**5.1 Individual factors**

Individual factors play a role in the process of being LTFU from treatment. Sometimes, the results may contradict between different studies, probably due to the cultural, social, and other variations of the study settings.

Among the various sociodemographic characteristics, age is a recognized factor associated with LTFU. Studies from India, Brazil, and China revealed that elderly patients have higher LTFU [4, 68–70], whereas studies from Norway, Botswana, and South Africa suggested that adolescents have significant risk [8, 30, 71]. One study from the UK even suggested a wider range of age of 15–44 years as a high-risk group for LTFU [11]. Regarding gender, studies uniformly suggest that higher LTFU was found in males, as seen in Kenya, Ethiopia, Georgia, and Uzbekistan [7, 18, 41, 72].

Residence plays a role in the mechanism of LTFU. In Pakistan, the rural residence is associated with LTFU [73], whereas in Uzbekistan, the urban residence is associated with LTFU [18]. This may be caused by access to the treatment center since being far from the treatment center is also associated with LTFU [74]. Transportation should be improved to increase accessibility toward the treatment center. Alternatively, they could be built in the hard-to-reach areas. Both approaches include challenges, and ultimately, these challenges may be what cause LTFU. Further discussion regarding different providers will be given in the next section.

Education plays a role in the development of LTFU. Brazilian researchers have found out that less than 8 years of schooling increases the risk of LTFU [4]. In addition, scarce TB knowledge is a risk factor for LTFU [75], and better TB knowledge a protective factor [5]. Therefore, health education and proper counseling should always be at the heart of every anti-TB treatment program.

Financial factors should also be considered while giving treatment, and programs without such considerations will likely to result in high LTFU. A study from Uzbekistan found that joblessness contributes toward LTFU [18]. This is confirmed by a study from China which found that pre-school children, unemployed laborers, and retirees have a higher rate of LTFU [76]. Patients with low income have financial constraints to complete treatment leading to LTFU as seen in India [77], a lower middle-income country. A similar phenomenon has been observed in South Korea, a high-income country [78]. Even in the USA, it was found that homelessness is associated with LTFU [79, 80], which might be due to low income. Therefore, regardless of the country, patients with low income still have barriers against treatment completion.

LTFU is also associated with alcohol abuse, tobacco use, smoking, and illicit drug use. Association between alcoholism and LTFU was observed in India [77], Philippines [5], and Congo [74], tobacco use in Georgia [41], smoking in Brazil [75], and illicit drug use in Norway [30], Georgia [41], and the UK [81]. Therefore, before initiating treatment, personal history should be carefully taken to find out these risk factors, and special attention should be given to such patients.

There are also certain disease-specific factors that are associated with LTFU. Those who were previously LTFU tend to be LTFU again. This was confirmed by studies conducted in Brazil [4], Kenya [7], Uzbekistan [18], and Korea [78]. Caution should be taken while planning treatment for such patients. Studies from Nigeria and Ethiopia both point out that smear-negative TB patients were more likely to be LTFU [72, 82]. However, the opposite was observed in the UK where smear-positive pulmonary TB patients were more likely to be LTFU [11]. Researchers also found that patients with extrapulmonary TB were more likely to be LTFU [71, 83]. Co-morbid diseases such as diabetes mellitus and human immunodeficiency virus (HIV) infection also cause hindrance against TB treatment conditions [7, 71, 84].

#### **5.2 Treatment support services**

The treatment providers should give support to the patients since a perceived lack of provider support is a barrier to regular follow-up [77], and receiving any type of assistance and support from the providers can protect against LTFU [5]. They need to build up trust [5] from the patients. An intervention program targeting these factors will be described later in the chapter. Lastly, the timing of the treatment services should be flexible according to the needs of the patients [77], but this may not be an easy task to implement.

#### **5.3 Diagnosis and treatment**

The timing of the treatment is important since those who initiate the treatment late (beyond and within 30 days of onset) are more likely to be LTFU [85]. Those who initiate it late may not have enough motivation, will, or knowledge to continue taking treatment until they are cured. Moreover, the timing of treatment interruption is found to be the most important during the intensive phase [7]. This stage should be particularly targeted while conducting interventions against LTFU.

Different providers have different abilities to retain the patients. In Korea, patients treated by a non-pulmonologist were found to be more likely to default from TB treatment [78]. In Myanmar, patients treated by private practitioners were more likely to be LTFU [86]. An interesting situation was observed in Nigeria where patients treated at private, not-for-profit (PNFP) DOT facilities were more likely to be LTFU [87]. The researchers concluded that "Patients managed at PFP [private, for-profit] DOT facilities were probably richer, had better education, nutrition, and knowledge of TB than patients managed at PNFP

**117**

**Table 1.**

*Loss to Follow-Up (LTFU) during Tuberculosis Treatment*

DOT facilities…" Indeed, the factors causing LTFU are not simple, and they are correlated with each other. Therefore, intervention should be addressed not only on a single problem but also targeted toward the patient as a whole. Furthermore, the provider should also be consistent throughout the different stages of treatment since different providers in the intensive phase and continuation phase are

Studies from the USA and India have found that drug side effects are associated with LTFU [49, 77]. The researchers from the Philippines take one step further regarding this concept, stating 'patients' self-rating of the severity' as an associated factor [5]. Indeed, some side effects, such as hepatitis, of the anti-tuberculosis drugs are already severe. However, some side effects, such as vomiting, might need self-rating since different patients may perceive differently. It would be interesting

Factors such as migration and social stigma also contribute toward LTFU. LTFU

In countries where TB is a social stigma, treatment is very difficult and sensitive [77]. The patients may not want the health workers to give counseling. They do want to take treatment since the news of having TB may spread to the community, causing discrimination. In such places, secret treatment sessions should be initiated to control LTFU rates. In contrast, in Korea, the absence of TB stigma is associated with LTFU [78]. The authors wrote "TB stigma might motivate patients to receive TB treatment, thus increasing adherence to TB treatment." Therefore, before starting the TB treatment program, it is important to make community observations first to find out whether TB sigma can

In theory, interpersonal factors such as family dynamics, household role, peer influence, and partner and family relationships were thought to influence LTFU [5]. However, to our knowledge, none of the studies to date supports the association of

**LTFU risk Score** Immigration 1 Living alone 1 Living in an institution 2 Previous anti-TB treatment 2 Poor patient understanding 2 Intravenous drug use (IDU) 4 Unknown IDU status 1

*A predictive scoring instrument for tuberculosis lost to follow-up outcome [86].*

is common among the migrant population particularly in developed countries where there is an inward movement of people from the developing countries. Studies from the UK had repeatedly revealed this association [11, 50, 86, 89]. Researchers from the USA also found that birth outside the USA or Canada is associated with LTFU [80]. Higher LTFU among migrants has also been observed in Asian

to research which kind of patient rates which side effect as severe.

countries such as South Korea and China [70, 76, 90].

*DOI: http://dx.doi.org/10.5772/intechopen.81900*

associated with LTFU [88]**.**

**5.4 Drug side effects**

**5.5 Social factors**

cause or prevent LTFU.

LTFU with these factors.

DOT facilities…" Indeed, the factors causing LTFU are not simple, and they are correlated with each other. Therefore, intervention should be addressed not only on a single problem but also targeted toward the patient as a whole. Furthermore, the provider should also be consistent throughout the different stages of treatment since different providers in the intensive phase and continuation phase are associated with LTFU [88]**.**
