عوامل تعیین‌کننده دوره زمانی منفی‌شدن اسمیر خلط بیماران سل ریوی در استان همدان: یک مطالعه همگروهی تاریخی

Background & Objectives: Tuberculosis (TB) is the largest single cause of death from infectious diseases and has a ten rating of global burden of disease. Despite the availability of effective treatment for pulmonary TB, sputum conversion of patients affected by various factors. This study aimed to determine the time course of sputum conversion in patients and possible affected factors in this process. Methods: In this Retrospective cohort study, 440 patients with smear-positive pulmonary TB in Hamadan province from 21 March 2006 to 20 March 2012 referred to health centers were included. Demographic, clinical data and treatment status of patients, including the time of sputum smear negative were extracted using TB Register software from patient registry. Time to sputum conversion was considered monthly during the patient’s treatmentand shown by Kaplan-Meier survival curve. The effects of some determinants including gender, location, age group and number of bacilli in the sputum of patients at the beginning of treatment were determined using Cox proportional hazard regression model. Results: From 440 patients with smear-positive pulmonary TB, 51% (221 patients) were male and 49% (219 patients) were female. Fifty seven percent (57%) were living in urban and others in rural. The median of sputum conversion was 3 months. Totally, sputum conversion rate at the end of month 2 and 3 were 69% and 88%, respectively. Conclusion: Our findings revealed that there has been a considerable difference between the expected sputum conversion rate and the observed rate in Hamadan province, Iran.