Risk Factors for Recurrent Tuberculosis among Successfully Treated Patients in Israel, 1999-2011.

BACKGROUND

Recurrent tuberculosis (TB) is one of the indices used to assess the effectiveness of the Israeli National TB Programs (NTP).

OBJECTIVES

To estimate the incidence of recurrent TB in Israel and to identify the associated risk factors.

METHODS

We conducted a retrospective cohort study of all TB patients who were Israeli citizens and diagnosed between 1999 and 2011 with a treatment outcome recorded as "success." We compared those who had recurrent TB with those who did not. In addition, a nested case-control study included all those who had recurrent TB with a random sample from this cohort matched by age, gender, and year of TB diagnosis.

RESULTS

Of 3515 TB patients diagnosed between 1999 and 2011, 37 (1.05%) had recurrent TB during the follow-up period, with an incidence rate of 1.55 cases per 1000 person-years (PY). Male gender [hazard ratio (HR) 3.2, 95% confidence interval (95%CI) 1.4-7.4], human immunodeficiency virus (HIV) infection (HR 3.9, 95%CI 1.5-10.4), positive sputum culture [odds ratios (OR) 2.7, 95%CI 1.1-6.9], and low adherence to anti-TB treatment (OR 3.2, 95%CI 1.0-10.3) were found to be risk factors for recurrent TB.

CONCLUSIONS

Male gender, HIV infection, positive sputum culture, and low adherence to anti-TB drugs during the initial TB episode were risk factors for developing recurrent TB.