Late‐onset PTSD and coping strategies for frontline nurses during the COVID‐19 epidemic in China

Abstract Aim To evaluate the late‐onset post‐traumatic stress disorder (PTSD) situation, coping strategies and social supports for frontline clinical nurses 6 months after involvement in fighting against coronavirus disease 2019 (COVID–19) outbreak in China. Design A cross‐sectional design. Methods We recently randomly distributed a questionnaire online to Chinese nurses who had taken care of COVID‐19 patients since the end of January 2020. The questionnaire was made up of three professional scales, the impact of event scale‐revised, simplified coping style questionnaire and social support rating scale included. Results The general prevalence of late‐onset PTSD among frontline nurses was 88.19%. Nurses who worked in Hubei Province (the kindle place of the COVID‐19 outbreak) showed lower risk of late‐onset PTSD symptoms than those who did not. We also found that positive coping strategies were correlated with less late‐onset PTSD symptoms. Meanwhile, getting more social supports could help these nurses to obtain positive coping strategies.


| INTRODUC TI ON
The coronavirus disease 2019 (COVID-19) pandemic has been initially reported in Hubei Province, China , and has been seriously endangering human health and life worldwide. As of 6 November 2020, over 48.5 million COVID-19 cases and 1.2 million deaths have been reported (World Health Organization, 2020). Because of the widespread and serious spread of the disease, a large number of medical workers are needed in the fight against the epidemic, and nurses are the largest group among them. Chinese frontline clinical nurses had begun the fight against the COVID-19 epidemic since the end of January 2020. Under this circumstance, during this catastrophic epidemic, they were not only under great physical challenges but also faced high psychological stress. Excessive workload has been verified as a statistically significant stressor for nurses, which would affect their mental health (Maharaj et al., 2018;Watanabe & Yamauchi, 2018).
Several studies have investigated that medical staff experienced psychological conditions, such as anxiety and depression Lai et al., 2020). Post-traumatic stress disorder (PTSD) is a mental disorder defined by intrusive recollections, avoidant behaviour and hyperarousal following the experience of a horrifying traumatic event (Kirkpatrick & Heller, 2014). PTSD symptoms often come out 1-6 months after the triggering event. Late-onset PTSD, nonetheless, may be easily overlooked, diagnosed over 6 months after the traumatic event or termination of long-term exposure (Utzon-Frank et al., 2014). At present, China is largely under control, and the post-epidemic era is coming.
However, the influence of this late-onset psychological stress is gradually coming out.
Coping strategies are vital to influence individual stress levels (Labrague et al., 2017). Coping strategies usually consist of positive and negative categories. When faced with stress, individuals with positive coping strategies have positive thoughts and solutions (e.g. constructive actions). In contrast, negative coping strategies are recognized as palliative coping strategies and negative appraisals under stressful conditions (e.g. avoidance) (Ding et al., 2015). Moreover, several studies suggested that nurses adopting positive coping strategies had a statistically significant correlation with their better job performance and satisfaction, which can promote patients' safety (Li et al., 2017;Zhou et al., 2017). Therefore, positive coping strategies of nurses against the COVID-19 pandemic would be a crucial factor in nurses' mental health and patients' outcome.
Social support is considered another important factor influencing mental health . Social support comes from one's social environment, including family members, friends, colleagues, parties, communities, media, unions and even society. Previous research identified that good social support could positively affect mental health (Saltzman et al., 2020). In addition, social support may affect coping strategies (Tesfaye, 2018). Consequently, the lateonset PTSD situation of frontline clinical nurses may be influenced by their social supports.
From the above, coping style and social support may be closely related to late-onset PTSD. Several studies are trying to figure out the relations between them. Such as a study conducted to define social support and coping as predictors of PTSD among traffic survivors (Okech et al., 2018). Another study focused on the influence of social support and coping style on chronic PTSD after floods and found that better social support, the positive coping style could significantly improve the long-term prognosis of patients with PTSD (Dai et al., 2016). Therefore, our study is to assess the late-onset PTSD, coping strategies and social supports situation for frontline clinical nurses 6 months after involvement in fighting against the COVID-19 outbreak in China, call for more attention to the mental health problems of these nurses and give timely and sufficient support to them.

| Study overview
A questionnaire was distributed online to Chinese nurses who had directly contacted COVID-19 patients since the end of January 2020. The questionnaire was made up of three professional scales, IES-R, SCSQ and SSRS included. Then, the late-onset PTSD, coping strategies, social supports and their associations for frontline nurses were assessed. Several steps are taken when conducting this study and involve: a. Finding the aim of our study, which is the late-onset PTSD situa- f. Data analysis, participants were divided into "Hubei" and "non-Hubei" groups and student t test was used to compare the differences between them; in addition, Pearson's correlation and regression analysis were used, which is explained in more detail below,

| Study setting and participants
We conducted a cross-sectional study at the end of July. Firstly, we designed the electrical questionnaire by Questionnaire Star, a professional online survey platform in China. Then, the questionnaires were randomly distributed to frontline nurses fighting against the COVID-19 epidemic by Wechat, which is China's largest real-name communication app by a number of users. Moreover in this way, we can make sure all the people who filled out the questionnaire were frontline nurses. 873 questionnaires were received from 28th July to 30th July, of which 9 were ruled out because they were finished in 2 min, and the answers were highly consistent. Therefore, a total of 864 questionnaires were qualified finally. Hubei Province is believed to be the first place where COVID-19 became popular in China and where the epidemic is much more severe than in other places in China. We divided these frontline nurses into 2 groups. One group was those who had worked in Hubei Province (the kindle place of COVID-19 outbreak) during the COVID-19 epidemic, and the other group was the ones that had worked outside Hubei Province. All participants provided written informed consent, and participants were anonymous. It is not required by our institution to obtain research ethical committee approval for a survey with a non-clinical sample and anonymized data, but we still obtained approval for the study protocol from the institutional review board (Ethics Committee) of the 3rd Xiangya Hospital, Central South University (20005-IRB).

| Measurement of PTSD
Post-traumatic stress disorder was assessed by the impact of event scale-revised (IES-R) checklist (Noda et al., 2018). It can be used to evaluate the performance and severity of PTSD, and it is also a good predictor for the occurrence of PTSD. There are 22 items in this scale, including three dimensions of invasive symptoms (8 items), avoidance symptoms (8 items) and high arousal symptoms (6 items), and each item with a Likert rating scale from 0-4. The Cronbach's alpha was 0.89, the split-half reliability was 0.93 and the relevance validity of the scale was 0.55. The score interval of the IES-R scale was as follows: 0-8 were divided into subclinical symptoms; 9-25 are classified as mild; 26-43 are classified as moderate; and 44-88 are classified as severe.

| Measurement of coping strategies
The coping strategies were measured by the simplified coping style questionnaire (SCSQ) (Su et al., 2018). The SCSQ is a 20-item instrument consisting of 2 subscales: positive coping (12 items) and negative coping (8 items). Each item of the SCSQ ranked on a 4point Likert scale ranging from 0 points to 3 points. The SCSQ had adequate content validity, internal consistency and test-retest reliability in Chinese (Xiao, 1994). In this study, the Cronbach's alpha of the positive coping and negative coping were 0.904 and 0.877, respectively.

| Measurement of social support
Social support was measured by the social support rating scale (SSRS) (Xiao et al., 2020). The SSRS is a 10-item instrument consisting of 3 subscales: objective social support (3 items), subjective social support (4 items) and support utilization (3 items). Items 6 and 7 were rated on a 9-point Likert scale ranging from 0 points to 8 points; the other items are recorded on a 4-point Likert scale ranging from 1 point to 4 points. Higher scores indicate higher levels of social support. In the present study, the Cronbach's alpha of the 3 subscales ranged from 0.678-0.756.

| Data analysis
Questionnaire results were summarized from the imported Excel file and analysed using SPSS version 18.0 software (IBM Corporation).
Descriptive statistics were used to present the sample characteristics and study variables. Continuous variables were expressed as an average with a standard deviation (SD). Categories variables were expressed as numbers and percentages. Student t test was used to compare the differences in IES-R, SCSQ and SSRS scores between "in Hubei" and "outside Hubei" groups. Student t test was used to compare the differences in IES-R scores between "male" and "female" groups. The level of significance was set as 0.05. Pearson's correlation and regression analysis were used to analyse the relationship between social support, coping strategies and late-onset PTSD symptoms. Analysis of variance and coefficient of determination (R square) were calculated to test the linear model. A Q-Q Plot was made by SPSS to check the normality, linearity and heteroscedasticity of the residuals. Thus, the rationality of regression analysis was verified. were relative with high stress (Yuwanich et al., 2015). The details of the demographic characteristics of respondents were shown in Table 1.

| Late-onset PTSD symptoms
The average score of the IES-R checklist was 27.0417 (full mark 88 points). 762 of 864 respondents (88.19%) scored more than 9 points, which can be classified as mild late-onset PTSD symptoms. 403 of 864 respondents (46.64%) scored more than 26 points (a moderate  Table 2a. The average score of avoidance, intrusion, hyperarousal and total score of male nurses in the IES-R checklist were all higher than females. This result demonstrated that male nurses were more probably to have late-onset PTSD symptoms than females (Table 2b).
Compared with nurses who had worked outside Hubei Province during the epidemic, the nurses who had worked in Hubei Province got fewer late-onset PTSD symptoms. The average score of nurses who worked outside Hubei Province during the pandemic was 27.65 (SD = 14.96), while the score of nurses who worked in Hubei Province during the pandemic was 25.16 (SD = 14.54). The difference between these two groups was statistically significant to avoidance and hyperarousal dimensions. However, there was also no statistical difference in the intrusion dimension between these two groups (Table 2c).

| The coping strategies of nurses
The mean scores of positive and negative coping strategies were 2.01 and 1.33, respectively, which indicated the participants tended to take positive measures against the COVID-19 epidemic. The median of item "I tried to get away from it by eating, drinking, smoking, using drugs or medicine, etc." and "I refuse to think too much about it" was 0, revealing that most participants would not take these measures. The details of coping strategies were shown in Table 3a.
We compared the coping strategies of the "nurses who worked outside Hubei Province" group with "nurses who worked in Hubei Province" group; no statistical differences were found (Table 3b).

| The correlation between coping strategies and late-onset PTSD symptoms
In order to investigate the correlation between coping strategies and late-onset PTSD symptoms, we did a regression analysis (Table 4), which displayed that if the respondents took more positive strategies like "I tried to look on the bright side of things," "I didn't take it too seriously," "I confided my troubles to my family, friends or colleagues" and "I tried to make myself feel better by engaging in hobbies, leisure activities, and recreation" in the daily life, the less late-onset PTSD symptoms they would possess (t < 0 and p < .05).
Some items in the negative coping strategies, such as "I tried to get away from it for a while by resting or taking vacation," "I tried to get away from it by eating, drinking, smoking, using drugs or medicine, etc.," "I refuse to think too much about it" and "I had fantasies or wishes about how things might turn out" might lead to severer lateonset PTSD symptoms (t > 0 and p < .05).

| D ISCUSS I ON
Overall, the general prevalence of experiencing late-onset PTSD was 88.19% among participants fighting against COVID-19 during the epidemic in China. Nurses who worked in Hubei Province (the kindle place of COVID-19 outbreak) showed a lower risk of late-onset PTSD symptoms than those who worked outside Hubei Province.
We also found that positive coping strategies were correlated with less late-onset PTSD symptoms. Besides, social supports could help these nurses to obtain positive coping strategies. COVID-19, due to its infectivity, lethality and unpredictability, could cause a huge psychological shock to frontline nurses. They have to face and bear more and more mental pressure, working load, poor sleep quality etc. (Jansson et al., 2019). Our results demonstrated that male nurses were preferential to have severer late-onset PTSD symptoms than female ones, consistent with a previous study . This could be explained by the fact that women are more probably to express their feelings (Street & Dardis, 2018 We found nurses tended to take positive coping strategies facing the COVID-19 epidemic, and this might be due to that the whole society had increased nurses' confidence and motivation by encouraging and stimulating positive emotions, so that they could gain respect, pride and satisfaction in their epidemic prevention and control .
There was no statistical difference between nurses working in and outside Hubei Province on coping strategies. One possible explanation is that they received similar educations and developed coping strategies to cope with the stress of their daily work. Six months after the outbreak, life has returned to normal, and their coping strategies are becoming more and more alike. Also, there was no statistical difference between nurses working in and outside Hubei Province on social support. After they got their lives back on track, they got a sufficient amount of support.
According to Tesfaye's study, as mentioned earlier, social support and plan-full problem-solving were the most preferred strategies for nurses to cope with stress. Therefore, social support was also a key factor in nurses' coping strategies. In our study, sufficient and effective social supports were found in Chinese clinical nurses fighting against the COVID-19 epidemic. This result should be partly ascribed to the Chinese government and health management system for its providing enough objective support to increase nurse confidence and motivation to complete the task, such as improving working and rest condition, maintaining physical and mental health, increasing salary and allowances, priority promotion of professional title, implementing industrial injury recognition, promising their children to access to the best educational resources, employment as an establishment staff, strengthening humanistic care and improving a safer practice environment (Henan, 2020). In this study, the correlation between the tendency of nurses to take negative behaviours and the degree of social support was not statistically significant. It was assumed that nurses had sufficient social support overall so that even with relatively less social support, they still tended to take positive coping strategies rather than negative coping strategies. However, we believe that we cannot rule out the opportunity that they are relevant to some extent, resulting in the unclear definition of negative coping measures in the items of the scale. In the next experiment, if we try to further explore the correlation between negative behaviours and social measures, it will be better to re-define and re-list negative coping measures in a more detailed and clearer way.

TA B L E 5 b
The comparison of social support between nurses who has been in/to Hubei or not during the COVID-19 epidemic

| Future implications and recommendation
These findings suggest that the government, policymakers and the whole society need to pay more attention to psychological health among nurses while combating COVID-19. The prevalence of late-onset PTSD symptoms is very high among Chinese frontline nurses. Not only should they get the care and attention during or shortly after the epidemic, but also the long-term also care should never be overlooked.
The COVID-19 has been seriously endangering public health.
The nurse is one of the largest numbers of medical workers to fight against the COVID-19 pandemic. We studied that sufficient social support of clinical nurses against the COVID-19 pandemic is related to effective coping strategies and fewer late-onset PTSD symptoms. Government should develop interventions for assisting clinical nurses to get more social support in such situations. For example, we can give them access to hear the voice of encouragement and gratitude from the public.
In addition, our study shows that positive coping strategies were related to fewer late-onset PTSD symptoms. If nurses develop healthy coping strategies in their daily work, it would be easy for them to reduce the stress when handling an emergency, which may lead to fewer PTSD symptoms subsequently. For this reason, interventions from health system should throw emphasis on improving their abilities to face challenges and guiding them using healthy coping strategies against stress.
Finally, adequate protection and appropriate preferential treatment are very necessary. Measurements such as improving working and rest conditions, increasing salary and allowances, priority promotion of professional title, promising their children to access to the best educational resources inspired many nurses to work hard in combat with COVID-19. In this way, they can devote themselves to work without worries.

| Limitations
Despite useful findings, there are some limitations in our study. First, the information on marital status, the position and educational background of the participants were not collected. However, these items may be related to the late-onset PTSD symptoms, coping strategies and social support to some extent. Second, we found that the correlation between the tendency of nurses to take negative behaviours and the degree of social support was not statistically significant, which is unexpected. Nevertheless, we cannot find a reasonable explanation.
Thus, further study to verify this result and find the reason is required.

| CON CLUS IONS
Our results suggested that Chinese frontline clinical nurses fighting against the COVID-19 epidemic had a high risk to suffer from late-onset PTSD symptoms 6 months after the COVID-19 outbreak.
Nurses who stayed or went to Hubei Province to fight against the COVID-19 epidemic showed less late-onset PTSD symptoms than those who worked outside Hubei Province. However, there were no statistical differences in coping strategies and social support between these two groups above. Chinese frontline nurses tended to take positive coping strategies rather than negative coping strategies, and positive coping strategies were related to less late-onset PTSD symptoms. The social support Chinese nurses obtained was sufficient. We should pay more attention to the mental health problems of these nurses and give timely and sufficient help to them.

ACK N OWLED G EM ENTS
The authors would like to thank the participants of this study for their support and collaboration.

CO N FLI C T O F I NTE R E S T
None declared.

AUTH O R CO NTR I B UTI O N S
All authors have agreed to the final version.

DATA AVA I L A B I L I T Y S TAT E M E N T
The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.