The results of this study showed that 24% of the patients under study were readmitted from the first 30 days of discharge. This is largely consistent with the study of Kumar Dharmarajan et al. 2017, Corey Fehnel et al. 2015, Jeremiah Brown et al. 2014, Sheida Sajjadi et al. 2016, and Nahid Hatam et al. 2014.
Regarding the study of readmission rates, there have been numerous studies abroad and in Iran that have suggested different rates for readmission. The difference between the results may be due to different factors such as admission unit, clinical and demographical conditions of patients and etc. (8)
According to the present study, 94 cases (53.72%) were under 65 years of age with the highest readmission rate. The results of this study are inconsistent with any of the studies. There is no credible evidence to justify the discrepancy of this study with previous studies, but the cultural differences, background knowledge and information of patients, individual characteristics of the subjects under study, mentality and judgment of people towards health centers, livelihood and economical status will be among those factors.
Maybe further studies with larger sample size can determine the relationship between age and readmission. There may also be a different result from reviewing readmission in a longer span of time (14).
According to the present study, the highest rate of readmission was found in 123 male cases (69.43%). In 2018, Ronald Chamberlain et al reported more readmissions in men (15). In a 2014 study by Jeremiah Brown et al., The mean age of patients discharged for acute myocardial infarction was 78.4 with 51.6% male, which is consistent with this study (16). On the other hand, this is inconsistent with the study of Menal Etemadi et al. (2017), in which 54% of patients were female and 46% were male (17). This discrepancy may be because men have a higher risk of having coronary artery disease than women before the age of menopause, but after menopause, the risk of coronary artery disease increases (18).
The results of this study on the most common clinical factors (cardiovascular) affecting readmission are largely consistent with the studies done by Chun Shing Kwok et al (2017), which claims, the most common cardiac causes are acute coronary syndrome (17.1%), unstable angina (11.6%) and heart failure (9.8%)(5). Also, Cashel O'Brien et al (2017) reported ischemic heart disease and heart failure (4), which is also in line with this study.
Also in the Lucia Fernandez et al (2017) study, most readmissions were related to cardiovascular causes (60%) and heart failure were the most common cause (34%) (20). And Harlan et al. (2011) reported that the most primary diagnosis at the time of discharge for readmissions, was heart failure (17%), acute myocardial infarction (7%), coronary atherosclerosis (4%), pneumonia (3%), and acute kidney failure (3%).
However, in the 2010 Heydari et al. study, readmission rates of cardiac patients were 57% and the highest frequency was in patients with valvular heart disease and heart failure (13). But in the current study, factors such as acute coronary syndrome, anterior myocardial infarction, coronary atherosclerosis, chronic obstructive pulmonary disease, sodium levels at first admission, and blood pressure level at first admission were affective.
The most common underlying factors (comorbidities) effective in readmissions reported in this study are largely consistent with the study of Ronald Chamberlain et al. (2018). She referred to factors such as renal failure, chronic pulmonary disorder, diabetes, depression, and electrolyte fluid dysfunction after admission to patients with CHF (15). However in other studies such as Mahek Shah et al. In 2018 other factors including infection (11.7%), respiration (9.2%), injury/burn/ poisoning related to conditions (7.8%), Gastrointestinal/hepatic biliary/pancreas (6.9%) and genital system disorders (4.6%) have been cited as the most common causes of non-cardiovascular disease (19). Also, Chun Shing Kwok et al. (2017) have mentioned for various reasons for non-cardiac readmissions including gastrointestinal infection (4.3%), gastrointestinal problems (4.9%), bleeding (3.7%), dizziness, Syncope or falls (3%) and pulmonary embolism (4.2%). (5) Since most of the above studies have been conducted in developed countries that depending on the type of culture and lifestyle are at different levels than developing countries the results could be different from the research done in Iran.
In developed countries, more has been done in terms of culturing and providing post-discharge education to patients and informing patients about the importance of pursuing treatment which can affect the effective factors in readmission.