Background: To improve the effectiveness of lung cancer screening using low-dose computed tomography (LDCT), the presence of smoking-related comorbidities that may significantly affect mortality in this group should be taken into account. Material and methods: A questionnaire survey and spirometry tests were conducted in a group of 730 respondents as part of a lung cancer screening study between 2016 and 2018. People diagnosed with COPD underwent a three-year follow-up to assess the incidence of medical events. Results: Our study confirmed that cardiovascular diseases (CVDs) were the most common comorbidities in patients who were diagnosed with COPD and participated in LDCT lung cancer screening. Among the CVDs, the most common were arterial hypertension (45.8%) and coronary artery disease (12.5%). Tobacco-related diseases (e.g. CVD, lung cancer, and exacerbations of COPD) were the leading causes of emergency department visits and hospitalizations. The number of visits due to COPD in specialized clinics more than doubled in the observed period. Conclusions: Properly planned screening tests allow not only for the detection of the disease for which they were designed but also for the assessment of comorbidities. In patients undergoing lung cancer screening, it is justified to extend the diagnostics to include spirometry.