ABSTRACT:

Background:

Tuberculosis is a serious public health problem that still persists in the world and in Brazil. The municipality of São Paulo, Brazil, is among the prioritized ones in the country for disease control.

Objective:

To describe the epidemiological profile of all new tuberculosis cases in São Paulo municipality reported between the years 2006 and 2013.

Methods:

The variables selected for the study were: socioeconomic, demographic and clinical-epidemiologic obtained through the online information system TB-WEB. A descriptive analysis of the data was performed to undertake the comparison among the years. To study the historical series, linear trend analysis was held.

Results and discussion:

There was an increase in the tuberculosis incidence rate in children under 15 years and in homeless people. The cure rate has improved as the proportion of completion of supervised treatment and the proportion of cases diagnosed by primary care clinics. The disease is unevenly distributed within the municipality of São Paulo and there are districts that were not able to improve the tuberculosis control.

Conclusion:

The municipal tuberculosis program control needs to target the vulnerable groups and the regions of the city where the incidence rates are higher.

Keywords:
Tuberculosis; Epidemiology; Public health; Health evaluation; Epidemiological surveillance; Large cities

INTRODUCTION

Despite being preventable and curable, tuberculosis (TB) remains one of the most serious threats to global public health, being the second leading cause of death among infectious diseases¹1. World Health Organization. Global Tuberculosis Report, 2015. Geneva: WHO, 2015..

In Brazil, the disease is associated with vulnerable populations, poverty and agglomerated urban areas with high population density²2. Harling G, Castro MC. Health & Place: a spatial analysis of social and economic determinants of tuberculosis in Brazil. Health Place. Elsevier; 2014;25:56-67. http://dx.doi.org/10.1016/j.healthplace.2013.10.008
http://dx.doi.org/10.1016/j.healthplace.... .

The municipality of São Paulo, a priority for the control of TB³3. Santos J. Resposta brasileira ao controle da tuberculose. Rev Saúde Pública [Internet]. 2007 [cited on 2015 Nov 14];41:89-93. Available from: Available from: http://www.scielo.br/scielo.php?pid=S0034-89102007000800012&script=sci_abstract&tlng=pt
http://www.scielo.br/scielo.php?pid=S003... , is a large metropolis permeated by social inequalities, where an important part of the population is inserted in the urban space in a precarious way and difficult access to public goods⁴4. Silveira C, Carneiro Junior N, Marsiglia RM, Eds. Projeto inclusão social urbana Nós do Centro: metodologia de pesquisa e de ação para inclusão social de grupos em situação de vulnerabilidade no centro da cidade de São Paulo. São Paulo: Fundação Arnaldo Vieira de Carvalho / Faculdade de Ciências Médicas da Santa Casa de São Paulo; 2009..

Considering the relevance of TB in the MSP, and that the disease acts as an indicator of public health and the efficiency of health services⁵5. Dye C. Tuberculosis 2000-2010: Control, but not elimination. Int J Tuberc Lung Dis. 2000;4(12 Suppl. 2):S146-52., the objective of this study was to describe the epidemiological profile of all new TB cases reported between 2006 and 2013.

METHODS

Descriptive epidemiological study carried out in the MSP between the years of 2006 and 2013. All new TB cases residing in the municipality and reported within the period were included in the analysis. The definition for a new case was considered to be a patient who was diagnosed with the disease and that had never undergone anti-TB treatment, or had done so for up to 30 days⁶6. Brasil. Ministério da Saúde. Secretaria de Vigilância em Saúde. Departamento de Vigilância Epidemiológica. Manual de recomendações para o controle da Tuberculose no Brasil. Brasília; 2011. 288p.. Patients with a change of diagnosis and detainees were excluded.

The data were extracted from the TB-WEB, an online information system of the state of São Paulo (SSP) that stores the records of the TB notification form. The year 2006 was chosen as the initial year since it was the definitive implementation of this system.

Access to secondary data was possible after authorization from the Tuberculosis Control Group of the Center for Epidemiological Surveillance (CES) and approval of the Scientific Committee of the Department of Collective Health of the School of Medical Sciences of Santa Casa de São Paulo. There is no conflict of interests of the authors in relation to the subject studied.

The variables used in the study were based on the items of the TB notification form standardized by CES of the SSP, namely: sex, age, race/color, type of address, disease classification, type of treatment, tests performed, type of discovery and outcome situation.

The incidence rates of TB per 100,000 inhabitants/year were calculated using the population extracted from the Foundation State System of Data Analysis (SEADE) website.

EpiInfo 7 was used for frequency analysis, linear trend test, c² test, and 95% confidence interval (95%CI). A statistical significance level of 0.05 was established.

Regarding to the spatial distribution, thematic maps were prepared with the annual TB incidence rate by administrative district for the years 2006, 2010 and 2013 using the free code software QGis.

RESULTS

In the study period, the incidence rate of TB per 100,000 inhabitants/year went from 52.6 in 2006 to 49.5 in 2013 (Graph 1); however, the reduction was not statistically significant (p = 0.078).

The annual incidence rate of the disease among men seems to remain stable (p = 0.267) (Graph 2), and in 2013 it was 2.03 times higher than that of women (95%CI 1.98 - 2.06). There was a trend towards an increase in the annual incidence of TB among children aged 0 to 14 years (p = 0.007), and a tendency of reduction in the age groups of 15 to 59 years (p = 0.022) and 60 years and over (p = 0.047) (Graph 3). The proportion of TB patients without fixed residence increased from 2.7% in 2006 to 5.5% in 2013 (p < 0.001).

Indigenous people represented the highest annual TB incidence rate in the MSP in 2010, being 724.9 cases per 100,000 inhabitants/year, representing a relative risk of 19.0 (95%CI 15.5 - 23.4) when compared to the annual incidence rate in white people. Black people also had a high annual incidence rate: 87.0 per 100,000 inhabitants/year.

The pulmonary clinical form remained predominant. There was a greater targeting of the diagnoses for Primary Care (outpatient demand and active search/contact investigation) and improvement in the cure rate within the study period (Table 1).

Chest X-ray demand decreased in the period (Table 1) and testing for human immunodeficiency virus (HIV) increased. The expansion of supervised treatment improved, and it was adopted for 60.5% (95%CI 59.2 - 61.7) of TB patients in 2013 (Table 1).

Improvement in information and data collection was observed for all studied variables, with emphasis on type of treatment and race/color.

The TB incidence rate/year is distributed in a very diversified way in the geographical space of the MSP, and the administrative districts that presented high incidence rates/year for the whole period of the study were: Bom Retiro, República, São Miguel, Lajeado, Brasilândia, Barra Funda, Belém, Brás and Pari (Figure 1).

DISCUSSION

The reduction of the incidence of TB in the MSP has been occurring slowly, as has been observed in other regions with high disease burden⁷7. Dheda K, Barry CE, Maartens G. Tuberculosis. Lancet. 2016;387(10024):1211-26.. This study allowed to identify that some groups increased their participation in the context of the disease, especially the children and the homeless people.

Infant TB represents a sentinel event within a community, indicating recent transmission, the source of which is an infectious adult with pulmonary TB⁸8. Shingadia D, Novelli V. Diagnosis and treatment of tuberculosis in children. Lancet Infect Dis [Internet]. 2003 [cited on 2015 Nov 15];3(10):624-32. Available from: Available from: http://www.sciencedirect.com/science/article/pii/S1473309903007710
http://www.sciencedirect.com/science/art... . The increase in TB among children demonstrates, therefore, that health services are not performing the early diagnosis⁹9. Lima JA, Icaza EES, Menegotto BG, Fischer GB, Barreto SSM. Clinical and epidemiological characteristics of contagious adult of tuberculosis in children. J Bras Pneumol [Internet]. 2004 [cited on 2015 Nov 15];30(3):243-52. Available from: Available from: http://www.scielo.br/pdf/jbpneu/v30n3/v30n3a10.pdf
http://www.scielo.br/pdf/jbpneu/v30n3/v3... and the adequate treatment of smear-positive cases in adults¹⁰10. Nair N. Childhood tuberculosis : public health and contact tracing. 2001;97-102..

A high number of cases of TB among homeless people has also been demonstrated in other studies¹¹11. Romaszko J, Bucin´ski A, Kuchta R, Bednarski K, Zakrzewska M. The incidence of pulmonary tuberculosis among the homeless in north-eastern Poland. Cent Eur J Med [Internet]. 2013 [cited on 2015 Nov 15];8(January 2011):283-5. Available from: Available from: https://link.springer.com/article/10.2478/s11536-012-0114-9
https://link.springer.com/article/10.247... ^,1212. Khan K, Rea E, Mcdermaid C, Stuart R, Chambers C, Wang J, et al. Active tuberculosis among homeless persons, Toronto, Ontario, Canada, 1998-2007. Emerg Infect Diseases [Internet]. 2011 [cited on 2015 Nov 15];17(3):357-65. Available from: Available from: http://www.ncbi.nlm.nih.gov/pubmed/21392424
http://www.ncbi.nlm.nih.gov/pubmed/21392... , including in the state of São Paulo¹³13. Ranzani OT, Carvalho CRR, Waldman EA, Rodrigues LC. The impact of being homeless on the unsuccessful outcome of treatment of pulmonary TB in São Paulo State, Brazil. BMC Med [Internet]. 2016 [cited on 2015 Nov 15];14(1):41. Available from: Available from: http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=4804546&tool=pmcentrez&rendertype=abstract
http://www.pubmedcentral.nih.gov/article... . This population is considered an important source of infection¹¹11. Romaszko J, Bucin´ski A, Kuchta R, Bednarski K, Zakrzewska M. The incidence of pulmonary tuberculosis among the homeless in north-eastern Poland. Cent Eur J Med [Internet]. 2013 [cited on 2015 Nov 15];8(January 2011):283-5. Available from: Available from: https://link.springer.com/article/10.2478/s11536-012-0114-9
https://link.springer.com/article/10.247... , and its illness is associated with the presence of other morbidities (such as HIV, liver diseases, mental illness and substance dependence), and difficult access to health services. In addition, this group presents a high proportion of death due to TB¹²12. Khan K, Rea E, Mcdermaid C, Stuart R, Chambers C, Wang J, et al. Active tuberculosis among homeless persons, Toronto, Ontario, Canada, 1998-2007. Emerg Infect Diseases [Internet]. 2011 [cited on 2015 Nov 15];17(3):357-65. Available from: Available from: http://www.ncbi.nlm.nih.gov/pubmed/21392424
http://www.ncbi.nlm.nih.gov/pubmed/21392... and a strong relation with treatment failure¹³13. Ranzani OT, Carvalho CRR, Waldman EA, Rodrigues LC. The impact of being homeless on the unsuccessful outcome of treatment of pulmonary TB in São Paulo State, Brazil. BMC Med [Internet]. 2016 [cited on 2015 Nov 15];14(1):41. Available from: Available from: http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=4804546&tool=pmcentrez&rendertype=abstract
http://www.pubmedcentral.nih.gov/article... .

As was observed in this study, TB in Brazil is also associated with black and indigenous people, since these groups face discriminatory barriers both to use the health care network and to obtain better income opportunities²2. Harling G, Castro MC. Health & Place: a spatial analysis of social and economic determinants of tuberculosis in Brazil. Health Place. Elsevier; 2014;25:56-67. http://dx.doi.org/10.1016/j.healthplace.2013.10.008
http://dx.doi.org/10.1016/j.healthplace.... .

If, on the one hand, the clinical profile of the disease did not change, the proportion of diagnoses performed by the different services changed, and the chest radiography request decreased. The lower participation of emergency and hospital services in the diagnosis of TB may explain part of the decrease in requests for pulmonary imaging¹⁴14. Selig LIA, Belo M, Jose A, Alves L, Cunha DA, Teixeira EG, et al. Deaths attributed to tuberculosis in the state of Rio de Janeiro. 2004;30(4):417-24..

The increase in diagnosis through active case search and contact investigation was verified in this study. Such actions are feasible and efficient to improve case detection and thus reduce transmission and incidence of TB, especially when targeted at at-risk groups, including children who are contacts of TB patients with positive smear microscopy¹⁵15. Yuen CM, Amanullah F, Dharmadhikari A, Nardell EA, Seddon JA, Vasilyeva I, et al. Turning off the tap: Stopping tuberculosis transmission through active case-finding and prompt effective treatment. Lancet [Internet]. 2015 [cited on 2015 Nov 15];386(10010):2334-43. Available from: Available from: http://dx.doi.org/10.1016/S0140-6736(15)00322-0
http://dx.doi.org/10.1016/S0140-6736(15)... ^,1616. Fox GJ, Nhung NV, Sy DN, Lien LT, Cuong NK, Britton WJ, et al. Contact Investigation in Households of Patients with Tuberculosis in Hanoi, Vietnam: A Prospective Cohort Study. PLoS One. 2012;7(11):5-11.. However, it is worth mentioning that hospital and emergency services still represent an important part of the responsibility for diagnosing TB in the MSP.

Despite the improvements seen in increasing HIV testing and higher TB cure rates, advances need to be made to test all TB patients for HIV, and treat more than 85% of them, as recommended by the World Health Organization¹1. World Health Organization. Global Tuberculosis Report, 2015. Geneva: WHO, 2015..

The expansion of the supervised treatment perceived in this study is a very positive advance for the control of TB in the MSP, since this strategy promotes increase of cure rates among vulnerable populations, improves adherence to treatment and protects TB patients from negative outcomes of disease¹⁷17. Reis-Santos B, Pellacani-Posses I, Macedo LR, Golub JE, Riley LW, Maciel EL. Directly observed therapy of tuberculosis in Brazil: associated determinants and impact on treatment outcome. Int J Tuberc Lung Dis [Internet]. 2015 [cited on 2015 Nov 16];19(10):1188-93. Available from: Available from: http://www.ncbi.nlm.nih.gov/pubmed/26459531
http://www.ncbi.nlm.nih.gov/pubmed/26459... .

The significant variation in the annual incidence rate of TB per administrative district in the MSP shows that the distribution of the disease is uneven in its urban space. It can be said that the disease is more strongly located in the central and peripheral regions of the city, areas with greater crowding of people and presence of social vulnerability. In the city of Vitória (Espírito Santo), the highest incidence rate for TB also occurred in the poorest areas of the city¹⁸18. Maciel ELN, Pan W, Dietze R, Peres RL, Vinhas SA, Ribeiro FK, et al. Spatial patterns of pulmonary tuberculosis incidence and their relationship to socio-economic status in Vitoria, Brazil. Int J Tuberc Lung Dis. 2010;14(11):1395-402..

As in any study with secondary data, the gaps found in completing the information were a limitation for the present study. In spite of this fragility, it was possible to reach the proposed objective and, even, to observe the progress regarding the quality of information throughout the years of study.

CONCLUSION

This study made possible the knowledge of the epidemiological profile of TB in the MSP from 2006 to 2013. Advances were made in the treatment of the disease, verified through higher cure rates and greater reach of supervised treatment. The diagnosis of the infection was also positively favored, since it has been more accomplished by Primary Care. However, it is worth mentioning the increase in cases among children and homeless people, and the permanence of the disease in certain regions of the city, suggesting the need to target the TB surveillance actions for these groups, in order to achieve better results in the control of the disease.

References

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History