Study population
Health questionnaires were sent out to patients quarterly after discharge and focused on physical as well as mental well-being. Demographic information was acquired through a baseline questionnaire and partly through the MST clinical database. For the current study, questionnaires completed 6 months after hospital discharge were coupled via patient study number to the retrospectively collected clinical patient data and selected for analysis. By combining the two databases it is possible to determine which patients develop post-COVID-19 syndrome and the nature of the treatments and medications these patients have undergone while admitted to the hospital. Thus, making it possible to identify possible associations between drug treatments and the development of post-COVID-19 syndrome. The combined database consists of patients 18 years or older that were admitted to the hospital (MST) due to COVID-19 symptoms confirmed using a polymerase chain reaction (PCR) test, who have completed the informed consent form and have sufficient proficiency in the Dutch language.
OutcomesPost-COVID-19 syndrome presence 6 months after hospital discharge was determined using the following questions out of the Post COVID database. Question 1: “In general, how would you describe your health at the moment?”. Question 2: “compared to one year ago, how would you rate your health in general now?”. Question 3: “during the past 4 weeks, to what extent has your physical health or emotional problems interfered with your normal social activities with family, friends, neighbors, or groups?”. Question 4: “For the following 4 statements regarding fatigue, please indicate how you have been feeling during the past 2 weeks”. Question 5: “have you felt downhearted or anxious?”. Question 6: “are you occasionally short of breath?”. Using the above-stated questions, three definitions were created to determine post-COVID-19 syndrome status, each consisting of 4 questions (figure 2 ). Definition 1 consists of questions 1, 2, 3 and 5. Definition 2 consist of question 1, 2, 3 and 4. Definition 3 consists of questions 1, 2, 3 and 6. If a patient fit one or more definitions based on the answers they provided, they were categorized as having post-COVID-19 syndrome. A combination of the first question being answered with “fair” or “poor” the second question with “Somewhat worse or much worse now than one year ago” and the third question with “slightly to very severe” combined with “mostly true” or “definitely true” for statements regarding experiencing fatigue and “mostly false” or “definitely false” for statements regarding being fit of the fourth question or “slightly to very severe” for the fifth or sixth questions prompted the patient to be categorized as having developed post-COVID-19 syndrome. Due to the broad nature of the definition of post-COVID-syndrome, the aforementioned questions were implemented to encompass the essence and to give body to this definition. The first 3 questions were chosen to capture the burden of post-COVID-19 symptoms and their effect on the physical, mental, and general health of patients. While the fourth, fifth and sixth questions are meant to encompass common symptoms of post-COVID-19 syndrome [22,23].