Determinant factors for mortality during treatment among tuberculosis patients: Cox proportional hazards model

Abstract

Background: Investigating the survival of tuberculosis (TB) patients is one of the main parts of the TB control program. It can be related to many factors. This study aimed to estimate the survival experience and its associated factors among these patients.

Methodology: All TB patients detected during March 2005 to 31 September 2014 were entered into this prospective cohort. Each patient was investigated from the diagnosis date and followed until the last available information during treatment. Data analysis was performed using Kaplan Meier and multivariate Cox regression models.

Results: The survival experience of 2493 TB patients was investigated 73.7% of which were pulmonary type. Mean and median survival time were 6.5 and 6.2 months respectively. The incidence rate of death among patients during the treatment courses was 0.99 (95% confidence interval: 0.84-1.1) per 100 person-months. Controlling the confounders, the incidence (95% confidence interval) of death was significantly higher among men (HR=1.8; 1.2-2.6), diabetic patients (HR=1.7; 1.2-2.6), cancerous patients (HR=4.8; 2.6-8.8) and HIV positive patients (HR=22.1; 7.3-66.4).

Conclusion: This study showed that male gender, TB/HIV co-infection and concurrent development of TB and cancer were determinant factors of death during the treatment period of TB.

Keywords: Cox regression; Death; Survival; Tuberculosis.