Study design
The Multicenter Delay in Patients Experiencing AMI in Shanghai (MEDEA FAR-EAST) study was a multicenter cross-sectional study aimed to assess the in-depth barriers contributing to the pre-hospital delay in Chinese AMI patients. The patients were recruited from four hospitals with coronary care units in Shanghai (Tongji-Hospital, Tenth-Hospital, Yangpu-Hospital, and 455 People's Hospital). The conceptual framework and methods of the MEDEA FAR-EAST study have been described in detail previously [17].
Briefly, the major inclusion criterion was hospitalization with an AMI, which was confirmed by typical symptoms at onset and elevated cardiac biomarkers (troponin I or troponin T) as well as a corresponding ECG-diagnosis. The exclusion criteria were out-of-hospital cardiac arrest, cognitive impairment, and language barriers.
Standardized operation procedures (SOPs) were implemented to avoid reporting bias. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). The study was approved by the Ethics Commission of Tongji-University affiliated Tongji-Hospital (伦审-KYSB- 2016-74) and informed consent was taken from all the patients. This approval is applicable to all participating centers.
Samples and Data collection
The study included a total of 257 AMI patients with atypical chest pain from April 2016 to January 2017 in the MEDEA FAR-EAST study. All patient information consisted of a three-part evaluation (a bedside interview conducted by trained study personnel, a self-administered questionnaire by patients, and basic epidemiological and medical information collected from the hospital's patient charts).
Measures
Pre-hospital delay time (PHT) and (patient’s decision delay time) DT
PHT was defined as the time interval between symptom onset and arrival at the hospital door. DT was defined as the elapsed time from symptom onset to seeking medical care or call EMS (emergency medicine service). PHT was composed of DT and transport time. Considering that the characteristics of the chest pain may be related to the choice of transportation, we took PHT as the primary outcome and DT as the secondary outcome. PHT and DT were expressed in minutes.
Asking patients to recall the time point when the acute symptoms began remained a challenge. Therefore, the onset-time was triangulated by trained personnel in the interview [18], using events from the patient’s daily routine to establish the chronology of symptom-onset to minimize recall bias.
Classification of chest pain
Patients were asked to answer whether the chest pain was intermittent or continuous and then were divided into intermittent chest pain group or persistent chest pain group by bedside interviews.
Similarly, patients were assigned to different subgroups based on the bedside interview questionnaire on the severity of pain and the impact on daily life (not at all, a little, medium, strong, very strong).
Psychological measures
Anxiety was assessed with the Generalized Anxiety Disorder scale (GAD-7) composed of 7 items, rated on a 4-point Likert scale ranging from 0-21. GAD-7 score≥10 points indicate anxious patients [19].
Depression was assessed using the Major depression inventory (MDI), which generates DSM-IV and ICD-10 diagnoses by the patients' self-reported symptoms. Depression is defined as at least five symptoms present in the MDI scale, of which at least one must be a “core” symptom (core symptoms including lack of energy, depressed mood, and lack of interest) [20].
Subjective wellbeing was evaluated through the WHO-5, rated on a 6-point Likert scale ranging from 0 to 25. Multiplication by 4 results in a total score of 0 to 100. WHO-5 score ≤ 50 indicates suboptimal well-being [21].
Denial regarding cardiac illness was assessed by the Cardiac Denial of Impact Scale (CDIS), ranging from 8 to 40. A score of ≥25 indicates cardiac denial [22].
The somatic symptom burden was captured by the somatic symptom scale (SSS-8) [23], which comprises 8 items, ranging from 0 to 32. 12 points or more (ranked as “high” and “very high”) was considered higher somatic symptom burden.
Fear of death and stress event were asked to answer “yes” or “no”.
Data analysis
The chi-square test was used to calculate the percentage of baseline characteristics and behavioral response of patients with persistent and intermittent chest pain, which was displayed as n (%). The independent sample t-test was used to calculate two groups of data following normal distribution, which was shown as mean ± SD. A Nonparametric Wilcoxon test was used to calculate the difference of PHT, DT, and DT/PHT among groups, which was shown as median (IQR). Spearman correlation analysis was used to explore the correlation between PHT, DT, and chest pain subgroups. A multiple linear regression model was used to evaluate the relationship between the characteristics of chest pain (persistent pain and intermittent pain) and PHT, DT.
SPSS 23.0 was used for all statistical analysis,p<0.05 was considered statistically significant. The analysis and description in this paper follow the STROBE guidelines for cross-sectional studies [24].