Setting, participants, and survey design
The study was conducted at Sinai Health, which is comprised of two sites, an acute care teaching hospital and a rehabilitation hospital, with a combined staff of over 6000, in Toronto, Canada. All hospital staff, aged 18 years or older, including hospital employees, physicians, learners, volunteers, and employees of third parties (e.g. retail employees) were invited via posters and hospital emails to participate in a longitudinal survey, distributed quarterly from the fall 2020 until spring 2022, with a follow-up measure in the spring of 2023, eight surveys in all.
Surveys were completed using online software (Alchemer, Louisville, CO) that adheres to privacy standards in Ontario, Canada (Personal Health Information Protection Act). All participants completed measures of emotional exhaustion and psychological distress at all time points, and of posttraumatic (PTSD) symptoms at T1, T3, T5, T7 and T8. Measures of depersonalization and personal accomplishment were also completed at all time points, but only by the 50% of participants randomly selected for a longer version of the survey. Scores for depersonalization and personal accomplishment were only included in the analysis for healthcare professionals (nurses, doctors, and members of other regulated healthcare professionals and their students) because nonprofessional participants requested a “not applicable” option for items on these scales after the T1 survey, and subsequently often used this option. For the first five surveys, participants received a gift card at the end of each completed survey valued at $15 US converted to Canadian currency. For surveys six to eight, the value of the gift card was increased to $20 US.
This study was approved by the Sinai Health Research Ethics Board (20-0084-E). All survey participants provided informed consent. All procedures were performed in accordance with relevant guidelines and regulations.
During the recruitment phase, 884 potential participants consented to receive surveys. Of these, 538 (61%) completing the first survey (T1, conducted September 21-November 15, 2020) which included the baseline measure of emotional exhaustion. These 538 formed the cohort for further follow-up. The participation rate at subsequent time points, with the numerator comprised of those participants who completed a valid measure of emotional exhaustion, psychological distress, or both was T2: 485/538 (90%), T3: 424/538 (79%), T4: 409/538 (76%), T5: 395/538 (73%), T6: 372/538 (69%), T7: 350/538 (65%), T8:289/538 (54%). The latter 289 participants were included in the current analysis.
Instruments
Emotional exhaustion, depersonalization and personal accomplishment were measured with the Maslach Burnout Inventory: Human Services Survey for Medical Personnel25. The emotional exhaustion (nine items), depersonalization (five items), and personal accomplishment (eight items) were each calculated as the sum of items scored 0 to 6. Across time points, Cronbach’s alpha ranged from 0.94 to 0.96 (emotional exhaustion, n = 289), 0.84-0.90 (depersonalization, n = 82), and 81-0.89 (personal accomplishment, n = 82).
Psychological distress, which is comprised of depressive and anxiety symptoms, was measured with the Kessler K6, which has 6 items scored from 0 to 4, yielding a range of 0–24 [27]. The K6 strongly discriminates between community cases and non-cases of psychiatric disorders diagnosed by structured interview [27] and has acceptable sensitivity and specificity [28]. In this cohort Cronbach’s alpha across time-points ranged from 0.85 to 0.90 (n = 289).
Posttraumatic symptoms were measured with the Impact of Events Scale-Revised (IES-R) [29], a 22-item measure that assesses hyperarousal, avoidance, and intrusion caused by traumatic events. Respondents are asked to identify a stressful life event (in this case specified as “working during COVID-19”) and then to rate how much they were bothered by 22 types of difficulty in the past 7 days (each scored from 0 to 4). The Cronbach’s alpha for the full scale at each time-point this measure was used (T1, T3, T5, T7, T8) ranged from 0.94 to 0.96 (n = 289).
Analysis
Descriptive statistics were used to characterize the sample. Participants were sorted into four categories of job-type as previously described24: nurses, other healthcare professionals, other personnel with patient contact, and other personnel without patient contact. Patient contact was determined by participants’ endorsement of the statement that “in the past month, my work has involved direct contact (within 2 metres for more than 15 minutes) with” patients.
To make the scales of various measures directly comparable, scores on all measures at all time points were converted to standardized scores (0 = full group mean at T1, units = standard deviations from T1 mean).
Changes over time, differences in scores by occupational group and the interaction of these variables were tested by repeated measures analysis of variance (ANOVA) with participants who did not provide valid measures at each time point excluded. The Greenhouse-Geisser correction was applied to tests of within-subjects effects when Mauchly’s test of sphericity indicated that sphericity could not be assumed. Standardized scores were plotted by occupational group at each time point in order to interpret significant results from ANOVA.
To test if the Spring 2023 (T8) value of each measure differed from the T7 measure (representing potential improvement as case rates declined and public health measures were relaxed) or differed from T1 (representing potential improvement from the early impact of the pandemic effects), difference scores were calculated: T8 – T7 and T8 – T1. Confidence intervals on difference scores were calculated to determine if they differed from zero, indicating change over time. All analyses were carried out using IBM SPSS Statistics 28 (Armonk, New York).