Risk of Incident Tuberculosis Disease in a Large Integrated Health Care System in California, 2004-2022

Few studies have assessed tuberculosis (TB) disease incidence and risk in a large US-based cohort with long-term longitudinal follow-up.

In a retrospective cohort study from 2004 to 2022, we assessed risk of incident microbiologically confirmed TB disease using Cox proportional hazards models. Primary exposures were (1) nativity and (2) high-risk medical conditions for progression to TB disease.

Among 4 761 427 adults with 35 591 565 person-years (PY) of follow-up, 12.3% were born in TB-endemic countries and 5.5% had a high-risk medical condition. In all, 1463 had incident TB disease (incidence rate, 4.11/100 000PY), with persons born in TB-endemic countries (incidence rate [IR], 17.6/100 000PY; 95% CI, 16.4-18.7/100 000PY) having higher TB disease rates than US-born persons (IR, 1.27/100 000PY; 95% CI, 1.09-1.44/100 000PY), with an adjusted hazard ratio (aHR) of 15.3 (95% CI, 13.2-17.9). Persons with high-risk conditions (IR, 11.3/100 000PY; 95% CI, 10.0-12.6/100 000PY) had higher TB disease rates than persons without any conditions (IR, 2.63/100 000PY; 95% CI, 2.43-2.82/100 000PY). Persons with HIV infection (aHR, 3.77; 95% CI, 2.7-3.89), hematologic malignancy (aHR, 1.62; 95% CI, 1.17-2.22), diabetes mellitus (aHR, 2.85; 95% CI, 2.53-3.20), end-stage renal disease (aHR, 2.84; 95% CI, 2.07-3.20), and those who had received corticosteroids (aHR, 1.39; 95% CI, 1.10-1.77) or other immunosuppressants (aHR, 2.37; 95% CI, 1.73-3.24) had significantly increased TB disease risk compared with persons without those conditions. Persons born in TB-endemic countries accounted for 79.1% all TB cases among persons with high-risk conditions.

Persons born in TB-endemic countries are the largest group and have the highest risk for developing TB disease in the United States, and thus should be prioritized for LTBI screening and treatment.