Nurse-Led Community Health Worker Adherence Model in 3HP Delivery Among Homeless Adults at Risk for TB Infection and HIV

Tuberculosis (TB) is the prototypical disease of poverty as it disproportionately affects marginalized and impoverished communities. In the US, TB rates are unacceptably high among homeless persons who have a 10-fold increase in TB incidence as compared to the general population. In California, the rate of TB is more than twice the national case rate and recent TB outbreaks have been alarming. Among persons with active TB disease, over 10% die during treatment, with mortality being even higher among homeless persons with TB. While TB can be prevented by treating TB infection (TBI) before it develops into infectious, symptomatic disease, individual factors such as high prevalence of psychosocial comorbidities, unstable housing and limited access to care have led to poor adherence and completion of TBI treatment among homeless persons.

Given the complex health disparity factors that affect TBI treatment adherence among homeless persons, this study will assess the feasibility of a theoretically-based novel model of care among persons with TBI and complex chronic illnesses. This study will evaluate an innovative, community-based intervention that addresses critical individual level factors which are potential mechanisms that underlie health disparities in completing TBI treatment among the predominantly minority homeless. The study hypothesis is that improving these conditions, and promoting health by focused screening for TBI, and early detection and treatment for these vulnerable adults will improve TB treatment completion and prevent future TB disease.

The proposed theoretically-based health promotion intervention focuses on: 1) completion of TBI treatment, 2) reducing substance use; 3) improving mental health; and 4) improving critical social determinants of TB risk (unstable housing and poor health care access) among homeless adults in the highest TB prevalence area in Los Angeles. A total of 76 homeless adults with TBI will receive this program which includes culturally-sensitive education, case management, and directly observed therapy (DOT) delivery of medication among patients who have been prescribed 3HP (12 weeks treatment for latent TB infection) by a medical provider. This study will determine whether this intervention can achieve higher completion rates than the 65% completion rate among homeless persons reported by previous TB programs.

Tuberculosis (TB) is a global public health threat, which is driven by social factors, including poverty, inadequate housing, malnutrition, and substance use. In the United States (US), TB disproportionately impacts homeless populations. When compared to the general population, homeless persons have a 10-fold increase in TB incidence. Lack of stable housing and living in congregate settings are predisposing factors for TB Infection (TBI). Homeless persons who develop active TB disease are also at higher risk of death during TB treatment due to mental illness and substance use. Even one TB case among a homeless person can easily lead to widespread TB transmission due to crowded, poorly ventilated, and congregate living situations. Therefore, an extensive public health response is needed for each case of infectious TB disease that develops among homeless persons.

Given the significant public health impact of TB among homeless persons, development of effective interventions to prevent TB among homeless persons that are theoretically-based and advance science in the area of best adherence strategies to minimize these health disparities can lead to significant benefits for patients and further reduce the disparity in TB rates between homeless and housed persons. While adherence to traditional TBI treatment with 6 to 9 months of isoniazid (INH) has been dismal, over the last few years, a promising treatment option in form of a 12-dose combination therapy (3HP; rifapentine \[RPT\] plus isoniazid \[INH\]), delivered once weekly as directly observed therapy (DOT), has achieved treatment completion rates of 82%. However, homeless populations who are at high risk for TBI have complex, multi-dimensional barriers to TBI treatment adherence. Thus, TBI treatment programs in this population have yielded marginal results of 65% completion to date. Among homeless persons, health disparities are accentuated by additional barriers to TBI treatment adherence, including substance use, mental disorders, and unstable housing.

Given the complex factors that affect TBI treatment adherence among homeless persons, the research team developed a theoretically-based novel model of care that has been successfully investigated in other disadvantaged populations. This model involves understanding the behavioral, psychological, and environmental influences on health and developing culturally-tailored interventions to reduce health disparities, and promote health. By engaging nurses, physicians, and community health workers (CHW), the investigators have developed a team-based approach to better understand and support medication adherence by engaging individuals as active partners in managing their own health. This scientific contribution has the potential to be highly significant as new models of care are being proposed to improve timely entry, engagement and retention in care, and supportive services for homeless persons and other vulnerable populations affected by complex health disparities impacting treatment adherence. The pilot study builds on the investigators' extensive three decades of research with homeless persons in improving health, including TBI treatment adherence, HBV vaccination, and adherence to HIV therapy.

This study will assess the impact of the TBI program that the investigators have developed, as a single arm intervention study, among 76 eligible TBI homeless adults on completion of 3HP treatment, decrease in drug and alcohol use, improved access to care and mental health, and shelter stability. Completion of 3HP will be compared to a minimum standard completion rate of 65%. This small pilot will generate the effectiveness data for a future R01 application to evaluate the intervention in a definitive randomized-controlled trial (RCT).

Eligibility Criteria:
Inclusion Criteria:

* self-reported homeless adults (past six months);
* age 18 or older;
* willing to provide informed consent;
* positive for TBI
* reported current or recent substance use (past three years)

Exclusion Criteria:

* screened as having active TB or currently treated for TBI;
* history of treatment for active TB or TBI;
* a serum aspartate aminotransferase (AST) level of 3-5 times the upper limit of normal;
* HIV infected AND receiving antiretroviral therapy (as 3HP is not recommended yet in this group);
* not able to speak English or Spanish;
* testing pregnant (as 3HP is not recommended in this group); and
* judged to be cognitively impaired