METHODS: A multi-center retrospective study design was used to collect data from TB patients in four different states of Malaysia, namely Penang, Sabah, Sarawak, and Selangor. The study included medical records of TB patients admitted to the selected hospitals in the period from January 2006 to March 2009. Medical records with incomplete data were not included. Patient demographics and clinical data were collected using a validated data collection form.

RESULTS: Of all patients with TB (9337), the prevalence of smokers was 4313 (46.2%). Among smokers, 3584 (83.1%) were associated with pulmonary TB, while 729 (16.9%) were associated with extrapulmonary TB. Male gender (OR = 1.43, 95% CI 1.30-1.58), Chinese ethnicity (OR = 1.23, 95% CI 1.02-1.49), Sarawak indigenous ethnicity (OR = 0.74, 95% CI 0.58-0.95), urban residents (OR = 1.46, 95% CI 1.33-1.61), employed individuals (OR = 1.21, 95% CI 1.09-1.34), alcoholics (OR = 4.91, 95% CI 4.04-5.96), drug abusers (OR = 7.43, 95% CI 5.70-9.60) and presence of co-morbid condition (OR = 1.27, 95% CI 1.16-1.40) all showed significant association with smoking habits. This study found that 3236 (75.0%) patients were successfully treated in the smokers' group, while 4004 (79.7%) patients were non-smokers. The proportion of deaths (6.6%, n = 283), defaulters (6.6%, n = 284) and treatment interruptions (4.7%, n = 204) was higher in the smokers' group.