Analyse des Exacerbations of Chronic Pulmonary Disease Tool als Prädiktor für akute Exazerbationen bei Chronisch obstruktiver Lungenerkrankung

Patients with COPD experience a considerable restriction of their performance, mobility, independence and ultimately also their quality of life due to the disease. Acute exacerbations contribute to a worsening of their health status, therefore they influence the course of the disease and prognosis significantly. The concept of AECOPD and its severity as well as its therapy is not uniform, which makes the identification of patients at risk more difficult. In the existing literature, authors proposed the term of symptomatic exacerbations, which should be recorded by so-called PROs, as a supplement to the previous exacerbation definition. In the PACE- study, exacerbation predictors are sought in COPD patients during inpatient PR. To this end, this dissertation addresses a PRO, the EXAcerbations of Chronic Pulmonary Disease Tool (EXACT). Using this 14- item questionnaire, patients document their daily symptoms. The aim of the editors is to record symptomatic exacerbations as well as their duration and severity. The questionnaire’s Total Score is used for this purpose. In addition, it includes three subordinate domain scores (breathlessness, chest symptoms and cough and sputum). As early as three days before clinically diagnosed AECOPD, there was a significant increase in all EXACT- scores compared with the control group whose patients had no exacerbation during PR. This finding highlights the questionnaire as a measurement tool to detect exacerbations early so that future therapeutic intervention or even prevention of AECOPD can be achieved. When considering the threshold values established by the editors for detecting symptomatic exacerbations, there is little overlap of clinically diagnosed and symptomatic (as defined by EXACT) exacerbations. However, in contrast to EXACT- exacerbations, clinically diagnosed events led to lung function decline at the end of PR. Thus, the suitability of the questionnaire to identify relevant AECOPD events following the authors’ defined thresholds cannot be demonstrated in this study, at least in the observed period of time. Previous work has discussed symptomatic exacerbations as a complementary variable to the conventional exacerbation definition. It is also striking that the group of patients with AECOPD had a significantly higher EXACT- score from the beginning of PR than the control group. These patients had a significantly worse FEV1 and a more frequent history of exacerbations. It can be assumed that the set thresholds are not equally applicable for all COPD patients. However, leaving these aside, there is a significant increase in Total Score before AECOPD. In the future, the questionnaire could be used to document the progression of symptoms and to help patients decide whether to seek medical help at an early stage. For the sake of practicability, this documentation should be done electronically and should be monitored by the patient's physician. So far, mainly anamnestic indicators and diagnostic measuring instruments, for which laboratory tests and equipment are required, are known exacerbation predictors. Therefore, a diary completed by patients themselves could be a useful addition and easy to use documentation, especially for outpatient care. In order to validate this and to better assess compliance, a longer period of time should be investigated in the future. With regard to the secondary outcomes of this dissertation, there were gender- specific differences between the studied groups. Female study participants were older on average, had a lower FEV1 and more frequent exacerbations in the past. However, all of these risk factors were not statistically significant. The association between gender and the risk of developing AECOPD during PR could not be demonstrated. In addition, we investigated whether the EXACT Total Score, as a documentation of symptoms, depicts improvement during PR. This could not be proven, the Total Score showed a stable course during PR. It can be argued that the score reflects the long- term level of patients well and reacts in case of acute deterioration, but is not very susceptible to minor fluctuations. However, this would also needed to be assessed over a longer period of time. The secondary outcomes also included the domain scores of the EXACT questionnaire. Here, a significant difference could also be found between the groups up to three or four days before AECOPD. In summary, all EXACT- scores show a relevant worsening of symptoms already before clinical diagnosis and thus provide the possibility of early detection of acute exacerbations.