Continuity of Care for Patients with Tuberculosis Relocating to Other Countries — CureTB Program, 2016–2023

Abstract

Patients who have received a diagnosis of tuberculosis (TB) disease face barriers to continuing and completing TB treatment when they relocate between countries, potentially resulting in lower treatment completion rates. Treatment for TB disease can range from 6 months to more than 2 years in duration; failure to complete treatment increases the risk for TB transmission and emergence of drug resistance. CDC’s CureTB program makes follow-up TB care referrals for persons relocating to or from the United States, either as temporary visitors or when returning to their home countries, by providing information directly to public health authorities at patients’ destinations. To evaluate program performance, public health officials examined 2016–2023 CureTB referral outcomes and treatment completion rates. Among 6,944 referral requests received from U.S. or foreign authorities during 2016–2023, approximately one half (3,912; 56%) were for patients with suspected TB, and approximately one third (2,404; 35%) were for patients with confirmed TB. Among patients who had received a diagnosis of TB for whom a request for a referral was made, CureTB made referrals for 1,741 (72%), including 1,622 (93%) persons relocating to other countries and 119 (7%) relocating to U.S. destinations. Referrals were not required for 522 (22%) persons, and referrals could not be completed for 141 (6%) because information needed to contact the patient was insufficient. Overall, within 12 months of referral, 1,379 (79%) of 1,741 referred patients completed treatment. Among 1,287 (74%) referred patients for whom data on timing of initiation of care were available, treatment completion rates were highest (91%) for 637 patients linked to treatment ≤30 days after departure, followed by 89% for 505 patients linked within 1–3 months, and 85% for 145 linked within 3–12 months. Timely initiation of care can facilitate continuity of care and support completion of TB treatment. CureTB supports the global goals of reducing TB transmission, improving treatment completion rates, and enhancing progress toward TB elimination in the United States; the program can serve as a model for other countries.

Introduction

Worldwide, 10.8 million persons received a new diagnosis of tuberculosis (TB) disease during 2023 (1). TB remains a global public health concern because of its high rate of transmission, potential for drug resistance, associated morbidity and mortality, effect on the health of populations at risk for exposure, and challenges in diagnosis and treatment (1). The 9,633 new TB diagnoses in the United States during 2023 represented a 15.6% increase compared with the 8,332 cases reported during 2022 and an 8.3% increase compared with the 8,895 cases reported during 2019, the year preceding the onset of the COVID-19 pandemic (2). Patients who have received a TB diagnosis might relocate to another country before finishing their treatment, as was documented for 3.3% of patients who received a diagnosis of TB in the United States during 2016 (3). Although baseline TB treatment completion rates specific to persons relocating are not available, those who relocate are generally at higher risk for failure to complete treatment because they might face unique challenges, including language barriers, unfamiliarity with health care systems, and other socioeconomic barriers to accessing services at their destination (4,5). Furthermore, lack of medical documentation (including results of mycobacterial cultures, drug susceptibility testing, and treatment history) from the site where evaluation and treatment were initiated could delay or hinder clinical care in destination countries. Treatment for TB disease can range from 6 months to more than 2 years in duration; failure to complete treatment increases the risk for TB transmission and emergence of drug resistance (6).

The CureTB program, started in 1997 by the San Diego County Tuberculosis Control and Refugee Health program and managed by CDC since 2016, facilitates treatment continuity for patients who relocate into or out of the United States before completing their TB treatment.* CureTB initially supported patients relocating between the United States and Mexico, with limited subsequent expansion to include Central America. During 2016, CDC expanded services to facilitate worldwide referrals to the public health system in the destination country for persons relocating out of or into the United States. CureTB receives requests for referrals from TB programs across the United States, other federal agencies, and national TB programs worldwide.

CureTB works primarily with patients who receive a diagnosis of TB while visiting or living in the United States and are returning to their home countries during treatment or who are returning to the United States after receiving a diagnosis of TB abroad. The CureTB referral process is not used for applicants for U.S. residency, for whom completion of TB treatment is required before travel to the United States if a diagnosis of TB is received during their required overseas medical examinations.

CureTB referrals help facilitate information exchange between origin and destination public health authorities regarding patients’ TB diagnoses, treatment, and outcomes. CureTB staff members interview clients, irrespective of location, to collect and confirm their contact information, including full names, telephone numbers, and addresses in both the United States and abroad. During these interviews, staff members use motivational interviewing strategies (7,8) to educate clients about the importance of continuing their TB care after leaving their country of origin and encourage active involvement in their own care and treatment. To facilitate continuity of care, CureTB sends accurate clinical and contact information for these persons to public health authorities (TB programs) at their destination. In addition, CureTB assists in retrieving information about previous treatments and accepts referral requests for household contacts of persons who have received a diagnosis of infectious TB disease. Referred patients with a diagnosis of TB disease are managed according to treatment protocols of the national TB program of the destination country. To minimize the risk for TB transmission during relocation, when CDC is aware of a person with suspected or confirmed TB disease before travel occurs, CDC works with the health department to ensure that the person is considered noninfectious at the time of travel, per CDC criteria for commercial or international travel.^† Noninfectious is defined as having at least three consecutive negative sputum smears for acid-fast bacilli; at least two consecutive negative cultures (for persons with drug-resistant disease); and having received a sufficient number of doses of effective treatment as determined by smear status, presence or absence of cavitary disease on chest radiograph, and presence or absence of drug resistance.

An analysis of CureTB data from 2012–2015 demonstrated that 78% (343 of 440) of referred patients with confirmed TB (both outbound from and inbound to the United States) completed treatment (3). This report updates the previous evaluation, focusing on referrals processed during 2016–2023, the program’s expansion during this period, and outcomes for referred patients who have confirmed TB disease.

Methods

Description of CureTB Referral Requests

CureTB maintains a database of all referral requests (i.e., requests for assistance obtaining ongoing TB care at a person’s destination or information about previous TB care) received by the program, referrals made, and referral outcomes. CureTB receives requests for five types of referrals: 1) notification of a laboratory-confirmed TB case as defined by the Council of State and Territorial Epidemiologists or as defined by the national TB program of the referring country, 2) notification of a suspected TB case (i.e., a patient with an incomplete TB evaluation [with pending test results]), 3) request for clinical history, 4) notification of a close contact of a patient who received a confirmed diagnosis of TB, and 5) request for a source case investigation to identify an index patient. CureTB does not make referrals for latent TB infection (LTBI) because LTBI management protocols vary by country, whereas treatment of TB disease is standardized across countries (Box).

Possible Referral Outcomes

For referred patients who received a confirmed diagnosis of TB, CureTB staff members request outcome information from public health authorities at patients’ destinations ≤30 days after the referral and every 2 months thereafter until treatment is completed, or for 12 months for patients who refuse treatment or are lost to follow-up. Requests for referral for patients who received a confirmed diagnosis of TB can result in seven possible outcomes: 1) referral not required, 2) courtesy notification only (insufficient contact information), and, for those referred, 3) completed treatment, 4) lost to follow-up, 5) refused treatment, 6) treatment stopped by provider, and 7) death (Box).

Identification and Analysis of 2016–2023 CureTB Referrals

Referrals for January 1, 2016–December 31, 2023, were extracted from the database. Data were analyzed by type of request, requesting agency and jurisdiction, whether the request was for a person outbound from or inbound to the United States, and for those outbound, the destination country. For patients who received a confirmed diagnosis of disease, the number of months from referral until initiation of care in the destination country and patient outcomes were analyzed. Descriptive analyses were conducted using SAS (version 9.4; SAS Institute). This activity was reviewed by CDC, deemed not research, and was conducted consistent with applicable federal law and CDC policy.^§

Results

CureTB Referral Requests

During 2016–2023, CureTB received 6,944 referral requests, an increase of approximately 400% compared with the 1,347 requests received during 2012–2015, when the program primarily supported patients relocating between the United States and Mexico (3). These 6,944 referral requests included 3,912 (56%) suspected TB cases, 2,404 (35%) confirmed TB cases, 296 (4%) close contact notifications, 276 (4%) clinical history requests, and 56 (1%) source case identification requests (Table). Four requests for LTBI referrals were excluded from the analysis. The median age of referred persons was 36 years (IQR = 27–49 years).

Outcomes of Referrals Made for Patients Who Received a Laboratory-Confirmed Diagnosis of TB

Among the 2,404 patients who received a confirmed diagnosis of TB disease, 522 (22%) did not require a referral per CureTB because the patient left the country of origin with ≤30 days of therapy remaining (with referring jurisdictions encouraged to provide treatment for patients to take with them and follow-ups with patients after departure to confirm treatment completion), or they did not need a referral because they ultimately did not leave the country (Supplementary Figure). For 141 (6%) patients with insufficient contact information, the referral process was not completed, and CureTB issued only a courtesy notification; no outcome data were available for these patients because health authorities at the destinations could not locate them for ≥12 months. CureTB made referrals for 1,741 (72%) patients, including 1,622 (93%) to 100 other countries and 119 (7%) to U.S. destinations. Among all referred patients, 1,379 (79%) completed treatment (1,270 [78%] for non-U.S. destinations and 109 [92%] for U.S. destinations), 235 (14%) were lost to follow-up, 55 (3%) died, 52 (3%) refused treatment, and 20 (1%) had treatment stopped by a provider. A similar percentage of CureTB-referred patients (82%; 466 of 571) completed treatment during 2020–2022 as did patients during 2016–2019 (80%; 660 of 824).

Treatment Completion by Interval Between Departure from the United States and Initiation of Care at Destination

Among 1,287 (74%) referred patients who received a confirmed diagnosis of TB disease for whom information on the interval between departure and initiation of care in their destination country was available, 637 (49%) were linked to care ≤30 days after leaving the originating country, with a treatment completion rate of 91%. An additional 505 (39%) were linked to care within 1–3 months and 145 (7%) within 3–12 months, with treatment completion rates of 89% and 85%, respectively (Figure).

Discussion

During 2016–2023, CureTB referrals for persons relocating to or from the United States resulted in an overall 79% treatment completion rate, which remained stable during the COVID-19 pandemic and increased slightly from the 78% reported in the previous evaluation (3). During the analysis period, the program expanded from focusing primarily on Mexico to including all destination countries, with referrals made to or received from 100 countries; the average volume of annual referral requests approximately tripled compared with the previous analysis (3). Fostering international partnerships helps to ensure secure transfer of clinical and contact information and continuity of care for patients who receive a diagnosis of TB transitioning between different countries’ health systems. CureTB is initiating the process of formalizing international referral agreements to strengthen collaboration and coordination across health systems.

The CureTB program is designed to reduce impediments to TB treatment completion after international relocation. However, effectiveness of the referral process might be limited by external barriers, including language or socioeconomic factors, patient mistrust on the basis of stigma or legal concerns, or access to resources in the destination country, such as transportation or interpreter access, which can affect patients’ ability or willingness to complete treatment. Requesting a CureTB referral as soon as program staff members are aware a client is planning to relocate internationally allows staff members to explain the referral process, confirm the accuracy of contact information, educate the client before departure regarding the importance of completing TB treatment, provide individualized guidance and support to address challenges, and encourage active participation in care. Conversely, referral requests that occur at the time of or after a person’s departure, or with inaccurate or incomplete contact information, hinder both the ability of CureTB staff members to complete the education process and of authorities in destination countries to locate these persons. Furthermore, although overall treatment completion rates for patients who received a diagnosis of TB disease were high, they declined from 91% to 85% when the interval between departure and initiation of care at the destination exceeded 3 months. Timely and complete referrals enable public health authorities in receiving countries to make early contact, continue the process initiated by the referring facility and CureTB staff members, and avoid treatment interruptions, which can increase the risk for TB transmission and emergence of drug resistance (6).

Limitations

The findings in this report are subject to at least two limitations. First, incomplete or inconsistent data collection prevented a more detailed analysis. CureTB can only make referrals when a request for referral is received. Improved coordination with and communication among national TB programs could improve referral rates. Second, when a receiving country did not provide treatment completion data, loss to follow-up was assumed, which might have resulted in underestimates of treatment completion.

Implications for Public Health Practice

CureTB supports global goals of reducing TB transmission and emergence of drug resistance through efforts to improve treatment completion rates among patients who receive a diagnosis of TB. By facilitating treatment of patients relocating to the United States or who might return after visiting another country, the program has the potential to reduce the risk for introducing TB into the United States and thereby support progress toward national TB elimination. The CureTB program can serve as a model for other countries’ public health strategies aimed at improving outcomes for patients relocating between countries.