A total of 5822 participants opened the link to the survey during the assessment period. For the here presented analyses, all participants who did not reach question 9 of the questionnaire (commencement of content-based questions) (N = 479) were excluded. From this population (n = 5343), all persons not working in direct patient care (administration: n = 608; science: n = 240; other reason for not working in patient care: n = 199; missing data: n = 627) were excluded leaving 3669 participants. Due to potential biased values in the “average overtime” variable, N = 1 (reported -80 h/week) and N = 12 (reported > 30 h/week), a total of N = 13 subjects were excluded for this variable (extreme values that exceeded the 75%-quartile or were below the 25% quartile by more than ten times of the IQR).
61.0% of the participants were female and our sample covered the complete age range of HCWs. The distribution of occupational groups included 11.7% residents, 8.6% head physicians/chief of departments, 23.8% physicians/board-certified physicians, 35.9% nurses, 8.4% psychologists, 4.5% social workers, and 7.1% working in other areas of patient care. 40.1% worked in university hospitals and 59.9% in non-university hospitals. 19.2% worked in the emergency room, ICU, or on a special COVID-19 ward. See Table 1 and Supplementary Table 1 for demographic information.
COVID-19-related demographic information
2.8% of all participants were tested positive for COVID-19 at the time of responding to the survey and 26.5% belonged to the COVID-19 risk group due to pre-existing medical conditions, age, or other factors. Participants worked on average 2.01 h overtime since the beginning of the COVID-19 pandemic (minimum = − 26; maximum =+ 30; Mdn = 0.00; 95% CI for the mean 1.87–2.15; SD = 4.07; N = 3414) treated on average 3.11 patients with COVID-19 (minimum = 0; maximum = 350; SD = 11.06; Mdn 0.00; 95% CI for the mean = 2.74–3.47; N = 3493), and reported to have on average 1.20 friends or family members tested positive for COVID-19 (minimum = 0; maximum = 50; Mdn = 0; 95% CI for the mean = 1.11–1.29; SD = 2.75; N = 3541).
Overall response patterns
With regard to subjective burden, high ratings were reached regarding the questions of subjective mental stress (question 10), of worrying about the personal future (question 26), of worrying regarding the well-being of the family (questions 27) and of the fear to catch the virus and to pass it on to family or friends (question 29). On the other hand, low scores of agreement were reported with regard to a lack of time in personal life (question 24) and a reduced sleep quality (question 30). Evaluating structural factors of the hospitals, participants rated the information policy, the measures taken by the hospitals to provide safety equipment (question 19), the communication strategy (questions 20), and the preparation of the hospital for the pandemic (questions 22) mostly positive. Importantly, low ratings emerged for the question of feeling left alone by the employer (question 13) and most participants strongly agreed that they are willing to continue working in the healthcare system after the pandemic (question 33). See Table 2 for the descriptive statistics of all answers of the complete sample.
Contrasting MD, nurses, and other hospital staff
ANOVA showed significant differences between groups in the average hours of overtime per week (Welch test: F(2, 2224.7) = 92.88, p < 0.0005) with more overtime hours among nurses (2.60 ± 4.30) and MDs (2.09 ± 4.44) compared to other staff (0.80 ± 2.04) (p < 0.0005 each). The contrast between nurses and MDs did not reach the adjusted significance threshold (p = 0.0079). Group differences were detected in the number of patients treated who were positive for COVID-19 (Welch test: F(2, 2318.6) = 72.20, p < 0.0005). MDs (4.28 ± 14.81) treated numerically more patients than nurses (2.99 ± 7.40) (p = 0.008, not reaching the adjusted significance threshold) and other staff (0.65 ± 3.57) (p < 0.0005). Nurses treated more patients than other staff (p < 0.0005). Regarding the number of family members and friends having been tested positive, again, significant differences between groups differences were detected (Welch test: F(2, 2140.28) = 23.72, p < 0.0005). MDs (1.46 ± 2.98) reported higher numbers than nurses (1.13 ± 2.81) (p = 0.005, not reaching the adjusted significance threshold) and other staff (0.75 ± 1.94) (p < 0.0005). Nurses reported higher numbers than other staff (p = 0.0012). Chi-square tests showed differences in the distribution of several demographic variables (Supplementary Table 2). From particular importance, a higher proportion of females were detected in the nurses and other groups and more participants were tested positive for COVID-19 among MDs and in the nurse group.
In all questions with our 5-item Likert-scale, Kruskal–Wallis tests showed between-group differences. In general, nurses reached higher values on questions representative for subjective mental stress and an increased subjective burden (questions 9, 10, 12, 24, 25, 26, 27, 29, or 30) compared to both other groups. Nurses reached lower values on questions regarding the agreement with information policies, experienced support and preparation of the hospital regarding the COVID-19 pandemic (questions 11, 13, 14, 19, 20, 21, and 22). Overall, MDs reported lower values on stress- and subjective burden-related questions and achieved higher agreement with regard to structural measures and information policies. Even though we found significant group differences for all questions, the descriptive data (means, medians) showed that these differences were mostly subtle. Please see Table 3 for descriptive data and statistics of the three-group comparisons. As the proportion of females was higher among nurses and other groups compared to MDs, we performed all analyses separately for men and women (see Supplementary Tables 3 and 4) with subsequently mainly confirming the findings from the whole group.
Contrasting participants working on ICU/ER and COVID-19 wards to all others
Assuming that staff working on ICU, ER, and COVID-19 wards is exposed to a higher risk of being in contact with COVID-19 patients, we contrasted these groups together with all other participants. Those participants worked on average more hours overtime (3.36 ± 5.03 vs. 1.69 ± 3.74, Welch test: F(1, 833.0) = 63.5, p < 0.0005), treated on average more patients with COVID-19 (8.48 ± 17.42 vs 1.82 ± 8.40, Welch test: F(1, 750.6) = 93.6, p < 0.0005), and had on average more family members or friends who were COVID-19 positive (1.46 ± 3.56 vs 1.14 ± 2.52, Welch test: F(1, 854.8) = 4.8, p = 0.029, trend). Participants working on ICU/ER/COVID-19 wards were more often COVID-19 positive (p < 0.0005), but belonged less often to the COVID-19 risk group (p = 0.013 (trend)). No differences in gender distribution between both groups (p = 0.205) were detected (for differences in other demographic variables and complete test statistics, see Supplementary Table 5). Overall, participants working in ICU/ER/COVID-19 wards reported higher rates of agreement with questions investigating stress and subjective burden and had lower rates of agreement with questions on structural measures and information policies. No group differences were detected with regard to subjective concerns about the future (question 26), to the fear to catch the virus (question 28), and to the question whether non-COVID-19 patients are adequately treated in the given setting (question 31). Higher rate of agreement was reported with regard to the adequate care of COVID-19 positive patients (question 32) among those participants working on ICU/ER/COVID-19 wards. Again, means and medians were in general comparable between groups (see Table 4).