CORRESPONDENCE

 

Prevalence of primary HIV-associated thrombocytopenia in a central South African population

 

 

To the Editor: Haematological abnormalities are common manifestations in HIV-positive individuals. Thrombocytopenia (platelet count <150 x 10⁹/L) is one of the major haematological abnormalities in HIV-positive individuals in South Africa (SA).^[1] Thrombocytopenia may develop at any stage of the HIV infection, and can have many underlying causes.^[2-4] Primary HIV-associated thrombocytopenia (PHAT) is thrombocytopenia in HIV-positive individuals in the absence of any secondary causes.^[5] Proposed mechanisms include immune-mediated destruction of platelets and decreased platelet production following megakaryocyticinfection by HIV.^[2] PHAT may cause clinically significant bleeding, and when left unrecognised, may complicate patient management.^[6,7] SA has the highest prevalence of HIV globally.^[8,9] Consequently, we hypothesised that PHAT should have a high prevalence in our population.

Ethics approval from the Health Sciences Research Ethics Committee of the University of the Free State (ref. no. UFS-HSD2020/1752/2302), as well as permission from the Free State and Northern Cape Departments of Health, and Academic Affairs and Research Office of National Health Laboratory Service (NHLS), was obtained to perform the study. We extracted full blood count reports from the laboratory information system of specimens submitted to the NHLS laboratories at four hospitals in our region (National District Hospital, Pelonomi Regional Hospital and Universitas Academic Hospital in Bloemfontein, and Robert Mangaliso Sobukwe in Kimberley).

A total of 6 068 patient files were screened from February 2021 to April 2022 (Fig. 1). Of the 6 068 patients, 902 (14.86%) had thrombocytopenia, of whom 640 (70.95%) were HIV- positive. After excluding all patients with additional cytopenias, 269 patients (42.03%) remained.

 

 

The medical files of all isolated thrombocytopenia cases were subsequently screened, and patients excluded when possible secondary causes for the decreased platelet count (e.g. drugs, COVID-19, TB, hepatitis, abnormal liver and kidney function, and pseudothrombocytopenia) were identified.

Ultimately, 42 patients were considered to have probable PHAT, with an estimated prevalence of 0.69% in our total patient population. This proportion increases to 6.56% of all HIV-positive individuals with thrombocytopenia and 15.61% of HIV-positive patients with isolated thrombocytopenia. A previous local study^[10] (KwaZulu-Natal, SA) found the prevalence of thrombocytopenia in their population to be 14.9%, which corresponds to our study prevalence of 14.86%. One global study^[6] reported the prevalence of thrombocytopenia in HIV-positive individuals to be 17.9%. However, unlike our study, they did not further exclude comorbidities to determine the prevalence of PHAT. The prevalence of immune thrombocytopenia in hospitalised patients (4.6%) was determined to be slightly lower in a previous SA study^[10] than the prevalence of PHAT in HIV-positive individuals in our study (6.56%).

Most PHAT patients in our study (71.43%) were on antiretroviral treatment (ART), suggesting that ART exposure was not protective against the development of PHAT This contrasts with reports of improvement in cytopenias subsequent to ART.^[1,5,6]

We conclude that PHAT remains a concern in HIV-positive patients in our region, even after the rollout of the Universal Test and Treat ART treatment campaign.

Asymptomatic, isolated thrombocytopenia may go undetected until life-threatening bleeding occurs. Therefore, it is imperative to identify patients with PHAT and monitor their disease progression to improve patient management.

Lomari Geertsema

Human Molecular Biology Unit, School of Biomedical Sciences, Faculty of Health Sciences, University of the Free State, Bloemfontein, SA

Anne-Cecilia van Marle

Department of Haematology and Cell Biology, School of Pathology, Faculty of Health Sciences, University of the Free State, Bloemfontein, SA, and National Health Laboratory Service, Universitas Academic Business Unit, Bloemfontein, SA

Walter J Janse van Rensburg

Human Molecular Biology Unit, School of Biomedical Sciences, Faculty of Health Sciences, University of the Free State, Bloemfontein, SA jansevrwj@ufs.ac.za

 

References

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