Tuberculosis Drug Levels and Continuous Glucose Monitoring in Diabetic Patients

Diabetes significantly increases the risk of developing active tuberculosis (TB). Diabetic patients who do develop TB have worse treatment outcomes and overall mortality. TB also worsens blood glucose control in diabetics, the mechanism of which is not well understood. The incidence of type 2 diabetes is rising globally, and consequently diabetes and TB co-infection is increasingly common, and improving outcomes in this cohort is of growing importance. Low TB drug levels in diabetic patients have been postulated as a reason for these worse outcomes. There is however contradictory evidence in the literature that TB drug levels really are consistently and significantly lower in diabetics compared with non-diabetics. If this were shown to be the case, performing therapeutic drug monitoring in diabetic patients may be a straightforward way to improve outcomes. Improving blood glucose control may also lead to improved outcomes, however there is nothing previously in the literature looking at detailed blood glucose monitoring in diabetic patients being treated for TB. This study is planned as a case control study comparing 24 non-diabetic patients commencing TB treatment with 24 cases who have both TB and diabetes. Samples for post-dose TB drug levels will be taken at 2 time points at weeks 2, 8 and 16. These will be analysed via population pharmacokinetics to compare pharmacokinetic profiles between the 2 groups, with the hypothesis that the diabetic group will have a significantly lower exposure to TB drugs than the non-diabetic group. The diabetic group will also be asked to wear a continuous glucose monitor (blinded Dexcom) for 10 days at baseline and week 16, with data compared between the 2 time points.