Latent TB Testing Strategies May Miss High Risk Populations

Current latent tuberculosis infection (LTBI) testing practices are missing some important high-risk groups, such as individuals born outside the United States, according to study findings published in Clinical Infectious Diseases.

Researchers sought to obtain a better understanding of gaps in current testing practices for LTBI, which account for over 80% of TB cases in the United States. The researchers obtained electronic health record data from Kaiser Permanente Southern California to identify factors associated with LTBI testing and positivity. The study was conducted from January 1, 2008, through December 31, 2019, among participants at least 18 years of age.

A total of 3,816,884 individuals were eligible for LTBI testing (mean [SD] age, 43.5 [16.1] years; 52% female; 37% White; and 37% Hispanic), of whom 706,367 (18%) were tested for LTBI. Among the eligible individuals, 1,211,971 had at least 1 risk factor for LTBI based on current screening guidelines.

Of the 706,367 individuals who had LTBI testing, 60,393 (9%) tested positive (60% female; 33% aged 18-35 years; 49% Hispanic; and 26% Asian/Pacific Islander). A total of 210,025 participants who had at least 1 LTBI risk factors based on the California Department of Public Health guidelines were tested for LTBI; among these individuals, positivity occurred in 8% of those immunosuppressed before the initial LTBI test and in 22% of those born in a country with an increased TB rate.

Men had lower odds of getting tested for LTBI vs women (adjusted odds ratio [aOR], 0.50; 95% CI, 0.50-0.51). Younger age groups had greater odds of LTBI testing compared with older groups, and the odds of testing were increased among non-Hispanic Black individuals compared with White individuals. Being born in a country that had an increased TB rate was associated with lower odds of testing (aOR, 0.88; 95% CI, 0.87-0.89]), compared with being born in the United States.

Male participants also had higher odds of testing positive for LTBI (aOR, 1.32; 95% CI, 1.30-1.35) compared with female individuals, and older individuals had higher odds of testing positive compared with younger age groups. The odds for testing positive were greater among individuals identifying as Asian/Pacific Islanders (aOR, 2.78; 95% CI, 2.68-2.88), Hispanic (aOR, 2.45; 95% CI, 2.38-2.52), and Black (aOR, 2.28; 95% CI, 2.20-2.37) vs White. Greater neighborhood deprivation was linked to increased odds of LTBI positivity (index quintile 5 vs 1: aOR, 1.17; 95% CI, 1.12-1.23).

Diabetes was associated with greater odds for a positive LTBI test, and the odds of testing positive were lower in individuals with a history of organ transplant, use of high-dose steroids or immunosuppressants, dialysis, leukemia, and HIV infection. The odds of having a positive test among patients with a history of hepatitis B or hepatitis C infection were increased (aOR, 1.45; 95% CI, 1.34-1.57 and aOR, 1.54; 95% CI, 1.44-1.66, respectively). Being born in a country that had an increased TB rate (aOR, 3.40; 95% CI, 3.31-3.49), travel to a TB endemic country within less than 30 days (aOR, 1.74; 95% CI, 1.62-1.86]), and previous exposure to TB (aOR, 4.19; 95% CI, 3.91-4.50) were associated with higher odds of testing positive.

Among several limitations, some TB risk factors were identified at any time during the study period, regardless of timing relative to LTBI testing, and patients with a LTBI diagnosis code without an accompanying LTBI test were excluded. Also, data on country of birth were missing for more than half of the study population.

“Increasing testing in high-risk individuals who are missed by the current testing practices is a priority,” stated the investigators. “Further, routine assessment for TB risk factors, some of which are poorly documented in current clinical practice, such as place of birth and travel history, is needed to more appropriately test high risk populations.”

Disclosure: Some of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.

This article originally appeared on Pulmonology Advisor