Hypothesis one: Patients with severe chest pain [pain score ≥ 7] will have higher complication rate than other patients [mild and moderate]. Hypothesis two: After controlling socio-demographics [age, gender, smoking status] and clinical characteristics [history of Diabetes Mellitus [DM], Hypertension [HTN], previous MI, previous angina, stent use, previous Coronary Artery Bypass Graft [CABG], pain duration, morphine use, beta-blocker use, nitrate, and thrombolytic use], pain scores will be an independent predictor for complications after AMI. Hypothesis three: After controlling socio-demographics [age, gender, smoking status] and clinical characteristics [history of DM, HTN, previous MI, previous angina, stent use, previous CABG, pain duration, pain severity, beta-blocker use, nitrate, and thrombolytic use] morphine use will be an independent predictor for complications after AMI.
2. MATERIALS AND METHODS
2.1. Research Design, Sample, and Setting
A prospective observational design was used in this study. The accessible population of interest was all patients with STEMI visiting Emergency Departments [ED] in four hospitals [one from each sector: Royal Medical Services [RMS], teaching, private, and governmental] from July-October, 2020.
Intended participants were selected using the consecutive sampling technique. All patients diagnosed with STEMI and met the eligibility criteria were approached [a confirmed diagnosis of STEMI evidenced by electrocardiogram changes and elevated cardiac enzymes, and being older than 18 years] until the needed sample size was reached [Fig. ]. If the patient developed in-hospital complications before measuring chest pain or receiving Morphine in ED, they were excluded from the study. This aimed to discover the longitudinal, cause-and-effect aspect of the medical problem. Moreover, if patients were hemodynamically unstable, they were excluded from the study.
The required sample size was determined by power analysis using G* power software. The following assumptions were used: [a] medium effect size of 0.25, [b] a significance level of α < 0.05, [c] power of 80%, and [d] statistical tests used to test the research hypotheses; one-way ANOVA for hypothesis one, and the logistic regression for hypotheses two and three. For the logistic regression, 27% as an estimated incidence rate of complications was used [] in addition to 14 independent variables. Based on these assumptions and statistical tests, the required sample size was 250. However, about 15% of the calculated sample size was added to create a more representative sample and overcome the suspected attrition and incomplete questionnaires that might occur. Therefore, the total sample size was 300 participants.
2.2. Ethical Considerations
Ethical approvals were obtained from all IRB committees before data collection started [IRB#: Faculty 2019-2020- 4-4]. Participants were fully informed about the nature, purpose, expectations, significance, benefits, risks, and type of required data, including the review of their medical records after discharge. Participation was voluntary, and informed consent was obtained before data collection started. All collected data were saved securely in a protected place keeping confidential and sharing only with the Principal Investigator and the co-investigators.
2.3. Procedures
After ethical approvals from all sites were gained, the PI contacted the head nurse of each selected ED and the Intensive Care Unit [ICU] departments and explained the study. Head nurses were informed to call the PI when there is admission with an AMI diagnosis. The PI met each participant, and the study was explained to the patient and their family members. If the participant agreed to participate in the study, a consent form was signed, including permission to review the medical record. When the participant was hemodynamically stable [MAP≥70 mm Hg] and within 72 hours [mean [SD], 42 [] hours] of admission and per their preference, an interview was conducted to answer the sociodemographic questionnaire including necessary basic information of age, gender, marital status, severity and duration of chest pain. All other data were obtained from the medical records after participants were discharged.
It is worthy to note that the data collection was done during the COVID-19 pandemic. As well-trained personnel in academia, research, and clinical, PI used all protective measures and collaborated with the healthcare team during this period. The PI followed all necessary protocols announced by the government and the hospitals. Moreover, the PI has a 24-hours permit to go in and out, even during COVID 19 quarantine issued by the government.
2.4. Measurement of Variables
2.4.1. Clinical and Sociodemographic Characteristics
These information were collected either during patients interview or through medical records review after discharge: age, gender, marital status, smoking status, vital signs, the severity of chest pain on [a zero to ten scale], duration of chest pain in minutes, history of previous AMI, previous CABG, HTN, angina, DM, and stent use. Medications given in ED including Morphine, beta-blockers, thrombolytics, and any other analgesics. Moreover, the dose of Morphine in the ED was recorded in milligrams, then the use of Morphine was coded as either zero indicating ‘no use’ or one indicating ‘use.’ Morphine use in ICU was not recorded since most of the complications mentioned above usually occur in the ED or the first 24-72 hours after the event [, ].
2.4.2. In-Hospital Complications
In-hospital complications were determined by the presence of any of the following during the period of hospitalization after admission: [i] re-infarction; [ii] acute recurrent ischemia; [iii] ventricular fibrillation; [iv] sustained ventricular tachycardia [> 15 seconds], or any ventricular tachycardia requiring pharmacological and/or electrical intervention; [v] supra-ventricular tachyarrhythmia with hemodynamic instability; [vi] in-hospital death; [vii] acute pulmonary edema and [viii] cardiogenic shock [, , ]. These complications were recorded after morphine administration and pain measurement till the patient was discharged. The total number of complications was recorded for hypothesis one testing. In addition, the development of complication was recoded as one indicating “occurred” and zero “did not occur” for hypotheses two and three testings.
2.5. Statistical Analysis
Data were analyzed using the Statistical Package for Social Science [SPSS version 25.0 for Windows]. The statistical significance was considered at α < 0.05. Descriptive statistics were used to describe and summarise all demographic and clinical variables. Mean, standard deviation, and range were used to describe the continuous variables. Frequency and percentage were used to describe the nominal variables. Additionally, the incidence was calculated for the following complications: acute recurrent ischemia, re-infarction incidence, supraventricular tachycardia incidence, sustained ventricular tachycardia, ventricular fibrillation, and ventricular tachycardia, cardiogenic shock, pulmonary edema, and in-hospital death.
2.5.1. Hypothesis One
One-way ANOVA with post hoc analysis was conducted to explore the impact of the chest pain severity on the number of complications developed after AMI.
2.5.2. Hypothesis Two
To test this hypothesis, two steps were done—step one: bivariate correlation between sociodemographic and clinical characteristics with complications. Person’s r was used for continuous variables and Spearman’s rho for categorical variables. The correlation was considered statistically significant in this step alone if p was