Latent Classes of Personality Traits and Their Relationship with Workplace Bullying among Acute and Critical Care Nurses

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Introduction
Workplace bullying, as a workplace stressor, refers to the negative behaviors of work-related harassment, ofense, and exclusion that an individual frequently and repeatedly experiences in the workplace for more than six months (at least once a week) [1].Research has shown that workplace bullying is more common and severe for nurses than other professions [2], especially for acute and critical care nurses who work in the emergency room and intensive care unit [3].Workplace bullying not only has adverse efects on the physical and mental health of nurses [4], but also causes job burnout [5], increases the turnover tendency of nurses [6], and even afects the quality of nursing care and threatens the life safety of patients [6].Terefore, more attention should be paid to identifying risk factors for workplace bullying among acute and critical care nurses.
Personality traits refer to the stable and unique psychological and behavioral patterns that distinguish oneself from others and are shaped under the combined action of congenital heredity and acquired environmental conditions.Previous studies have shown that personality traits, as a typical variable refecting individual diferences, play a signifcant role in predicting individuals' exposure to workplace bullying [7][8][9].For example, Balducci et al. [10] found that neuroticism was positively correlated with workplace bullying among 609 public sector employees in Italy.However, most studies focus on the relationship between a certain personality trait (e.g., neuroticism and agreeableness) and workplace bullying from a variablecentered perspective and neglect that diferent types of personality traits can exist simultaneously.
Latent profle analysis (LPA) [11] is a person-centered statistical analysis identifying diferent subgroups within populations that share certain outward characteristics.LPA can be used to analyze the relationship between personality traits and workplace bullying when taking diferent types of personality traits into consideration simultaneously.Studies have shown that individuals with the same level of personality traits show diferent characteristics in diferent dimensions [12,13].However, the relationship between the latent classes of personality traits and workplace bullying remains underinvestigated.
Terefore, this study aimed to apply LPA to explore diferent potential classes of personality traits of acute and critical care nurses and to analyze their relationship with workplace bullying.

Study Participants.
From April to September 2022, a total of 245 acute and critical care nurses in a 3 A-grade hospital in Shandong Province were selected as participants by the convenience sampling method.Te inclusion criteria for acute and critical care nurses were as follows: (1) registered nurse with valid license; (2) working in the acute and critical care departments for more than 3 months (three months is a probation period); and (3) informed consent and voluntary participation.Te exclusion criteria were: not having been employed as a nurse in this hospital.

Procedures.
In this study, the online questionnaire collection was carried out through the "Wenjuanxing" platform with the support of the consent of the nursing department and head nurses of all departments in the hospital.Te study followed the principles of voluntary participation and informed consent with the ethics approval number 2020-R-061.Before completing the questionnaire, the objective and procedure of the questionnaire were detailed.Finally, 245 valid questionnaires were collected.

Sociodemographic Characteristics.
Personal characteristics include sex, age, level of education, and marital status; job-related characteristics include average monthly income, employment relationship, professional title, working years, night shift involvement, number of monthly night shifts, and weekly working hours.

Chinese Big Five Personality Inventory Brief Version (CBF-PI-B).
Te CBF-PI-B [14] was used to assess personality traits by acute and critical care nurses.It comprises 40 items and can be classifed into 5 dimensions (i.e., neuroticism, extroversion, openness, agreeableness, and conscientiousness).Each item was rated on a 5-point scale, with a point from 1 to 5 indicating "strongly disagree" to "strongly agree."Te higher the total score of each dimension is, the more obvious the corresponding personality characteristics are.Cronbach's alpha of the total scale in this study was 0.878.

Negative Acts Questionnaire (NAQ).
Te NAQ was developed by Einarsen and Notelaers [15] and was translated into Chinese by Hongjing Xun [16] in 2012.It has been widely used in the measurement of workplace bullying sufered by Chinese nurses.Te NAQ has 22 items and includes 3 dimensions (i.e., individual-related negative acts, work-related negative acts, and organizational injustice).A 5-point scale was used to rate each item, with a point from 1 to 5 indicating "never," "occasionally," "monthly," "weekly," and "daily," respectively.Te higher the total score is, the higher the level of workplace bullying nurses experience.Cronbach's alpha of the total scale in this study was 0.980.

Statistical Methods.
Firstly, for continuous variables conforming to a normal distribution, mean and standard deviation (SD) were used for description; for non-normal distribution data, median and interquartile range (IQR) were used for description; for categorical variables, frequency and percentage were used for description.
Secondly, LPA was conducted to identify latent profles of personality traits.We started with a one-profle model and gradually increased the number of profles until the optimal model was identifed.Te model was comprehensively evaluated according to Entropy, Bootstrap likelihood ratio test (BLRT), Lo-Mendell-Rubin adjusted likelihood ratio test (LMR), Akaike information criteria (AIC), Bayesian information criteria (BIC), sample-size-adjusted Bayesian information criterion (aBIC).Te smaller the AIC, BIC, and aBIC values are, the better the ftting degree is.Entropy ranges from 0 to 1, with higher values (value ≥ 0.8) indicating a clearer classifcation [17].When the results of LMR and BLRT are <0.05, it indicates that the K class model is superior to K-1 class model [18].
Tirdly, the chi-square test was used to analyze sociodemographic diferences of potential personality traits among nurses in acute and critical care units.
Fourthly, the Kruskal-Wallis test was used to explore the relationship between the latent classes of personality traits of nurses and workplace bullying.
Fifthly, the Wilcoxon-Mann-Whitney test and Kruskal-Wallis test were used to analyze the diferences in workplace bullying among acute and critical care nurses with diferent sociodemographic characteristics.
Finally, multiple linear regression was conducted to analyze the relationship between latent profles of personality traits and workplace bullying, and statistically signifcant demographic variables in the univariate analysis were controlled as covariates.Te signifcance level was set at α � 0.05 (two sides).SPSS 25.0 and Mplus 8.0 were used for statistical analyses.1, six models were obtained by ftting from one to six latent classes, respectively.Te entropy values of the 2-class to 6-class models were >0.8, indicating good accuracy of these models.As the number of latent classes increased, AIC, BIC, and aBIC gradually decreased.In the model of Class 4, the P values of both LMR and BLRT were signifcant; indicating that the model of Class 4 was superior to the model of Class 3, but the P value of LMR of the model of Class 5 was nonsignifcant.Terefore, the model of Class 4 was determined as the optimal model.

Latent Profles of Personality Traits among Acute and Critical Care Nurses. As shown in Table
To verify the reliability of the analysis results of the above latent classes, the average posterior probability of diferent models is shown in Table 2. Te results showed that the average posterior probability (column) of the four latent classes (row) of nurses' personality traits ranged from 0.786 to 0.954, indicating that the model ftting results of the four latent classes were reliable.
Te frst class (49.0%) called the "C1 negative group" scored higher on the neurotic dimension than the C2 fexible group and the C4 stable group but lower than the C3 neurotic group and the lowest on the dimensions of conscientiousness, agreeableness, openness, and extroversion.Te second class (16.0%) had the lowest score on the dimension of neuroticism and the highest score on other dimensions and was named as "C2 fexible group."Te third class (18.1%) had the highest score on the dimension of neuroticism, moderate scores on the dimensions of conscientiousness, agreeableness, openness, and extroversion, and was named as "C3 neurotic group."Te fnal class (16.9%) had low scores in neuroticism, openness, and extroversion and high scores in conscientiousness and agreeableness, indicating conservative personality and stable mood, and was labeled as "C4 stable group" (Figure 1).

Te Diferences in Sociodemographic Characteristics of Nurses in Diferent Latent Classes of Personality Traits.
Univariate analysis results showed that there were statistically signifcant diferences (P < 0.05) in age, professional title, and monthly night shift number of nurses in diferent latent classes of personality traits (Table 3).Flexible group were older than neurotic group nurses.Compared with acute and critical care nurses of high professional titles, those with low professional titles accounted for a higher proportion in negative group and neurotic group.Compared with those without night shifts, acute and critical care nurses with night shifts accounted for a higher proportion in negative group and neurotic group.

Relationship between Latent Classes of Personality Traits
and Workplace Bullying among Acute and Critical Care Nurses

Disparity between Latent Classes of Personality Traits and Workplace Bullying among Acute and Critical Care
Nurses.As shown in Table 4, the dimensions and total scores of workplace bullying showed signifcant diferences in the latent classes of personality traits among acute and critical care nurses (P < 0.001).Post hoc analysis showed that the C1 negative group and the C3 neurotic group scored higher than the fexible group and stable group in the two dimensions of individual-related negative acts and workrelated negative acts and the total score of negative acts.In the dimension of organizational injustice, the neurotic group scored higher than the fexible group and the stable group, and the negative group scored higher than the fexible group.

Discussion
Tis study found four heterogeneous groups of personality traits among acute and critical care nurses, including negative, neurotic, fexible, and stable groups.Te stable group (16.9%) was introverted but rigorous, got along well with others, and had stable emotions.Te fexible group (16.0%) was rigorous, extroverted, highly tolerant and empathetic to others, and able to handle interpersonal relations fexibly.
Although the stable and fexible groups had been identifed in previous studies [12,13], this study still proposed two new groups of personality traits, namely, negative group and neurotic group.Te negative group (49.0%) was introverted, indiferent to others with low social participation, and may show a negative attitude at work.Te neurotic group (18.1%) was overly sensitive, lowly tolerant to others, prone to anxiety, and had an unstable personality.Te reason may be related to the job content of emergency and critical care departments.Acute and critical care nurses face and rescue more critically ill patients with more workload, working time, work pressure, and night shifts, which may induce negative attitudes and negative emotions [19,20], so there are the negative group and neurotic group.

Journal of Nursing Management
In this study, there were signifcant diferences in age, professional title, and number of monthly night shifts among latent classes of personality traits.Flexible group nurses were older than neurotic group nurses.Compared with acute and critical care nurses of high professional titles, those with low professional titles accounted for a higher proportion in the negative group and neurotic group.Compared with those without night shifts, acute and critical care nurses with night shifts accounted for a higher proportion in the negative group and neurotic group, which was consistent with the results of previous studies [12].It is worth noting that the negative group and neurotic group were prone to anxiety, depression, and other negative emotions [21] and more likely to have career burnout [12].Consistently, this study revealed that the negative group and the neurotic group exhibited higher overall scores of workplace bullying when compared to both the fexible group and the stable group, indicating a greater susceptibility to workplace bullying.Terefore, nursing managers should pay more attention to negative and neurotic nurses.
Multiple linear regression results showed that compared with the neurotic group, the negative, stable, and fexible groups all sufered from less workplace bullying considering nurses' sociodemographic characteristics and working hours as the potential confounders.Tis was consistent with the results of previous studies that personality traits are closely related to workplace bullying [9,22].Tis study found that nurses prone to workplace bullying did not have a single personality trait but a personality type composed of several personality traits.Individuals with low neuroticism, high conscientiousness, high agreeableness, high extroversion, and high openness and individuals with low neuroticism, high conscientiousness, high agreeableness, low extroversion, and low openness were not prone to workplace bullying [23].According to the Victim Precipitation Teory [24], certain characteristics or behaviors exhibited by people may become their weaknesses, attract others' encroachment, and make them the targets to be hurt.Acute and critical care nurses in the neurotic group are emotionally unstable, difcult to get along with others and easy to be isolated by colleagues, and become the target of bullying.Nurses in both the fexible group and stable group are introverted or extroverted and can maintain a responsible and rigorous attitude with less negative emotions and better deal with interpersonal relationships; hence, they are less likely to be bullied by colleagues [25].

Limitations
Tere are several limitations of the present study.Firstly, using a cross-sectional design, this study could not predict the longitudinal trajectory of nurses' exposure to workplace bullying, nor could it draw a causal relationship between potential categories of personality and workplace bullying, which needs to be confrmed by more empirical studies in the future.Secondly, the representativeness of the existing study participants is limited.Tis study only surveyed nurses in the emergency critical care department of a 3 A-grade hospital, and the sample size was small.Tird, confounding factors such as

Conclusion
Tere are four subtypes of personality traits among acute and critical care nurses: the negative group, fexible group, neurotic group, and stable group.Nurses in the neurotic group are more likely to sufer from workplace bullying.It is necessary to identify the personality traits of nurses and develop interventions to reduce workplace bullying.

Implications for Nursing Management
Tere are several implications for nursing management.First, hospital managers should pay attention to neurotic and negative nurses who are prone to workplace bullying.Although their personality characteristics are stable and not easy to change, managers should take active and efective measures to help them, such as setting up psychological counseling departments and psychological healing teams in the department to help nurses who have been bullied get rid of the adverse efects.Guide them to build good interpersonal relationships and maintain their mental and physical health.Second, hospital managers can help nurses to understand and cope with workplace bullying by organizing training related to workplace bullying, and carry out targeted training for nurses with diferent personality characteristics and diferent ages, so as to improve the awareness and handling ability of nurses.Tird, department leaders can form a positive nursing work atmosphere by organizing team building activities or constructing department culture.At the same time, they can set a team work mode, comprehensively consider the characteristics of nurses, work ability, and other factors to assign team members, form a mutual help and harmonious group work atmosphere, and increase the ability to resist workplace bullying.In addition, hospital managers can take the potential characteristics of nurses' personality traits as a reference index for the selection of nursing talents and the allocation of departments, assign nurses with diferent personalities to suitable departments, and select nursing talents more suitable for emergency and critical department posts [26].

Figure 1 :
Figure 1: Latent classes of personality traits in acute and critical care nurses.
Test and Kruskal-Wallis Test Were Used to Analyze the Diferences in Workplace Bullying among Acute and Critical Care Nurses with Diferent Sociodemographic Characteristics.Te normality test of workplace bullying sufered by nurses showed a skewed distribution.Terefore, the Wilcoxon-Mann-Whitney test and Kruskal-Wallis test were used to analyze the relationship between sociodemographic characteristics and workplace bullying.Te results showed that age, marital status, weekly working hours, and average monthly income of participating nurses correlated with workplace bullying signifcantly (P < 0.05).
3.3.3.Multiple Linear Regression Was Conducted to Analyze the Relationship between Latent Profles of Personality Traits and Workplace Bullying.Multiple linear regression analysisshowed that after controlling for age, marital status, weekly working hours, and average monthly income, compared with the neurotic group, the negative group (B � −6.227, P < 0.05), stable group (B � −16.562,P < 0.001), and fexible type (B � −19.208,P < 0.001) reported lower levels of workplace bullying (Table5).

Table 2 :
Average posterior probability of latent classes of personality traits in acute and critical care nurses.

Table 3 :
Distribution comparison of latent classes of personality traits among acute and critical care nurses with diferent demographic characteristics (n (%)).
Note.P-values in bold are statistically signifcant for an alpha of 0.05.

Table 4 :
Disparity between latent classes of personality traits and workplace bullying among acute and critical care nurses.

Table 5 :
Relationship between latent classes of personality traits and workplace bullying among acute and critical care nurses.