Original Contribution
Weekend Effect in Children With Stroke in the Nationwide
Inpatient Sample
Malik M. Adil, MD; Gabriel Vidal, MD; Lauren A. Beslow, MD, MSCE
Downloaded from http://stroke.ahajournals.org/ by guest on June 17, 2017
Background and Purpose—Studies have demonstrated differences in clinical outcomes in adult patients with stroke
admitted on weekdays versus weekends. The study’s objective was to determine whether a weekend impacts clinical
outcomes in children with ischemic stroke and hemorrhagic stroke.
Methods—Children aged 1 to 18 years admitted to US hospitals from 2002 to 2011 with a primary discharge diagnosis of
ischemic stroke or hemorrhagic stroke were identified by International Classification of Disease, 9th Revision, codes.
Logistic regression estimated odds ratios and 95% confidence intervals for in-hospital mortality and discharge to a nursing
facility among children admitted on weekends (Saturday and Sunday) versus weekdays (Monday to Friday), adjusting for
potential confounders.
Results—Of 8467 children with ischemic stroke, 28% were admitted on a weekend. Although children admitted on weekends
did not have a higher in-hospital mortality rate than those admitted on weekdays (4.1% versus 3.3%; P=0.4), children
admitted on weekends had a higher rate of discharge to a nursing facility (25.5% versus 18.6%; P=0.003). After adjusting
for age, sex, and confounders, the odds of discharge to a nursing facility remained increased among children admitted
on weekends (odds ratio, 1.5; 95% confidence interval, 1.1–1.9; P=0.006). Of 10 919 children with hemorrhagic stroke,
25.3% were admitted on a weekend. Children admitted on weekends had a higher rate of in-hospital mortality (12%
versus 8%; P=0.006). After adjusting for age, sex, and confounders, the odds of in-hospital mortality remained higher
among children admitted on weekends (odds ratio, 1.4; 95% confidence interval, 1.1–1.9; P=0.04).
Conclusions—There seems to be a weekend effect for children with ischemic and hemorrhagic strokes. Quality
improvement initiatives should examine this phenomenon prospectively. (Stroke. 2016;47:00-00. DOI: 10.1161/
STROKEAHA.116.013453.)
Key Words: hospital mortality ◼ hospitalization ◼ International Classification of Diseases
◼ intracranial hemorrhages ◼ stroke
C
hildhood stroke is among the top 10 causes of death
among children in the United States.1,2 Recent literature
indicates that >2000 children with the diagnosis of stroke
were discharged from US hospitals in each of the years 2000,
2003, and 2006.3 In North America and Europe, childhood
stroke incidence ranges from 2 to 13 per 100 000 children per
year in those aged <18 years.1,4–6 Studies provide consistent
estimates that 39% to 54% of all childhood strokes are hemorrhagic.5–7 A study from a northern California health system
demonstrated hemorrhagic stroke (HS) had an incidence of
1.4 per 100 000 person-years in children aged >28 days.8
In one of the largest studies that analyzed the weekend effect
among the top 100 causes of in-hospital mortality, weekend
admissions were associated with a 4% increase in mortality for
any condition. However, this study did not analyze the weekend effect on admissions because of stroke.9 In adults, the incidence of stroke increases during weekends and other stressful
periods.10–12 Previous studies13,14 have demonstrated differences in
the quality of care and clinical outcomes in adult patients with
stroke admitted on weekdays versus weekends. However, there
are no data available on differences in clinical outcomes among
pediatric stroke patients admitted on weekends versus weekdays.
Knowing whether differences exist in outcomes based on admission period (weekday versus weekend) and then understanding
the causes of these different outcomes could lead to improvements in quality of care for children with stroke. Therefore, the
objective of this study was to determine whether the weekend
effect on clinical outcomes exists in children with ischemic stroke
(IS) and HS using a large national sample.
Methods
The analysis was based on data files from the National Inpatient
Sample (NIS), 2002 to 2011. A comprehensive synopsis on NIS data
is available at http://www.hcup-us.ahrq.gov. The NIS is a deidentified
Received March 13, 2016; final revision received March 17, 2016; accepted March 18, 2016.
From the Department of Neurology, Ochsner Neuroscience Institute, Ochsner Clinic Foundation, New Orleans, LA (M.M.A., G.V.); and Departments of
Pediatrics and Neurology, Yale University School of Medicine, New Haven, CT (L.A.B.).
Presented in part at the International Stroke Conference, Nashville, TN, February 11–13, 2015.
The online-only Data Supplement is available with this article at http://stroke.ahajournals.org/lookup/suppl/doi:10.1161/STROKEAHA.
116.013453/-/DC1.
Correspondence to Malik M. Adil, MD, Ochsner Clinic Foundation, 1514 Jefferson Hwy, New Orleans, LA 70121. E-mail malikmuhammad.adil@
gmail.com
© 2016 American Heart Association, Inc.
Stroke is available at http://stroke.ahajournals.org
DOI: 10.1161/STROKEAHA.116.013453
1
2 Stroke June 2016
Downloaded from http://stroke.ahajournals.org/ by guest on June 17, 2017
database; therefore, no institutional review board approval was
required.
Children aged 1 to 18 years admitted because of IS or HS were
identified using the International Classification of Disease, 9th
Revision, Clinical Modification (ICD-9-CM) primary diagnosis
codes 433 to 434 and 436 to 437 for IS and 430 to 432 for HS.
Patients were categorized as having been admitted on weekdays
(Monday through Friday) versus weekends (Saturday or Sunday), a
distinct variable in the NIS database that is calculated from the original admission date. The NIS database does not allow identification
of specific admission hours. Patients with missing data on the day of
admission were excluded. We performed separate analyses to determine whether the weekend effect exists in children with IS and HS.
Study variables included were age, sex, race/ethnicity, and comorbidities obtained from Agency for Healthcare Research and Quality
comorbidity data files, including diabetes mellitus, hypertension,
congestive heart failure, renal failure, chronic lung disease, deficiency anemia, valvular heart disease, fluid and electrolyte disorder,
liver disease, AIDS, obesity, paralysis, solid tumor without metastasis, metastatic cancer, alcohol abuse, and coagulopathy.
ICD-9-CM secondary diagnosis codes identified secondary diagnoses in children with IS and HS, such as aphasia (784.3), hemiplegia and hemiparesis (342), migraine (346), cerebral artery dissection
(443.2), anomalies of the cerebrovascular system, which include arteriovenous malformations of the brain and other congenital anomalies
of the cerebral vessels (747.81), coma (780.01), fever (780.60), moyamoya disease (437.5), hydrocephalus (331.3–331.4), seizure (345),
meningitis (320.0–322.9), congenital heart disease (745–747), altered
mental status (780.97), cardiomyopathy (425), systemic lupus erythematosus (710), pneumonia (486, 481, 482.8, and 482.3), urinary
tract infection (599.0 and 590.9), sepsis (995.91, 996.64, 038, 995.92,
and 999.3), deep venous thrombosis (451.1, 451.2, 451.81, 451.9,
453.1, 453.2, 453.8, and 453.9), pulmonary embolism (415.1), illicit
drug abuse (305.6–305.7), atrial fibrillation (427.3), nicotine dependence (305.1), dyslipidemia (272.0), and sickle cell disease (282.6).
We also used ICD-9-CM primary and secondary procedure codes to
estimate the percentage of children who underwent in-hospital procedures including ECG (89.5), echocardiography (88.72), computed
tomography (87.03), magnetic resonance imaging (88.91), ultrasound
head and neck (88.71), cardiac catheterization (88.5), valvular repair
(35.0–35.9), cerebral angiography (88.41), thrombolytic therapy
(99.10), craniotomy (01.2, 01.24), clipping (39.51 and 39.52), coiling (39.71 and 39.79), dialysis (54.98 and 39.95), cardiopulmonary
resuscitation (99.60), intubation (96.04), mechanical ventilation
(96.72), transfusion (99.04), and gastrostomy (431.1–431.9).
Hospitals were categorized by US geographic region as Northeast,
Midwest, West, and South. The admitting hospitals were classified
as teaching or nonteaching; teaching hospitals were those that have
an American Medical Association–approved residency program or
have membership in the Council of Teaching Hospitals.15 Hospitals
were further characterized into small, medium, or large size based
on available hospital beds. The definition of large size may vary
from exceeding 325 to exceeding 450 acute hospital beds depending on the location and characteristics of the hospital.
Outcome Measures
We determined the length of stay (LOS) and hospital charges (amount
billed for services but not specific amounts received in payment).
Discharge status was categorized into home/selfcare, nursing facility (includes skilled nursing facilities and inpatient rehabilitation),
unknown, and in-hospital mortality.
Statistical Analysis
SAS 9.3 software (SAS Institute, Cary, NC) was used to convert NIS
database data into weighted counts to generate national estimates
following Healthcare Cost and Utilization Project recommendations.
We performed univariable analyses with χ2 tests for categorical variables and t tests for continuous variables to identify differences in
study variables and end points among children admitted with IS and
HS during weekends versus weekdays. Two logistic regression models were created. Model 1 included all patients, and logistic regression analysis was used to identify the association between weekend
admission and odds of in-hospital mortality. Model 2 included
patients who were discharged alive, and logistic regression analysis was used to identify the association between weekend admission
and odds of discharge to a nursing facility (versus home/selfcare).
Logistic regression models were adjusted for age (as a continuous
variable), sex, and confounding factors (as categorical variables)
that were significant (P≤0.05) in univariable analyses. We performed
subanalyses for patients with IS and HS in which we examined each
outcome measure in children aged 1 to 12 years and in those aged 13
to 18 years separately. We chose to dichotomize age at 12/13 years
because this is the typical time point at which children undergo
puberty. In the subanalyses, factors that were significant for the age
group in univariable analyses at the 0.05 level were included in the
multivariable model. When a variable had 10 or fewer patients, we
reported that variable as <11 in accordance with the Healthcare Cost
and Utilization Project data requirements because small numbers of
observations (ie, individual discharge records) reported in publications increase the risk for identification of individuals.
Results
Ischemic Stroke
Of 8467 children aged 1 to 18 years with IS, 28% were
admitted on a weekend. Mean age and sex distribution in the
weekend and weekday groups were not different. Comorbid
conditions, hospital size, insurance status, and hospital teaching status were not different between groups. The rate of
weekend admission was higher in hospitals located in the
Western region of the United States (P=0.02) and was lower
in hospitals located in the Southern region of the United States
(P=0.04; Table I in the online-only Data Supplement).
The rate of seizures was higher on weekends compared
with weekdays (7.2% versus 4.3%; P=0.03), whereas moyamoya disease was less frequent in the weekend group compared with the weekday group (5.5% versus 10.5%; P=0.004).
In-hospital procedures were not different between the groups.
Children admitted on weekends had a higher rate of discharge to nursing facilities (25.5% versus 18.6%; P=0.003).
In-hospital mortality was not different among children admitted on weekends versus weekdays (4.1% versus 3.3%; P=0.4).
The LOS (8±10 versus 7±12 days; P=0.003) and mean hospital charges ($73 295±$96 223 versus $53 022±$70 913;
P<0.0001) were significantly greater among children admitted
on weekends versus weekdays (Table 1).
After adjusting for age, sex, and confounding factors, the
odds of discharge to a nursing facility was greater among
children admitted on weekends than among those admitted
on weekdays (odds ratios [ORs], 1.5; 95% confidence interval
[CI], 1.1–1.9, P=0.006; Table 2).
In a subanalysis in which we dichotomized children by age
(1–12 and 13–18 years), among those aged 1 to 12 years, discharge to a nursing facility was more common among those
admitted on weekends versus weekdays (OR, 1.58; 95% CI,
1.02–2.46; P=0.04), after adjusting for seizure, moyamoya,
and mechanical ventilation. In-hospital mortality was not
significantly different in the younger age group among those
admitted on weekends versus weekdays (OR, 1.60; 95% CI,
0.81–3.31; P=0.2), after adjusting for seizure, moyamoya,
and mechanical ventilation. Among those aged 13 to 18
Adil et al Weekend Effect in Children With Stroke 3
Table 1. Secondary Diagnoses, In-Hospital Procedures,
and Discharge Outcomes of Patients With Ischemic Stroke
According to Strata Defined by Weekend Status: Nationwide
Inpatient Sample, 2002 to 2011
Secondary Diagnosis
Weekend (1848)
Weekday (6619)
P Value
Table 1. Continued
Secondary Diagnosis
Weekend (1848)
Valvular repair
Weekday (6619)
P Value
<11
31 (0.5%)
0.9
Cerebral
angiography
470 (25.4%)
1856 (28.0%)
0.3
Thrombolytic
therapy
34 (1.9%)
115 (1.7%)
0.9
Fever
29 (1.6%)
87 (1.3%)
0.7
Altered mental status
23 (1.3%)
30 (0.5%)
0.2
Aphasia
34 (11.3%)
62 (9.6%)
0.3
26 (0.4%)
0.3
660 (35.7%)
2009 (30.3%)
0.06
Cardiopulmonary
resuscitation
18 (1.0%)
Hemiplegia and
hemiparesis
226 (3.4%)
0.08
42 (0.6%)
0.7
Mechanical
ventilation
109 (5.9%)
<11
Migraine
58 (3.1%)
300 (4.5%)
0.2
Intubation
158 (8.5%)
441 (6.7%)
0.3
Intracerebral
hemorrhage
18 (1.0%)
110 (1.6%)
0.3
Dialysis
38 (2.0%)
100 (1.5%)
0.5
Gastrostomy
43 (2.3%)
97 (1.5%)
0.3
Subarachnoid
hemorrhage
<11
<11
0.4
Blood transfusion
108 (5.8%)
487 (7.4%)
0.3
Cerebral artery
dissection
53 (0.2%)
240 (3.6%)
0.4
Length of stay in
days, mean (SD)
8±10
7±12
0.003*
Arteriovenous
malformation
29 (1.5%)
48 (0.7%)
0.2
Hospital charges,
mean (SD)
$73 295±$96 223
$53 022±$70 913
<0.0001*
Moyamoya disease
101 (5.5%)
692 (10.5%)
0.004*
Hydrocephalus
52 (2.8%)
152 (2.3%)
0.6
Home/selfcare
1301 (70.4%)
5155 (77.9%)
0.007*
Seizure
134 (7.2%)
286 (4.3%)
0.03*
Nursing facility
471 (25.5%)
1225 (18.6%)
0.003*
<11
30 (0.4%)
0.5
Unknown
0 (0%)
14 (0.2%)
Congenital heart
disease
212 (11.5%)
699 (10.6%)
0.6
In-hospital
mortality
76 (4.1%)
219 (3.3%)
Cardiomyopathy
43 (2.3%)
110 (1.7%)
0.4
Sickle cell disease
152 (8.2%)
680 (10.3%)
0.3
Systemic lupus
erythematosus
47 (2.6%)
111 (1.7%)
0.3
Pneumonia
47 (2.6%)
117 (1.8%)
0.4
Deep venous
thrombosis
<11
74 (1.1%)
0.2
Urinary tract
infection
60 (3.3%)
223 (3.4%)
0.9
Sepsis
<11
36 (0.5%)
0.9
Pulmonary embolism
<11
<11
0.3
Illicit drug abuse
<11
19 (0.3%)
0.9
<11
12 (0.2%)
0.8
Echocardiography
323 (17.5%)
951 (14.4%)
0.2
Computed
tomography
137 (7.4%)
547 (8.3%)
0.6
Magnetic
resonance
imaging
526 (28.5%)
1575 (23.8%)
0.1
Ultrasound head
and neck
24 (1.3%)
61 (0.9%)
0.6
Cardiac
catheterization
19 (1.1%)
23 (0.3%)
0.2
Coma
Downloaded from http://stroke.ahajournals.org/ by guest on June 17, 2017
Meningitis
In-hospital procedure
ECG
(Continued )
Discharge disposition
0.4
*Statistically significant.
years, neither discharge to a nursing facility (OR, 1.41; 95%
CI, 0.94–2.12; P=0.09) nor in-hospital mortality (OR, 0.50;
95% CI, 0.14–1.65; P=0.2) was more common among those
admitted on weekends versus weekdays, after adjusting for
moyamoya.
Hemorrhagic Stroke
Of 10 919 children aged 1 to 18 years with HS, 25.3% were
admitted on a weekend. Mean age and sex distribution in
the weekend and weekday groups were not different. The
proportion of children with obesity was significantly higher
among children admitted on weekends compared with those
admitted on weekdays (2% versus 1%; P=0.04). The rate
of weekend admission was higher in hospitals located in
the Western region of the United States (P=0.05). Patients
with Medicare/Medicaid insurance were more likely to
have admissions on weekdays compared with on weekends.
Hospital size and hospital teaching status were not different between the groups (Table II in the online-only Data
Supplement).
The rate of deep vein thrombosis was lower in children
admitted on weekends compared with those admitted on weekdays (0.1% versus 0.9%; P=0.006). The rates of mechanical
ventilation, intubation, gastrostomy, and blood transfusion
were significantly higher among children admitted on weekends compared with those admitted on weekdays. Children
admitted on weekends had a higher in-hospital mortality
4 Stroke June 2016
Table 2. Effect of Weekend Admission on Study End Points in Children Admitted With Ischemic Stroke
Unadjusted
Outcomes
OR (95% CI)
Model 1 (analysis
including all
patients)
Discharged alive
Model 2 (analysis
including surviving
patients)
Home/selfcare
Reference
Nursing facility
1.5 (1.2–2.0)
In-hospital mortality
Adjusted for Age and Sex
P Value
Reference
1.2 (0.7–2.1)
OR (95% CI)
P Value
Reference
0.4
1.2 (0.7–2.1)
0.003†
1.5 (1.1–2.0)
Adjusted for Age, Sex, and
Potential Confounders*
OR (95% CI)
P Value
Reference
0.4
1.2 (0.7–2.0)
0.004†
1.5 (1.1–1.9)
Reference
0.6
Reference
0.006†
CI indicates confidence interval; and OR, odds ratio.
*Moyamoya disease and seizure.
†Statistically significant.
Downloaded from http://stroke.ahajournals.org/ by guest on June 17, 2017
rate (12% versus 8%; P=0.006). The rate of discharge to a
nursing facility was not different among children admitted
on weekends versus weekdays (22% versus 20%; P=0.3).
LOS (10±13 versus 9±14 days; P=0.0004) and mean hospital charges ($168 069±$191 459 versus $85 013±$119 630;
P<0.0001) were significantly greater among children admitted on weekends versus weekdays (Table 3).
After adjusting for age, sex, and confounding factors, inhospital mortality was higher among children admitted on
weekends compared with those admitted on weekdays (OR,
1.4; 95% CI, 1.1–1.9; P=0.04; Table 4).
In a subanalysis in which we dichotomized children by
age (1–12 and 13–18 years), among those aged 1 to 12 years,
discharge to a nursing facility was not more common among
those admitted on weekends versus weekdays (OR, 1.12;
95% CI, 0.76–1.65; P=0.5), after adjusting for mechanical
ventilation. In-hospital mortality was not significantly different in the younger age group among those admitted on
weekends versus weekdays (OR, 1.46; 95% CI, 0.92–2.31;
P=0.09), after adjusting for mechanical ventilation. Among
those aged 13 to 18 years, discharge to a nursing facility was
not more common in those admitted on weekends versus
weekdays (OR, 1.12; 95% CI, 0.80–1.56; P=0.5). However,
the in-hospital mortality rate was higher among those admitted on weekends versus weekdays (OR, 1.60; 95% CI, 1.12–
2.45; P=0.04).
Discussion
The weekend effect is a phenomenon that exists for many
medical conditions in which patients admitted on the weekend have poorer outcomes compared with patients admitted on weekdays with the same disease process.9 Although
several studies have demonstrated a weekend effect among
patients with adult stroke,13,14 there are no data available
about a possible weekend effect among pediatric patients
with stroke. In the present study, we used a large national
sample and found that a weekend effect does exist for both
pediatric IS and HS.
In our study, 28% of children hospitalized primarily for IS
were admitted on a weekend. In-hospital mortality did not differ among children with IS admitted on weekend days versus
weekdays. Although a difference in mortality might not exist, it
is also possible that the low mortality rate in both groups (4.1%
weekends; 3.3% weekdays) did not allow for detection of a
difference in this sample. However, children with IS admitted
on weekends had a higher rate of discharge to a nursing facility
compared with those admitted on weekdays, even after adjusting for age, sex, and other potential confounders. In subanalyses by age group, we found similar trends among those aged 1
to 12 years and 13 to 18 years for discharge to a nursing facility
although the finding did not reach statistical significance in the
older age group.
A study using the NIS database reported no weekend
effect on in-hospital mortality and discharge disposition
between weekend and weekday admissions for 599 087
adult patients with IS.16 Another large study conducted in
acute care hospitals in California, which included 24 565
adult patients with IS, found no significant difference in the
mortality rate between weekend and weekday admissions.17
However, Saposnik et al13 found that adult patients with IS
admitted on weekends had an increased rate of mortality and
were less likely to be discharged to the same place of residence than those admitted on weekdays. After adjusting for
confounding factors, weekend admission increased the risk
of mortality by 14%. In the Get with the Guidelines-Stroke
Program, off-hour (weekends and weeknights) IS presentation was associated with slightly higher in-hospital mortality.14 Hospital admission for IS outside the United States on
weekend days compared with weekdays has been associated
with higher mortality in Canada,13,18 Sweden,19 Japan,20 and
Taiwan.21
One study22 examined whether comprehensive stroke centers (CSCs) overcome the weekend versus weekday gap in
stroke treatment and mortality. No such difference in mortality was observed at CSCs on weekends versus weekdays. In
another study of 2 CSCs,23 a total of 2211 adult patients were
included. Patients were categorized into 4 groups: an intracerebral hemorrhage group, an arterial IS group not treated with
intravenous tissue-type plasminogen activator, an arterial IS
treated with tissue-type plasminogen activator, and a transient ischemic attack group. No significant differences were
found in any group after adjustment for site, age, admission
National Institutes of Health Stroke Scale score, and blood
glucose, with respect to the rate of symptomatic intracerebral hemorrhage, modified Rankin Scale score on discharge,
discharge disposition, 90-day modified Rankin Scale score,
or 90-day mortality when comparing weekend and weekday
admissions.23 These 2 studies suggest that organization of
Adil et al Weekend Effect in Children With Stroke 5
Table 3. Secondary Diagnoses, In-Hospital Procedures, and Discharge Outcomes of
Patients With Hemorrhagic Stroke According to Strata Defined by Weekend Status;
Nationwide Inpatient Sample 2002 to 2011
Secondary Diagnosis
Fever
Weekend (2770)
Weekday (8149)
P Value
83 (3%)
202 (2%)
0.5
Altered mental status
11 (0.3%)
67 (0.8%)
0.2
Aphasia
114 (4%)
350 (4%)
0.8
Hemiplegia and hemiparesis
398 (14%)
1136 (14%)
0.8
Coma
103 (4%)
224 (3%)
0.2
35 (1%)
132 (2%)
0.5
Arteriovenous malformation
Migraine
312 (11%)
769 (9%)
0.2
Moyamoya disease
25 (0.8%)
49 (0.6%)
0.4
Downloaded from http://stroke.ahajournals.org/ by guest on June 17, 2017
Hydrocephalus
597 (22%)
1498 (18%)
0.1
Seizure
164 (6%)
424 (5%)
0.5
Meningitis
39 (1%)
127 (2%)
0.7
44 (2%)
125 (2%)
0.9
15 (0.5%)
21 (0.2%)
0.3
30 (1%)
107 (1%)
0.6
21 (0.7%)
57 (0.6%)
0.9
74 (3%)
159 (2%)
0.3
<11
78 (0.9%)
0.006*
Urinary tract infection
165 (6%)
311 (4%)
0.06
Sepsis
24 (1%)
87 (1%)
0.6
Illicit drug abuse
44 (2%)
69 (0.8%)
0.1
56 (2%)
106 (1.3%)
0.2
Congenital heart disease
Cardiomyopathy
Sickle cell disease
Systemic lupus erythematosus
Pneumonia
Deep venous thrombosis
In-hospital procedure
Echocardiography
Computed tomography
302 (11%)
768 (9%)
0.3
Magnetic resonance imaging
297 (11%)
820 (10%)
0.6
<11
40 (0.4%)
0.6
Cerebral angiography
984 (36%)
2632 (32%)
0.1
Craniotomy
114 (4%)
415 (5%)
0.3
Clipping
86 (3%)
208 (3%)
0.4
Coiling
189 (7%)
476 (6%)
0.4
Ultrasound head and neck
Cardiopulmonary resuscitation
<11
43 (0.5%)
0.5
Mechanical ventilation
355 (13%)
741 (9%)
0.02*
Intubation
488 (18%)
1145 (14%)
0.04*
Dialysis
70 (0.1%)
51 (0.6%)
0.8
Gastrostomy
102 (4%)
155 (2%)
0.05*
Blood transfusion
314 (11%)
603 (7%)
0.006*
10±13
9±14
0.0004*
$168 069±$191 459
$85 013 ±$119 630
<0.0001*
Home/selfcare
1807 (65%)
5824 (71%)
0.007*
Nursing facility
610 (22%)
1637 (20%)
0.3
<11
19 (0.2%)
0.7
339 (12%)
660 (8%)
0.006*
Length of stay in days, mean (SD)
Hospital charges, mean (SD)
Discharge disposition
Unknown
In-hospital mortality
*Statistically significant.
6 Stroke June 2016
Table 4. Effect of Weekend Admission on Study End Points in Children Admitted With Hemorrhagic Stroke
Unadjusted
Outcomes
OR (95% CI)
Model 1 (analysis
including all patients)
Discharged alive
Model 2 (analysis
including surviving
patients)
Home/self-care
Reference
Nursing facility
1.2 (0.9–1.5)
In-hospital mortality
Adjusted for Age and Sex
P Value
OR (95% CI)
Reference
1.6 (1.2–2.1)
P Value
Reference
0.006†
1.5 (1.2–2.1)
1.1 (0.9–1.5)
OR (95% CI)
P Value
Reference
0.007†
Reference
0.3
Adjusted for Age, Sex, and
Potential Confounders*
1.4 (1.1–1.9)
0.04†
Reference
0.3
1.0 (0.8–1.3)
0.9
CI indicates confidence interval; and OR, odds ratio.
*Obesity, blood transfusion, mechanical ventilation, and deep vein thrombosis.
†Statistically significant.
Downloaded from http://stroke.ahajournals.org/ by guest on June 17, 2017
stroke care, such as that provided by CSCs, may eliminate
the weekend effect. The Thrombolysis in Pediatric Stroke
trial led to improved preparedness by participating centers
for acute diagnosis and management of children presenting
with stroke.24 Initiatives to increase readiness of hospitals
that treat children with stroke and to standardize pediatric
stroke protocols may help to eliminate the weekend effect
in children.
In our study, 25.3% of children hospitalized primarily for
HS were admitted on a weekend. Children with HS admitted on weekends had a 1.4-fold increased in-hospital mortality rate compared with children admitted on weekdays even
after adjustment for age, sex, and confounders. In subanalyses by age group, we found similar trends among those aged
1 to 12 years and 13 to 18 years for in-hospital mortality
although the finding did not reach statistical significance in
the younger age group. However, the rate of discharge to a
nursing facility was not different among children admitted
on weekends versus weekdays.
In adult literature on HS, weekend admission for intracerebral hemorrhage was associated with increased riskadjusted mortality. After adjusting for potential confounders,
weekend admission was associated with an increased risk
of in-hospital mortality by 12%.25 Weekend admission, however, has not been associated with mortality among patients
hospitalized with subarachnoid hemorrhage.26
In our study, LOS and mean hospital charges in both IS
and HS were significantly greater among children admitted
on weekends versus weekdays. Also, in our study, among
children with HS, rates of mechanical ventilation, intubation,
gastrostomy, and blood transfusion were significantly higher
among children admitted on weekends compared with those
admitted on weekdays. These increased rates of procedures
associated with greater illness severity might contribute to
the increased LOS and higher total charges observed. Many
studies have demonstrated the weekend effect on total hospital
charges and LOS in patients with adult stroke.16
One explanation for longer hospital stays and higher charges
among patients admitted on weekends is that, although hospitals may be able to administer acute treatments such as intensive care or thrombolytics on weekends, other services such as
nutritional services, speech/swallow therapy, physical therapy,
occupational therapy, case management, and discharge disposition services may be under staffed on weekends.16
In our study, the rate of weekend admission to teaching
versus nonteaching hospitals was not different for children
admitted with IS or HS. A large adult study conducted in acute
care hospitals in California found that the weekend effect was
larger in major teaching hospitals compared with that in nonteaching hospitals.17 In our study, tissue-type plasminogen
activator administration was not different on weekends versus
weekdays. In adult stroke literature, tissue-type plasminogen
activator administration has been reported to be more common on weekends than weekdays.22,27
There are many potential explanations for the weekend
effect found in the present pediatric study. Weekend shifts
often have fewer physicians and nurses, and practitioners caring for patients on weekends may have decreased familiarity
with patients.9,28–30 As previously reported in adults, the weekend effect may also be due, in part, to the availability of interventional procedures because they are often less likely to be
performed on weekends.31 For example, sedation services for
magnetic resonance imaging and other diagnostic procedures
for children may not be available on the weekends at some
institutions.
There are several limitations to the present study. The NIS
is an administrative clinical database in which no information
was available on cause of death, stroke severity, imaging findings, size of stroke or hemorrhage, or graded outcome scales.
The study has limitations inherent to the NIS data set, namely,
the accuracy of the diagnosis and procedure codes listed in the
discharge summaries. We used primary ICD-9-CM codes for
identifying patients with IS, which had a true positive rate of
up to 84% in previous population-based studies.32 However,
the yield may be lower in the pediatric population. In 1 pediatric study from a single tertiary care center, ICD-9 codes for IS
had accuracies of 46% to 83%.33 For adults with intracerebral
hemorrhage, the sensitivity, specificity, and positive predictive values of ICD-9 codes were 85%, 96%, and 89%, respectively.34 We used primary ICD-9-CM codes for identifying
patients with subarachnoid hemorrhage, which had an accuracy of 79%35 and a positive predictive value of 76%36 in previous population-based studies. It is also possible that comorbid
conditions, medical complications, and in-hospital procedures
were under-reported. The NIS data ascertain whether patients
were admitted on a weekend (Saturday or Sunday) but do not
identify the specific day of the week that patients were admitted. Thus, it was not possible to perform a sensitivity analysis
Adil et al Weekend Effect in Children With Stroke 7
Downloaded from http://stroke.ahajournals.org/ by guest on June 17, 2017
in which weekend admissions were defined as those that occur
on Fridays, Saturday, or Sundays. Furthermore, we were not
able to examine differences in outcome for children admitted on holidays. Variations in hospital staffing levels and staff
expertise at the time a patient is hospitalized are not measured
in this database. Also, it was not possible to determine whether
rates of admission to intensive care units versus regular hospital floors were different on weekends versus weekdays because
admission unit is not recorded in the NIS. Finally, among those
with IS, there was a higher rate of seizures and a lower prevalence of moyamoya among those admitted on weekends versus
weekdays, but the reasons for and implications of these findings are unclear, and these findings could even be spurious.
Without the ability to review the charts, the authors were unable
to explore these results in more detail. However, seizures are
a common presenting feature of childhood stroke,37 and moyamoya38 is a common arteriopathic cause of childhood stroke,
so these variables were maintained in the multivariable analyses for IS. Additional study is needed to determine whether
the presentations or underlying causes of stroke are different
among those admitted on weekends versus weekdays and how
these features might contribute to the observed weekend effect.
Despite limitations, our results were consistent among the outcomes measured and with previous adult literature.13,26,39 Our
use of a national database allowed comprehensive coverage
of stroke-related hospitalizations across the country among a
large sample of pediatric patients with stroke.
Conclusions
Children with IS admitted on weekends had a higher rate of
discharge to a nursing facility, and children admitted with
HS on weekends had a higher rate of in-hospital mortality. Although additional research is needed to replicate our
findings, it is possible that certain disparities or variations
in resources, expertise, or the number of healthcare providers working during weekends exist, which may explain the
weekend effect observed in this study. The continued establishment of pediatric CSCs and standardized stroke protocols
like the ones used by participating centers in the Thrombolysis
in Pediatric Stroke trial24 may eliminate the weekend effect
just as this phenomenon seems to have been eliminated among
adult CSCs. Studies are required to understand factors that
affect care and may provide new avenues for implementing
quality improvement initiatives. Continued initiatives aimed
at expediting treatment of children with acute stroke should
be encouraged.
Disclosures
None.
Reference
1. Lynch JK, Hirtz DG, DeVeber G, Nelson KB. Report of the National
Institute of Neurological Disorders and Stroke workshop on perinatal
and childhood stroke. Pediatrics. 2002;109:116–123.
2. National Center for Health Statistics. Leading Causes of Death and
Numbers of Deaths, According to Age: United States, 1980 and 2001.
CDC Web site. 2001. http://www.Cdc.Gov/nchs/data/hus/hus04trend.
Pdf#032. Accessed January 5, 2016.
3. Engle R, Ellis C. Pediatric stroke in the U.S.: estimates from the kids’
inpatient database. J Allied Health. 2012;41:e63–e67.
4. Schoenberg BS, Mellinger JF, Schoenberg DG. Cerebrovascular disease
in infants and children: a study of incidence, clinical features, and survival. Neurology. 1978;28:763–768.
5. Broderick J, Talbot GT, Prenger E, Leach A, Brott T. Stroke in children
within a major metropolitan area: the surprising importance of intracerebral hemorrhage. J Child Neurol. 1993;8:250–255.
6. Giroud M, Lemesle M, Gouyon JB, Nivelon JL, Milan C, Dumas R.
Cerebrovascular disease in children under 16 years of age in the city of
Dijon, France: a study of incidence and clinical features from 1985 to
1993. J Clin Epidemiol. 1995;48:1343–1348.
7. Fullerton HJ, Wu YW, Zhao S, Johnston SC. Risk of stroke in children:
ethnic and gender disparities. Neurology. 2003;61:189–194.
8. Jordan LC, Johnston SC, Wu YW, Sidney S, Fullerton HJ. The importance of cerebral aneurysms in childhood hemorrhagic stroke: a population-based study. Stroke. 2009;40:400–405. doi: 10.1161/STROKEAHA.
108.518761.
9. Bell CM, Redelmeier DA. Mortality among patients admitted to hospitals
on weekends as compared with weekdays. N Engl J Med. 2001;345:663–
668. doi: 10.1056/NEJMsa003376.
10. Pasqualetti P, Natali G, Casale R, Colantonio D. Epidemiological chronorisk of stroke. Acta Neurol Scand. 1990;81:71–74.
11. Wang H, Sekine M, Chen X, Kagamimori S. A study of weekly and seasonal variation of stroke onset. Int J Biometeorol. 2002;47:13–20. doi:
10.1007/s00484-002-0147-x.
12. Saposnik G, Baibergenova A, Dang J, Hachinski V. Does a birthday
predispose to vascular events? Neurology. 2006;67:300–304. doi:
10.1212/01.wnl.0000217915.06544.aa.
13.Saposnik G, Baibergenova A, Bayer N, Hachinski V. Weekends: a
dangerous time for having a stroke? Stroke. 2007;38:1211–1215. doi:
10.1161/01.STR.0000259622.78616.ea.
14. Reeves MJ, Smith E, Fonarow G, Hernandez A, Pan W, Schwamm
LH; GWTG-Stroke Steering Committee & Investigators. Off-hour
admission and in-hospital stroke case fatality in the get with the
guidelines-stroke program. Stroke. 2009;40:569–576. doi: 10.1161/
STROKEAHA.108.519355.
15.Description of Data Elements Nationwide Inpatient Sample (NIS).
Healthcare Cost and Utilization Project Web site. https://www.hcup-us.
ahrq.gov/db/nation/nis/DataElements_NIS_2001_CORE.pdf. Accessed
January 2, 2016.
16. Hoh BL, Chi YY, Waters MF, Mocco J, Barker FG 2nd. Effect of weekend compared with weekday stroke admission on thrombolytic use, inhospital mortality, discharge disposition, hospital charges, and length of
stay in the Nationwide Inpatient Sample Database, 2002 to 2007. Stroke.
2010;41:2323–2328. doi: 10.1161/STROKEAHA.110.591081.
17. Cram P, Hillis SL, Barnett M, Rosenthal GE. Effects of weekend admission and hospital teaching status on in-hospital mortality. Am J Med.
2004;117:151–157. doi: 10.1016/j.amjmed.2004.02.035.
18. Fang J, Saposnik G, Silver FL, Kapral MK; Investigators of the Registry
of the Canadian Stroke Network. Association between weekend hospital presentation and stroke fatality. Neurology. 2010;75:1589–1596. doi:
10.1212/WNL.0b013e3181fb84bc.
19. Janszky I, Ahnve S, Ljung R. Weekend versus weekday admission and
stroke outcome in sweden from 1968 to 2005. Stroke. 2007;38:e94,
author reply e95.
20. Hasegawa Y, Yoneda Y, Okuda S, Hamada R, Toyota A, Gotoh J, et al;
Acute Stroke Rehabilitation Study Group. The effect of weekends and
holidays on stroke outcome in acute stroke units. Cerebrovasc Dis.
2005;20:325–331. doi: 10.1159/000087932.
21. Tung YC, Chang GM, Chen YH. Associations of physician volume
and weekend admissions with ischemic stroke outcome in Taiwan: a
nationwide population-based study. Med Care. 2009;47:1018–1025. doi:
10.1097/MLR.0b013e3181a81144.
22. McKinney JS, Deng Y, Kasner SE, Kostis JB; Myocardial Infarction
Data Acquisition System (MIDAS 15) Study Group. Comprehensive
stroke centers overcome the weekend versus weekday gap in stroke
treatment and mortality. Stroke. 2011;42:2403–2409. doi: 10.1161/
STROKEAHA.110.612317.
23. Albright KC, Raman R, Ernstrom K, Hallevi H, Martin-Schild S, Meyer
BC, et al. Can comprehensive stroke centers erase the ‘weekend effect’?
Cerebrovasc Dis. 2009;27:107–113. doi: 10.1159/000177916.
24. Bernard TJ, Rivkin MJ, Scholz K, deVeber G, Kirton A, Gill JC, et
al; Thrombolysis in Pediatric Stroke Study. Emergence of the primary pediatric stroke center: impact of the thrombolysis in pediatric stroke trial. Stroke. 2014;45:2018–2023. doi: 10.1161/
STROKEAHA.114.004919.
8 Stroke June 2016
Downloaded from http://stroke.ahajournals.org/ by guest on June 17, 2017
25. Crowley RW, Yeoh HK, Stukenborg GJ, Medel R, Kassell NF, Dumont
AS. Influence of weekend hospital admission on short-term mortality after intracerebral hemorrhage. Stroke. 2009;40:2387–2392. doi:
10.1161/STROKEAHA.108.546572.
26.Crowley RW, Yeoh HK, Stukenborg GJ, Ionescu AA, Kassell NF,
Dumont AS. Influence of weekend versus weekday hospital admission
on mortality following subarachnoid hemorrhage. Clinical article. J
Neurosurg. 2009;111:60–66. doi: 10.3171/2008.11.JNS081038.
27. Kazley AS, Hillman DG, Johnston KC, Simpson KN. Hospital care
for patients experiencing weekend vs weekday stroke: a comparison of
quality and aggressiveness of care. Arch Neurol. 2010;67:39–44. doi:
10.1001/archneurol.2009.286.
28. Petersen LA, Brennan TA, O’Neil AC, Cook EF, Lee TH. Does housestaff discontinuity of care increase the risk for preventable adverse
events? Ann Intern Med. 1994;121:866–872.
29. Thorpe KE. House staff supervision and working hours. Implications of
regulatory change in New York State. JAMA. 1990;263:3177–3181.
30. Tarnow-Mordi WO, Hau C, Warden A, Shearer AJ. Hospital mortality in
relation to staff workload: a 4-year study in an adult intensive-care unit.
Lancet. 2000;356:185–189.
31. Bell CM, Redelmeier DA. Waiting for urgent procedures on the weekend
among emergently hospitalized patients. Am J Med. 2004;117:175–181.
doi: 10.1016/j.amjmed.2004.02.047.
32. Broderick J, Brott T, Kothari R, Miller R, Khoury J, Pancioli A, et al.
The Greater Cincinnati/Northern Kentucky Stroke Study: preliminary
first-ever and total incidence rates of stroke among blacks. Stroke.
1998;29:415–421.
33. Golomb MR, Garg BP, Saha C, Williams LS. Accuracy and yield of
ICD-9 codes for identifying children with ischemic stroke. Neurology.
2006;67:2053–2055. doi: 10.1212/01.wnl.0000247281.98094.e2.
34.Tirschwell DL, Longstreth WT Jr. Validating administrative data in
stroke research. Stroke. 2002;33:2465–2470.
35. Leppälä JM, Virtamo J, Heinonen OP. Validation of stroke diagnosis in
the National Hospital Discharge Register and the Register of Causes of
Death in Finland. Eur J Epidemiol. 1999;15:155–160.
36. Spolaore P, Brocco S, Fedeli U, Visentin C, Schievano E, Avossa F, et
al. Measuring accuracy of discharge diagnoses for a region-wide surveillance of hospitalized strokes. Stroke. 2005;36:1031–1034. doi:
10.1161/01.STR.0000160755.94884.4a.
37. Abend NS, Beslow LA, Smith SE, Kessler SK, Vossough A, Mason S, et al.
Seizures as a presenting symptom of acute arterial ischemic stroke in childhood. J Pediatr. 2011;159:479–483. doi: 10.1016/j.jpeds.2011.02.004.
38. Amlie-Lefond C, Bernard TJ, Sébire G, Friedman NR, Heyer GL, Lerner
NB, et al; International Pediatric Stroke Study Group. Predictors of cerebral arteriopathy in children with arterial ischemic stroke: results of the
International Pediatric Stroke Study. Circulation. 2009;119:1417–1423.
doi: 10.1161/CIRCULATIONAHA.108.806307.
39. Roberts SE, Thorne K, Akbari A, Samuel DG, Williams JG. Mortality
following stroke, the weekend effect and related factors: record linkage
study. PLoS One. 2015;10:e0131836. doi: 10.1371/journal.pone.0131836.
Weekend Effect in Children With Stroke in the Nationwide Inpatient Sample
Malik M. Adil, Gabriel Vidal and Lauren A. Beslow
Stroke. published online April 26, 2016;
Downloaded from http://stroke.ahajournals.org/ by guest on June 17, 2017
Stroke is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231
Copyright © 2016 American Heart Association, Inc. All rights reserved.
Print ISSN: 0039-2499. Online ISSN: 1524-4628
The online version of this article, along with updated information and services, is located on the
World Wide Web at:
http://stroke.ahajournals.org/content/early/2016/04/26/STROKEAHA.116.013453
Data Supplement (unedited) at:
http://stroke.ahajournals.org/content/suppl/2016/04/26/STROKEAHA.116.013453.DC1
Permissions: Requests for permissions to reproduce figures, tables, or portions of articles originally published
in Stroke can be obtained via RightsLink, a service of the Copyright Clearance Center, not the Editorial Office.
Once the online version of the published article for which permission is being requested is located, click
Request Permissions in the middle column of the Web page under Services. Further information about this
process is available in the Permissions and Rights Question and Answer document.
Reprints: Information about reprints can be found online at:
http://www.lww.com/reprints
Subscriptions: Information about subscribing to Stroke is online at:
http://stroke.ahajournals.org//subscriptions/
1
Supplemental Material
“Weekend effect” in children with stroke in the Nationwide Inpatient Sample
Malik M. Adil, MD1, Gabriel Vidal, MD1, Lauren A. Beslow, MD, MSCE2;
1. Departments of Neurology, Ochsner Neuroscience Institute, Ochsner Clinic Foundation,
New Orleans, LA
2. Departments of Pediatrics and Neurology, Yale University School of Medicine, New
Haven, CT, USA
Corresponding author:
Malik M Adil, MD
Ochsner Clinic Foundation,
1514 Jefferson Hwy
New Orleans, LA 70121
Tel (504) 842-7965
Email: [email protected]
2
Table I: Demographic, comorbid conditions, and hospital characteristics of ischemic stroke
patients according to strata defined by “Weekend status”. Nationwide Inpatient Sample 20022011.
Weekend (1848)
Weekday (6619)
Age in years mean (SD)
10±6
11±5
0.3
Female sex
760 (41.2%)
3065 (46.5%)
0.08
White
710 (49.3%)
2498 (49.5%)
0.8
African American
324 (22.5%)
1198 (23.7%)
0.8
Hispanic
277 (19.2%)
845 (16.7%)
0.3
Other
130 (9.0%)
508 (10.1%)
0.7
Diabetes mellitus
54 (2.9%)
91 (1.4%)
0.06
Hypertension
164 (8.9%)
577 (8.7%)
0.9
Dyslipidemia
13 (0.7%)
13 (0.2%)
0.2
Atrial fibrillation
<11
24 (0.4%)
0.7
Congestive heart failure
32 (1.8%)
88 (1.3%)
0.5
Deficiencies anemia
108 (5.9%)
327 (5.0%)
0.5
Valvular heart disease
66 (3.6%)
202 (3.1%)
0.6
Chronic lung disease
146 (8.0%)
525 (8.0%)
0.9
Fluid and electrolyte disorder
176 (9.6%)
594 (9.1%)
0.7
Liver disease
<11
14 (0.2%)
0.9
Coagulopathy
80 (4.4%)
292 (4.4%)
0.9
Renal failure
62 (3.4%)
147 (2.2%)
0.2
Obesity
52 (2.8%)
190 (2.9%)
0.9
Paralysis
138 (7.6%)
566 (8.6%)
0.5
Solid tumor without metastasis
45 (2.5%)
75 (1.1%)
0.2
Metastatic cancer
9 (0.5%)
29 (0.5%)
0.9
Alcohol abuse
<11
24 (0.4%)
0.7
Nicotine dependence
47 (2.6%)
156 (2.4%)
0.8
p-value
Race/ethnicity
Co-morbid conditions
3
Hospital size
Small
219 (11.9%)
730 (11.1%)
0.6
Medium
420 (22.8%)
1688 (25.6%)
0.3
Large
1201 (65.3%)
4163 (63.3%)
0.5
Medicare/Medicaid
687 (37.2%)
2450 (37.2%)
0.9
Private HMO
1035 (56.0%)
3614 (54.7%)
0.6
No insurance
126 (6.8%)
536 (8.1%)
0.4
Northeast
302 (16.4%)
1134 (17.2%)
0.7
Midwest
414 (22.4%)
1444 (21.8%)
0.8
South
653 (35.3%)
2736 (41.3%)
0.04*
West
478 (25.9%)
1305 (19.7%)
0.02*
Non-teaching
214 (11.6%)
890 (13.5%)
Teaching
1625 (88.4%)
5691 (86.5%)
Insurance status
Hospital regions
Teaching status
Abbreviations: SD = standard deviation, *= statistically significant
0.3
4
Table II: Demographic, comorbid conditions and hospital characteristics of hemorrhagic stroke
patients according to strata defined by “Weekend status”. Nationwide Inpatient Sample 20022011.
Weekend (2770)
Weekday (8149)
Age in years mean (SD)
11±5
11 ±6
0.2
Female sex
1228 (44%)
3322 (41%)
0.1
Whites
1118 (51%)
3039 (47%)
0.2
African Americans
256 (12%)
982 (15%)
0.6
Hispanics
506 (23%)
1709 (26%)
0.2
Others
301 (14%)
709 (12%)
0.1
Diabetes mellitus
44 (2%)
95 (1%)
0.4
Congestive heart failure
<11
28 (0.3%)
0.5
Deficiencies anemia
122 (4%)
345 (4%)
0.8
Valvular heart disease
33 (1%)
154 (2%)
0.1
Chronic lung disease
176 (6%)
513 (6%)
0.9
Fluid and electrolyte disorder
343 (13%)
1047 (13%)
0.7
Liver disease
<11
37 (0.4%)
0.7
Coagulopathy
213 (8%)
711 (9%)
0.4
Renal failure
37(1.3%)
81(1.0%)
0.5
Obesity
49 (2%)
51 (1%)
0.04*
Paralysis
298 (11%)
867 (11%)
0.9
Solid tumor without metastasis
90 (3%)
287 (4%)
0.7
Metastatic cancer
19 (1%)
95 (1%)
0.2
Alcohol abuse
26 (0.9%)
51 (0.6%)
0.5
Nicotine dependence
41 (1%)
122 (2%)
0.9
Small
340 (12%)
876 (11%)
0.3
Medium
522 (19%)
1692 (21%)
0.3
Large
1902 (69%)
5524 (68%)
0.6
p-value
Race/ethnicity
Co-morbid conditions
Hospital size
5
Insurance status
Medicare/Medicaid
955 (34%)
3210 (39%)
0.03*
Private HMO
1539 (56%)
4202 (52%)
0.1
No insurance
265 (10%)
728 (9%)
0.6
Northeast
537 (19%)
1525 (19%)
0.7
Midwest
504 (18%)
1610 (20%)
0.4
South
988 (36%)
3181 (39%)
0.1
West
741 (27%)
1833 (22%)
0.05*
Non-teaching
312 (11%)
927 (11%)
Teaching
2452 (89%)
7165 (89%)
Hospital regions
Teaching status
Abbreviations: SD = standard deviation, *= statistically significant
0.9