ABSTRACT
SETTING: Primary health care clinics. OBJECTIVES: To determine the prevalence of diabetes mellitus (DM) in tuberculosis (TB) patients using glycated haemoglobin (HbA1c), and to compare the performance of laboratory and point-of-care (POC) HbA1c measurement. METHODS: This was a cross-sectional study of 325 patients. Screening was at POC using laboratory HbA1c methods; DM was confirmed by the oral glucose tolerance test (OGTT). Multivariate regression analysis was performed to determine predictors of HbA1c. RESULTS: Mean laboratory-derived HbA1c was significantly higher than mean POC HbA1c (P = 0.007). Of 83 subjects who underwent OGTT, 2 (2.4%) were diagnosed with DM, 3 (3.60%) with impaired fasting glucose and 15 (18.1%) with impaired glucose tolerance. Twelve (14.5%) had an HbA1c of î¶6.50% using POC HbA1c and 21 (25.3%) using laboratory HbA1c. In multivariate regression analysis, age and weight were positively associated with both laboratory and POC HBA1c, while duration of anti-tuberculosis treatment was negatively associated with both. CONCLUSION: Glucose and HbA1c levels fell with increased duration of anti-tuberculosis treatment, suggesting that the optimal time for DM screening in this population was at least 5 months after TB was first diagnosed. Our data suggest that the use of HbA1c is inappropriate for testing glycaemia in patients with TB.
