Swallowing Dysfunction in Respiratory Diseases : Prevalence and risk factors in COPD and COVID-19

Abstract: Objective: Swallowing dysfunction, dysphagia, is a common, sometimes dangerous, and often neglected problem that affects many people. The prevalence is estimated to be approximately 8% in the general population which makes it as common as e.g. diabetes or asthma. Dysphagia can cause serious complications like malnutrition, aspiration pneumonia and even death. The aims of this thesis were to gain further knowledge and a broader understanding of the prevalence, characteristics and risk factors of swallowing dysfunction in patients with respiratory diseases. Specifically Chronic Obstructive Pulmonary Disease, COPD, and COVID-19 after invasive mechanical ventilation.Study I is a prospective explorative study of 51 COPD patients in stable phase. Swallowing function was evaluated through a questionnaire and through two swallowing tests (water and a cookie) and lung function was measured through a spirometry. The prevalence of self- reported swallowing dysfunction was 65% and the screened prevalence was 49%. There was a negative correlation between lung function and both measurements of swallowing function, i.e. the poorer the lung function the more dysphagia symptoms.Study II is a cross-sectional multi-centre study where we examined the prevalence of self-reported swallowing dysfunction in 571 COPD patients. Additional tests were: spirometry, physical capacity, mMRC and CAT. Subjective swallowing symptoms were found in 33% of the patients. More prevalent in symptomatic patients and patients with lower physical capacity. A high score on the mMRC or CAT and a classification in GOLD groups B and D may be predictive of a swallowing dysfunction and should be addressed by the COPD nurse or physician.Study III is a cross-sectional study of 30 COPD patients hospitalized with a severe exacerbation. Their swallowing function was compared to a control group. The main results of this study were that the prevalence of swallowing dysfunction, both patient-reported and screened in patients hospitalised with a COPD exacerbation, was high. In addition, the AECOPD group was almost three times more likely to suffer from self-reported dysphagia compared to the control group.Study IV is a longitudinal cohort study of swallowing function in 28 COVID-19 patients post invasive mechanical ventilation. Dysphagia was found in 71% of the patients at baseline and it was associated with number of days in the hospital and in the ICU. At discharge from the hospital swallowing function and tolerance of oral intake had improved significantly.Conclusion: Swallowing dysfunction is prevalent both in COPD and in COVID-19 patients post invasive mechanical ventilation.