Effect of smoking on treatment outcome among tuberculosis patients in Malaysia; a multicenter study

Amer Hayat Khan,Syed Azhar Syed Sulaiman,Malik Obaid Ullah,Mohamed Azmi Hassali,Kashif Ullah Khan,Omer Mateen,Long Chiau Ming

doi:10.1186/s12889-020-08856-6

Abstract

BackgroundSmoking plays a key role in the development of tuberculosis (TB) infection and is also a predictor of poor TB treatment prognosis and outcomes. The current study was conducted to determine the prevalence of smoking and to assess the effects of smoking on treatment outcomes among TB patients.MethodsA 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.ResultsOf 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.ConclusionsSmoking has a strong influence on TB and is a major barrier towards treatment success (OR = 0.76, 95% CI 0.69–0.84, p < 0.001). Therefore, the findings indicate that smoking cessations are an effective way to decrease treatment failure and drug resistance.

Highlights

Smoking plays a key role in the development of tuberculosis (TB) infection and is a predictor of poor TB treatment prognosis and outcomes
Male gender (OR = 1.43, 95% confidence interval (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
Smoking has a strong influence on TB and is a major barrier towards treatment success (OR = 0.76, 95% CI 0.69–0.84, p < 0.001)

Summary

Introduction

Smoking plays a key role in the development of tuberculosis (TB) infection and is a predictor of poor TB treatment prognosis and outcomes. Various components of the cigarette smoke such as free radicals of oxygen, acrolein, formaldehyde and carbon monoxide increase the oxidative stress in smokers, affecting the bronchial mucosa and increasing the threat of Mycobacterium tuberculosis infection [8]. This might be the reason for less effective TB treatment outcomes among specific populations [9, 10]. The prevalence of TB in Malaysia decreased significantly compared to the early 1990s, Malaysia was still ranked as an intermediate burden country by the World Health Organization (WHO) in 2018 with an incidence rate of 92/100,000 and estimated mortality rate of 4.9/100,000 population [1]

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Conclusion