OBJECTIVE: 1) To determine the prevalence of diabetes mellitus and impaired fasting glucose (IFG) in patients with TB and HIV co-infection, and 2) to investigate the effect of fasting plasma glucose (FPG) on rifampicin (RIF) and isoniazid (INH) serum concentrations.

DESIGN: Retrospective data analysis of a cohort of HIV-infected adults with newly diagnosed pulmonary TB. Plasma glucose and TB drug levels were obtained at Week 0, 2, 8 and 24 of TB treatment.

RESULTS: A total of 107 patients were included in this analysis. Random plasma glucose ≥200 mg/dL was found in 1/53 (2%) participant at Week 0. The prevalence of FPG ≥ 126 mg/dL decreased from 8/41 (20%) at Week 2 to 3/89 (3%) at Week 24. IFG (100-125 mg/dL) was observed in 23/41 (56%) participants at Week 2, and 39/89 (44%) at Week 24. FPG was inversely correlated with lower area under the curve (AUC_0-24h) for RIF (c = -0.52; 95%CI -0.84 to -0.21; P = 0.001). FPG was not associated with lower INH AUC_0-24h.

CONCLUSION: We found a high prevalence of FPG ≥ 126 mg/dL, which decreased significantly during treatment, and a high proportion of IFG at the end of TB treatment. Higher FPG was associated with lower AUC for RIF.