Statistical methods
TB, death
REGRESSION
Analyses were performed using SAS (SAS Institute, version 9.4). Between-group comparisons for categorical variables were estimated by Chi-squared test with a two-sided significance level of .05. The intention-to-treat (ITT) analysis included all participants enrolled in the two groups. The per-protocol analysis included participants who completed the study regimen. The cumulative incidence and incidence rate per 100 person-year with 95% confidence interval (CI) was calculated at 24 months. The differences in the incidence of active TB between the preventive treatment and untreated control groups were assessed using a one-sided significance level of .05. Due to lost to follow-up issues, Kaplan–Meier time-event analysis was used. Person-year for each participant was calculated based on the quarterly and annual follow-up records for 24 months after treatment. If the participants did not participate in the two-year survey, the duration for which they remained in the study was calculated based on the records of the last completed quarterly follow-up. If the participants had died of other causes, the person-years were calculated based on the records of time of death. If necessary, Cox proportional hazards regression models and an unconditional multiple logistic regression analysis would be performed to identify respective potential risk factors related with TB incidence and drug-related side-effects.