Introduction : The relationship between smoking and COVID-19 remains controversial, between a protective factor and a death-risk-increaser during the pandemic. However, its respiratory impact after the infection is poorly described. We aimed to study the role of tobacco in the persistence of respiratory post COVID-19 syndrome.

Methods : A retrospective study including 348 patients hospitalized in the pneumology department 2 of A.Mami Hospital for moderate to severe COVID-19 infection between October 2020 and August 2021. Patients were divided into two groups according to their smoking status:G1 smokers(n=89) and G2 non-smokers(n=259).

Results: Our population consisted of 187 men (53,7%) and 161 women (46,3%), with a mean age of 57,78±13,48 years. The mean smoking rate was 34,41±28,26 pack-year.

At three months post COVID-19, the dyspnea was more frequent in G1(24,5% Vs 23,5%, p=0,959), cough and chest pain less frequent in G1 with respectively 3,4% Vs 6,4%, p=0,407 and 2,2% Vs 2,9%, p=1. Parenchymal distortion on the three-month follow-up CT scan was noticed within 54,7% of smokers and 29,2% of non-smokers and was significantly correlated with smoking(p=0,001).

At six months after discharge,smokers had more dyspnea (20,22% Vs 16%, p=0,46),and less cough and chest pain with respectively 3,4% Vs 4% ,p=1 and 1,1% Vs 2,5%,p=0,67. The six-month follow-up CT scan showed parenchymal distortion in 40,9% of G1 and 46,7% of G2(p=0,795).

In terms of respiratory function, the mean percentage of diffusing capacity of the lungs for carbon monoxide(DLCO) was similar in the 2 groups with 73,85±20,08 in G1 and 73,33±15,99 in G2 (p=0,860).

Conclusion: Our study showed that smoking is a significant predictor pf parenchymal sequelae at three months post COVID-19.