Senior Statistician at the South African Medical Research Council (SAMRC), Dr Nobuhle Mchunu is delighted with her PhD achievement.
‘As a Biostatistician, my role is to help clinical researchers make informed, data-driven decisions that shape health policies and guidelines,’ said Mchunu. ‘At the SAMRC and beyond, I work with researchers, scientists and students, providing statistical expertise for clinical trials and biomedical studies. This includes designing studies, determining appropriate sample sizes, developing analysis plans and performing advanced statistical analyses.’
Her PhD research focused on developing personalised screening intervals using an advanced statistical model – multivariate joint modelling. ‘We simultaneously modelled CD4 counts and viral load trajectories over time to predict the risk of death,’ she explained.
Unlike traditional methods that use a one-size-fits-all approach at fixed-intervals (eg follow-up at every six months for all patients), Mchunu generated personalised follow-up schedules based on a cumulative risk function that accounted for each patient’s specific health data, such as their CD4 count, viral load trends and time since their last visit.
‘This method tailors screening schedules, allowing stable, low-risk patients to have fewer visits while ensuring that high-risk patients are monitored more frequently,’ she said. ‘This personalised strategy not only optimises healthcare efficiency and minimises unnecessary clinic visits, but also ensures timely interventions for those who need it most.’
Mchunu’s research is particularly relevant as it fills a gap in the joint modelling literature by incorporating censored longitudinal outcomes (eg viral loads), offering a more flexible and accurate approach to complex data scenarios.
A manuscript based on her work is currently under review in a statistical journal, and she has two additional International Statistical Institute (ISI) peer-reviewed publications stemming from her PhD research. She has also co-authored 14 peer-reviewed ISI publications.
Mchunu’s PhD research was largely inspired by the SAPIT (Starting Antiretroviral Therapy at Three Points in Tuberculosis) trial, conducted by the Centre for the AIDS Programme of Research in South Africa (CAPRISA).
‘This groundbreaking study demonstrated that initiating antiretroviral therapy (ART) alongside tuberculosis (TB) treatment significantly reduced mortality rates among co-infected individuals,’ said Mchunu. ‘SAPIT played a pivotal role in changing global treatment guidelines, which previously recommended delaying ART until TB treatment was completed.’
While SAPIT made a significant impact, it used a one-size-fits-all approach, measuring CD4 count and viral load at fixed six-month intervals, regardless of individual health status.
‘My research advances the SAPIT trial by adopting a personalised, data-driven approach. By using multivariate joint modeling, we tailored follow-up intervals based on each patient’s unique health factors, such as their CD4 count, viral load and overall risk profile, providing a more efficient and individualised healthcare approach.’
Mchunu’s research has the potential to revolutionise patient care by introducing a personalised approach to screening for individuals co-infected with TB and HIV.
By tailoring screening intervals based on each patient’s health status, healthcare resources can be optimised, reducing unnecessary testing and allocating resources more effectively. This is especially important in high-burden, resource-limited settings similar in many parts of Africa, where healthcare systems often face significant challenges.
‘For patients showing signs of deterioration, more frequent monitoring enables timely interventions, preventing complications and improving health outcomes,’ said Mchunu.
Her approach contributes to the growing field of precision medicine by using data-driven methods to provide individualised care, ensuring that interventions are tailored to the specific needs of each patient.
While the research is focused on the application of TB/HIV co-infection, the methodology is broadly applicable to other research domains, offering a framework for personalised healthcare strategies in various medical fields.
‘This approach has broad implications, as it not only enhances current patient care protocols but also lays the groundwork for future clinical trials and the development of biomarker-guided therapies,’ said Mchunu.
Mchunu plans to develop a practical web tool that clinicians can use to tailor personalised screening intervals for patients at outpatient clinics based on their unique risk profiles.
‘This tool can enhance clinical decision-making by providing real-time, data-driven recommendations,’ said Mchunu, who is committed to building capacity in joint modelling by mentoring colleagues and postgraduate students in Biostatistics, and fostering international research collaboration.
Mchunu paid tribute to the SAMRC Biostatistics Research Unit for funding her research and providing the necessary time and resources for her to pursue her studies. She thanked her fiancé and family for their support, and recognised her PhD supervisors – Professor Henry Mwambi, Professor Dimitris Rizopoulos and Dr Tarylee Reddy – for their expertise and guidance. Additionally, her mentor, fellow UKZN alumnus Dr Nonhlanhla Yende-Zuma, had a profound impact on her growth, providing invaluable advice and helping her navigate challenges with clarity and confidence.
Mchunu shared this advice for those pursuing or considering a PhD: ‘The journey can be challenging, but with dedication, perseverance and the right support, it’s possible to overcome any obstacles. By staying focused on your goals and believing in your abilities, hard work will ultimately pay off.’
Said Mwambi: ‘Nobuhle is a true UKZN role model for future biostatisticians and statisticians. She has done all her studies at UKZN, namely her undergraduate degree, honours, masters (in collaboration with CAPRISA), and PhD (in collaboration with a professor of Biostatistics in The Netherlands), and is now a Senior Statistician at the South African Medical Research Council. She is indeed a great motivation to others!’
Words: Sally Frost
Photograph: Sethu Dlamini
