Synergy between low body mass index and hyperglycemia at baseline increases tuberculosis incidence among people living with HIV.

OBJECTIVES Low body mass index (BMI) and hyperglycemia are each important risk factors for tuberculosis (TB). However, the contribution of synergy between low BMI and hyperglycemia to risk of TB among people living with HIV (PLHIV) is unexplored. We compared TB incidence among PLHIV with different exposure profiles to low BMI (BMI < 18.5 kg/m2) and hyperglycemia (random blood glucose ≥140 mg/dl). DESIGN AND METHODS We conducted a cohort study using data of PLHIV (≥15 years) who enrolled in Myanmar's Integrated HIV Care Program between 2011 and 2017. We used their follow-up data until 2018 to determine TB incidence. RESULTS Among 20,865 PLHIV included in this study, 7,610 (36%) had low BMI only, 1,324 (6%) had hyperglycemia only, and 465 (2%) patients had concurrent low BMI and hyperglycemia (joint exposure) at baseline. During a median follow-up of 2.2 years (IQR: 0.5, 4.2), 3,628 (17%) developed TB (6.7, 95% CI: 6.5,7.0 cases per 100 person-years [PY]). TB incidence among PLHIV with joint exposure was 21.0 (95% CI: 18.0, 24.7), with low BMI only was 10.9 (95% CI: 10.4, 11.4), with hyperglycemia only was 5.2 (95% CI: 4.4, 6.3) and with no exposure was 4.6 (95% CI: 4.4, 4.9) cases per 100PY. The attributable proportion of incident TB due to synergy between low BMI and hyperglycemia was 0.23 (95% CI: 0.06, 0.36). CONCLUSIONS Synergy between low BMI and hyperglycemia was associated with increased excess TB incidence in PLHIV. TB preventive treatment, nutritional support, and hyperglycemia management should be evaluated as interventions to reduce TB risk in PLHIV with joint exposure.