title: The incidence of recurrence of tuberculosis and its related factors in smear-positive pulmonary tuberculosis patients in Iran: A retrospective cohort study.
abstract: OBJECTIVE
  Studying the recurrence of smear-positive pulmonary tuberculosis (TB) is a convenient way to evaluate the effectiveness of TB control programs and identify vulnerable patients. In the present study, the rate of recurrence of TB and its predictors were determined in Iran.
  
  
  METHODS
  This study was a retrospective cohort. Eligible people were patients with smear-positive TB who were diagnosed from 2002 to 2011. The end of the follow-up time was December 2013. The number of people who entered the cohort was 1,271 subjects. In order to determine the predictors of recurrence, multivariate logistic regression was used. Analysis was done using SPSS 20.
  
  
  RESULTS
  The recurrence incidence was 8.3% and in 85.9% of these patients, it occurred in the time interval of 1-5 years after successful treatment. The recurrence rate was not significantly related to gender, age group, and diabetes. But it was significantly higher in patients whose sputum smear grading before treatment was 2 + or more, patients with positive sputum smear at the end of the second month of the treatment, patients who had completed treatment, and patients who were smokers (P < 0.05).
  
  
  CONCLUSIONS
  Our study showed that a considerable percentage of smear-positive pulmonary TB patients experience recurrence and that some patients are at a higher risk of recurrence.
authors.affiliation: Department of Biostatistics and Epidemiology, Health Sciences Research Center, Faculty of Health, Mazandaran University of Medical Sciences, Sari, Iran.
authors.forename: Mahmood
authors.initials: M
authors.lastname: Moosazadeh
authors.affiliation: Department of Biostatistics and Epidemiology, Kerman University of Medical Sciences, Kerman, Iran.
authors.forename: Abbas
authors.initials: A
authors.lastname: Bahrampour
authors.affiliation: Department of Epidemiology, School of Public Health, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Mahshid
authors.initials: M
authors.lastname: Nasehi
authors.affiliation: Department of Biostatistics and Epidemiology, Environmental Health Engineering Research Center, Kerman University of Medical Sciences, Kerman, Iran.
authors.forename: Narges
authors.initials: N
authors.lastname: Khanjani
keywords: Incidence; recurrence; relapse; tuberculosis