INTRODUCTION :
Every year 1.8 million people in India develop tuberculosis (TB). India accounts for one-fifth of the global TB incidence and is estimated to have the highest number of active TB cases amongst the countries of the world. Many hospitals in India handle large number of tuberculosis cases. The emergence of multidrug resistant tuberculosis has been reported to have caused outbreaks among health care workers in many hospitals. Various authorities have recommended measures to prevent the nosocomial transmission of tuberculosis.
However scientific data demonstrating the efficacy of these measures is lacking.
Delayed diagnosis of active pulmonary TB among hospitalized patients is common and believed to contribute significantly to nosocomial transmission.
Various studies reported a risk of infection among workers exposed to patients with tuberculosis that was four to six times higher than the risk among unexposed workers. However the risk of tuberculosis among health care workers varies considerably among and within hospitals.
Epidemiological studies are needed to identify the high-risk subgroups among health care workers and to identify potential risk factors for transmission of disease. Such observations would lead to further implementation of cost effective infection control measures and analysis of the efficacy of such measures with respect to developing countries like India. These measures might prevent or retard the nosocomial transmission of tuberculosis to both patients and to health care workers.
AIMS AND OBJECTIVES :
1. To identify the risk factors for acquiring tuberculosis among health care workers at a tertiary level teaching hospital in South India.
2. To determine the incidence of tuberculosis among health care workers.
3. To identify the factors associated with a delay in the diagnosis of tuberculosis among health care workers.
MATERIALS AND METHODS :
RESEARCH PROTOCOL:
DESIGN:
1. Prospective and retrospective descriptive cohort study design for determining the incidence of clinical tuberculosis disease among health care workers and to determine the clinical profile of tuberculosis disease among the target population.
2. Case control study design to determine the specific risk factors for acquiring tuberculosis in the target population. Prospectively (from April 2003- August 2004) and retrospectively (from January 1994- March 2003) collected cases will be used.
DURATION:
From April 2003 to August 2004, a sixteen month period.
LOCATION:
Departments of General Medicine units I, II and III, Staff Students Health Services.
SUBJECTS:
INCLUSION CRITERIA:
Health care workers employed at Christian medical college hospital, Vellore who are diagnosed to have tuberculosis.
EXCLUSION CRITERIA:
i. Patients who were diagnosed to have active tuberculosis or have received treatment for tuberculosis prior to joining the health care facility.
ii. Patients diagnosed to have tuberculosis during the pre employment screening.
iii. Patients who are having a relapse of tuberculosis during the study period and if the index episode is prior to January 1994.
RESULTS :
The results of the study are summarized here. The results will be presented in three sections. The first section depicts data regarding the clinical profile of health care workers who developed tuberculosis. The second section
deals with the associations of a more than median delay in the diagnosis of tuberculosis (case-control study). The third section is a case control study designed to identify the risk factors for developing tuberculosis among the health care workers.
CONCLUSIONS :
Health care workers had a higher incidence of tuberculosis than the general population. The incidence of tuberculosis disease among health care workers was 314 cases per 100,000 person years. The incidence of sputum positive pulmonary tuberculosis was 111.06 per 100,000 person years.
• The main sub type of tuberculosis was sputum positive pulmonary. Among the extra pulmonary cases tuberculous lymphadenitis constituted the majority.
• Among health care workers at our institute the only risk factors that were independently associated with tuberculosis were a body mass index <19 Kg/m2 and employment in medical wards.
• No occupational subgroups were found to have an independently increased risk for acquiring tuberculosis.
• There was a significant delay in diagnosis of cases of tuberculosis. The mean delay was 37.98 days. The delay in the diagnosis of smear positive cases could contribute to nosocomial transmission of tuberculosis
