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European Heart Journal Advance Access published March 3, 2014

CLINICAL RESEARCH

European Heart Journal
doi:10.1093/eurheartj/ehu033

Prevention and epidemiology

Outbursts of anger as a trigger of acute
cardiovascular events: a systematic review
and meta-analysis†
Elizabeth Mostofsky 1,2, Elizabeth Anne Penner 3, and Murray A. Mittleman 1,2*
1
Cardiovascular Epidemiology Research Unit, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, 375 Longwood Avenue, Room 423, Boston, MA
02215, USA; 2Department of Epidemiology, Harvard School of Public Health, Boston, MA, USA; and 3Department of Internal Medicine, New York-Presbyterian Hospital/Weill Cornell
Medical Center, New York, NY, USA

Received 9 July 2013; revised 8 January 2014; accepted 20 January 2014

Short-term psychological stress is associated with an immediate physiological response and may be associated with a transiently higher risk of cardiovascular events. The aim of this study was to determine whether brief episodes of anger trigger
the onset of acute myocardial infarction (MI), acute coronary syndromes (ACS), ischaemic and haemorrhagic stroke, and
ventricular arrhythmia.
.....................................................................................................................................................................................
Methods
We performed a systematic review of studies evaluating whether outbursts of anger are associated with the short-term
and results
risk of heart attacks, strokes, and disturbances in cardiac rhythm that occur in everyday life. We performed a literature
search of the CINAHL, Embase, PubMed, and PsycINFO databases from January 1966 to June 2013 and reviewed the
reference lists of retrieved articles and included meeting abstracts and unpublished results from experts in the field.
Incidence rate ratios and 95% confidence intervals were calculated with inverse-variance-weighted random-effect
models. The systematic review included nine independent case-crossover studies of anger outbursts and MI/ACS
(four studies), ischaemic stroke (two studies), ruptured intracranial aneurysm (one study), and ventricular arrhythmia
(two studies). There was evidence of substantial heterogeneity between the studies (I 2 ¼ 92.5% for MI/ACS and
89.8% for ischaemic stroke). Despite the heterogeneity, all studies found that, compared with other times, there was
a higher rate of cardiovascular events in the 2 h following outbursts of anger.
.....................................................................................................................................................................................
Conclusion
There is a higher risk of cardiovascular events shortly after outbursts of anger.

----------------------------------------------------------------------------------------------------------------------------------------------------------Keywords

Anger † Cardiovascular disease † Case-crossover † Epidemiology

Introduction
In addition to long-term risk factors for cardiovascular disease, there
are several physical, psychological, and chemical triggers that are
associated with a transiently higher risk of cardiovascular events.1
Several studies have reported that episodes of anger are associated
with a transiently higher risk of myocardial infarction (MI),2 – 4 acute
coronary syndrome (ACS),5,6 ischaemic7 and haemorrhagic
stroke,8 and arrhythmia.9,10 However, since some of these studies
were based on small sample sizes with few exposed cases, the
results were often reported with low precision. Furthermore,
there has been no systematic evaluation to compare the results
and examine whether there is consistency across studies of the

same cardiovascular outcome and whether the association is of
similar magnitude across studies of different types of cardiovascular
outcomes. Therefore, we performed a systematic review of the literature to summarize the body of research testing the hypothesis
that outbursts of anger trigger the onset of cardiovascular events
and to summarize the literature on whether there are factors that
modify the magnitude of the association.

Methods
We followed the Meta-Analysis of Observational Studies in Epidemiology11 protocol throughout the design, implementation, analysis, and
reporting for this study.

†

All work was performed at the Cardiovascular Epidemiology Research Unit, Beth Israel Deaconess Medical Center.

* Corresponding author. Tel: +1 6176327653, Fax: +1 6176327698, Email: mmittlem@bidmc.harvard.edu
Published on behalf of the European Society of Cardiology. All rights reserved. & The Author 2014. For permissions please email: journals.permissions@oup.com

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Aim

Page 2 of 7

E. Mostofsky et al.

Literature search

Data extraction
Using a standardized form, two readers (E .M. and E.P.) independently and
in duplicate reviewed the list of identified articles and extracted data from
selected articles, with disagreements adjudicated by a third reader
(M.A.M.). For articles that did not include all of the necessary data for
the meta-analysis, we contacted authors for additional information.
The following details were recorded for each study: first author, year
of publication, geographic location of study, whether the study was
restricted to incident events, anger scale, hazard period, control
period, the number of cases in the study, the number of cases exposed
during the hazard period and the incidence rate ratio (IRR), and corresponding lower and upper 95% CI. If the studies used a cohort or
case – control design, we recorded covariates included in the statistical
models; if the study used a self-controlled case series or case-crossover
design, we recorded covariates for time-varying confounding. When analyses of the same populations were reported more than once,2,4,13 the
largest study4 was included in the meta-analysis. When case-crossover
studies reported estimates using either a referent of usual frequency of
anger episodes over several months or a referent of anger episodes at
the same time on the prior day, we included the estimates based on
the usual frequency data in our meta-analysis.

Assessment of study quality
We qualitatively assessed study quality by recording the training of
interviewers, blinding of hypothesized hazard periods, and timing
between the onset of the cardiovascular event and subsequent
assessment of perceived anger.

Statistical analysis
We used DerSimonian and Laird14 inverse-variance-weighted randomeffect models to pool the relative risks from individual studies. We
evaluated heterogeneity across studies with the Cochrane Q statistic.15
We calculated the I2 statistic to quantify the proportion of betweenstudy heterogeneity that is attributable to variability in the association
rather than sampling variation; values of 25, 50, and 75% were considered
to represent low, medium, and high heterogeneity, respectively.16,17
Using the Begg and Mazumdar18 and Egger et al.19 tests and visual inspection of a funnel plot,19 we explored the possibility of publication bias
due to missing or different estimates from small studies with less precise estimates compared with larger studies with greater precision.

Figure 1 Selection of studies included in a meta-analysis of shortterm risk of cardiovascular events following episodes of anger.

We conducted stratified analyses to evaluate the influences of incident
vs. recurrent events and MI vs. ACS, and we carried out sensitivity analyses excluding one study at a time to explore whether the results
were driven by a single study. For ease of interpretation, we estimated
the absolute risk of cardiovascular events associated with outbursts of
anger of varying frequency for individuals at low (5%), medium (10%),
and high (20%) 10-year risk of coronary heart disease,20 as previously
described.21 The analyses were performed with Stata statistical software
version 12.0 (StataCorp, College Station, TX, USA) using the metan
package. All hypothesis tests were two-sided. P , 0.10 was considered
indicative of statistically significant heterogeneity, and all other P-values
were considered statistically significant at ,0.05, two-sided.

Results
The literature search identified 6870 publications, and after excluding
1299 duplicates, an additional 5565 articles were excluded after the
review of the title or abstract (Figure 1). Table 1 summarizes the
characteristics of the eligible studies. The meta-analysis included
nine independent case-crossover studies, including seven that were
published between 1995 and 2013, a meeting abstract on anger as
a trigger of arrhythmia10 and unpublished results of anger as a
trigger of ischaemic stroke. Combined, there were 4546 cases of
MI, 462 cases of ACS, 590 cases of ischaemic stroke, 215 cases of
haemorrhagic stroke, and 306 cases of arrhythmia. The meta-analysis
of anger outbursts as a trigger of cardiovascular events is presented in
Figure 2.
There are several sources of between-study heterogeneity. Our
systematic review includes that studies conducted in the USA,4,9,10
Sweden,3 England,5 Israel,6 and the Netherlands.8 One study6

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One person (E.M.) performed a literature search of the CINAHL,
Embase, PubMed, and PsycINFO databases from January 1966 to June
2013 using the key words ‘anger’, ‘hostility’, ‘aggression’, ‘mental stress’,
and ‘cardiovascular diseases’ without restrictions. We also reviewed
the reference lists of retrieved articles and included meeting abstracts
and unpublished results from experts in the field. We reviewed all articles
with an abstract, suggesting that it was relevant. Studies were eligible for
review if (i) the design was a cohort, a case – control, a self-controlled case
series, or a case-crossover study; (ii) the investigators reported relative
risks and 95% confidence intervals (95% CI) for the association
between outbursts of anger and MI, ACS, ischaemic or haemorrhagic
stroke, and arrhythmia; and (iii) the investigators evaluated hazard
periods for triggers occurring within 1 month before event onset. We
considered articles in any language. We did not include studies that evaluated the impact of laboratory-induced anger on myocardial ischaemia
and intermediate outcomes, such as blood pressure or cardiovascular
reactivity, and we did not include case-crossover studies using a bidirectional sampling design12 since experiencing a cardiovascular event may
alter exposure to anger episodes, resulting in reverse causation.

Page 3 of 7

Information not available.
A total of 107 confirmed ventricular arrhythmias requiring shock were reported by 42 patients. The 17 anger-associated shocks occurred in 14 patients, with 3 patients reporting 2 anger-associated shocks and 11 patients one each.
b

a

3.2 (1.8 –5.7)
15 (7.5)
1h
Ventricular arrhythmia
Albert et al. (2006)10 USA

Prior 12 months

Onset Anger Scale (≥5)

199

1.4 (0.8 –2.4)
14 (13.1)
Same day of the week and time
of Day 1 week later
15 min –2 h

Hedges diary (≥3)

107b

1.8 (1.0 –3.2)
17 (15.9)
Same day of the week and time
of Day 1 week later
Ventricular arrhythmia
Lampert et al. (2002)9 USA

0 –15 min

Hedges diary (≥3)

107b

1.7 (0.8 –3.5)

6.3 (1.6 –25.0)

6 (1.5)

2 (0.9)

390

215

Onset Anger Scale (≥5)

Onset Anger Scalea
Prior 12 months
Ruptured intracranial aneurysm

1h

2h
Ischaemic stroke
SOS (unpublished) USA

Vlak et al. (2011)8 the Netherlands

Prior 12 months

4.3 (2.2 –8.6)

7.60 (4.3 –13.7)
15 (7.5)
200
Onset Anger Scale (≥5)
2h
Ischaemic stroke
Koton et al. (2004)7 Israel

Prior 12 months

6.2 (3.6 –10.9)
a

a

209

209
Onset Anger Scale (≥4)

Onset Anger Scale (≥4)

Prior 12 months

Prior 12 months

1st h
Incident acute coronary syndrome
Lipovetzky et al.(2007)6 Israel

2nd h

5.7 (3.0 –10.6)

7.3 (5.2 –10.2)
44 (17.4)
253
Acute coronary syndrome
Strike et al. (2006)5 UK

2h

Prior 6 months

Onset Anger Scale (≥3)

10 (1.5)
660

2.4 (2.0 –2.9)
110 (2.8)
3886
Onset Anger Scale (≥5)

Onset Anger Scale (≥5)
Prior 12 months

Prior 12 months
2h

Incident myocardial infarction
Mo¨ller et al. (1999)3 Sweden

2h

Myocardial infarction
Mostofsky et al. (2013)4 USA

Incidence rate ratio
(95% confidence
interval)
Exposed
cases, n (%)
Total
sample
Anger measure (cut-off)
Referent period
Hazard
period
Outcome
First author, year, country

Studies on anger outbursts as a trigger of cardiovascular events in the following 2 h
Table 1

asked about workplace anger outbursts, and all other studies asked
about anger episodes at any time. All but one9 of the studies identified
in our systematic review used the Onset Anger Scale,2 but they used
different cut-offs to define exposure. In addition, the studies used different protocols for administering the questions regarding the usual
frequency and timing of anger outbursts at each level: (i) some studies
reported that they administered a structured interview3 – 7 by trained
personnel,3,4 and other studies used a questionnaire completed by
the patient;8,9 (ii) most studies reported that questions about anger
outbursts were completed within hours9 or days3,4,6,7,9 of the
index cardiovascular event, whereas in one study,8 two -thirds of
the patients completed the questionnaire .2 weeks after their
stroke; and (iii) most studies3,4,6,9 reported that in order to minimize
recall bias, patients were not informed of the duration of the
hypothesized hazard period, whereas one study8 reported that
they specifically asked about anger outbursts during the pre-specified
hazard period.

MI and ACS
Two studies3,4 examined as an endpoint and another two studies5,6
examined ACS as an endpoint; two studies were restricted to incident events,3,6 and two included incident and recurrent events.2,5
All four studies used the Onset Anger Scale2 with different cut-offs
for defining exposure. One study6 reported separate estimates for
each hour prior to MI onset, and the other studies3,5,22 reported a
single estimate for the 2 h prior to MI onset. Therefore, we first
meta- analysed the results for the first 2 h in the study with separate
estimates6 and included this pooled estimate (RR ¼ 5.36, 95% CI:
3.49 –8.24) in our meta-analysis of the four studies on anger outbursts and MI/ACS. Based on the random -effect meta-analysis,
there was a 4.74 (95% CI: 2.50–8.99; P , 0.001) times higher risk
of MI or ACS in the 2 h following outbursts of anger compared
with other times. There was evidence of heterogeneity between
the four studies (Cochran Q test for heterogeneity: Q ¼ 39.80, P ,
0.001; I 2 ¼ 92.5%). Since there was high between-study heterogeneity, a pooled estimate may not be appropriate, but the results
suggest that despite differences between studies, there is evidence
of higher MI/ACS risk following episodes of anger.
The results were stronger for studies of incident events (IRR ¼
5.47, 95% CI: 3.83–7.80; Q ¼ 0.02, P ¼ 0.86; I 2 ¼ 0%) than for
studies including both incident and recurrent events (IRR ¼ 4.17,
95% CI: 1.42– 12.26; Q ¼ 31.96, P , 0.001; I 2 ¼ 96.9%) and higher
for studies of ACS (IRR ¼ 6.45, 95% CI: 4.80– 8.99; Q ¼ 1.24, P ¼
0.27; I 2 ¼ 19.1%) than studies of MI (IRR ¼ 3.52, 95% CI: 1.54–
8.06; Q ¼ 6.47, P ¼ 0.01; I 2 ¼ 84.5%). In sensitivity analyses excluding each study, the results were not meaningfully altered, though
the pooled estimate was lower when we removed one study5
(IRR ¼ 4.04, 95% CI: 2.13– 7.66) and higher when we removed one
study4 (IRR ¼ 6.37, 95% CI: 5.00–8.13). The Begg (P ¼ 1.00) and
Egger regression tests (P ¼ 0.21) and the funnel plot provided no
evidence of substantial publication bias, but since we had a small
number of studies, formal assessment of publication bias may not be
appropriate.

Ischaemic and haemorrhagic stroke
In addition to the one published study7 of anger outbursts and ischaemic stroke, we included results from the Stroke Onset Study (SOS).23

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.............................................................................................................................................................................................................................................

Outbursts of anger as a trigger of cardiovascular events

Page 4 of 7

E. Mostofsky et al.

Both studies included individuals with either incident or recurrent
events and both used the Onset Anger Scale with a cut-off of ≥5
to examine ischaemic stroke risk in the 2 h following anger outbursts.
Based on the meta-analysed data, there was a 3.62 (95% CI: 0.82–
16.08; P ¼ 0.09) times higher rate of ischaemic stroke in the 2 h following an outburst of anger compared with other times. Since there
was evidence of heterogeneity between the two studies (Q ¼ 9.84,
P ¼ 0.002; I 2 ¼ 89.8%), a pooled estimate may not be appropriate.
There was one study8 on outbursts of anger and the risk of ruptured
intracranial aneurysms that reported a 6.30 (95% CI: 1.60–25.0)
times higher rate of ruptured intracranial aneurysm in the hour
following an outburst of anger.

Ventricular arrhythmia
There was one published study9 and one meeting abstract,10 reporting that anger episodes are a trigger of ventricular arrhythmia. Since
the two studies used different designs, different anger measures
and evaluated different hazard periods, the results could not be
meta- analysed, but both reported statistically significant associations
for a higher risk of ventricular arrhythmia immediately following outbursts of anger. In a study of 277 patients who had received implantable cardioverter defibrillators (ICD) for standard indications
(clinical or inducible ventricular arrhythmia),9 patients were asked

to record their activities and emotions in the 15 min and 2 h prior
to any ICD shocks that they received using a 5-point Likert scale to
rate the intensity of anger; they filled out a similar diary 1 week
later at the same time of day. One hundred and seven shocks were
reported by 42 patients. Compared with other times, there was a
1.83 (95% CI: 1.04–3.16) times higher rate of ventricular arrhythmia
in the 15 min after an anger outburst and a 1.35 (95% CI: 0.77–2.35)
times higher rate in the following 15 min to 2 h. In the multicenter
Triggers of Ventricular Arrhythmias prospective nested casecrossover study,10 1188 ICD patients were interviewed regarding
their usual frequency of anger at entry into the study and at follow-up
intervals; after each ICD discharge, participants were interviewed
about episodes of anger in the hour prior to ICD discharge. Compared with other times, there was a 3.20 (95% CI: 1.80–5.70) times
higher rate of ventricular tachycardia or ventricular fibrillation in
the hour following moderate levels of anger and 16.7 (95% CI:
8.12–34.5) times higher in the hour after intense anger.

Absolute risk
Although the relative risk of a cardiovascular event following outbursts of anger is large and statistically significant, anger episodes
may be rare and the heightened cardiovascular risk is transient so
the impact on an individual’s absolute risk of a cardiovascular event

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Figure 2 Meta-analysis of the nine studies examining the short-term risk of cardiovascular events in the 2 h* following outbursts of anger. The solid
vertical line indicates no association; the diamonds indicate the combined estimates. * ¼ One study (Lipovetzky) reported separate estimates for
each hour prior to MI onset. We meta-analyzed these two estimates and included this pooled estimate in our meta-analysis of MI/ACS.

Outbursts of anger as a trigger of cardiovascular events

disease per 10 000 individuals per year according to frequency of
anger outbursts according to low (5%), medium (10%), or high
(20%) 10-year risk of coronary heart disease.

is small. However, the absolute risk is higher for individuals with a
higher baseline cardiovascular risk and individuals who have frequent
outbursts of anger (Figure 3). For instance, based on the combined
estimate of a 4.74 times higher rate of MI or ACS in the 2 h following
outbursts of anger, the absolute impact of one episode of anger per
month is only one excess cardiovascular event per 10 000 individuals
per year at low (5%) 10-year cardiovascular risk and four excess cardiovascular events per 10 000 individuals per year at high (20%)
10-year cardiovascular risk. The absolute impact is higher for individuals with more frequent episodes of anger; five episodes of anger
per day would result in 158 excess cardiovascular event per 10
000 per year for individuals at low (5%) 10-year cardiovascular risk
and a similar frequency of anger outbursts would be associated
with 657 excess cardiovascular events per 10 000 per year
among individuals at high (20%) 10-year cardiovascular risk.

Discussion
Based on the totality of the evidence, there is a higher risk of MI, ACS,
ischaemic and haemorrhagic stroke, and arrhythmia in the 2 h following outbursts of anger. It is possible that some of the between-study
heterogeneity is due to regional differences in the type of anger expression and the interpretation of the questions. Although all but
one9 of the studies used the Onset Anger Scale,2 they had different
cut-offs to define exposure and different procedures for administering the scale. Therefore, in addition to differences in the baseline risk
between the populations under study that may modify the risk from
an event triggered by outbursts of anger, these study protocol differences may have contributed to the heterogeneity between studies of
each outcome. Furthermore, although one may be tempted to infer
that the heterogeneity in the magnitude of the association by the type
of cardiovascular event is due to different biological mechanisms
linking anger and the outcome of interest, it may also be at least
partially due to these differences in study procedures.

Only three studies4,9,10 evaluated whether greater levels of anger
intensity are associated with a greater level of cardiovascular risk, so
we could not conduct a dose–response meta-analysis pooling estimates for different levels of anger intensity. However, both studies
on ventricular arrhythmia9,10 reported stronger associations for
being furious than for being moderately angry, and in another
recent study,4 there was a greater MI risk for each increment in
anger intensity.
Several studies evaluated whether the risk of a cardiovascular
event triggered by anger outbursts may be mitigated by medical
history, socioeconomic factors or regular medication use.
However, sample sizes for stratifying on potential modifiers were
small, so most of these differences were not statistically significant.
Anger-associated events were more common among patients with
lower levels of education, but it was not related to cardiovascular
risk factors, having a previous MI, or the presence or absence of premonitory symptoms.13 Use of beta-blockers,2 – 4,6,7,24 aspirin,2,6
calcium antagonists,6,24 or nitrates24 may lower the risk from each
outburst of anger. The studies on haemorrhagic stroke and arrhythmia did not evaluate whether medical history or behavioural and environmental factors modify the risk of an event triggered by outbursts
of anger.
The impact of anger outbursts may be modified by trait anger. It is
possible that an individual with an angry temperament is constantly at
a relatively high level of physiological activation and is acclimated to
the physiological response to anger. Therefore, he/she may experience a smaller spike in risk following each anger outburst than a
person with a lower level of trait anger who is not used to the physiological response from outbursts of anger, though the absolute risk
may be higher from accumulating more high-risk episodes over
time. One study3 reported a lower risk of incident MI from each
episode of anger among individuals with more frequent outbursts
and individuals who tend to express their anger, but in one study,4
the association was not materially different by levels of trait anger.
In addition to differences in risk, the frequency of outbursts is likely
higher among people with an angry temperament. One study25
reported that patients who reported at least moderate anger in the
0 –15 min before ICD shock reported higher levels of trait anger,
hostility and aggressiveness, and lower levels of anger control, suggesting that those with higher trait anger have a higher frequency of
anger outbursts that are intense enough to trigger an arrhythmia.
There are several potential mechanisms linking anger outbursts
and cardiovascular events. Psychological stress has been shown to increase heart rate and blood pressure, and vascular resistance. This
sympathetic activation is likely a common pathway for ischaemic
and haemorrhagic events as well as cardiac arrhythmia. Haemodynamic changes may cause transient ischaemia and/or disruption
of vulnerable plaques, especially among susceptible patients. Furthermore, it may stimulate an inflammatory and pro-thrombotic
response, including increased platelet aggregation and plasma viscosity and decreased fibrinolytic potential. These changes may lead to an
increased prevalence of plaques that are vulnerable to disruption and
a higher probability of thrombotic occlusion, resulting in an ischaemic
event.1,26,27
We have previously discussed the net impact of cardiovascular
events triggered by outbursts of anger.1 The relative risks estimated
in this meta-analysis indicate that there is a higher risk of

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Figure 3 Estimated number of excess cases of coronary heart

Page 5 of 7

Page 6 of 7

Some medications may help sever the link between anger episodes
and cardiovascular events by lowering the frequency of anger
outbursts or by lowering the risk from each anger episode. In addition
to the potential benefits of beta -blockers to break the link between
anger outbursts and cardiovascular events, paroxetine and other
serotonin-specific reuptake inhibitors may reduce the frequency of
anger outbursts and improve impulse control.30 Although it has not
been rigorously evaluated in a randomized clinical trial, it is possible
that psychosocial interventions may help lower the risk of cardiovascular events associated with outbursts of anger. Now that there is
consistent evidence that anger outbursts are associated with a transiently higher risk of cardiovascular events, further research is needed
to identify effective pharmacological and behavioural interventions to
mitigate the risk of cardiovascular events triggered by outbursts of
anger.

Funding
This work was supported by grants T32-HL098048 and F32-HL120505
from the NIH at the National Institutes of Health.
Conflict of interest: no funding organization had any role in the design
and conduct of the study; collection; management, analysis and interpretation of the data; and preparation, review, or approval of the manuscript;
and decision to submit the manuscript for publication.

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cardiovascular events after outbursts of anger among individuals at
risk of a cardiovascular event, but because each episode may be infrequent and the effect period is transient, the net absolute impact on
disease burden is extremely low. However, with increasing frequency
of anger episodes, these transient effects may accumulate, leading to a
larger clinical impact. In addition, long-term risk factors for cardiovascular disease such as obesity and cigarette smoking and subclinical or
established cardiovascular disease raise the baseline risk of acute cardiovascular events in any given hour. Therefore, assuming no differences in the relative risks, the absolute impact of anger outbursts
will be higher among individuals with known risk factors.
Since residual confounding in the included studies and betweenstudy heterogeneity is a concern in meta-analyses to summarize observational studies with different patient characteristics, the results
should not be assumed to indicate the true causal effect of anger episodes on cardiovascular events.28 However, the results were fairly
consistent across studies even though they were conducted .18
years in diverse populations, and the findings were robust to sensitivity analyses using different control periods. These studies used the
case-crossover design29 to compare each individual’s level of anger
immediately prior to the cardiovascular event to anger levels at
other times. Since each individual serves as his/her own comparator,
the association between anger outbursts and cardiovascular disease
is not confounded by stable health characteristics. Although the casecrossover design eliminates confounding by stable health characteristics, there can still be confounding by factors that change over time.
However, some of the studies4 showed that the results were not
materially altered after adjusting for potential confounding by
co-exposures such as anxiety, physical activity, coffee consumption,
and alcohol consumption. Premonitory symptoms may elicit feeling
of anger and anxiety, resulting in reverse causation. However, in an
analysis restricted to patients with no premonitory symptoms,3 the
association was even stronger, and in one study4 the outcome was
defined based on symptom onset rather than hospital admission
time. Patients might have attempted to explain their cardiovascular
event by overestimating anger episodes immediately before
symptom onset and underestimating their exposure during the
control period, resulting in recall bias and an overestimation of the
association between outbursts of anger and cardiovascular risk.
However, most of the studies ascertained information about anger
episodes using structured interviews and the patients were not
informed of the hypothesized duration of the hazard period. Since
results that are not statistically significant are often difficult to
publish, our systematic review may be subject to publication bias.
However, we conducted a broad comprehensive search of several
databases and reference lists of relevant articles, and we included
unpublished data and meeting abstracts.
In conclusion, based on our review of nine case-crossover studies
of individuals that experienced cardiovascular events, there is a
higher risk of MI, ACS, ischaemic and haemorrhagic stroke, and arrhythmia in the 2 h following outbursts of anger, with differences
between the studies resulting in different magnitudes of the association. Since there is large heterogeneity between the studies, combined estimates of the IRR may not be meaningful. Yet, despite the
differences between the studies, there was consistent evidence of a
higher risk of cardiovascular events immediately following outbursts
of anger.

E. Mostofsky et al.

Outbursts of anger as a trigger of cardiovascular events

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