop, making it difficult to fight infections.”

“Clinical markers such as CD4 cell count and viral-load count (number of HIV particles in a ml of blood) provide information about the progression of HIV/Aids in infected individuals. These markers fully define the immunology and the virology of HIV-infected individuals, thereby giving us a clear picture of how HIV/Aids evolve within an individual.”

Dr Shoko continues: “The development of highly active antiretroviral therapy (HAART) has helped substantially to reduce the death rate from HIV. HAART reduces viral load-count levels, blocking replication of HIV particles in the blood, resulting in an increase of CD4 cell counts and the life expectancy of individuals infected with HIV. This has made CD4 cell counts and viral-load counts the fundamental laboratory markers that are regularly used for patient management, in addition to predicting HIV/Aids disease progression or treatment outcomes.”

In the treatment of HIV/Aids, medical practitioners prescribe combination therapy to attack the virus at different stages of its life cycle, and medication to treat the opportunistic infections that may occur. “The introduction of combined antiretroviral therapy (cART) has led to the dramatic reduction in morbidity and mortality at both individual level and population level,” states Dr Shoko.

Once HIV-positive patients are put on cART, the effectiveness of treatment is monitored after the first three months and a further follow-up is done every six months thereafter. During the monitoring stages, CD4 cell count and viral load is measured. Patients are also screened for any tuberculosis (TB) co-infection and checked for any signs of drug resistance. These variables determine whether or not there is a need for treatment change.

She continues: “Previous studies on HIV modelling could not include both CD4 cell count and viral load in one model, because of the collinearity between the two variables. In this study, the principal component approach for the treatment of collinearity between variables is used. Both variables were then included in one model, resulting in a better prediction of mortality than when only one of the variables is used.”

“Viral-load monitoring helps in checking for any possibilities of virologic failure or viral rebound, which increases the rate of mortality if not managed properly. CD4 cell count then comes in to monitor the potential development of opportunistic infections such as TB. TB is extremely fatal, but once detected and treated, the survival of HIV/Aids patients is assured,” Dr Shoko explains.

Markov model

She applied the Markov model in her study. The model, named after the Russian mathematician Andrey Markov, represents a general category of stochastic processes, characterised by six basic attributes: states, stages, actions, rewards, transitions, and constraints.

According to Dr Shoko, Markov models assume that a patient is always in one of a finite number of discrete states, called Markov states. All events are modelled as transitions from one state to another. Each state is assigned a utility, and the contribution of this utility to the overall prognosis depends on the length of time spent in each state. For example, for a patient who is HIV positive, these states could be HIV+ (CD4 cell count above 200 cells/mm3), Aids (CD4 cell count below 200 cells/mm3) and Dead.

“Markov models are ideal for use in HIV/Aids studies, because they estimate the rate of transition between multiple-disease states while allowing for the possible reversibility of some states,” says Dr Shoko, quoting Hubbard and Zhou.

“Relatively fewer HIV modelling studies include a detailed description of the dynamics of HIV viral load count during stages of HIV disease progression. This could be due to the unavailability of data on viral load, particularly from low- and middle-income countries that have historically relied on monitoring CD4 cell counts for patients on ART because of higher costs of viral load-count testing,” Dr Shoko concludes

News Archive

In January 1, 2003, the Qwa-Qwa campus of the University of the North (Unin) was incorporated into the University of the Free State (UFS).

2003-02-07

FREDERICK FOURIE

IN January 1, 2003, the Qwa-Qwa campus of the University of the North (Unin) was incorporated into the University of the Free State (UFS).

While this is merely the beginning of a long and complex process, it does represent a major milestone in overcoming the apartheid legacy in education, realising the anti-apartheid goal of a single non-racial university serving the Free State.

The incorporation is also part of the minister's broader restructuring of the higher education landscape in South Africa - a process which aims to reshape the ideologically driven legacy of the past.

In contrast to the past educational and social engineering that took place, the current process of incorporating the Qwa-Qwa campus of Unin into the UFS is informed by three fundamentally progressive policy objectives, clearly outlined in the education white paper 3: (A framework for the transformation of higher education):

To meet the demands of social justice to address the social and structural inequalities that characterise higher education.

To address the challenges of globalisation, in particular the role of knowledge and information processing in driving social and economic development.

To ensure that limited resources are effectively and efficiently utilised, given the competing and equally pressing priorities in other social sectors.

Besides informing the way the UFS is managing the current incorporation, these policy objectives have also informed the transformation of the UFS as an institution over the past five years.

In 2001, former president Nelson Mandela lauded the success of the UFS in managing this transformation, by describing the campus as a model of multiculturalism and multilingualism. This was at his acceptance of an honorary doctorate from the UFS.

Indeed our vision for the Qwa-Qwa campus as a branch of the UFS is exactly the same as it is for the main UFS campus - a model of transformation, academic excellence, community engagement and financial sustainability, building on the histories and strengths of both the Qwa-Qwa campus and the UFS (Bloemfontein campus).

Realising this vision will be a giant leap forward in establishing a unified higher education landscape in the Free State.

In more concrete terms, the UFS is working towards this vision by focusing on the following areas of intervention: access and equity; academic renewal; investment in facilities; and sound financial management.

These interventions are being made not to preserve any vestiges of privilege or superiority, but precisely to increase access for students from poor backgrounds and to promote equity and representivity among all staff.

The current growth phase of the UFS has seen student enrolment almost double over the past five years, in particular black students, who now constitute approximately 55 percent of the student population of nearly 18 000 (including off-campus and online students).

But it has not just been a numbers game. Our approach has been to ensure access with success.

Our admissions policy, coupled with the academic support and "career preparation" programmes we offer, have resulted in significant successes for students who otherwise would not have been allowed to study at a university.

This will be continued at Qwa-Qwa as well.

Our academic offerings too have undergone dramatic change. We have become the first university in the country to offer a degree programme based on the recognition of prior learning (RPL).

This is not just a matter of academic renewal but of access as well, especially for working adults in our country who were previously denied a university education.

As for the sound financial management of the UFS (including the Qwa-Qwa campus), this is being done not for the sake of saving a few rands and cents, but for the greater value to our society that comes from having sustainable institutions.

It is sustainable universities that can make long-term investments to fund employment equity, provide information technology for students, upgrade laboratories, construct new buildings, develop research capacity, and provide a safe environment for students and staff, as is happening now at the UFS.

As a result of such management, a practical benefit for prospective students at the Qwa-Qwa campus of the UFS will be lower academic fees in some cases compared with the Unin fees.

As is the case with all these processes, there are concerns from staff and students at Qwa-Qwa and the broader community of the region that the Qwa-Qwa campus serves.

To get the campus viable and to ensure its continuation in the short term, tough choices had to be made by the minister of education regarding which programmes to offer and fund.

But we have been encouraged by the community's understanding that these concerns can be addresed over time as the campus becomes financially viable.

Meetings between the top mangement of the UFS and community representatives, staff and students at Qwa-Qwa have laid the basis for building a climate of trust in such a complex process.

We should not be captives of the past divisions but build this new unified higher education landscape that can meet our country's developmental needs.

It should be a higher education landscape that is based on broadening access, promoting equity and social justice, developing academic excellence, and the effective and efficient management of scarce resources. This should be our common common objective.

Professor Frederick Fourie the rector and vice-chancellor of the University of the Free State (UFS)

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