Demographic risk factors for extra-pulmonary tuberculosis among adolescents and adults in Saudi Arabia.

Hawra Al-Ghafli,Mushira Enani,Sahal Al Hajoj,Sahar Althawadi,Bright Varghese,Abdulrahman Alrajhi,Ali Albarrak,Sameera Al Johani,Noura Elkizzi,Shampa Anupurba

doi:10.1371/journal.pone.0213846

Abstract

Despite low infectious potential of extrapulmonary tuberculosis (EPTB), it poses significant clinical challenges in terms of diagnosis and treatment monitoring. Understanding the main demographical risk factors for disease characteristics of EPTB plays a crucial role in speeding up diagnosis process and improving overall clinical experience. The aim of this study was to investigate the main demographical and clinical risk factors for EPTB among adults and adolescents for the first time in Saudi Arabia. A cross-sectional multicenter study was carried out on a collection of 902 extrapulmonary Mycobacterium tuberculosis complex (MTBC) isolates with demographical and clinical data. All isolates were subjected to spoligotyping and 24-loci based MIRU-VNTR typing. The association between two potential variables was assessed using odd ratios (OR) calculations. Independent risk factors for EPTB and diseases characteristics of EPTB were identified using multivariate regression model analyses. Gender was found to be significantly associated with lymph node, gastrointestinal, central nervous system and urogenital TB. Lymph node TB showed statistical association to age group below 25 years, non-Saudis and South East Asian ethnicity. While gastrointestinal TB demonstrated an association with patients above 60 years old, and Saudis. Multivariate analysis showed that gender is an independent risk factor to urogenital TB (p 0.03) and lymph node TB (p 0.005). On the other hands, South Asian (p 0.01) and South East Asian (p 0.03) ethnicities were both identified as independent risk factors significantly associated with EPTB. MTBC lineages, site of infections, gender, HIV and smear positivity showed no significant association. Nationwide qualitative-studies are highly warranted in the future to further understand the main demographic risk factors for disease characteristics of EPTB.

Highlights

Tuberculosis (TB) remains an enormous public health threat [1]
Etiological agents of TB, members of Mycobacterium tuberculosis complex (MTBC), primarily invade the host respiratory tract with majority of TB patients being diagnosed with active pulmonary TB (PTB) infections
Compromised host-immune system increases the risk of more serious TB manifestations such as concurrent extra-pulmonary TB (EPTB)

Summary

Introduction

Etiological agents of TB, members of Mycobacterium tuberculosis complex (MTBC), primarily invade the host respiratory tract with majority of TB patients being diagnosed with active pulmonary TB (PTB) infections. Compromised host-immune system (e.g. due to synergism of HIV and MTB infections) increases the risk of more serious TB manifestations such as concurrent extra-pulmonary TB (EPTB) (a clinical presentation of TB that entitles the dissemination of mycobacterial bacilli in both pulmonary and extra-pulmonary sites). This is largely due to failure of hostimmune system to enclose Mycobacterium tuberculosis (MTB) bacilli within lung parenchyma. Investigating the main risk factors associated with EPTB clinical phenotype is a crucial step towards speeding up diagnosis process and improving overall clinical experience for patients

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Conclusion