Background: Smoking remains a significant issue that increases the prevalence of multiple sclerosis (MS) and its progression to secondary progressive forms.

Objectives: The goal is to identify the relationship between smoking and disease progression in MS patients who have undergone autologous hematopoietic stem cell transplantation (auto-HSCT) at the Centro de Hematología y Medicina Interna, Clínica Ruiz, Puebla, Mexico.

Methods: This retrospective study involved MS patients treated with auto-HSCT, followed for 12 months. The response to transplantation was measured using the difference in Expanded Disability Status Scale (EDSS) scores before and 12 months after the transplant. A difference of -0.5 or greater indicated a good response, while a difference below 0.5 indicated a poor response.

Results: The study included 419 patients, with a median age of 47 years (IQR: 40-53). The majority were non-smokers (315) compared to smokers/ex-smokers (104). In patients with PMSS, EDSS stabilization at 12 months was observed in both smokers/ex-smokers (median 6, interquartile range (IQR) = 1 vs. 6, IQR = 1, p = 0.466) and non-smokers (median 6, IQR = 1 vs. 6, IQR = 1.5, p = 0.001), although non-smokers showed a statistically significant difference.

Conclusion: Smoking may negatively impact MS progression, especially in its progressive forms. (Rev Invest Clin. 2024;76(5):223-9).