Treatment-seeking delays in patients with acute myocardial infarction and use of the emergency medical service

Abstract

Objectives

To investigate treatment-seeking delays in Chinese patients with acute myocardial infarction (AMI) and to compare sex differences in this behaviour.

Methods

A descriptive cross-sectional study was undertaken in patients with AMI, admitted to one of three hospitals in Shanghai, China. A treatment-seeking behaviour questionnaire was administered to each patient within 48 h of hospital admission.

Results

In total, 250 patients were included: 159 men and 91 women. The median time for patients with AMI to make a treatment-seeking decision was 130 min. Women took significantly longer to seek treatment than men (240 min versus 120 min). The majority of patients (70.8%) took >1 h to decide to seek treatment. The emergency medical service (EMS) was used by 77 (30.8%) of patients, and these patients had a significantly shorter prehospital delay time than those who transported themselves to hospital. Predictive factors for using the EMS were pain level and rating AMI symptoms as severe.

Conclusions

Chinese patients with AMI had a significant prehospital delay time and women took longer than men to seek treatment. Public awareness of the importance of seeking immediate medical assistance for AMI via the EMS needs to be increased in China.

Keywords

Acute myocardial infarction emergency medical service sex treatment-seeking delay

Introduction

Coronary heart disease (CHD) is the leading cause of morbidity and mortality worldwide.¹ Based on data from the Third National Survey of Residents (2008) in China, which identified heart disease as the fourth leading cause of death in China, the Chinese Ministry of Health has estimated that 1.4 million (100.61/100,000) Chinese people die of heart diseases each year.² Historically, studies of CHD have mainly focused on the male population. As women tend to have CHD after the menopause, they are more likely to present with symptoms at an older age than men.³ Early cardiac events in women are frequently unrecognized by healthcare professionals or by the women themselves,³ which may delay timely treatment seeking and clinical decision making.

Treatment-seeking delay consists of three phases: (i) the patient decision time, defined as the time from symptom onset to the decision to seek medical help; (ii) the transportation time, defined as the time from making a decision to seek treatment to the first medical contact; (iii) the in-hospital time, defined as the time from first medical contact to hospital arrival and acceptance of medical treatment.⁴ The patient decision time represents the longest phase of delay and is the phase in which the biggest reductions could be made, if patients were able to recognize symptoms in a more timely manner. A study of 271 Korean hospitalized patients diagnosed as having a first-time acute myocardial infarction (AMI) showed that only ∼40% visited a clinic in response to any prodromal symptom.⁵

Acute myocardial infarction is the most serious type of CHD and prompt treatment is critical in avoiding further complications. The benefits of treatment depend on the time between symptom onset and initiation of reperfusion therapy.⁶ The Myocardial Infarction Triage and Intervention Trial reported a seven-fold decrease in mortality in patients treated with reperfusion therapy within 70 min of symptom onset.⁷ Furthermore, a study in 536 patients with AMI (66% of whom were men) found that prehospital delay in seeking treatment was a predictor of in-hospital complications.⁸ Despite the known associations between prehospital delay and clinical outcomes, a US study in middle-aged and elderly patients admitted to hospital with AMI demonstrated that the time between symptom onset and patients seeking treatment had remained almost the same throughout a 20-year period.⁹

The emergency medical service (EMS) provides timely emergency management and treatment of AMI, and rapid ambulance transportation to hospital; the use of the EMS by patients with AMI, however, remains low in China.¹⁰ The present study aimed to investigate the extent of treatment-seeking delays in male and female patients with AMI treated at one of three Chinese hospitals. In addition, the study examined reasons for underutilization of ambulance transportation by these patients.

Patients and methods

Study Population

Patients were recruited into this descriptive cross-sectional study between January 2010 and November 2010, according to purposive sampling in three university-affiliated tertiary teaching hospitals in Shanghai, China (Renji Hospital, Renjin Hospital, and Xinhua Hospital). Patient cases were selected for inclusion if they satisfied all of the following criteria: had AMI confirmed by electrocardiogram or cardiac markers; were <80 years of age; were fully conscious and coherent (being able to clearly describe the main symptoms of AMI that they had experienced and the specific time at which their AMI symptoms started). Patients who had other serious physical or mental disorders were excluded.

The study protocol was approved by the Institutional Review Board of Shanghai Jiao Tong University School of Medicine, Xinhua Hospital, Shanghai, China. Written informed consent was obtained from each of the study participants.

Treatment-seeking Behaviour Questionnaire

The treatment-seeking behaviour questionnaire was first described by Johansson et al.¹¹ to explore ambulance use in patients with AMI in Sweden. Permission was obtained from the authors to translate the questionnaire into Chinese. After translation was completed by the investigator (X.W.), a back translation was undertaken in collaboration with two bilingual experts, to ensure translation quality. Some of the patient demographic information items were modified further, to make these questions more suitable for Chinese patients. All data were collected from patients within 48 h of hospital admission by the same investigator, who distributed the questionnaires in a noncoercive manner and was attentive to each patient’s clinical condition.

The final version of the treatment-seeking questionnaire had three domains, comprising 39 items: (i) demographic and baseline characteristics, 15 items; (ii) treatment-seeking decision, 16 items; (iii) transportation, eight items. Reliability and validity tests for the translated questionnaire were undertaken by inviting four cardiology experts to review the questionnaire content. Each expert was asked to judge the items of the questionnaire for suitability; if an item was deemed to be unsuitable, the experts provided advice for a revision. After two rounds of modification, the content validity score was determined to be 98%. Twenty random AMI cases (mean [SD] age 64.7 years, 11 [55%] males and nine [45%] females) treated in hospital, but not included in the main analysis, were also selected to test the user-friendliness of the questionnaire, in order to ensure that all of the questions were clear and easy to answer. The internal consistency of the questionnaire was determined to be good, with a Cronbach’s α of 0.72, calculated using the SPSS® statistical package, version 11.0 (SPSS Inc., Chicago, IL, USA) for Windows®.

Definition of Treatment Delay

Definitions of the different phases of treatment-seeking delay have been described.⁴ Briefly, these phases are: the patient decision time (time from symptom onset to the decision to seek medical help); the transportation time (time from making a treatment-seeking decision to first medical contact); the in-hospital time (time from first medical contact to hospital arrival and acceptance of medical treatment, or time from hospital arrival to acceptance of medical treatment in patients who self transported).

The method of transportation was categorized as self transportation or use of the EMS. The EMS category included patients who initially went to hospital by ambulance; it did not include those who initially used public transport to seek treatment at a local community clinic or a primary level hospital, but who were subsequently transferred to a tertiary hospital by ambulance.

Statistical Analyses

The α significance level was set at 0.05 and the tolerance error was set at 0.02, based on data from a previous study in which the patient decision time was reported as >1 h in 48% of patients with AMI.¹¹ According to the sample size formula, n = t²pq/(p*δ)², ≥109 patients were needed for the present study. One of the aims of this analysis was to compare differences in treatment-seeking behaviour between male and female patients, meaning that inclusion of ≥250 patients with AMI was required.

All statistical analyses were performed using the SPSS® statistical package, version 11.0 (SPSS Inc.). Treatment-seeking delay times were presented as median (25^th–75^th percentile). The χ²-test was used to compare use of the EMS between sexes. As some data did not meet normal distribution criteria for parametric testing, nonparametric statistics were applied using the Mann–Whitney U-test test, to examine the difference in the treatment-seeking delay time between male and female patients. Univariate and multivariate logistic regression analyses were used to determine predictive factors for the use of the EMS. The criteria for variables to be entered into (or removed from) the regression model were set at P < 0.05 and P > 0.10, respectively.

Results

A total of 250 patients with AMI were included in the study. Clinical and demographic characteristics of the study participants were calculated and are presented by frequency or descriptive statistics in Table 1.

Table 1.

Clinical and demographic characteristics of 250 Chinese patients admitted to a university-affiliated teaching hospital with acute myocardial infarction (AMI). Data obtained using a treatment-seeking behaviour questionnaire.

Characteristic	Patients with AMI n = 250
Age, years	63.5 (55–70)
Sex
Male	159 (63.6)
Female	91 (36.4)
BMI, kg/m²	24.03 ± 2.63
Family history of CHD
Yes	157 (62.8)
No	93 (37.2)
Marital status
Married	202 (80.8)
Single^a	48 (19.2)
Educational level
Primary	55 (22.0)
Junior	34 (13.6)
Senior	100 (40.0)
University	48 (19.2)
Master’s degree and above	13 (5.2)
Medical insurance
Yes	222 (88.8)
No	28 (11.2)
Work status
Employed	96 (38.4)
Unemployed^b	154 (61.6)
Occupation^c
Factory worker	107 (42.8)
Teacher	37 (14.8)
Farmer	30 (12.0)
Manager	50 (20)
Businessperson	6 (2.4)
Other	20 (8.0)
Smoking status
Yes^d	164 (65.6)
Never	86 (34.4)
History of AMI
Yes	27 (10.8)
No	223 (89.2)
Comorbid disease
Hypertension	87 (34.8)
Type 2 diabetes mellitus	43 (17.2)
Dyslipidaemia	30 (12)

Data presented as mean ± SD, median (25^th–75^th percentile) or n (%) of patients.

Including unmarried, divorced, widowed or separated.

Including retired patients.

Including details of the occupations in which patients spent the majority of their working life; patients were not necessarily employed in these specific occupations at the time when the questionnaire was administered.

Including smokers who had stopped smoking.

BMI: body mass index; CHD: coronary heart disease.

For the overall study population, the median patient decision time was 130 min (25^th–75^th percentile, 50–480 min), the median transportation time was 30 min (20–41 min), and the median in-hospital time was 20 min (15–30 min). The patient decision time was divided into specific time categories (Table 2); the majority of patients (70.8% [177/250]) took >1 h following symptom onset to make treatment-seeking decisions.

Table 2.

Distribution of patient decision time among 250 Chinese patients admitted to a university-affiliated teaching hospital with acute myocardial infarction (AMI), as determined by a treatment-seeking behaviour questionnaire.

Patient decision time, h	Patients with AMI, n (%)
≤1	73 (29.2)
>1–≤3	68 (27.2)
>3–≤6	40 (16.0)
>6	69 (27.6)

Patient decision time defined as time from AMI symptom onset to the decision to seek medical help.

There were no significant differences between male and female patients with AMI in terms of age, body mass index, history of disease, family history, educational level, marital status, occupation and work status (data not shown). Nonparametric statistics demonstrated a significantly longer patient decision time and in-hospital time in female patients compared with male patients (P = 0.001 and P = 0.048, respectively; Table 3). There was no significant between-sex difference in transportation time.

Table 3.

Median duration of each treatment-seeking phase stratified by sex among Chinese patients admitted to a university-affiliated teaching hospital with acute myocardial infarction (n = 250) as determined by a treatment-seeking behaviour questionnaire.

Sex	n (%)	Duration of treatment-seeking phase, min
Sex	n (%)	Patient decision time	Transportation time	In-hospital time
Male	159 (63.6)	120 (40–240)	30 (20–40)	20 (15–30)
Female	91 (36.4)	240 (120–600)	30 (20–45)	30 (15–40)
Z-value		−3.336	−1.681	−1.976
Statistical significance^a		P = 0.001	NS	P = 0.048

Data presented as median (25^th–75^th percentile) or n (%) of patients.

Patient decision time, time from symptom onset to the decision to seek medical help; transportation time, time from making a treatment-seeking decision to first medical contact; in-hospital time, time from first medical contact to hospital arrival and acceptance of medical treatment, or time from hospital arrival to acceptance of medical treatment in patients who self transported.

Statistical analyses undertaken using the Mann–Whitney U-test.

NS: no statistically significant between-group differences (P ≥ 0.05).

A total of 77 (30.8%) patients arrived at hospital by ambulance, having sought the help of the EMS (Table 4). Patients who utilized the EMS had significantly shorter patient decision and transportation times compared with those who transported themselves to hospital (P < 0.001 for both comparisons). Male patients were more likely to choose the EMS when they experienced acute chest pain, compared with females (59/159 [37.1%] male versus 18/91 [19.8%] female; χ² = 8.152, P = 0.004).

Table 4.

Median patient decision time and transportation time in 250 Chinese patients with acute myocardial infarction (AMI), according to mode of transport to a university-affiliated teaching hospital following AMI symptom onset.

Transport mode	n (%)	Duration of treatment-seeking phase, min
Transport mode	n (%)	Patient decision time	Transportation time
EMS	77 (30.8)	50 (10–125)	25 (20–40)
Self transportation	173 (69.2)	240 (120–490)	30 (20–60)
Z-value		−6.654	−6.173
Statistical significance^a		P < 0.001	P < 0.001

Data presented as median (25^th–75^th percentile) or n (%) of patients.

Patient decision time, time from symptom onset to the decision to seek medical help; transportation time, time from making a treatment-seeking decision to first medical contact.

Statistical analyses undertaken using the Mann–Whitney U-test.

EMS: Emergency Medical Service.

In univariate logistic regression analysis, age, sex, previous experience of similar symptoms, pain level, being forced to seek treatment by others, previous use of the EMS, family history of CHD, rating of symptoms as serious, belief that symptoms were cardiac-related and use of physician-prescribed medication for previous AMI symptoms were all found to have a significant influence on utilization of the EMS (P < 0.05), and were, therefore, entered into the multivariate logistic regression model. The forward multivariate logistic regression analysis identified that being female, being forced to seek treatment by others, previous experience of similar symptoms and previous use of the EMS were associated with a patient being less likely to use the EMS (P ≤ 0.032, Table 5). Pain level and a rating of symptoms as serious were associated with patients being more likely to utilize the EMS (P ≤ 0.002, Table 5).

Table 5.

Multivariate logistic regression analysis to determine predictive factors for utilization of the Emergency Medical Service (EMS) by Chinese patients following the onset of acute myocardial infarction symptoms.

Factor	β	Statistical significance^a	Odds ratio	95% CI
Female	−0.857	P = 0.032	0.424	0.193, 0.930
Being forced to seek treatment by others	−0.886	P < 0.001	0.412	0.283, 0.600
Previous experience of similar symptoms	−1.683	P < 0.001	0.186	0.076, 0.453
Pain level	0.391	P < 0.001	1.478	1.230, 1.776
Rating of symptoms as serious	0.661	P = 0.002	1.936	1.286, 2.915
Previous use of the EMS	2.154	P < 0.001	0.116	0.038, 0.350

CI: confidence interval.

Statistical analyses undertaken using the Mann–Whitney U-test.

Discussion

Encouraging patients with symptoms of AMI to seek timely treatment, by reducing the time spent making that decision, is an important public health issue. The present study demonstrated that the median patient decision time in Chinese patients with AMI symptoms was 130 min, which is longer than the decision times reported for other countries. For example, the ASSENT-3 PLUS trial showed that the median patient decision time was 125 min in France and Spain, 121 min in the UK, 90 min in Finland, 95 min in Germany and The Netherlands, 98 min in Canada, and 110 min in Sweden.¹²

Research indicates that patients who receive treatment within the first 2 h of presenting with AMI symptoms are at a reduced risk of further cardiac complications.¹³ In the present study, the median transportation and in-hospital times were 30 min and 20 min, respectively, so ideally the patient decision time needed to be <1 h to achieve this 2-h goal. Only 29.2% of patients, however, had a patient decision time ≤1 h. These findings highlight the importance of educating Chinese patients to seek medical attention as soon as possible after the onset of AMI symptoms, in order to reduce the incidence of irreversible myocardial damage.

The present study findings demonstrated that patients with AMI were more likely to call an ambulance if they believed that their symptoms were serious, thus confirming the findings from the Swedish study.¹¹ Fewer patients responded to their symptoms by calling an ambulance (30.8%) in the present study compared with reports from other countries (including the USA [41%], UK [85%], Japan [68%], Korea [56%] and New Zealand [66%].¹⁴ We consider that this may be related to the low efficiency and low awareness of the EMS in China, despite government efforts to improve it. The patients included in the present study may have expected to wait for a longer time period if they contacted the EMS, compared with if they self-transported to hospital. The cost of the EMS in China may also have influenced their decision to self transport. In addition, some patients may not have had the basic health information and knowledge to use EMS when they experienced a heart attack. Results of the present study also demonstrated that being forced to seek treatment by others did not encourage patients to use the EMS. These findings indicate that social factors associated with treatment-seeking behaviour need to be investigated in greater depth, in future research.

Cardiovascular disease is the leading cause of death in females, and studies have demonstrated that women with CHD are underdiagnosed and undertreated.^15,16 In the present study, significantly longer patient decision times and in-hospital times were observed in female compared with male patients, which was consistent with a study demonstrating a median prehospital delay time of 255 min in women.¹⁷ Although research has shown that women are becoming more educated with regard to cardiovascular risk factors, this increased awareness has not yet translated into the behavioural changes that would sustain cardiac health.¹⁸ Taken together, these findings suggest that further research focusing on women’s cardiac health is required to encourage healthy cardiovascular behaviours.

The present study demonstrated that women were less likely than men to utilize the EMS in order to get to hospital. In Chinese culture, women take more responsibility for caring for the whole family and their children, and this often takes priority over seeking medical attention when symptoms of AMI manifest. Therefore, the beliefs and values of Chinese women may play an important part in guiding their health-seeking behaviours.

Patients using the EMS after the onset of AMI symptoms in the present study had a significantly shorter prehospital delay time (patient decision time plus transportation time) compared with those who transported themselves to hospital (75 min versus 270 min, respectively). These data are consistent with a study conducted in 105 patients in Australia, which also showed a significant difference in prehospital delay time between patients using the EMS or transporting themselves to hospital (126 min versus 468 min, respectively).¹⁹ The importance of seeking immediate medical assistance via the EMS is highlighted by these data, indicating reductions in prehospital delay time in association with the use of the service.

In conclusion, the present study demonstrated that Chinese patients experiencing symptoms of AMI did not immediately seek proper medical treatment; only a minority used the EMS to reach hospital. In China, there is a considerable need to raise public awareness of the importance of seeking immediate medical assistance from the EMS when experiencing the symptoms of AMI, in order to limit the extent of permanent myocardial damage.

Footnotes

Declaration of Conflicting Interest

The authors declare that there is no conflict of interest.

Funding

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

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