Predictors of latent tuberculosis infection treatment completion in the United States: an inner city experience

AN ESTIMATED 9–14 million persons in the United States have latent tuberculosis infection (LTBI), and are therefore at risk for progression to active tuberculosis (TB) disease.1 Diagnosis and treatment of LTBI (TLTBI) have been identified by the Centers for Disease Control and Prevention (CDC) and the Institute of Medicine as a major strategy for elimination of TB in the United States.2,3 Approximately 200 000–300 000 individuals are treated annually for LTBI in the United States, with reported TLTBI completion rates in the United States ranging from 20% to 65% for a 6-month course of self-administered treatment, while some studies found higher completion rates.4 In a national survey, Horsburgh et al. reported 47% completion among patients treated in 2002.5 Better understanding of factors associated with TLTBI completion rates is essential to efforts to eliminate TB in this country. The challenge of TLTBI is particularly critical in inner city neighborhoods such as New York City’s Central Harlem, where rates of TB greatly exceed the national average (23.2 vs. 4.4/100 000 in 2007, respectively6) and elevated rates of human immunodeficiency virus (HIV) infection increase the population vulnerable to TB. Harlem has long been a predominantly African-American community and is home to a growing African immigrant population. Potential barriers to medication adherence in Harlem include poverty, drug and alcohol use, homelessness, fragile or inadequate social support networks, low awareness of available low-cost or free health care services, and a dearth of culturally appropriate health care. TB-related social stigma, which gives rise to fears of discrimination and isolation, may also impede acceptance and completion of TLTBI. Few studies have examined predictors of adherence and completion of TLTBI, and the few that have been conducted in inner city populations have focused on selected demographic groups7–11 rather than broader clinic populations.12–15 Furthermore, few prior studies have given significant attention to TB attitudes. The objectives of the present study were to assess TLTBI completion rates and predictors of completion, including TB knowledge and attitudes, among an inner-city cohort. Foreign birth, homelessness, and current substance use were hypothesized a priori to be risk factors for TLTBI non-completion.