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Title Efficiency of Local Stroke Center Network in Northern District of Japan : A Survey Under the Auspices of Departmentof Health and Welfare, Hokkaido Prefectural Government.
Author(s) 大西, 浩介
Citation 北海道大学. 博士(医学) 甲第11930号
Issue Date 2015-06-30
DOI 10.14943/doctoral.k11930
Doc URL http://hdl.handle.net/2115/60247
Type theses (doctoral)
Note 配架番号：2177
File Information Kousuke_Oonishi.pdf
Hokkaido University Collection of Scholarly and Academic Papers : HUSCAP
学 位 論 文
Efficiency of Local Stroke Center Network in Northern District of
Japan: A Survey Under the Auspices of Department of Health and
Welfare, Hokkaido Prefectural Government.
（北日本の地域脳卒中センターネットワークの効率性：
北海道庁保健福祉部後援の調査）
北 海 道 大 学
大 西 浩 介
1
論文の種類: 学位論文
表題: Efficiency of Local Stroke Center Network in Northern district of Japan: a survey
under the auspices of department of Health and Welfare, Hokkaido Prefectural
Government.
短縮題名: Efficiency of Stroke Center Network in Hokkaido
著者: 大西 浩介* 玉腰 暁子** 数又 研* 鐙谷 武雄*
所属機関: *北海道大学 大学院医学研究科・医学部 脳神経外科
**北海道大学 大学院医学研究科・医学部 公衆衛生学講座
所属の主任教授: 寶金 清博
原稿総頁数: 34 頁
図の総数: 1 枚
表の総数: 5 枚
連絡者氏名宛先・電話番号・Fax 番号・電子メールアドレス:
大西浩介・札幌市西区山の手 3 条 9 丁目 1－12 Tel・Fax: 011‐613‐8425
e-mail: [email protected]
2
INTRODUCTION
Stroke has been a leading cause of long-term disability and death [1] [2]. In Japan,
age-adjusted mortality of stroke has decreased due to advances of its prevention
through treatment, but it is still a major cause of death [3-5]. To standardize and
improve acute stroke care, it was recommended that 2 levels of stroke centers be
established, and they are being adopted in the United States and the world: a primary
stroke center (PSC) and a comprehensive stroke center (CSC) [6-8]. Formation of stroke
centers within a stroke system of care began in 2003 based on recommendations from
the Brain Attack Coalition (BAC), an expert panel dedicated to promote communication
between all of the different medical specialty organizations. The BAC established
criteria for PSCs and CSCs, and more than 1000 stroke centers are certified in the
United States [9-13]. The key elements of PSCs include acute stroke treatment,
neurosurgical service if available, ability to perform brain imaging, laboratory services
24 hours every day, and written care protocols. It is recommended that possible strokes
be transported to the nearest PSC or CSC and then be transferred to CSC if necessary
[6] [7]. The CSCs require expensive components such as intensive care unit, acute
stroke team, neurosurgical services, endovascular specialists, and MRI on 24 hour basis
[7]. In 2011, it is reported that BAC recommendations and subsequent establishment of
3
CSCs and PSCs modestly decreased risk of death after ischemic stroke with increased
use of tPA [14]. In the United States, many stroke patients still live in areas without
ready access to PSCs and CSCs, and it would be impractical to cover all sparsely
populated areas. To deliver acute stroke care in all settings, formation of acute
stroke-ready hospitals (ASRHs) is recommended [9].
In Japan, concept of stroke center is relatively new. Stroke patients are treated mainly
in prefectural government approved stroke centers equipped with neuroimaging,
endovascular treatment, tPA therapy, and neurosurgery including
extracranial-intracranial bypass and aneurysm clipping on 24 hour basis. Of the 245
emergency hospitals in Hokkaido, we investigated prefectural government approved 78
stroke hospitals, of which 58 are equivalent to CSC proposed by the BAC [6] but the
remaining 20 are not.
Hokkaido is the second largest, northernmost island of Japan with a total area of 83,457
square kilometers. The census population in 2009 was 5.5 million, constituting 5.6
percent of the Japanese population. Gross Domestic Product per capita is about 3.4
million yen in 2009 (at that time, the exchange rate was 116 yen [Japan] to
$1.00[United States]), and agriculture is the main source of income. The distribution of
physicians across Hokkaido is unequal, with undersupply in rural areas, and with the
4
greatest concentration in metropolitan Sapporo city and surrounding cities [15] [16].
The Ministry of Health, Labor, and Welfare (MHLW) of Japan has been putting
emphasis on the strategies for the control of four major diseases (cancer, stroke, acute
myocardial infarction, and diabetes mellitus) and for promotion of five medical services
(emergency medicine, disaster medicine, rural medicine, perinatal medicine, and
pediatric medicine including pediatric emergency medicine) in revised Medical Service
Law that came into effect in April 2007 to facilitate establishing and maintaining
medical care system to provide high-quality, balanced distribution of medical service
throughout the country, and each prefectural government is responsible for developing
and implementing its own healthcare plan. The central government makes funds
available to promote the achievement of prefectural healthcare plan. To evaluate the
current state and needs of prefecture, each prefectural government initiated survey for
implementation of strategic management of four diseases and five medical services to
facilitate targeted intervention. Each prefectural government reports on the prehospital
time intervals and interhospital transfer rate of acute stroke that are not academic
survey, while several other studies on this subject are only in a hospital or community
settings [17-19]. To our knowledge, this is the first comprehensive study of its kind in
Japan that focuses on the pre-diagnosis time intervals and interhospital transfer in the
5
whole prefecture. We also showed whether and how living in areas without CSC is
related to high rate of interhospital transfer.
METHODS
Study Participants
The study was carried out during the two weeks of each January and July from July
2009 to January 2011, a total of four 2-week sessions. All stroke patients who were
admitted to the 78 stroke hospitals were consecutively registered during the study
period. Eligible patients were those who presented to the hospital within 7 days after
stroke onset. Patient of inhospital stroke was excluded. There was no intervention in
this study but it only observed outcomes as part of standard care at each hospital.
Data Collection and Informed Consent
Since prefectural government initiated and promoted this investigation based on
national policy which has legal binding force, neither approval of the institutional
review board of each hospital nor consent from each patient was sought. Approval for
performing this study was obtained by the Hokkaido Cardio-cerebrovascular Disease
Subcommittee, which is a multidisciplinary stakeholder committee including Hokkaido
Prefectural Government, Hokkaido Medical Association, all three academic hospitals,
6
major medical centers, cardiovascular centers, rehabilitation centers, and the Fire and
Disaster Management Agency (FDMA).
All efforts were made to protect patients’ confidentiality. All information was collected
and documented by each hospital personnel into worksheets without the patients’
names and addresses, and they were sent back by the participating hospitals to the
Hokkaido Prefectural Government. Although our survey was almost mandatory, there
were several nonresponders. Prefectural government officials made repeated telephone
contact to prompt the participating hospitals to make certain the questionnaire was
completed in full and returned.
In Japan, all residents are covered by mandatory public health insurances which are
supported by all the people, and medical services are provided at no cost to the poorest
and at a low price to all others, hence availability of treatment is ensured. It is
customary in Japan to transport any patients with acute condition to emergency
facilities, or for patients to go to the hospital on their own, and 24 hours round the clock
EMS is available free of charge every day. Therefore, almost all suspected stroke
patients visit or are referred to hospital and are captured in our case identification
process.
Questionnaire
7
Each questionnaire that is mailed biannually to stroke center contain data collection
instrument with a closed-question format. The questionnaire consisted of 31 items as
follows: time of onset; time of emergency call; time of EMS arrival on-scene; time of
arrival to the hospital; time of diagnosis; time of arrival to and departure from first and
second intervening hospital if present; and time of diagnosis at intervening hospital or
at final receiving hospital. Other questions are mode of transport (ambulance, helicopter,
private vehicle, taxi, walk-in arrival, or others), mode of transport used for interhospital
transfer, gender, age, onset place (home, workplaces, public places, road, or others),
patients’ place of residence and place of treatment (name of city, town, and village),
witness status, stroke subtype (cerebral infarction, intracerebral hemorrhage, SAH,
transient ischemic attack, and others). Use of tPA or neurosurgical intervention was
also recorded together with each hospital arrival time, diagnosis time, and treatment
initiation time. The presence or absence of cardiopulmonary arrest, prehospital
defibrillation, prehospital endotracheal intubation, and peripheral venous access in the
prehospital setting is also questioned. Data are compiled and anonymized into a single
Excel worksheet.
Health Service Area and CSC
Japan consists of 47 prefectures, and in each prefecture, health service areas (HSAs) are
8
organized into primary, secondary, and tertiary levels. The HSA, which has also been
termed in other countries as health area, health zone, or health district, is geographic
area designated by the Japanese MHLW in which each prefecture and local health
planners assess and identify needs of health service of each area. A HSA is relatively
self-contained concerning the provision of routine health services. Hokkaido prefecture
is divided into 179 primary health service areas (PHSAs) to match the administrative
boundaries of cities, towns, and villages which provide the first contact with the
healthcare system for patients (Figure 1). Japan has 348 secondary health service areas
(SHSAs), and Hokkaido contains 21 of them, which were divided according to 14
subprefectures’ boundaries, populations, cities, medical resources, expertise, and land
area from which a central hospital is accessible within a reasonable time. The SHSAs
also provide therapy for primary cases but mainly focus on acute intervention,
stabilization, and sometimes referral or transfer for definitive care at the tertiary
hospitals. Tertiary health service areas (THSAs) provide advanced, state of the art
medical care for a whole or a part of prefecture. Among 47 prefectures, 45 contain only
one THSA. Nagano prefecture contain two THSAs, and Hokkaido contain six because of
their geographically large and complex area. Among six THSAs, the largest is Douou
(central Hokkaido) with 3 million population including metropolitan Sapporo city, 129
9
emergency hospitals, four critical care centers, of which one is academic advanced
critical care center and one is academic critical care center [15]. The organization of the
EMS is managed by FDMA, which enabled the fire station of each 179 PHSAs to cover
entire Hokkaido.
Japan has a system of stratified emergency care and transfer, and emergency facilities
are classified into three levels: primary, secondary, and tertiary. Emergency patients
who were considered to be in good condition are initially transferred to emergency
hospitals. There are 3918 emergency hospitals in Japan in 2010 which are certified by
the prefecture, of which 266 are critical care centers that provide care for severe cases
such as stroke, acute myocardial infarction, pneumonia, burns, and trauma [20]. Of
these 266 hospitals, 32 are advanced critical care centers that also treat complex types
of stroke, severe burns, major trauma, and heavy intoxication. In Hokkaido, there are
11 critical care centers, of which two are academic critical care centers and one is
academic advanced critical care center.
To classify 78 stroke hospitals under survey, we applied the term “CSC” to match the
definition proposed by the BAC. We divided 78 stroke hospitals into two groups: CSCs
and non-CSCs to achieve appropriate statistical analysis. Then we divided 21 SHSAs
into two groups according to the presence or absence of CSC (Table 5). Due to the small
10
number of patients in 6 rural SHSAs lacking a CSC, these 6 SHSAs were combined into
one group, which is regarded as rural area with lower acute stroke care capacity. The
remaining 15 SHSAs with CSCs, where medical resources are considered to be
comparatively abundant, were also combined into one group to compare proportions of
patients who underwent interhospital transfer.
The definition of our CSC is almost the same as that of presented by the BAC. One
difference is that some of our CSCs do not necessarily care more than 20 cases of
subarachnoid hemorrhage (SAH) per year and accomplish more than 10 craniotomies
per year [7]. But our low-volume CSCs usually have excellent surgical outcomes and
recommendation for CSC does not exclude such low-volume centers. Neuroendovascular
specialist is necessary component of a CSC, but our CSCs are not necessarily equipped
with such specialist. In Japan, all neuroendovascular specialist received specific
training and accumulated significant experience of procedures. They will be called to
see the patient within 2-3 hours from the other CSCs if needed. Another difference is
that it is uncommon in Japan for CSCs to have an educational role for other hospitals
and for health care professionals in a region, or to establish a stroke registry [7]. This
may be explained by the fact that Japan has one of the lowest physician density per
100,000 population, and national health expenditure as percentage of gross domestic
11
product is not high among OECD countries [21].
We examined regional disparity mainly according to the 6 THSAs, not to the 21 SHSAs
because the small number of patients within each SHSA’s subgroup makes statistical
comparison inappropriate. We calculated in-hospital delay, defined as the time from
hospital arrival to diagnosis, of which we excluded interhospital transfer patients. This
is because intervening hospitals generally lack neurologists or neurosurgeons and
sometimes may not lead to definitive diagnosis and treatment (Figure 3).
We used Geographic Information System (GIS), which enable us to handle varieties of
geographic information. We obtained geographic data from the Ministry of Land,
Infrastructure and Transportation website [22]. By using the data management
function of GIS software SuperMap (SuperMap Japan Inc., Tokyo, Japan), we created
the map of Hokkaido showing border of primary, secondary, and tertiary health service
area that is based on spatial information (Figure 1).
Statistical Methods
Median values were mainly calculated and analyzed because the skewed distribution of
the data made the medians more appropriate and descriptive than means. Categorical
data are presented as number (percentages) unless indicated otherwise. Continuous
data are presented as mean (SD) or median (IQR). As a first step of the statistical
12
analysis, the homogeneity of variance assumption was tested using Levene test for the
studied variable because of the unequal number of cases. The Kolmogorov-Smirnov and
Shapiro-Wilk tests were used to examine the normality of distribution of the data. For
comparison of normally distributed continuous variables, Student’s or Welch’s t tests
was used. The Mann-Whitney test was also used to compare medians because some of
the data were unevenly distributed. ANOVA or Kruskal-Wallis tests were used to
compare mean and median differences for continuous variables in baseline
characteristics. The Chi-square tests were used for between-group comparisons of
categorical data. The extended Fisher’s exact test was used to compare proportions in
categorical characteristics between the groups. Statistical significance was considered
at P<0.05. All statistical analyses were performed with SPSS (Version 13.0J; SPSS
Japan Inc, Tokyo, Japan).
RESULTS
The baseline characteristics of the patients are presented in Table 1. Mean age of all
stroke patients was 72.1 (standard deviation (SD): 13.6, median (MD): 74.0) years.
Mean age of the stroke patients was 69.9 (SD: 12.5, MD: 71.0) years in men and 75.1
(SD: 14.3, MD: 78.0) years in women (P<0.001). Mean age in Dounan THSA was 72.8
(SD: 13.8, MD: 75.0) years, 72.1 (SD: 13.7, MD: 74.0) years in Douou THSA, 73.0 (SD:
13
13.0, MD: 73.0) years in Douhoku THSA, 72.7 (SD: 12.7, MD: 75.0) years in Ohoutsuku
THSA, 70.3 (SD: 14.3, MD: 72.0) years in Tokachi THSA, and 71.6 (SD: 13.2, MD: 72.5)
years in Kushiro THSA. There was no significant difference in mean age among 6
THSAs (P=0.362). Mean age for patients with cerebral infarction was 71.1 (SD: 11.4,
MD: 72.0) years in men and 78.3 (SD: 11.6, MD: 80.0) years in women (P<0.000), for
intracerebral hemorrhage 67.6 (SD: 14.1, MD: 69.0) years in men and 70.8 (SD: 16.3,
MD: 74.0) years in women (P=0.027), for SAH 58.6 (SD: 14.8, MD: 61.0) years in men
and 64.3 (SD: 16.7, MD: 65.0) years in women (P=0.019), and for transient ischemic
attack 71.5 (SD: 13.6, MD: 73.0) years in men and 73.0 (SD: 16.9, MD: 75.5) years in
women (P=0.658). There was a significant difference in mean age among 5 stroke
subtypes (P=0.000).
Table 2 shows that there were significant differences in mean age by the place of onset
(P<0.000), witness status (P=0.020), and mode of transport (P=0.001) but was no
significant difference by the number of interhospital transfer (P=0.452). Mean age of
patients whose strokes occurred at home was 72.2 (SD: 12.7, MD: 74.0) years, at
workplace was 57.6 (SD: 9.9, MD: 59.0) years, at public place was 69.1 (SD: 15.7, MD:
70.0) years, and on road was 65.3 (SD: 16.1, MD: 68.0) years. Mean age for witnessed
patients was 72.5 (SD: 14.2, MD: 75.0) years and 71.7 (SD: 12.9, MD: 73.0) years for
14
unwitnessed patients. Mean age of patients who were transported by ambulance was
72.3 (SD: 14.2, MD: 74.0) years, 72.8 (SD: 13.6, MD: 75.5) years by taxi, 72.0 (SD: 13.0,
MD: 74.0) years by private vehicle, and 67.6 (SD: 12.3, MD: 69.0) years by walk-in.
Mean age for patients who underwent no interhospital transfer was 71.9 (SD: 13.8, MD:
74.0) years, 72.8 (SD: 13.0, MD: 75.0) years for one interhospital transfer, and 74.6 (SD:
9.2, MD: 77.5) years for two interhospital transfer.
There were 1317 patients (50.8%) who activated EMS (Table 3). Another 1275 patients
(49.2%) did not activate EMS. Among the 2 patients who activated EMS, mode of
transport is unknown for one patient and is private vehicle for another. The median
time of onset-to-EMS activation was 30 min (IQR: 8-127 min, mean: 3 hr 57 min, SD: 12
hr 16 min). In addition, 74.3% (762/1026) and 79.6% (817/1026) of patients activated
EMS within 2 and 3 hours of symptom onset, respectively.
The overall median time from EMS call to arrival on scene was 6 min (IQR: 5-9 min,
mean: 7 min, SD: 6 min), and 87.6% (1042/1189) of them were within 10 min. The mean
time from EMS arrival on-scene to hospital (which included time from EMS arrival
on-scene to first intervening hospital, if present) was 26 min (SD: 17 min, MD: 22 min,
IQR: 17-30 min) with 75.3% (880/1189) of them were within 30 min. There were 671
patients who underwent at least one interhospital transfer, twenty patients who
15
underwent two interhospital transfers, and was no case of three interhospital transfers.
Among the patients who underwent interhospital transfer, number of interhospital
transfer was unknown for six patients. There was no statistical difference in average
between the time from EMS arrival on-scene to hospital (without interhospital
transfers) and the time from EMS arrival on-scene to first intervening hospital
(P=0.541). The median time spent at first intervening hospital was 57 min (IQR: 19-102
min, mean: 1 hr 47 min, SD: 6 hr 28 min), which is defined as time from EMS arrival to
and departure from first intervening hospital. The total median time spent at first and
second intervening hospital was 4 hr 56 min (mean: 15 hr 12 min, SD: 24 hr 2 min),
which is the time from EMS arrival to first intervening hospital and departure from
second intervening hospital.
We calculated onset-to-hospital arrival time, which is the mixture of cases with and
without interhospital transfer, and for those who underwent interhospital transfer, the
hospital arrival time is defined as arrival time to initial hospital. Onset-to-hospital
arrival time was eligible for 80.5% (1060/1317) of patients for EMS group and 68.9%
(879/1275) for non-EMS group. For EMS users, the median time from onset to hospital
arrival was 1 hr 6 min (IQR: 40-160 min, mean: 4 hr 12 min, SD: 10 hr 51 min) and
82.6% (844/1022) were within 3 hours. For non-EMS group, the median time from onset
16
to hospital arrival was 6 hr 32 min (IQR: 2-22 hr, mean: 18 hr 52 min, SD: 27 hr 28 min)
and 54.5% (318/584) were within 3 hours.
Table 4 shows statistically significant differences among 6 THSAs in onset-to-EMS
activation time (P=0.024), EMS activation to EMS arrival on-scene time (P=0.001),
EMS arrival on-scene to hospital arrival time (P=0.000), hospital arrival to diagnosis
time (P=0.000), onset to diagnosis time (P=0.033), interhospital transfer rate (P=0.000),
but there was no significant difference by the EMS use rate (P=0.135).
Table 5 shows a comparison of interhospital transfer rate according to THSAs, SHSAs,
and to the presence or absence of CSCs with population data. There was a statistically
significant difference among all 6 THSAs in interhospital transfer rate (P<0.000).
Among all 6 THSAs, 18.0% (275/1527) of patients underwent interhospital transfer in
Douou THSA which are deemed urban, while 49.4% (86/174) underwent interhospital
transfer in Kushiro THSA which were deemed rural. In all 21 SHSAs, interhospital
transfer rate ranged from 8% to 95%. Of the patients from 6 rural SHSAs without CSCs,
79% (117/149) underwent interhospital transfer. This figure was higher than that of the
patients from 15 SHSAs with CSCs, in which only 23% (554/2445) underwent
interhospital transfer (P<0.000). Based on health service area population, 93.4% of the
Hokkaido population (about 5.2 million people) reside in SHSAs with a CSC which
17
provides neurosurgical coverage. We did not assess the difference in interhospital
transfer rate among all 21 SHSAs because of small patients’ number within each group.
18
DISCUSSION
We report the first description of regional disparity of acute stroke care in the whole
prefecture. Interhospital transfer rate was far greater in rural areas compared with
that in non-rural areas. EMS activation rate remains to be improved. About 360
thousand people (6.6% of the Hokkaido population) reside in SHSAs without CSC that
provides specialized stroke care and neurosurgical treatment.
In our study, all the 21 SHSAs contain at least one stroke center, emergency hospital, or
critical care center that is fully equipped with personnel with experience and expertise
in diagnosing and providing initial treatment for suspected stroke. Unfortunately, 6 of
the 21 SHSAs lack a stroke center which are poised to function as a CSC, and patients
of these 6 areas tend to undergo interhospital transfer (Table 5). Although these 6
SHSAs are located in rural settings with limited medical resources, previous studies
suggested that living in a rural setting is not a single cause of hospital arrival delay [23].
In Japan, the physician to population ratio is lower compared to other developed
countries [24] and the number of neurosurgeon is even more limited [16]. Construction,
maintenance, and running costs of neurosurgical operating room and personnel is high
[7]. So it is difficult to provide adequate neurosurgical care widely enough, especially in
rural areas. As described above, it is recommended that most acute stroke patients be
19
initially stabilized and provided with emergency care in PSCs [6]. Such patients would
then be transferred to CSCs with neurosurgical facilities, or the neurosurgeon will be
called to see the patient within 2 hours at the PSC if needed [6]. In our survey, 25.9%
(671/2594 cases) of patients underwent interhospital transfer (Table 2). There were no
statistically significant differences in onset to diagnosis time among 6 THSAs, but only
central Hokkaido THSA, which includes metropolitan Sapporo city, achieved low
interhospital transfer rate compared to rural settings (Table 4). Direct transfer of
suspected stroke to stroke centers is known to improve outcome and has been presented
in the literature [25] [26].
Stroke campaign aimed at improving awareness of stroke symptoms, risk factors, and
what to do in case of stroke have been intensively studied [27-30]. These studies
revealed that stroke campaign may increases public awareness to seek early medical
attention for suspected stroke [31] [32]. It also increases the rate of tPA use and
improves other aspects of acute stroke care [33] [34]. Other studies showed that the
EMS use rate among acute stroke patients is still not high enough [35] [36]. It is also
shown that stroke patients in Northeast region of the United States activate EMS more
often than those in other regions, and compared to Medicare patients, privately insured
and self-insured patients use EMS less frequently [37]. Our study showed overall EMS
20
use rate of 50.8% (1317/2594 cases), which suggests that further improvement of EMS
use rate is expected in stroke patients.
In our study, the median interhospital transfer time is 30 minutes, which is defined as
time from EMS departure from first intervening hospital to arrival to receiving hospital
(data not shown). This suggests that rapid evaluation of suspected stroke at the initial
hospital, as well as accurate and effective communication are required between the
hospital and the EMS personnel because narrow time window for stroke treatment and
long transport distances do not allow time loss especially for rural patients. We showed
that in some SHSAs without CSC, patients tend to undergo more interhospital transfer
than in SHSAs with CSC. For example, in Nemuro SHSA, 89% (32/36 cases) of stroke
patients were transferred to Kushiro SHSA (Table.5). Kushiro THSA is constituted of
two SHSAs: Nemuro SHSA and Kushiro SHSA. Kushiro SHSA has three CSCs,
whereas Nemuro SHSA lacks a CSC. The distance from the emergency hospital of
Nemuro SHSA to the CSCs of Kushiro SHSA is about 100 km away, without highway
access and the speed limit for an ambulance is 80 km/h. In Hokkaido, helicopter
transport is available on a limited basis, only during daytime and transport distance is
less than 100 km. In our study, only 6 of 2597 patients were transported by helicopter.
The median transfer time from Nemuro SHSA to Kushiro SHSA was 100 minutes and
21
this is three times longer than the average of 30 minutes, and is a great delay to
starting tPA or to perform emergency decompressive surgery. The median transfer time
from intervening hospital to receiving hospital was only 20 minutes in SHSAs with
CSCs, but it reaches 78 minutes in SHSAs without CSCs. Additionally, average
interhospital transfer rate is 78.5% (117/149 cases) in all SHSAs without CSC, whereas
only 23.8% (581/2445) of patients underwent interhospital transfer in all SHSAs with
CSC (Table.5). Some recommended further education of rural caregivers and remote
support from tertiary stroke centers to improve suboptimal stroke care in rural
prehospital and emergency department settings [38]. We have shown no statistically
significant difference in the EMS use rate, prehospital delay, and in-hospital delay
between central Hokkaido THSA and rural Kushiro THSA that includes Nemuro SHSA
which lacks a CSC (Table.4). But rural Nemuro SHSA has high interhospital transfer
rate of patients and increased transfer time, and possible solutions to such problems are
widespread use of helicopter transport [39] [40], further use of telemedicine [41-43],
diagnosis and initiation of treatment during transport [43-45], formation of Acute
Stroke-Ready Hospital which provides initial diagnostic services, stabilization,
emergency care, and treatment to acute stroke patients [9].
These findings have important implications for public health policy, design of regional
22
stroke system, hospital organization, clinical practice, and future stroke research. Such
data could assist in identifying rural or neurologically underserved areas that would
benefit from multifaceted program of public and professional education. Our data may
also help to improve the management of acute stroke care in the local hospital, to extend
stroke expertise to underserved areas, and to enable initiatives such as telemedicine
into the healthcare systems.
This study has some limitations. First, findings of the survey in Hokkaido prefecture
could not represent the whole country and could not be applied to other countries even
more. Second, since this was not a year round survey, it cannot be sure whether the data
of our study represent whole year. The reason for short data collection period was that
this survey was performed as part of routine clinical practice mainly due to lack of
financial and human support. Third, although we investigated 78 stroke hospitals with
overall facility response rate of 89.7%, some stroke patients may have been treated at
other hospitals. Fourth, some aged patient, terminally ill, or who are receiving
palliative care might be reluctant to be transferred or to be admitted to stroke-treating
hospitals. And patients with lower socioeconomic status tend to be reluctant to visit
hospital or to activate EMS even when some acute conditions occurred [46]. And even
though knowledge about stroke symptoms in general population is gradually increasing
23
[47], substantial proportion of people cannot recognize stroke symptoms as they are
happening [36]. Fifth, we did not record what percentage of patient are stroke mimics
and hence were excluded.
CONCLUSION
This study sought to capture all patients in one prefecture in certain periods, and
obtained comprehensive diagnostic investigation, which has allowed almost complete
categorization of stroke subtypes. This study revealed disparities in acute stroke care
among different SHSAs in Hokkaido, which is expected to provide basis for strategic
decision to make concerted effort to reduce regional inequalities.
ACKNOWLEDGEMENTS
The authors sincerely thank all participating hospital staff. We gratefully acknowledge
the contributions of Hisashi Uemura, Konomi Fukatsu at the Bureau of Health and
Safety, Department of Health and Welfare, Hokkaido Government for supporting the
study and data collection.
DISCLOSURES
The authors declare that there is no conflict of interest for any of the authors.
24
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33
Table1. Age distribution of patients according to gender, tertiary health service areas,
and stroke subtypes
* THSA: Tertiary Health Service Area †CI: cerebral infarction ‡ICH: intracerebral
hemorrhage §SAH: subarachnoid hemorrhage ¶TIA: transient ischemic attack
Table2. Age distribution of patients according to onset place, witness status, and mode
of transport
Table3. Distribution of time after stroke onset
*Onset to EMS activation time.
†EMS activation to EMS arrival on-scene time. EMS indicates emergency medical
service.
‡ Time from EMS arrival on-scene to stroke-treating hospital. Patients with
interhospital transfer were excluded.
§Time from EMS arrival on-scene to first intervening hospital.
¶Time from EMS arrival to first intervening hospital to EMS departure from first
intervening hospital.
#Time from EMS arrival to first intervening hospital to EMS departure from second
intervening hospital.
$Time from hospital arrival to diagnosis. Patients with interhospital transfer were
34
excluded.
**Patients with interhospital transfer were excluded.
Table 4. Median Delay Times, EMS Activation Rate, and Patient Transfer Rate by
Geographic Variables
Values are median (25th-75th percentile).
*Onset to EMS activation time. EMS indicates emergency medical service.
†EMS activation to EMS arrival on-scene time.
‡Time from EMS arrival on-scene to final receiving hospital. For patients who
underwent interhospital transfer, time from EMS arrival on-scene to initial intervening
hospital was counted.
§Hospital arrival to diagnosis time. Patients with interhospital transfer were excluded.
¶Onset to diagnosis time. Patients with interhospital transfer were excluded. Both
EMS users and non-users were mixed.
**Percentage of patient who used EMS.
#Rates of patient transferred from primary stroke center to other stroke center.
Statistical analyses were performed using Chi-square tests for between-group
comparisons (P<0.001).
Table 5. Regional differences in the percentage of stroke patients with interhospital
35
transfer and in the presence or absence of comprehensive stroke center divided by
tertiary and secondary health service area
* Tertiary Health Service Area
† Secondary Health Service Area
‡ Number of stroke patient.
§ Percentage of patient who underwent interhospital transfer.
¶ Presence of comprehensive stroke center; p, presence; a, absence. CSC indicates
comprehensive stroke center.
# Statistical analyses were performed using Chi-square tests for between-group
comparisons (P<0.001).
Figure 1. Regional map of health service area, comprehensive stroke center (circles),
and Sapporo city (4-point star) in the Hokkaido prefecture of Japan
Age (years)
≤39 40-49 50-59 60-69 70-79 80-89 ≥90 Total % Population % Sex Men 28 63 172 396 467 301 38 1 465 56.5 2 633 508 47.5 Women 24 38 85 195 278 373 136 1 129 43.5 2 913 051 52.5 Total 52 101 257 591 745 674 174 2 594 5 546 559THSA* Dounan
(south Hokkaido) 6 13 27 57 82 91 17 293 11.3 482 162 8.7
Douou (central Hokkaido)
31 65 147 346 437 401 100 1 527 58.9 3 402 024 61.3
Douhoku (north Hokkaido)
3 8 24 64 69 54 27 249 9.6 657 862 11.9
Ohoutsuku (north-east Hokkaido)
2 7 14 34 49 45 10 161 6.2 312 359 5.6
Tokachi (south-east Hokkaido)
6 6 23 52 56 35 12 190 7.3 353 867 6.4
Kushiro (eastern-most Hokkaido)
4 2 22 38 52 48 8 174 6.7 338 285 6.1
Total 52 101 257 591 745 674 174 2 594 5 546 559Stroke subtype CI† 12 45 157 380 562 507 142 1 805 69.6 ICH‡ 17 28 49 133 116 112 18 473 18.2 SAH§ 19 25 40 55 31 25 7 202 7.8 TIA¶ 3 2 8 18 29 23 6 89 3.4 Other 1 1 3 5 7 7 1 25 1.0 Total 52 101 257 591 745 674 174 2 594
Table1. Kousuke Oonishi
Age (years) Total ≤39 40-49 50-59 60-69 70-79 80-89 ≥90 Onset place Home 28 72 170 443 600 511 88 1 912 Workplace 6 11 41 41 9 0 0 108 Public place 5 5 11 33 36 20 8 118 Road 7 3 11 18 20 9 3 71 Other 6 10 24 56 80 134 75 385 Total 52 101 257 591 745 674 174 2 594 Witness status Witnessed 29 47 117 275 346 341 102 1 257 Not witnessed 23 54 140 316 399 333 72 1 337 Total 52 101 257 591 745 674 174 2 594 Mode of transport Ambulance 33 63 120 285 355 343 110 1 309 Helicopter 0 0 2 0 2 2 0 6 Taxi 3 10 16 27 58 57 7 178 Private vehicle 12 20 85 209 239 209 45 819 Walk-in arrival 4 5 15 37 39 17 1 118 Unknown 0 3 19 33 52 46 11 164 Total 52 101 257 591 745 674 174 2 594 Interhospital transfer None 41 82 193 448 535 491 132 1 922 One 11 19 61 138 199 176 41 645 Two 0 0 2 4 8 5 1 20 Unknown 0 0 1 1 3 2 0 7 Total 52 101 257 591 745 674 174 2 594
Table2. Kousuke Oonishi
Eligible patients (%) TotalPatient delay* Time (min) ≤9 10-29 30-59 60-119 120-179 ≥180 n 277 233 149 101 55 211 1 026 (77.9) 1 317 EMS arrival delay† Time (min) ≤3 4-6 7-9 10-19 20-29 ≥30 n 130 498 323 197 27 14 1 189 (90.3) 1 317 EMS transport delay‡ Time (min) ≤9 10-19 20-29 30-39 40-59 ≥60 n 19 324 420 148 94 46 1 051 (96.2) 1 092 EMS transport time to first intervening hospital§ Time (min) ≤9 10-29 30-59 60-89 90-119 ≥120 n 25 66 15 7 1 4 118 (17.6) 671 Intervening hospital delay at first intervening hospital¶ Time (min) ≤9 10-29 30-59 60-119 120-239 ≥240 n 77 55 92 124 63 29 440 (65.6) 671 Total delay at first and second intervening hospital# Time (hr) ≤2 3-4 5-6 7-24 25-48 ≥48 n 2 6 2 1 4 1 16 (80.0) 20 In-hospital delay$ Time (min) ≤19 20-39 40-59 60-119 120-179 ≥180 n 413 572 307 359 111 72 1 834 (95.4) 1 922 Total delay** Time (min) ≤29 30-59 60-89 90-119 120-179 ≥180 n 4 151 236 188 259 1123 1 961 (75.6) 2 594 EMS group Time (min) ≤29 30-59 60-89 90-119 120-179 ≥180 n 2 134 206 147 184 379 1 054 (80.0) 1 317 non-EMS group Time (min) ≤29 30-59 60-89 90-119 120-179 ≥180 907 (71.1) 1 275 n 2 17 28 41 75 7 Onset to t-PA administration time Time (min) ≤79 80-99 100-119 120-139 140-159 ≥160 n 1 3 9 12 14 11 50 (92.6) 54 Hospital arrival to initiation of neurosurgery time Time (hr) ≺1 1-3 4-5 9-11 12-23 ≥24 n 18 118 24 23 23 39 245 (95.3) 257
Table3. Kousuke Oonishi
Patient delay,*
min
EMS arrival delay,†
min
EMS transport
delay,‡ min
In-hospital delay,§
min
Total delay,¶
min
EMS user, ** (%)
Tertiary Health Service Area Dounan
(south Hokkaido) 47 (13-185) 6 (4-8) 24 (18-31) 35 (23-55) 162 (90-453) 54.3
Douou (central Hokkaido)
32 (8-132) 7 (5-9) 22 (17-30) 37 (21-67) 197 (90-800) 50.6
Douhoku (north Hokkaido)
21 (7-63) 6 (4-8) 21 (17-26) 30 (17-61) 137 (69-468) 53.4
Ohoutsuku (north-east Hokkaido)
14 (6-48) 6 (4-9) 16 (13-32) 33 (20-71) 260 (125-1030) 41.6
Tokachi (south-east Hokkaido)
25 (10-203) 6 (4-9) 26 (20-34) 43 (28-71) 140 (95-480) 53.2
Kushiro (eastern-most Hokkaido)
30 (6-120) 7 (6-9) 23 (17-30) 17 (7-47) 145 (65-617) 48.3
Total 30 (8-127) 6 (5-9) 22 (17-30) 35 (20-65) 180 (88-659) 50.8
Table4. Kousuke Oonishi
THSA* n ‡ Interhospital transfer, § (%) SHSA† n ‡ Interhospital transfer, §
(%) CSC¶ Population
Dounan 293 36
Minami Oshima 253 29
p 411 973 Minami Hiyama 19 95
a 28 029 Kita Oshima 21 67
a 42 160
Douou 1 527 18
Sapporo 1 007 15
p 2 318 327 Shiribeshi 89 38
p 238 752 Minami Sorachi 70 26
p 185 342 Naka Sorachi 82 16
p 122 120 Kita Sorachi 24 29
p 38 547 Nishi Iburi 115 14
p 213 135 Higashi Iburi 108 8
p 198 780 Hidaka 32 84
a 87 021
Douhoku 249 33
Kamikawa-Tyuubu 158 23
p 409 982 Kamikawa-Hokubu 33 39
p 73 003 Furano 12 92
a 46 347 Rumoi 15 33
p 57 555 Souya 31 52
p 70 975
Ohoutsuku 161 38
Kitami Abashiri 132 35
p 234 235 Engaru Monbetu 29 52
a 78 124
Tokachi 190 32
Tokachi 190 32
p 353 867
Kushiro 174 49
Kushiro 138 39
p 255 809 Nemuro 36 89
a 82 476
Total 2 594 26
Total 2 594 27
5 546 559
SHSAs with CSC 2 445 23
p 5 182 402 SHSAs without 149 79
a 364 157
Table5. Kousuke Oonishi
Figure1. Kousuke Oonishi
