Importance Tuberculosis (TB) was the leading infectious cause of death worldwide in 2023. Most US TB cases represent reactivation of latent TB infection (LTBI). Because LTBI treatment is approximately 90% effective for preventing TB disease, LTBI screening and treatment are primary strategies for US TB elimination. The Tuberculosis Epidemiologic Studies Consortium-III (TBESC-III) supports US TB elimination efforts by addressing LTBI among individuals at higher risk of infection seeking care in US primary care clinics.

Objective To characterize and measure outcomes across a longitudinal LTBI care cascade, from proportion of persons at higher risk through testing, diagnosis, and treatment.

Design Longitudinal study using patient-level electronic health record (EHR) data.

Setting Primary care clinics serving at least 10,000 non–US-born individuals annually from countries with high TB disease incidence rates (defined as ≥10 cases per 100,000 persons among expatriates living in the US).

Participants Persons at higher risk of TB infection, defined as non-US birth or, if unknown, a non-English language preference, who had a visit during the study period at a participating clinic.

Intervention(s) (for clinical trials) or Exposure(s) (for observational studies) Not relevant

Main Outcome(s) and Measure(s) Among participants without prior TB or LTBI testing, diagnosis, or treatment documented (ie, cascade eligible), we determined proportions: tested for TB infection, with available test results, with positive results, chest imaging ordered, LTBI diagnoses, and with LTBI treatment prescribed, started, and completed. Percentages were averaged across four sites representing multiple clinics.

Results Of 3.5 million persons seeking care, on average, 48% were at higher risk of TB infection, and 69% of these were cascade eligible. Among cascade eligible individuals, 14% were tested; 92% of those tested had available results, with 17% testing positive. Of those testing positive, 82% underwent chest imaging; 70% met LTBI diagnostic criteria. Among those diagnosed, 61% were prescribed treatment; 87% started treatment, with 56% completing treatment.

Conclusions and Relevance Although an average of 17% of participants tested had TB infection, most (average, 86%) higher-risk individuals were not tested; an average of 39% of those diagnosed were not prescribed treatment, and nearly half (average, 44%) did not complete treatment. Targeted interventions to increase LTBI testing and treatment completion among higher-risk individuals could facilitate more preventive treatment and reductions in TB-associated morbidity.

The authors have declared no competing interest.

The study was supported by funding from the Centers for Disease Control and Prevention (CDC) Tuberculosis Epidemiologic Research Consortium with the following collaborators: Denver Health and Hospital Authority (contract number 75D30121C12877), Kaiser Permanente Northern California (contract number 75D30121C12878), Public Health Seattle and King County (contract number 75D30121C12880), and University of California - San Francisco (contract number 75D30121C12879).

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

This study was reviewed by and conducted under the authority of the CDC and was determined to not be human subjects research (de-identified individual-level data)

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes

All data produced in the present study will be made publicly available after the conclusion of the contract.