Influence of Factors Affecting Quality of Life on in-Hospital Cardiovascular Events of Patients with Acute Myocardial Infarction with and without ST-segment Elevation

Background: Acute myocardial infarction (AMI), with and without ST-segment elevation (STEMI and NSTEMI, respectively), is the principal cause of cardiovascular morbidity and mortality in Brazil and around the world. Modifiable risk factors (RF) and quality of life (QOL) may correlate with the type of AMI. Objective: To evaluate the influence of QOL and RF on the type of AMI and in-hospital cardiovascular events in STEMI and NSTEMI patients. Methods: This was an observational, cross-sectional study. Patients with AMI attending four referral hospitals (three private and one public) for cardiovascular disease treatment were assessed for QOL using the Brazilian version of the 36-item short form survey. A p < 0.05 was considered statistically significant. Results: We evaluated 480 volunteers; 51% were treated in one of the private hospitals. In total, 55.6% presented with STEMI, and 44.4% with NSTEMI. Patients from the public hospital were 8.56 times more likely to have STEMI compared to those from the private hospitals. There was a higher prevalence of smokers in STEMI (p < 0.028) patients. QOL was not associated with the type of AMI. A negative patient perception of the physical health and pain domains was observed. Although a significant difference between the physical and the mental health domains was not observed, individual domains were correlated with some in-hospital outcomes. Conclusion: There was a higher prevalence of smokers among individuals with STEMI. Domains of QOL showed a statistically significant relationship with the occurrence of in-hospital cardiovascular events, with no difference between the types of AMI.

part of the research entitled "Adherence to drug treatment and lifestyle changes in patients with acute coronary syndrome" conducted in four renowned hospitals for cardiac treatments (three private and one public) in Aracaju, Sergipe, Brazil. 11

Subjects
Patients who presented with STEMI or NSTEMI were recruited by convenience sampling.We included patients of both genders, aged 18 years or older, diagnosed with AMI, and excluded patients with cardiogenic shock, unstable angina (UA), or Alzheimer's disease.

Variables analyzed
The following variables, collected from medical records were analyzed: educational attainment, marital status, clinical presentation (type of infarction), comorbidities -dyslipidemia, systemic arterial hypertension (SAH), smoking, diabetes mellitus (DM), and family history of coronary artery disease (CAD) -and in-hospital events.
We performed anthropometric measurementsweight, height, waist circumference, and body mass index (BMI).We also analyzed physical activity records using the International Physical Activity Questionnaire (IPAQ, short version), 12,13 and QOL using the Brazilian version of the Medical Outcomes Study Questionnaire 36-Item Short-Form Health Survey (SF-36). 14,15

Anthropometric measurements
Body weight, height, and BMI 16 of patients were determined.For body weight measurement, patients were dressed in light clothing, barefoot, standing on the platform of a digital scale (Filizola, 150 Kg) to the nearest 0.1 Kg.Height was measured to the nearest 0.1 m using a stadiometer (SECA).

Introduction
The global scenario reveals an increase in the incidence of cardiovascular diseases. 1According to a report by the Pan American Health Organization (PAHO) published in 2017, 17.7 million people died from cardiovascular disease in 2015, representing 31% of all deaths globally.It directly affects health-related costs, and causes reduction in job productivity and quality of life (QOL). 2,3ute coronary syndromes (ACS), including unstable angina (UA) and acute myocardial infarction (AMI) with and without ST-segment elevation (STEMI and NSTEMI, respectively) are among the main cardiovascular diseases. 4[7] According to the PAHO report, most cardiovascular diseases can be prevented by addressing behavioral RF, such as tobacco use, unhealthy diet, obesity, lack of physical activity, and use of alcohol, by implementing strategies for the general population. 2 Additionally, control of RF and adherence to healthy habits can be associated with better QOL. 8 QOL is related to the individual's perception of their own life, in connection with their goals and within the value system incorporated in decision-making. 9It depends on individual's economic status, physical and mental health, social protection, political stability, and the environment. 10e measurement of QOL provides valuable information about the individual and helps clinicians to choose the best forms of treatment and rehabilitation.Despite the relationship between RF and the lifestyle of individuals with cardiovascular disease, recommendations to investigate parameters of QOL for estimation of cardiovascular events (CVEs), are not well established, and require further research.Therefore, the present study aimed to assess whether patient QOL affects the type of AMI and in-hospital outcomes.

Quality of life
QOL was measured using the validated Portuguese language version 14 of the SF-36 questionnaire. 15e SF-36 consists of 36 questions that address eight domains (or dimensions) of two major components: the physical component that involves functional capacity (10 items), pain (two items), general health status (five items), and physical performance (four items), and the mental component that covers mental health (five items), emotional (three items), social (two items), and vitality (four items).There is also one question aimed to compare current health perceived by the patient with that of a year ago. 14,15

Data analysis
We analyzed the data using the software R, version 3.5.1.Univariate descriptive analysis was performed by calculating the frequencies (absolute and relative) for the categorical variables, and mean and standard deviation for the continuous variables.Continuous variables that were not normally distributed were described as median and interquartile range.
Continuous variables with normal and without normal distribution were compared using the unpaired Student's t-test and the Mann-Whitney, respectively.Distribution normality was assessed using the Shapiro-Wilk test.For categorical variables, the chi-square test or the Fisher's exact test, with 95% confidence interval, was used as appropriate.The odds ratio (OR) was also calculated.Significance level was set at 0.05 (p<0.05).

Ethical aspects
The study was approved by the Research Ethics Committee of the Federal University of Sergipe -CEP/ UFS on 06/07/2013 under nº 302.544.All procedures were performed following the 2013 update of the Declaration of Helsinki.Informed consent was obtained from all the participants included in the study.

Characteristics of the subjects
A total of 480 patients were included.Out of these patients, 267 (56%) had STEMI, and 213 (44%) had NSTEMI.Among them, 235 (49%) were treated in the public hospital, and 245 (51%) in private ones.The study sample was predominantly elderly and male.Most of them had complete elementary school and were married or lived with a partner.Regarding RF, most patients were overweight and had a sedentary lifestyle, were non-smokers, had SAH, dyslipidemia, and family history of CAD (Table 1).
Considering the type of hospital, 189 patients who were treated in the public hospital were diagnosed with STEMI, compared with 78 patients with STEMI who were treated in private hospitals.Therefore, in the public health system, 80% of the patients with AMI were diagnosed with STEMI, compared to 32% in the private hospitals (p < 0.001), indicating a relationship between the type of AMI and the type of hospital.People treated in the public hospital were 8.56 times more likely to have STEMI compared to those treated in the private hospitals (Table 2).
In addition, 183 (60%) of men had STEMI, compared to 84 (48%) of women.Men had a 1.62 times greater chance of having STEMI compared to women (p = 0.014).Low educational attainment and age group (between 18 and 49 years) also showed a significant relationship with the severity of infarction (Table 2).
Smoking, DM, SAH, dyslipidemia, obesity/overweight (BMI), and physical inactivity showed a significant relationship with the development STEMI.In the univariate analysis, these variables did not show any statistically significant differences related to the type of infarction (Table 2).

QOL, AMI type, and in-hospital outcome
Considering that the SF-36 score ranges from 0 to 100 (with 0 being the worst state and 100 the best state), the mean scores for all domains ranged from 41 to 69.Only the physical aspects of the domains and pain had a mean value below 50.Social and mental health domains had the highest averages (Table 3) 16 .Comparisons of mean SF-36 scores between STEMI and NSTEMI showed no statistically significant differences (Table 4). 17ble 5 18 shows the mean F-36 scores of AMI patients with and without in-hospital events.Functional capacity showed a statistically significant relationship in the univariate analysis with cardiovascular death (p < 0.024).Likewise, a statistically significant relationship between pain and acute and chronic renal failure (p < 0.041), and between cardiovascular death and physical performance (p < 0.040) was also found.Unexpectedly, we did not observe a statistically significant difference between the mean scores of physical and mental health regarding the CVEs that occurred during hospitalization.We observed an association between emotional domain and congestive heart failure (CHF) (p < 0.004).Vitality was significantly related to the onset of CHF (p < 0.045), cardiovascular death (p < 0.012), and reinfarction (p < 0.007).The social aspect also showed a statistically significant relationship with CVEs, including angioplasty (p < 0.049), myocardial revascularization (MR) (p < 0.033), cardiovascular death (p < 0.047), and reinfarction (p < 0.010).

Discussion
The study sample was predominantly elderly and male, and a family history of CAD was found in 58% of the patients.These three factors (age, sex, and history of CAD) are classified as non-modifiable RF.Among the modifiable RF, the most prevalent were obesity, hypertension, dyslipidemia, and physical inactivity; most patients were non-smokers or ex-smokers.
In a multicenter study carried out in Brazil, most patients were also male, with an average age varying between 61 and 65 years. 19International studies have also reported  higher incidences of AMI in male elderly populations. 20,21 Tis may be related to the high life expectancy and men's health gap, which causes an increased prevalence of these chronic-degenerative diseases.
Regarding the type of infarction, there was a higher prevalence of STEMI (56%) compared to NSTEMI (44%).Marino et al., 22 described the profile of patients with ACS and found a higher prevalence of STEMI patients (n = 214) compared with NSTEMI patients (n = 73). 22The literature shows that the incidence of STEMI and NSTEMI varies across the world, and that, in European countries, the incidence of NSTEMI has been increasing. 23,24garding the type of hospital (public vs. private), the number of patients attending public (49.2%) and private hospitals (50.8%) was similar.Regarding the type of AMI, the number of STEMI cases was higher in the public hospital than in private hospitals.This may be explained by the fact that the public hospital where the study was conducted is a referral center for cardiac surgery in the Brazilian Unified Health System (SUS).In the patient selection process for surgery, higher priority is given to patients with STEMI.
Regarding the relationship between the type of AMI and RF, there was a significant correlation between STEMI and smoking.The nicotine present in tobacco is the most addictive psychoactive drug, and responsible for raising heart rate and blood pressure, in addition to promoting thrombogenicity.Approximately 21% of deaths are associated with tobacco.Smoking also interferes with individuals' QOL. 25,26th respect to perception of health-related QOL by all the respondents, the mean scores for the domains of physical component and pain were low when compared with the dimensions of vitality, and social, emotional, and mental health.Studies that evaluated QOL during hospitalization observed a negative perception of QOL in both physical and pain domains, as well as of sleep and emotional reactions.The latter two were related to the type of AMI and the process of hospitalization. 27,28Angina, together with feelings triggered by hospitalization, can influence pain and physical aspects.
In the last decades, research investigating the QOL of cardiac patients has reported a decline in their physical capacity due to dyspnea and fatigue. 29,30 he present study corroborates these findings and reinforces that these individuals require proper management not only of pain but also of the decline in physical capacity.
Contrary to expectations, we found no significant difference in QOL between the two types of AMI.Another similar study 23 also found no significant difference between the AMI types, corroborating our results.This study also observed a reduction in patient QOL for all domains, except for the general health domain, following in-hospital CVEs. 23llon and Bhattacharjee, 31 in a case-control study, identified that individuals who suffered AMI had lower QOL in the domains of general, physical, and mental health compared to individuals without AMI.In the domains of sleep, emotional support, and life satisfaction, there were no differences between AMI survivors and the control group. 31en analyzing the relationship between QOL and in-hospital outcomes of our patients, we identified that functional capacity, physical, social, and vitality domains were associated with cardiovascular death.New episodes of AMI were related to the vitality and social domains, and CHF was associated with the emotional and vitality domains.Regarding pain, higher scores were reported by the patients with acute and chronic renal failure.
Furthermore, in the present study, the occurrence of sepsis was related to functional capacity, and angioplasty and myocardial revascularization (MR) were associated with the social domain.Contrary to our expectations mean scores for the physical and the mental health dimensions were not different when the in-hospital events were considered.Therefore, the social domain was related to a higher risk of in-hospital events.In a similar study, which evaluated the quality of life after MR surgery, we observed that the domain social relationships had the second highest score. 31According to Souza et al., 32 social support can act as a protective factor, by relieving stress during crises and facilitating the recovery from the disease. 32major scientific challenge is the improvement in the evaluation of mortality predictors as well as the establishment of appropriate treatment.However, it is common sense to combine the established RF and the factors known to interfere with patient's QOL for the creation of educational programs.One of the relevant achievements of the present study was to identify the differences in the QOL scores according to in-hospital events.These findings can serve as a basis for new scientific projects.Moreover, they prove that psychosocial factors are involved in the development and recovery from the disease.Some limitations should be considered when interpreting the results.The QOL questionnaire was administered retrospectively, and hence participants' responses relied on their memories.Additionally, since this is a generic tool, it did not focus on characteristics of AMI, and did not include diet as a risk factor.

Conclusion
In the present investigation, we observed that, compared with NSTEMI patients, a higher prevalence of smokers was observed among STEMI patients.The other RF evaluated were associated with both types of AMI equally.
We observed a negative perception in the domains of physical aspects and pain of QOL in STEMI and NSTEMI patients, with no difference in QOL between these two groups.Regarding the association of QOL with in-hospital CVEs, a significant association was found of physical and mental health with the occurrence of events.