Comparison of bacteriological conversion and treatment outcomes among MDR-TB patients with and without diabetes in Mexico: Preliminary data

Diabetes mellitus (DM) is a well-known risk factor for tuberculosis (TB). However, it is not known to what extent DM affects the outcome in patients with multidrug-resistant (MDR-TB) and extensively drug-resistant TB (XDR-TB) treated with second-line anti-TB drugs.

The objective of this study was to compare the microbiological evolution (sputum smear and culture conversion) and final outcomes of MDR/XDR-TB patients with and without DM, managed at the national TB reference centre in Mexico City.

Results

Ninety patients were enrolled between 2010 and 2015: 73 with MDR-TB (81.1%), 11 with pre-XDR-TB (e.g. MDR-TB with additional resistance to one injectable drug or a fluoroquinolone, 12.2%) and 6 (6.7%) with XDR-TB. Out of these, 49 (54.4%) had DM and 42 (86%) were undergoing insulin treatment.

No statistically significant differences were found in treatment outcomes comparing DM vs. non-DM MDR-TB cases: 18/32 (56.3%) of DM cases and 19/24 (79.2%) non DM patients achieved treatment success (p = 0.07). The time to sputum smear and culture conversion was longer (although not statistically) in patients without DM, as follows: the mean (±SD) time to sputum smear conversion was 53.9 (±31.4) days in DM patients and 65.2 (±34.8) days in non-DM ones (p = 0.15), while the time to culture conversion was 66.2 (±27.6) days for DM and 81.4 (±37.7) days for non-DM MDR-TB cases (p = 0.06).

Conclusions

The study results support the Mexican National TB programme to strengthen its collaboration with the DM programme, as an entry point for TB (and latent TB infection) screening and management.