Sample and Study Design
In this study, the convenience sampling method was used to select the patients with acute myocardial infarction hospitalized in the Department of Cardiology of a University Affiliated Hospital in Hangzhou, China. Inclusion criteria: (1) diagnosed with AMI; (2) aged between 18 and 60 years old. Exclusion criteria: (1) complicated with other serious diseases or serious complications; (2) dementia or other psychiatric diseases; (3) hearing impairment or communication impairment; (4) experienced traumatic events within half a year. The questionnaires were disseminated from January 2019 to December 2020. The questionnaire was written in Chinese and was conducted by a researcher fluent in Mandarin and the local dialects.
It is generally believed that the number of observations is at least 5-10 times of that of the variables. Considering a 10% loss-of-follow-up rate with the 30 items in the Stanford Acute Stress Reaction Questionnaire (SASRQ) , the sample size was 165-330. In the current study, a total of 203 questionnaires were disseminated, with 190 completed questionnaires returned, with an effective rate of 93.6%. The average age of the subjects was 49.99±8.07 years, ranging from 23 to 60 years.
Research ethics
This study was approved by the ethics committee of the Affiliated Hospital of Hangzhou Normal University (IRB's registration number: 2019 Ethics 02-HS-46). This study complies with the international declaration of Helsinki, the ethical examination and Approval Measures for biomedical research involving human beings (Implementation), and the requirements of relevant laws and regulations. There is no person under 18 in this study, so informed consent was obtained from all subjects.
Measures
Demographics
Demographic characteristics include gender, marital status, education level, occupation, payment method, number of stent implantation, complications, cardiac function (Killip classification), distribution of criminal vessels, and disease awareness.
Stanford Acute Stress Reaction Questionnaire (SASRQ)
The 30-item Stanford Acute Stress Reaction Questionnaire(SASRQ) measured participants’ ASD13. The questionnaire includes dissociation (10 items, mainly evaluating cognitive changes such as memory loss, the decline in environmental clarity and emotional changes such as numbness and lack of emotional response), reexperiencing of trauma (6 items, mainly evaluating physiological reactions such as physical symptoms caused by traumatic events and behavioral changes such as forced thinking of repeated unnecessary memory of traumatic events), avoidance (6 items, mainly assessing behavioral changes such as being away from others and avoiding things related to trauma events), anxiety and hyperarousal (6 items, mainly assessing behavioral changes such as sleep changes and panic attacks, cognitive changes such as decreased attention and emotional changes such as tension, anxiety, and irritability), and function impairment (2 items, mainly evaluating physiological reactions such as impairment of physical function). SASRQ is scored on a 5-point Likert scale ranging from 0 (not experienced) to 5 (very often experienced). The score range is 0-150 points. The total score of SASRQ ≥ 40 is positive for acute stress disorder. The higher the score, the more serious the acute stress disorder of the patient. The Cronbach's α coefficient of the scale was 0.87-0.95.
Experiences in Close Relationships Inventory (ECR)
Adult attachment was assessed using the Experiences in Close Relationships Inventory (ECR)14. ECR produces two scores: attachment-related avoidance and attachment-related anxiety scores. There are 36 questions on the scale, which adopts the 7-level scoring method. Strongly disagree, disagree, somewhat disagree, not sure, somewhat agree, agree, and strongly agree is recorded as 1-7 points respectively, of which 3, 15, 19, 22, 25, 27, 29, 31, 33, and 35 items are scored in reverse. The sum of odd item scores is the score of attachment-related avoidance, and even item score is the score of attachment-related anxiety. The higher the score, the higher the degree of attachment-related anxiety or avoidance. The Cronbach's α coefficient of the scale was 0.79-0.82.
Social Support Rating Scale (SSRS)
Xiao's Social Support Rating Scale (SSRS) was utilized to measure social support15. The scale has ten items, including objective support (3 items), perceived support (4 items), and support utilization (3 items). The score range is 12-66 points. The score below 35 points indicates a low level of social support, 35-45 points indicates a moderate level of social support, and the score greater than 45 points indicates a high level of social support. The scale has presented impressive validity and reliability in the Chinese population (Cronbach's α=0.949)16.
Statistical Analysis
Data was examined with SPSS Statistics 22.0 (IBM Corp., Armonk, MY, USA). Demographic characteristics, ASD, social support, and adult attachment using observed values, percentages, quartile, means, and standard deviations are all described. The differences in the participants’ ASD based on demographic characteristics were analyzed using the nonparametric rank-sum test. The relationship between social support, adult attachment, and ASD was assessed using Spearman’s correlation coefficients. Additionally, influencing factors of participants’ ASD were evaluated using multiple linear regression. The dependent variable was set as ASD, and the independent variables were set as perceived support, complications, attachment-related avoidance, and attachment-related anxiety.