Determinants of Poor Glycaemic Control in Adults with Diabetes in a High-HIV-Burden South African Diabetes Clinic

Background and study aim: South Africa faces overlapping epidemics of diabetes and HIV. Achieving glycaemic targets is essential to prevent complications, yet many patients remain uncontrolled. The Society for Endocrinology, Metabolism and Diabetes of South Africa (SEMDSA) defines HbA1c ≥8% as the threshold for treatment intensification. Whether HIV independently worsens glycaemic control remains uncertain.Patients and Methods: A retrospective cohort study was conducted at a tertiary-linked public diabetes clinic in KwaZulu-Natal (2021–2025). Adults with documented HIV status and HbA1c results were included. Covariates included BMI, systolic blood pressure, diabetes type, duration, and insulin or statin use. Missing data were handled using a Missing-Indicator Approach. Generalized estimating equations (GEE) analysed all visits clustered by patient, while ridge-penalized logistic regression assessed the latest visit per patient.Results: A total of 543 visits from 131 patients (33 HIV-positive, 98 HIV-negative) were analysed. Poor glycaemic control was frequent: 75.9% of visits had HbA1c ≥8% and 86.4% had HbA1c ≥7%; at the latest visit, 84.0% and 88.5%, respectively, were uncontrolled. In GEE models, HIV-positive status predicted HbA1c ≥8% (aOR 13.0, 95% CI 5.22–32.39, p