Negative tuberculin skin test result predicts all-cause mortality among tuberculosis patients with HIV and diabetes comorbidity.

PURPOSE: The purpose of this study was to determine if a negative tuberculin skin test (TST) result is associated with increased risk of mortality during tuberculosis (TB) treatment.

METHODS

We conducted a retrospective cohort study among patients aged ≥15 years with culture-positive TB reported to the Georgia State Electronic Notifiable Disease Surveillance System from 2009 to 2014. TST positivity was defined by the US Centers for Disease Control guidelines. All-cause mortality during TB treatment as well as HIV, diabetes, and end-stage renal disease status were collected from surveillance data. Log-binomial regression was used to estimate adjusted risk ratios and 95% confidence intervals.

RESULTS

Among 1186 culture-confirmed TB patients, 780 (65.8%) with a valid TST and TB treatment outcomes were eligible. Nearly one-third (242/780) had a negative TST result, and 5.6% died during treatment. The highest risk of death was observed among patients with a negative TST and HIV (12.5%) and a negative TST and diabetes (15.4%). Adjusting for confounders, the risk of death among patients with a negative TST was significantly greater compared with those with a positive TST (adjusted risk ratio 2.33 95% confidence interval 1.23-4.43).

CONCLUSIONS

A negative TST was associated with more than twice the risk of mortality during TB treatment after adjusting for immunosuppressive conditions.