**3. Results**

From 2012 to 2016, TST was administered to a total number of 404 immigrants. Of these, 36 patients were excluded from our analysis: 8 were born in Italy from undocumented parents and 28 were younger than 15 years. The final study population consisted of 368 immigrants: 186 (50.5%) and 182 (49.5%) were tested in 2012 and 2013, respectively. The demographic characteristics of the study population are reported in Table S1. Adherence to the various stages of the screening procedures and treatment outcomes are shown in Table 1.


**Table 1.** Compliance with the different steps of the algorithm and treatment outcomes.

TST: tuberculin skin test; CXR: chest-X-ray; QFT: quantiferon test; PE: pneumological examination; TB: tuberculosis; LTBI: latent tuberculosis infection.

Patients who did not return for the reading of TST amounted to 15.2%. Patients who did not undergo CXR, QFT and PE despite the prescriptions amounted to 11.3%, 19.1% and 7.1%, respectively. Finally, 90.2% of subjects completed all steps expected for the screening of active TB, considering TST reading and CXR/PE, when prescribed. In immigrants with a positive TST result, adherence was lower, since their path is usually longer. A total of 5 cases of active TB were diagnosed during the study period. After discharge from hospital, they were followed monthly at TBOA (Outpatient Activity dedicated to managemen<sup>t</sup> of LTBI and TB at CFF) and they all successfully completed the treatment.

The overall compliance with LTBI screening, which involved TST, CXR, QFT, and PE was 87.3%. Also in this case, adherence of patients with positive TST was observed to be lower (79.9%). LTBI treatment was prescribed to 28 patients, while only 20 out of 28 patients started prophylaxis with Isoniazid, because eight patients had increased levels of transaminases for chronic alcohol abuse or HBsAg, or they refused therapy. Eventually, 14 of the 20 patients who started IPT were able to complete the treatment, whereas 6 patients discontinued therapy voluntarily or after medical indication. HS for 2 years was indicated in 41 patients ye<sup>t</sup> only 6 completed all follow-up. Finally, 76.4% of immigrants completed the whole diagnostic and therapeutic protocol for active TB and LTBI. Considering only TST-positive ones, adherence decreased to 51%.

Tables 2 and 3 deal with the full path for the screening of active TB and LTBI. In multivariable analysis regarding the screening of active TB (Table 2), it is possible to appreciate that female sex, homelessness and age between 25–34 years were associated with a considerably lower rate of completion of the screening. On the contrary, a higher level of education, time of arrival in Italy for at least 5 years and the presence of cough were all associated with better compliance. With regard to LTBI (Table 3), being a native of the Americas, age between 25 and 34 years, employment, and homelessness were associated with considerably lower adherence. Refugee status, time of arrival in Italy for at least 5 years and the presence of cough were associated with better compliance. It is interesting to note that being from the Americas was associated with very low compliance for both active TB and LTBI screening (OR 0.27, 95% CI 0.05–1.44; OR 0.32, 95% CI 0.06–1.64, respectively). Table 4 outlines compliance with the full algorithm. As can be seen, age had a negative impact on adherence. In addition, being employed, homelessness and prostitution were associated with considerably lower compliance. Being a native of South-East Asia and the Western Pacific (OR 4.48, 95% CI 1.57–12.73), presence of cough, having been in Italy for a longer time, in particular for more than 5 years, and the attainment of higher education levels were observed to be related to a much higher probability of completion. Female Chinese patients' compliance with the protocol was substantially higher than in the rest of the population (OR 55.63, 95% CI 5.35–578), while Nigerians, Georgians, and Tunisians had lower levels of adhesion (Table S2).

Considering compliance with TST reading, both bivariate and multivariate analysis show that American and European origin, age between 25–34 years old, prostitution and homelessness were associated with considerably lower rates of return for the reading of the test. On the other hand, higher levels of education were associated with better compliance. In multivariable analysis, the presence of cough was the only symptom associated with greater compliance (OR 7.61, 95% CI 0.92–63.2) (Table S3). Compliance with CXR showed a positive correlation to the presence in Italy for at least 5 years, while a negative correlation was associated to the female sex (Table S4). Compliance with QFT was inversely correlated with education and positively associated with the age group 25–34 years (OR 3.80, 95% CI 0.87–16.53) (Table S5). Female sex, being a native of the Americas, and sufficient or good knowledge of Italian were associated with a 100%-rate of IPT completion. Conversely, refugees showed a tendency to refuse or to voluntarily stop the treatment, and higher education levels inversely correlated with the probability of completion (Table S6).


**Table 2.** Association between selected characteristics and compliance with screening for active tuberculosis (TB).

◦: TB incidence in the country of origin is sub-divided into 4 categories: 0–49, 50–99, 100–199, ≥200 per 100,000 population/year. \*: Meaning at least one among cough, hemoptysis, fever, chest pain, weight loss, fatigue, night sweats, chills or loss of appetite. \*\*: Education is sub-divided into three categories: illiterate/primary school, secondary school, high school/degree. \*\**◦*: Knowledge of Italian is sub-divided into three categories: none, sufficient, good. \*\*\*: Two-sample Mann–Whitney test. TB: tuberculosis; LTBI: latent tuberculosis infection; TST: tuberculin skin test; SE Asia: South-East Asia; OR: odds ratio; CI: confidence interval.



◦: TB incidence in the country of origin is sub-divided into four categories: 0–49, 50–99, 100–199, ≥200 per 100,000 population/year. \*: Meaning at least one among cough, hemoptysis, fever, chest pain, weight loss, fatigue, night sweats, chills or loss of appetite. \*\*: Education is sub-divided into three categories: illiterate/primary school, secondary school, high school/degree. \*\*◦: Knowledge of Italian is sub-divided into three categories: none, sufficient, good. \*\*\*: Two-sample Mann–Whitney test. TB: tuberculosis; LTBI: latent tuberculosis infection; TST: tuberculin skin test; SE Asia: South-East Asia.


**Table 4.** Association between selected characteristics and compliance with the full protocol (bivariate and multivariate analysis).

◦ TB incidence in the country of origin is sub-divided into 4 categories: 0–49, 50–99, 100–199, ≥200 per 100,000 population/year. \* Meaning at least one among cough, hemoptysis, fever, chest pain, weight loss, fatigue, night sweats, chills or loss of appetite. \*\* Education is sub-divided into three categories: illiterate/primary school, secondary school, high school/degree. \*\*◦ Knowledge of Italian is sub-divided into three categories: none, sufficient, good. \*\*\* Two-sample Mann–Whitney test. TST: tuberculin skin test; SE Asia: South-East Asia; TB: tuberculosis.
