**5.5 Social factors**

Factors such as migration and social stigma also contribute toward LTFU. LTFU 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 countries such as South Korea and China [70, 76, 90].

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 cause or prevent LTFU.

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 with these factors.


### **Table 1.**

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

### **5.6 Scoring instrument**

Based on the factors associated with LTFU, Rodrigo et al. have developed a scoring instrument to predict the probability of LTFU (**Table 1**) [91]. According to their original paper, "Scores of 0, 1, 2, 3, 4 and 5 points were associated with a lost to follow-up probability of 2.2% 5.4% 9.9%, 16.4%, 15%, and 28%, respectively." Incorporating the instrument in the process of history taking could help the healthcare providers in identifying patients who have the potential to be LTFU. Further interventions should be carried out to prevent these patients from becoming LTFU. Similar scoring systems could be developed in different regions, since there are always country-specific variations.
