Prevalence of post-traumatic stress disorder and its predictors following coronary artery bypass graft surgery

Post-traumatic stress disorder (PTSD) is a complex condition that results from exposure to a traumatic events (American Psychiatric Association (APA), 2013). According to the Diagnostic and Statistical Manual of Mental Disorders(DSM-5) (APA, 2013), a diagnosis of PTSD is made when the symptoms persist for more than 1 month after the traumatic event. These events include, but are not limited to, armed struggle, physical assault, sexual violence, kidnapping, terror attacks, torture, natural or man-made disasters, motor vehicle accidents or life-threatening illness. Having a life-threatening illness might not necessarily be considered a traumatic event, although incidents related to the illness, which may be sudden or tragic, can be triggered by it (APA, 2013).

Individuals with PTSD experience several distressing symptoms, classified into three categories: re-experiencing symptoms such as intrusive thoughts, nightmares or flashbacks; avoiding stimuli or reminders of the event; and physiological arousal (for example, hypervigilance, exaggerated startle response) (APA, 2013). Sensory disturbances can be distressing and have been associated with prolonged psychological distress and heightened physiological arousal (Kok et al, 2016). Individuals with PTSD often limit their social interactions, affecting their quality of life and psychosocial outcomes (APA, 2013). They may also experience reduced interest in usual activities and persistent anhedonia, and engage in irresponsible behaviours such as drug use or excessive alcohol consumption (APA, 2013). Further disability is seen in social and family relationships, work attendance, income status, occupational success, education levels and general quality of life (Hauer et al, 2013).

Cardiac surgery can be traumatic and stressful and, as a result, many people experience psychological difficulties following treatment. Patients after cardiac surgery are therefore at high risk of developing PTSD (Bluvstein et al, 2013; Bethell, 2014; Kok et al, 2016) and it may hamper full recovery (Gold, 2015; Kok et al, 2016). Tully (2013) suggested that PTSD occurs in up to 15% of patients after cardiac surgery; other authors indicate that prevalence rates for PTSD following cardiac surgery range from 10% to 38% (Boyer et al, 2013; Bethell, 2014). The level of PTSD tends to be higher among patients who undergo coronary artery bypass graft (CABG) surgery because they have restricted time in which to be emotionally prepared for this life-threatening situation. Many patients do not receive adequate information about the emotional consequences of undergoing major surgery (Boyer et al, 2013; Bethell, 2014; Kok et al, 2016).

PTSD is a common experience for patients with various cardiac syndromes; a meta-analysis of 24 studies showed that the prevalence estimates of PTSD varied from 0% to 32% (Edmondson et al, 2013). Variation in prevalence was reported following implementation of any treatment: implantable cardioverter defibrillator device (ICD) (35%) (Bhuvaneswar et al, 2014); myocardial infarction (17%) (Bluvstein et al, 2013; and post-CABG (12.7%) (Boyer et al, 2013; Hauer et al, 2013). Further, Edmondson et al (2013) studied the consequences of developing PTSD after cardiac surgery in a systematic review. The results indicated that cardiac surgery often has a serious and persistent psychological effect. The prevalence rates were between 8% and 18%. The negative consequences of PTSD in cardiac patients after different cardiac events could be physical (Paulus et al, 2013) or psychological (Kok et al, 2016), and lead to worsening of morbidity and increased mortality rates (Tulloch et al, 2014).

Tulloch et al (2014) examined several risk factors that have been associated with PTSD after cardiac surgery, related to the cardiac event, surgical process, intensive care environment, medical and psychological comorbidities, social support and socio-demographic factors. Kok et al (2016) found that being male, being older, with a longer duration of stay, a history of smoking, substance abuse and anxiety were considered significant risk factors that increased the likelihood of the development of PTSD in cardiac surgery patients. Boyer et al's (2013) study investigated fear appraisal as another risk of developing PTSD in 110 patients who had undergone emergency cardiac surgery. They observed that PTSD was more prevalent in those who perceived the event as overly life threatening.

The environment of the intensive care unit (ICU) is considered to be a physical and emotional stressor (Hauer et al, 2013). Whereas physical functioning after cardiac surgery improves over time, mental disorders as a result of high perioperative stress such as chronic anxiety, depression or PTSD can persist for months and years (Hauer et al, 2013; Bethell, 2014; Kok et al, 2016). The major risk factor for PTSD development in critically ill patients is the presence of traumatic memories from highly stressful experiences during ICU treatment (Hauer et al, 2013). Distress, anxiety and fear of death are all common emotional reactions to the surgical environment (Boyer et al, 2013; Bethell, 2014). Boyer et al (2013) described the ICU environment as being ‘terrifying’ and causing distress, depression, anxiety, delirium and PTSD.

An assessment of the prevalence of PTSD and identification of its predictors is needed. This would provide a realistic estimation of the magnitude of the problem, which is the first and basic step in the process of developing and implementing an intervention to reduce the prevalence of PTSD and prevent its associated consequences. In Jordan and other countries in the region, such studies are few in number. Thus, the aim of this study was to assess the prevalence, levels, and predictors of PTSD during the first month after CABG surgery among Jordanian patients.

Aim

This study aimed to answer the following research questions:

• What is the prevalence of PTSD among Jordanian patients following CABG surgery?
• What are the predictors of PTSD among Jordanian patients following CABG surgery?

Methods

Design

A descriptive survey design was used.

Setting

The Jordanian healthcare system has two main sectors: the governmental sector, where treatment is free for all medically insured patients, and the private sector, where patients pay their own costs. The study was conducted in a governmental specialised cardiac centre that provides diagnostic and therapeutic medical and surgical interventions for different cardiac diseases. It has a 215-bed capacity. It includes five cardiac catheterisation laboratories and six theatres for adult and paediatric cardiac surgery. It also has a 16-bed post-cardiac surgery ICU for adults and eight beds for children. The centre has four floors of male, female, and paediatric medical-surgical wards that receive different cardiac cases from Jordan and neighbouring countries. The numbers of cardiac operations performed on adult patients in 2017 and 2018 were 1350 and 1230 respectively.

Sample

A convenience sample was recruited from all eligible adult CABG patients admitted to the centre during the period of data collection (June–September 2019). On admission, patients were scanned for eligibility criteria by data sheet and those with a positive history of neurocognitive (dementia and delirium) or psychological problems (depression, PTSD) before surgery were excluded. Further, emergency cases (who went directly to surgery), and those who preferred not to participate were excluded.

Measurement and instruments

Data were collected using the socio-demographic and clinical data sheet and the Impact of Event Scale-Revised.

Socio-demographic and clinical data sheet

This sheet collects socio-demographic and clinical data about the participants: their age, gender, education level, working status, smoking, comorbidities, monthly family income, and marital status. Post-surgery information was also collected, including number of grafts, time of surgery, use of beta blockers, time spent on mechanical ventilation, and length of stay in hospital.

Impact of Event Scale-Revised (IES-R)

The IES-R was used to assess the level of PTSD (Weiss, 2007). It is a 22-item scale, originally developed by Horowitz et al (1979), and still one of the most widely used instruments in PTSD research (Tagay et al, 2004). Moreover, the IES-R has been successful in measuring stress reactions in both cardiac and critically ill populations (Doerfler and Paraskos, 2011).

For each item in the questionnaire, a 4-point response scale is provided to measure how frequently each symptom has occurred over the past 7 days (0=not at all, 1=rarely, 2=sometimes, 3=often, and 4=extremely). The total score can range from 0 to 88, with higher scores indicating higher levels of PTSD. The results are categorised as follows: a total score of ≤23 is considered normal; 24 to 32 means PTSD is of clinical concern but is not considered a diagnosis of PTSD, and 33 to 36 signifies the best cut-off for a diagnosis of PTSD; a score of ≥37 is considered high enough to become severe and destroy the immune system's functioning (Creamer et al, 2003). This scale has good internal consistency with Cronbach's alpha of 0.91 for the total score (Bethell, 2014). The Arabic version is reliable with Cronbach's alpha of 0.93.

Data collection procedure

Data collection was commenced after ethical approval was obtained from the appropriate authorities. Researchers visited the cardiac centre and patients who met the eligibility criteria were invited to participate in the study. After explaining the purpose of the study and obtaining their consent, participants were interviewed before the surgery and baseline data were collected using the study questionnaires. Participants were called 1 month after the surgery and were asked to complete PTSD-level questionnaires. They were sent a copy of the questionnaire a day before the interview to facilitate a telephone interview and to formalise the participants' understanding of the study questionnaires. Then, they were asked the questions over the telephone and the researchers wrote down their answers.

Ethical considerations

Approval was sought from the institutional review board (IRB) of the principal investigator's university and the cardiac centre's ethics committee before embarking on the study. Then, the researcher contacted the participants who met the eligibility criteria, to explain the goal and requirements of the study and to ask them to sign the consent form if willing. Participation was voluntary, and participants had the right to withdraw from the study at any time without affecting their treatment. All data were kept on a password-protected laptop, and only the research team had access to the data.

Data analysis

Statistical Package for the Social Sciences for Windows, version 21.0 (2012) was used. Preliminary data screening was conducted to deal with missing data and outliers before proceeding to the analysis. Descriptive analysis was conducted to describe sample characteristics in terms of central tendency measurement, variability measurement, and measures of symmetry. Standard data checking and cleaning were conducted. Level of measurement, missing data, presence of outliers, and data coding was confirmed. Univariate data screening was conducted for each variable to identify missing data, the pattern of missing data, skewness level, outliers, and normality for quantitative variables. A scatter plot and histogram were done for each variable to identify the presence of outliers. However, the data set was free from missing items (except for some demographics that were rechecked when researchers contacted the participants by telephone 1 month after discharge). Some outliers in age or length of stay in hospital were replaced by means, and with keeping its order and place in the data sets. Descriptive and inferential statistical analysis were conducted, the former employing means, frequency, percentages and standard deviation (SD); and the latter Spearman's correlation, chi-squared test and binary logistic regression to identify the predictors of PTSD. P values of 0.05 or less were considered significant.

Results

Sample characteristics

A total of 166 patients who were scheduled for elective CABG were interviewed 3 days before the surgery (on admission) and invited to participate in the study. Of these, five operations were cancelled, and three patients declined to participate. Therefore 158 patients completed the baseline data (95% response rate). However, on the follow-up data collection, five had died and another four did not answer the phone. Thus, valid and complete data from 149 respondents was analysed.

The mean age of the participants was 59 (SD=10. 2), ranging from 34 to 77 years. Most were male (87%), married (93%), and had a primary school education (71%) while 29% had received a secondary school education. The high percentage of married patients is because couples do not live together without being married in Jordan—this is not allowed by tradition, laws and religion. In addition, Jordan does not legally recognise same sex couples. In addition, 46% of the participants were currently smokers. The socio-demographic characteristics of the participants are presented in Table 1.

Further, 73% of patients were using beta blockers. The mean number of grafts was 3.5 (SD=0.89) and the mean duration of surgery 4.5 hours (SD=1.13). The mean time on mechanical ventilation was 8.4 hours (SD=2.85) and the mean length of stay in ICU was 3.7 days (SD=1.3). See Table 2.

Prevalence of PTSD among Jordanian patients 1 month after CABG surgery

The mean total score on the IES-R scale was 30.17 (SD=16.3). The results indicated that of the 149 patients, 65 (44%) had PTSD (had a mean score of 33 or above).

Patients (n=149) were classified according to IES-R scale as:

• 53 (36%) patients did not report PTSD symptoms,
• 31 patients (21%) had a clinical concern and needed follow-up
• 14 (9%) were diagnosed with PTSD-related symptoms
• 51 (34%) had a PTSD symptom that was considered as suppressing the immune system.

Predictors of PTSD among Jordanian patients 1 month after CABG surgery

A binary logistic regression was conducted, with PTSD coded as a dichotomous variable defined as present if the total score was 33 and above, and not present if the total score was below 33.

A bivariate analysis (ie chi-squared test and Spearman's correlation) was first conducted. The result of correlation analysis showed that there is an association between PTSD after surgery and use of beta blockers, length of stay in hospital, age, marital status, smoking, working status, and diabetes. These variables were used to build the model. Table 3 summarises the results of Spearman's r correlation.

All significant variables (the use of beta blockers; having diabetes, currently working, married, smoking, age, and length of stay in hospital) were entered into the regression analysis. The regression model was statistically significant (χ² (12) = 54.45, P<0.001). The proportion of variation in the outcome variable (presence of PTSD) is accounted for by the related predictors (R²=0.41). The full test model of the regression was statistically significant (χ²(12)=54.45, P=0.00). According to the Nagelkerk test, the proportion of variation in the outcome variable (presence of PTSD) is accounted for by the related predictors (Nagelkerk R²=0.41).

The model showed that length of stay in hospital (χ²(1)= 6.598, P<0.05) and age (χ² (1) = 4.920, P<0.05) predicted the occurrence of PTSD among CABG patients 1 month after discharge. For each additional day's stay in hospital, the odds of developing PTSD increased by 1.11. In relation to age, the probability of developing PTSD was higher in older patients, the odds increasing by 1.05 for every additional year in age. Table 4 presents the results of the binary logistic regressions analysis.

Discussion

In identifying the prevalence of PTSD among Jordanian patients 1 month after CABG, the authors found that 65 patients (44%) of the total sample had PTSD. However, lower prevalence rates were reported in cardiac patients (coronary artery disease, ischaemic heart disease and cardiac surgery), ranging from 13.7% to 17.6%, by Bethell (2014). Davydow et al (2013) reported that 20% of patients had PTSD after cardiac surgery. Further, Ackerman and Shapiro (2016) indicated that the prevalence of PTSD among patients after CABG ranged from 15% to 25%. Higher prevalence in cardiac patients (46%) has been reported (Bluvstein et al, 2013), but this was among a small sample of patients who had undergone ICD implementation, making the comparison invalid. The prevalence of PTSD in other populations was reported as even lower. For instance, PTSD among an ICU population ranged from 8% to 27% (Wade et al, 2013); general heart disease was 17.1% (Bluvstein et al, 2013); and in a population of cardiovascular ICU survivors, the level of PTSD was 16% after 3 months, decreasing to 15% after 1 year (Davydow et al, 2013).

The high prevalence might be explained by the lack of psychological support for the patients, and lack of disease and procedure-related information (Shdaifat and Al Qadire, 2020). Further, follow-up care might be inadequate as well, putting patients under stress and uncertainty (Shdaifat and Al Qadire, 2020). The result is alarming and needs to be followed up with another study to include more patients from different settings. Also, qualitative research methods may need to be implemented to understand factors contributing to this high prevalence.

The results of this study also showed that long hospitalisation after CABG predicts the occurrence of PTSD among patients. This result was consistent with a study by Stoll et al (2000) who found that 25.5% of CABG patients who stayed more than 2 days in ICU, and more than 12 days in hospital, developed PTSD. In a 5-year follow-up study, Gražulytė et al (2019) found that staying for more than 2 days in ICU after cardiac surgery, and more than 14 days in hospital, was a risk factor in developing PTSD. People with long periods of hospitalisation need more care and may have physical and/or psychological complications, stress and sleep problems. These conditions may interfere with their health and their perception of psychological integrity (Gražulytė et al, 2019). Hence, this variable needs to be studied further to conclude which variables result in longer hospitalisation and what are the factors that may reduce the duration of hospitalisation.

Older age was found to increase the risk of PTSD in this study. This result is consistent with others (Davydow et al, 2013; Marke and Bennett, 2013; Kok et al, 2016). However, this contradicted the results of another study on an acute coronary syndrome population; this meta-analysis of 24 studies reported that younger people are more at risk of developing PTSD than older people (Edmondson et al, 2013). Being old may interfere with sleep patterns, adaptation to new conditions, and fear of imminent death. These conditions are considered stressful for patients and may exacerbate PTSD development, especially after major surgery such as CABG (Edmondson et al, 2013).

Beta blockers were found to reduce the onset of PTSD in patients after cardiac surgery and other conditions (Krauseneck et al, 2010; Bluvstein et al, 2013). Beta blockers play an important role in reducing anxiety and erasing fearful memories (Krauseneck et al, 2010), helping to decrease the occurrence of PTSD in patients following CABG. The primary use of beta blockers was for heart rate control in this cohort of patients; however, the evidence about the positive effects on anxiety need to be evaluated. In this study there were no significant differences in the level of PTSD between patients who were using beta blockers and those who were not. This could be related to the type of beta blocker, the dosage, frequency, and onset of use in patients after CABG. As a result, more studies are needed to consider their effect on this population. Furthermore, there was no relationship between PTSD and other comorbidities. As no previous studies have explored this link, comparisons cannot be made; more studies are needed to discover such relationships. On the other hand, the literature links mechanical ventilation and gender with PTSD (Davydow et al, 2013; Wade et al, 2013; Kok et al, 2016), although the present study found no such significant relationship. More studies are therefore encouraged.

Limitations

The results of this study need to be read in the light of the following limitations. First, this study was conducted in one cardiac centre, which limits the generalisability of the results to similar settings. Nevertheless, the setting is the largest institute in Jordan, where more than three-quarters of cardiac surgery is performed annually, so some generalisation of the results may be possible. Second, the convenience sampling technique that was used may also limit the generalisability of the results. Third, no data were collected about obesity, this clinical variable might be a predictor for PTSD. Therefore prospective studies might need to include obesity as it may add to the body of knowledge. Finally, having only one follow up may be considered as a limitation; however, the literature supports the short time period, between 1 and 6 months.

Conclusion

The prevalence of PTSD 1 month after surgery was high. Older age and a long stay in ICU and hospital were the predictors of PTSD after CABG among this group of Jordanian patients. The PTSD level should be assessed and measured as an outcome of cardiac surgery, and intervention to manage it should be included in planning for the care of patients post-surgery. Nurses, who are usually at the frontline with patients, should consider using a robust tool and clinical interview to assess and evaluate the risks of PTSD to promote early detection and optimal management. This might be done by assessing the patients for factors that were found to be correlated with PTSD at admission and then following up those patients during the post-CABG clinic visits to enable early detection and management of PTSD. This follow up may include the consultation and involvement of psychiatric colleagues.

KEY POINTS

• Incidents related to the life-threatening illness, which may be sudden or tragic, might end with patients developing post-traumatic stress disorder (PTSD)
• Several risk factors that have been associated with PTSD after coronary artery bypass graft (CABG) surgery, are related to the cardiac event, surgical process, intensive care environment, medical and psychological comorbidities
• In this study 44% of patients experienced PTSD following CABG surgeries
• Standardised pre-procedure, during, and follow-up protocols for PTSD assessment and management should be implemented in clinical practice for patients undergoing CABG surgery

CPD reflective questions

• What is the definition of post-traumatic stress disorder (PTSD) and how is it different from other psychological disorders?
• Reflect on why someone undergoing coronary artery bypass graft surgery might be at risk of PTSD—what are some of the factors?
• What do you think could be done in your setting to reduce the burden and consequences of PTSD?