Risk of tuberculin conversion among healthcare workers and the adoption of preventive measures
- Iacopo Baussano1,
- Massimiliano Bugiani2,
- Aurelia Carosso2,
- Dario Mairano3,
- Anna Pia Barocelli4,
- Marina Tagna4,
- Vincenza Cascio5,
- Pavilio Piccioni2,
- Walter Arossa2
- 1Cancer Epidemiology Unit, CPO Piemonte, CeRMS, University of Turin, Turin, Italy
- 2CPA ASL 4, Regional Reference Centre for Tuberculosis Prevention, Turin, Italy
- 3Occupational Medicine, ASL 4, Turin, Italy
- 4Occupational Medicine, ASL 3, Turin, Italy
- 5Occupational Medicine, ASL 2, Turin, Italy
- Correspondence to: Dr I Baussano Cancer Epidemiology Unit, Università di Torino, Via Santena 7, 10126 Torino, Italy; iacopo.baussano{at}cpo.it
- Accepted 1 August 2006
- Published Online First 15 August 2006
Abstract
Background: In industrialised countries, occupational tuberculosis among healthcare workers (HCWs) is re-emerging as an important public health issue. To prevent and control tuberculosis transmission, several institutions have issued and implemented recommendations and practice guidelines.
Objectives: To estimate the annual rate of tuberculosis infection (ARTI; per 100 person-years) among HCWs in Turin, the capital of the Piedmont region of Italy, to identify factors associated with variations in the ARTI and to evaluate the efficacy of the regional guidelines to prevent and control tuberculosis.
Methods: The study was conducted between 1997 and 2004 on a cohort of HCWs. The tuberculosis infection was diagnosed through tuberculin skin testing (TST) conversion and defined as an induration increase of at least 10 mm from a previous negative TST. The ARTI and the hazard ratio for each at-risk subgroup, categorised according to working activities and settings, was estimated using exponential survival models. The efficacy of the regional guidelines was estimated by stratifying the analysis according to the moment of the implementation of the guidelines (before/after).
Results: The 2182 study participants were drawn from the dynamic cohort. The overall adjusted ARTI was 1.6 (95% CI: 1.3 to 1.9)/100 person-years. Different workplaces (eg, administrative and infectious diseases inpatient services) and occupations (eg, clerical and medical workers) were associated with significantly different ARTIs, ranging between 0.62 and 2.62 and between 0.61 and 1.71, respectively, whereas the TST conversion risk differed by about 16–68% and 30–60%, respectively. The implementation of the guidelines coincided with overall ARTI reductions of 1.3/100 person-years, and concurrently the variations between ARTIs of different occupations and workplaces disappeared.
Conclusions: The occupational risk categories for targeting the surveillance and prevention of tuberculosis transmission among HCWs were identified, and the introduction of preventive measures was observed to be effective in decreasing the overall risk of tuberculosis infection among HCWs.
- ARTI, annual rate of tuberculosis infection
- BCG, bacille Calmette–Guérin
- HCW, healthcare worker
- TST, tuberculin skin testing
Footnotes
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Published Online First 15 August 2006
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Funding: This study was performed with the grants of Regione Piemonte Italy, Assessorato Sanità, Progetti di Ricerca Sanitaria Finalizzata, 2003. The method applied in this study was developed in the framework of the projects supported by the Compagnia San Paolo-FIRMS.
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Competing interests: None.
