Prevalência e fatores associados à infecção pelo Mycobacterium tuberculosis entre agentes comunitários de saúde no Brasil, usando-se a prova tuberculínica

Classification and regression trees for predicting the risk of a negative test result for tuberculosis infection in Brazilian healthcare workers: a cross-sectional study

OBJECTIVES

Healthcare workers (HCWs) have a high risk of acquiring tuberculosis infection (TBI). However, annual testing is resource-consuming. We aimed to develop a predictive model to identify HCWs best targeted for TBI screening.

METHODOLOGY

We conducted a secondary analysis of previously published results of 708 HCWs working in primary care services in five Brazilian State capitals who underwent two TBI tests: tuberculin skin test and Quantiferon®-TB Gold in-tube. We used a classification and regression tree (CART) model to predict HCWs with negative results for both tests. The performance of the model was evaluated using the receiver operating characteristics (ROC) curve and the area under the curve (AUC), cross-validated using the same dataset.

RESULTS

Among the 708 HCWs, 247 (34.9%) had negative results for both tests. CART identified that physician or a community health agent were twice more likely to be uninfected (probability = 0.60) than registered or aid nurse (probability = 0.28) when working less than 5.5 years in the primary care setting. In cross validation, the predictive accuracy was 68% [95% confidence interval (95%CI): 65 - 71], AUC was 62% (95%CI 58 - 66), specificity was 78% (95%CI 74 - 81), and sensitivity was 44% (95%CI 38 - 50).

CONCLUSION

Despite the low predictive power of this model, CART allowed to identify subgroups with higher probability of having both tests negative. The inclusion of new information related to TBI risk may contribute to the construction of a model with greater predictive power using the same CART technique.

Knowledge, attitudes and practices of community health agents regarding pulmonary tuberculosis in a capital city in northeastern Brazil

This article analyses the knowledge, attitudes and practices of community health agents (CHAs) regarding tuberculosis in Recife, a municipality with a high incidence of tuberculosis and high treatment dropout rates in Brazil. The cross-sectional study was conducted with a representative sample of CHAs and a standardized questionnaire. The frequencies of the variables related to knowledge, attitudes and practices were described, and the association between satisfactory knowledge and appropriate practices of CHAs was analysed. Of the 401 eligible CHAs, 385 (96.0%) were interviewed. The majority were women (87.5%) aged ≥ 40 years (66.0%) and had been on the job for more than nine years (74.5%). A large percentage (61.7%) had satisfactory knowledge about tuberculosis, and this knowledge (75.8%) was associated with appropriate practices (p = 0.008). Regarding attitudes, 97.1% of CHAs were believed to be at risk of contracting tuberculosis, and 53.2% attributed this risk to their job. The results suggest the need for investment in training actions that may help improve tuberculosis indicators in the municipality.

Latent tuberculosis infection in healthcare workers in low- and middle-income countries: an updated systematic review

Healthcare workers (HCWs) are at increased risk of latent tuberculosis (TB) infection (LTBI) and TB disease.We conducted an updated systematic review of the prevalence and incidence of LTBI in HCWs in low- and middle-income countries (LMICs), associated factors, and infection control practices. We searched MEDLINE, Embase and Web of Science (January 1, 2005-June 20, 2017) for studies published in any language. We obtained pooled estimates using random effects methods and investigated heterogeneity using meta-regression.85 studies (32 630 subjects) were included from 26 LMICs. Prevalence of a positive tuberculin skin test (TST) was 14-98% (mean 49%); prevalence of a positive interferon-γ release assay (IGRA) was 9-86% (mean 39%). Countries with TB incidence ≥300 per 100 000 had the highest prevalence (TST: pooled estimate 55%, 95% CI 41-69%; IGRA: pooled estimate 56%, 95% CI 39-73%). Annual incidence estimated from the TST was 1-38% (mean 17%); annual incidence estimated from the IGRA was 10-30% (mean 18%). The prevalence and incidence of a positive test was associated with years of work, work location, TB contact and job category. Only 15 studies reported on infection control measures in healthcare facilities, with limited implementation.HCWs in LMICs in high TB incidence settings remain at increased risk of acquiring LTBI. There is an urgent need for robust implementation of infection control measures.

Tuberculosis infection among primary health care workers

OBJECTIVE

To estimate the prevalence of and determine the risk factors associated with latent Mycobacterium tuberculosis infection (LTBI) among primary health care workers in the city of Vitória, Brazil.

METHODS

This was a cross-sectional study with data collected through a survey regarding socio-demographic, occupational, clinical, and exposure characteristics, as well as knowledge about tuberculosis, conducted between 2011 and 2012. All participants underwent a tuberculin skin test (TST), and TSTs were read at 72 h by a trained professional.

RESULTS

A total of 218 primary health care workers participated in the study. The prevalence of TST positivity at the ≥ 10-mm and ≥ 5-mm cut-off points was, respectively, 39.4% (95% CI: 32.9-45.9) and 54.1% (95% CI: 47.4-60.7). Regarding occupational categories, community health agents had the highest proportion of TST positivity, regardless of the cut-off point (≥ 10 mm: 47.5%; and ≥ 5 mm: 60.5%). Regarding factors associated with TST results, "having had a previous TST" showed a statistically significant association with TST positivity at the ≥ 10-mm and ≥ 5-mm cut-off points (OR = 2.5 [95% CI: 1.17-5.30] and OR = 2.18 [95% CI: 1.23-3.87], respectively).

CONCLUSIONS

The prevalence of LTBI was found to be high among the primary health care workers in this sample. Therefore, we recommend the establishment of a periodic screening program for LTBI and implementation of effective biosafety policies for the prevention of this infection among primary health care workers.