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Tobacco modalities used and outcome in patients with acute coronary syndrome: an observational report
  1. Jassim Al Suwaidi1,
  2. Khalid Al Habib2,
  3. Rajvir Singh3,
  4. Ahmad Hersi2,
  5. Khalid Al Nemer4,
  6. Nidal Asaad1,
  7. Shukri Al Saif5,
  8. Ahmed Al-Motarreb6,
  9. Wael Almahmeed7,
  10. Kadhim Sulaiman8,
  11. Haitham Amin9,
  12. Jawad Al-Lawati10,
  13. Nizar Al Bustani7,
  14. Norah Q Al-Sagheer11,
  15. Waleed M Ali1
  1. 1Department of Cardiology, Hamad Medical Corporation (HMC), Qatar
  2. 2King Fahad Cardiac Center, King Khalid University Hospital, College of Medicine, Riyadh, Saudi Arabia
  3. 3Department of Research, Hamad Medical Corporation (HMC), Qatar
  4. 4Security Forces Hospital, Riyadh, Saudi Arabia
  5. 5Saud Al Babtain Cardiac Center, Dammam, Saudi Arabia
  6. 6Faculty of Medicine, Sana's University, Sana'a, Yemen
  7. 7Department of Cardiology, Sheikh Khalifa Medical City, Abu Dhabi, United Arab Emirates
  8. 8Department of Cardiology, Royal Hospital, Muscat, Oman
  9. 9Mohammed Bin Khalifa Cardiac Center, Bahrain
  10. 10Department of Non-Communicable Diseases Surveillance and Control, Ministry of Health Muscat, Oman
  11. 11Cardiac Center, Al-Thawra Hospital, Sana'a, Yemen
  1. Correspondence to Dr Jassim Al Suwaidi, Department of Adult Cardiology, Heart Hospital, Hamad Medical Corporation (HMC), P.O Box 3050, Doha, Qatar; jalsuwaidi{at}hotmail.com

Abstract

Aim The authors evaluated the prevalence and effect of the various tobacco use modalities among patients presenting with acute coronary syndrome (ACS) and compared them with non-tobacco and ex-tobacco users.

Methods An analysis of the 2nd Gulf Registry of Acute Coronary Events conducted between October 2008 and June 2009 and which included 7930 consecutive patients hospitalised with ACS was made. Patients initially were divided into non-tobacco users, ex-tobacco users and current tobacco users. Subanalysis according to the tobacco modality used was subsequently made: cigarette, waterpipe or smokeless tobacco users.

Results Overall, 2834 (36%) patients were current tobacco users, 306 (3.9%) patients were waterpipe smokers and 240 patients (3%) were oral tobacco users. When compared with non-tobacco and ex-tobacco users, overall current tobacco users were younger, more likely to be male subjects and less likely to have diabetes mellitus, hypertension and dyslipidaemia. Mortality rate (p=0.001) and overall cardiovascular events (p=0.001) were lower among current tobacco users when compared with the other two groups. After adjustment for baseline variables, tobacco use was not an independent predictor of adverse events. Subset analysis demonstrates oral tobacco users and waterpipe smokers were older and more likely to be women when compared with cigarette smokers. Among the various tobacco groups, inhospital mortality rates were significantly higher among the waterpipe smokers when compared with the other two groups.

Conclusions Clinical characteristics and outcomes of ACS patients depend on the tobacco modality used. Further studies are required to evaluate the impact of emerging tobacco use modalities on patients with coronary artery disease.

  • Acute coronary syndrome
  • ST-elevation myocardial infarction
  • non-ST elevation myocardial infarction
  • cigarette smoking
  • waterpipe smoking
  • smokeless tobacco
  • adult cardiology
  • coronary heart disease
  • myocardial infarction
  • ischaemic heart disease
  • public health
  • cardiology
  • anaesthesia in cardiology
  • audit
  • physiology
  • diabetes and endocrinology
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Introduction

Globally, 4.9 million deaths each year are attributed to tobacco use. This annual toll is expected to increase to 10 million within the next 20–30 years, with 70% of these deaths likely to occur in the developing countries, making tobacco use a global epidemic. Tobacco use is the single most modifiable risk factor contributing to premature cardiovascular morbidity and mortality. It is estimated that as many as 30% of all coronary heart disease deaths can be attributed to tobacco use.1 ,2 Although cigarette smoking is the commonest tobacco modality used, there are other types such as waterpipe smoking and smokeless tobacco3–10 in which data on their impact on patients of acute coronary syndrome (ACS) are limited. Furthermore, the recent decline in cigarette consumption in the USA is offset by increases in other tobacco product consumption. In a recent analysis of the Behavioral Risk Factor Surveillance System in the USA, there are 8.1 million (3.2%) smokeless tobacco product users, most commonly among individuals between 18 and 25 years of age. This increase is in part explained by the response of cigarette companies to the change in the pattern of consumption by entering other tobacco product markets including smokeless tobacco.5 More recently, the US Food and Drug Administration issued a final regulation related to the Tobacco Control Act that became effective 22 June 2010, which prohibits the sale of cigarettes and smokeless tobacco to individuals younger than 18 years of age.6

Waterpipe smoking is a centuries-old method in the Middle East and the Indian subcontinent that is increasingly becoming a worldwide phenomenon. Waterpipe smoking is now spreading to places outside the Middle East and has been heavily marketed to college populations and young adults in many Western countries.2 ,8–10 Using data from the 1st Gulf Registry of Acute Coronary Events (Gulf RACE-1) we recently reported a 4.4% prevalence of waterpipe smokers among ACS patients; waterpipe smokers had a worse inhospital outcome when compared with cigarette smokers.11 Herein, we review the prevalence, inhospital and 1-year outcome of various tobacco modalities use among patients with ACS and compare them with non-tobacco and ex-tobacco users using data from the 2nd Gulf RACE registry. We hypothesise that there is a high prevalence of tobacco use among Middle Eastern ACS patients and the clinical characteristics and outcome of ACS patients vary according to the tobacco modality used.

Methods

Patients

The data were collected from a 9-month prospective, multicentre study of the 2nd Gulf RACE registry that recruited 7939 consecutive ACS patients from six adjacent Middle Eastern Gulf countries (Bahrain, KSA, Qatar, Oman, United Arab Emirates and Yemen) between October 2008 and June 2009. Patients diagnosed with ACS, including unstable angina and non-ST- and ST-elevation myocardial infarction (NSTEMI and STEMI, respectively), were recruited from 65 hospitals. On-site cardiac catheterisation laboratory was available in 43% of the hospitals. The majorities of hospitals (71%) were tertiary care and had coronary care units on-site. There were no exclusion criteria and, thus, all the prospective patients with ACS were enrolled. The study received ethical approval from the institutional ethical bodies in all participating countries. Since the study was an observational study with no intervention, only verbal informed consent was obtained from all participants and this was approved by the ethical committees of all participating institutions. Diagnosis of the different types of ACS and definitions of data variables were based on the American College of Cardiology clinical data standards.12 ,13

Data collection

A Case Report Form for each patient with suspected ACS was filled out on hospital admission by assigned physicians and/or research assistants working in each hospital using standard definitions and was completed throughout the patient's hospital stay. All Case Report Forms were verified by a cardiologist and then sent online to the principal coordinating centre where the forms were further checked for mistakes before submission for final analysis. To avoid double counting of multiple admissions to the registry, patient-assigned ‘registry numbers’ were used. An enquiry about patients' survival at 1 and 12 months follow-up after discharge was made.14

Definitions of tobacco use

Information about tobacco use was obtained from the patient or a representative at the time of admission. Current tobacco users were considered to be those who reported tobacco use in any form regularly at entry to the study. Ex-tobacco users were considered to be those who used tobacco more than 1 year of the index admission. Non-tobacco users were patients who denied ever taking tobacco. Cigarette smokers were considered to be those who reported smoking cigarettes. Waterpipe smokers were considered to be those who reported waterpipe smoking at entry to the study. (A waterpipe consists of a head into which tobacco is placed, a body that is half-filled with water and a hose through which the user inhales (figure 1).) Often tobacco is flavoured (eg, apple, coffee and mint) and sweetened. When the user inhales, smoke passes through the water and hose into the lungs. Smoke inhalation can be substantial: a single waterpipe use episode can last 30–60 min and can involve more than 100 inhalations, each approximately 500 ml in volume. Thus, while smoking a single cigarette might produce a total of approximately 500–600 ml of smoke, a single waterpipe use episode might produce about 50 000 ml of smoke. Waterpipe and cigarette smoke contain some of the same toxins.2 ,15 Smokeless tobacco is tobacco consumed orally and not smoked, and includes moist oral snuff, chewing tobacco and tobacco used with betel liquid, areca nut and other ingredients.6 Many forms of smokeless tobacco products exist worldwide. In the USA, the predominate forms of smokeless tobacco products are snuff and chewing tobacco. While in the Middle East, the smokeless tobacco products are called Niswar, Zarda and Gutkha.6 Of the total 306 (3.9%) patients who were using waterpipe smoking, 130 patients were using it exclusively and only two of the 120 the smokeless tobacco users were using other tobacco modalities. For comparison among the various tobacco modality subtypes, comparison was performed only among patients who used only one modality of tobacco, that is, cigarette smoking, waterpipe smoking (130 patients) or smokeless tobacco (118 patients) use and hence patients who used more than one modality were excluded from this subanalysis.

Figure 1

Waterpipe smoking is common in cafes in the Middle East.

Statistical analysis

Baseline and clinical characteristics of patients are presented as means and SD for continuous variables, whereas frequency distribution and percentages are presented for categorical variables. One-way ANOVAs (parametric) with post hoc (Bonferroni) tests for continuous variables and χ2 tests for categorical variables have been used for comparing various independent variables according to tobacco use status. The association between cardiovascular risk factors (including overall tobacco use) and mortality was examined using multivariate logistic regression analysis. Adjusted ORs, with accompanying 95% CIs, were reported only for important independent variables. All p values were the results of two-tailed tests and values <0.05 were considered a statistically significant level. A p value of 0.0025 has been considered for statistical significance in χ2 tests for multiple comparisons. All data analyses were carried out using the Statistical Package for Social Sciences V.18.0 (SPSS Inc.).

Results

Overall, 1934 patients (24.3%) were diagnosed with unstable angina, 3622 patients (45.6%) with STEMI and 2386 patients (30.1%) with NSTEMI. Of these, 2834 patients (35.7%) were current tobacco users, 1363 patients (17%) were ex-tobacco users and 3742 patients (47%) were non-tobacco users.

Comparison of current tobacco with ex-tobacco and non-tobacco users

Clinical characteristics

When compared with non-tobacco and ex-tobacco users, current tobacco users were younger and more likely to be male subjects. Current tobacco users were less likely to have diabetes mellitus, hypertension, dyslipidaemia, prior cardiovascular disease and chronic renal failure. Current tobacco users were more likely to present with typical chest pain and STEMI while ex-tobacco and non-tobacco users were more likely to present with non-ST ACS. Admission heart rate and systolic blood pressure were lower among current tobacco and ex-tobacco users when compared with non-tobacco users. The prevalence of atrial fibrillation was lower among current tobacco users when compared with the other two groups (table 1).

Table 1

Clinical and biochemical characteristics of patients with acute coronary syndrome according to their tobacco status

Treatment

Overall, aspirin and β-blockers use were high and comparable among the various groups, while glycoprotein IIb/IIIa inhibitors use was low and was even lower among non-tobacco users. In STEMI patients, when compared with ex-tobacco and non-tobacco users, current tobacco users were most likely to receive either thrombolytic therapy or primary percutaneous coronary interventions. Current tobacco users were more likely to receive ACE inhibitors (ACE-I), clopidogrel and statins when compared with the other two groups. Overall, inhospital coronary angiography was performed in 32.5% of patients (table 2).

Table 2

Treatments and outcomes according to tobacco use status

At discharge, current tobacco users were more likely to be prescribed aspirin, clopidogrel, β-blockers, ACE-I and statins when compared with the other two groups. Calcium channel blockers prescription was lower among current tobacco users when compared with the other two groups.

Outcome

Inhospital outcome

Current tobacco users were less likely to have recurrent angina, recurrent myocardial infarction, heart failure, cardiogenic shock and inhospital mortality when compared with ex-tobacco and non-tobacco users. There were no significant differences among the three groups with regard to bleeding complications or stroke (table 2).

1-Month and 1-year outcome

Current tobacco users had significantly lower 1-and 12-month mortality rates when compared with the other two groups, while there were no significant differences in mortality rates between ex-tobacco and non-tobacco users (figure 2).

Figure 2

1- And 12-month mortality according to tobacco use (NT, non-tobacco users; ET, ex-tobacco users; CT, current tobacco users).

Comparison of waterpipe smokers with cigarette smokers and smokeless tobacco users

Clinical characteristics

Cigarette smokers when compared with waterpipe and smokeless tobacco users were younger while waterpipe smokers were more likely to be women, have hypertension and dyslipidaemia. Prior history of angina, myocardial infarction and percutaneous coronary interventions was more common among cigarette smokers when compared with the other two groups. Prior history of coronary artery bypass grafting, heart failure and chronic renal failure was comparable among the various groups. Waterpipe smokers were more likely to be ACE-I prior to admission when compared with the other two groups, while smokeless tobacco users were less likely to be on clopidogrel and β-blockers when compared with the other two groups (table 3).

Table 3

Clinical and biochemical characteristics of patients with acute coronary syndrome for important tobacco modalities

Cigarette smokers were more likely to present with typical ischaemic pain when compared with the other two groups. STEMI was commonest among smokeless tobacco users, followed by cigarette and waterpipe smokers. Waterpipe smokers were more likely to present with advanced Killip class (>1) when compared with the other two subgroups. Waterpipe and oral tobacco had higher admission heart rates when compared with cigarette smokers, while systolic and diastolic blood pressures were not found significant among the various groups.

Treatment

Clopidogrel, angiotensin receptor blockers, β-blockers, statins and calcium-channel blockers use on admission were comparable among the various groups. ACE-I use was higher and β-blockers use was lower among waterpipe smokers and smokeless tobacco subgroups when compared with cigarette smokers. Cigarette smokers were more likely to receive thrombolytic therapy when compared with the other two subgroups. Cigarette smokers and smokeless tobacco users were more likely prescribed aspirin when compared with waterpipe smokers on admission and at discharge.

Waterpipe smokers and smokeless tobacco users were more likely prescribed ACE-I and less likely prescribed β-blockers at discharge when compared with cigarette smokers. Clopidogrel, β-blockers, angiotensin receptor blocker and calcium channel blockers prescription at discharge were comparable among the various groups (table 4).

Table 4

Treatments and outcomes according to important tobacco modalities

Outcome

Inhospital outcome

Waterpipe smokers had a higher risk of recurrent ischaemia, requirements of mechanical ventilation and death compared with the other two groups. After adjustment for age and gender, the inhospital mortality rates remained significantly higher among waterpipe smokers when compared with cigarette smokers (OR 1.8, 95% CI 1.06 to 3.09), while no significant differences were observed between smokeless tobacco users and cigarette smokers (OR 0.99, 95% CI 0.53 to 1.85) (table 4) (figure 3).

Figure 3

Inhospital, 1- and 12-month mortality rate according to tobacco modality use: cigarette smoking, waterpipe smoking and smokeless tobacco use.

1-Month and 1-year outcome

Waterpipe smokers had a higher mortality rate at 1-month and 1-year follow-up when compared with cigarette smokers and smokeless tobacco users; however, this increase was not statistically significant (figure 3). Direct comparison between non-tobacco users and waterpipe smokers demonstrates higher inhospital (waterpipe smokers 8.5% vs 5.5% non-tobacco users) and 1-month mortality rate (12.2% waterpipe smokers vs 9.3% non-tobacco users) among waterpipe users even when compared with non-tobacco users; however, there were no significant differences in mortality rate at 1-year follow-up.

Logistic regression analysis

Tables 5 and 6 demonstrate multivariate predictors of inhospital, 1 month and 1 year of mortalities. Because the percentage of waterpipe and smokeless tobacco users was relatively low compared with non-tobacco users and cigarette smokers, for logistic regression analysis purposes the tobacco user groups were combined as one group. After adjustment for baseline variables, current tobacco use was not an independent predictor for inhospital, 1 month or 1 year mortality.

Table 5

Multivariate predictors for inhospital mortality of acute coronary syndrome patients according to tobacco status

Table 6

Multivariate predictors for mortality at 1 month and 1 year of acute coronary syndrome patients according to tobacco status

Discussion

The present study reports an overall 36% use of tobacco among ACS patients in six Middle Eastern patients. Consistent with the world literature, cigarette smokers were younger and had fewer cardiovascular risk factors; they were also more likely to present early with typical ischaemic symptoms. Cigarette smokers were also more likely to receive evidence-based therapy and had the lowest complication rates. To the best of our knowledge, the current study reports for the first time the prevalence and outcome of various tobacco types (including smokeless tobacco) used among patients presenting with ACS and compares them with that of non-tobacco and ex-tobacco users. Although the prevalence of waterpipe smoking and smokeless tobacco use was low, these patients exhibited different baseline characteristics and outcome when compared with cigarette smokers. The mean age of patients in these groups is older than cigarette smokers and comparable with that of non-tobacco and ex-tobacco users. Furthermore, although cigarette smoking appears to be predominately in male patients (>90%) in our study, significant proportions of waterpipe smokers were women (≈38.5%). Furthermore, they were less likely to be appropriately treated with evidence-based therapy. Waterpipe smokers had significantly higher inhospital mortality rates when compared with that of the other tobacco user subgroups and comparable with that of non-tobacco users. The current study suggests that the clinical characteristics and outcomes of ACS patients vary according to the tobacco modality used and extends our earlier observations from the 1st Gulf RACE registry, which was limited by inhospital data, lack of information about ex-tobacco users and smokeless tobacco users.11

Cigarette smokers versus non-smokers in ACS

Several studies have shown cigarette smokers to present at a much younger age (6–13 years) with ACS when compared with non-smokers.16–28 An individual cigarette smoker is more likely than a non-smoker to suffer from myocardial infarction and more likely to have lower mortality, a phenomena termed ‘smokers’ paradox’.24 The current study in Middle Eastern patients is consistent with these observations in which cigarette smokers were 7 years younger than non-nicotine users (52.7 years vs 60 years). Furthermore, cigarette smokers had lower inhospital and 1-month mortality rate when compared with non-smokers. This better outcome may be explained by significantly younger age and more favourable risk profile at admission among cigarette smokers as was observed in our study. After adjustment for baseline variables smoking there was no inhospital survival advantage related to smoking in patients admitted with ACS. The smokers' paradox may be more appropriately termed the ‘cigarette smokers' paradox’ as this phenomenon was not observed among waterpipe smokers and smokeless tobacco users.

Smokeless tobacco

Evidence suggests that the blood nicotine levels from smokeless tobacco use are similar to those of cigarette smoking.6 The use of smokeless tobacco has increased in the latter half of the 20th century, particularly in the USA, the Scandinavian countries and Southeast Asia with the presumption that it may be less harmful than cigarette smoking. Smokeless tobacco contains many of the same potentially noxious substances (nitrosamines and nicotine) as smoked tobacco. To date, limited studies (10 studies and two meta-analyses) reported the relationship between smokeless tobacco and cardiovascular health risks with conflicting findings. Six studies were performed in Sweden, four in the USA and one international study (INTERHEART study).29–40 Earlier, three studies originating from Sweden reported conflicting findings. Huhtasaari et al 29 ,30 in two population-based studies within the Northern Sweden centre of the World Heart Organization Multinational Monitoring of Trend and Determinants in Cardiovascular Disease reported lower risk of myocardial infarction with snuff dipping when compared with cigarette smoking. On the other hand, the 10-year follow-up study of Swedish healthy construction workers by Bolinder et al 31 reported a 40% excess risk of both cardiovascular and all-cause mortality among smokeless users. The risk appeared to be significant primarily in the younger age group. In the two published meta-analyses, one found positive associations with smokeless tobacco and the other found no associations.38 ,39 More recently, using the Atherosclerosis Risk in Communities Study, Yatsuya et al 40 reported an increased risk of cardiovascular disease with smokeless tobacco. To the best of our knowledge, this is the first study that evaluates the prevalence, clinical characteristics and outcome of smokeless tobacco patients presenting with ACS. Consistent with previous reports,5 ,6 ,29–40 smokeless tobacco patients were primarily men, 10 years older and were less likely to have hypertension, dyslipidaemia, chronic renal failure and prior cardiovascular disease when compared with cigarette smokers. Lack of increased prevalence of hypertension among smokeless tobacco is consistent with the majority of previous studies.6 Smokeless tobacco patients in the current study were also less likely to receive reperfusion therapy. There was a trend of worse outcome when compared with cigarette smokers.

Waterpipe smoking is a global epidemic

Waterpipe use in the Middle East had been in decline through most of the 20th century but experienced resurgence during the 1990s. In the Middle East, waterpipe smoking is becoming more popular especially among younger generations and several studies reported higher prevalence in the younger age; for example, in Egypt, 22% of 6762 men from two rural villages reported current or past use. Anecdotal reports indicate that waterpipe use has become a global phenomenon in recent years.2 ,8–10 ,15 ,41–47 It has been claimed that more than 100 million people worldwide smoke waterpipes daily, with use noted in Brazil, Canada, Germany, Korea, Ukraine and the USA. Factors thought to be responsible for the growing popularity of waterpipe use include: (a) the introduction of ma'assel, a sweet and aromatic processed tobacco that has greatly simplified the use of the waterpipe, (b) the apparent belief that it is safer than cigarettes because smoke is passed through water and (c) the dearth of information about the health effects of waterpipe smoking when compared with that of cigarette smoking. However, waterpipe use may be associated with greater toxicant exposure because longer use episodes as well as more and larger puffs lead to inhalation of as much as 100 times more smoke than from a cigarette.2 WHO47 has called for studying the health effects of waterpipe smoking. Unfortunately, studies on the health hazards of this smoking habit, especially cardiovascular disease, are scant.

Although the prevalence of waterpipe smoking in the current study is low, they were older than cigarette smokers and of comparable age with that of non-tobacco users. Furthermore, waterpipe smokers also had less favourable risk profile and, at presentation, they had significantly higher heart rate and diastolic blood pressure when compared with cigarette smokers and non-smokers, which is consistent with the observations from Gulf RACE11 registry and of Al-Safi et al. 8 In contrast to cigarette smokers who were less likely to present with advanced Killip class when compared with non-smokers, there was an increased incidence of advanced Killip class among waterpipe smokers. Furthermore, in contrast to cigarette smokers who had better outcome when compared with non-smokers, waterpipe smokers had worse outcome including higher mortality rate, recurrent myocardial ischaemia, heart failure, cardiogenic shock and death. It might be hypothesised that the older age, higher percentage of women and lower treatment of evidence-based therapy in this subgroup may in part explain their worse outcome when compared with cigarette smokers; this is consistent with our recent observations and that of others.11 ,48 ,49 Another possible explanation is the ‘toxic’ constituents of tobacco used in waterpipe smoking worsens outcomes through multiple mechanisms including its prothrombotic effects and coronary artery spasm; however, firm conclusions cannot be made because of the small sample size of waterpipe smokers and oral tobacco users in our registry and further larger scale studies are required to evaluate the validity of this interaction.

Study limitations

Our data were collected from an observational study, which is a limitation. The fundamental limitations of observational studies cannot be eliminated because of the non-randomised nature and unmeasured confounding factors. However, well designed observational studies provide valid results and do not systematically overestimate the results compared with the results of randomised controlled trials. Second, although the current study evaluates the prevalence and outcome of various modalities of tobacco use among ACS patients, because of the low number of waterpipe smokers and oral tobacco users, firm conclusions cannot be made and further studies are required to confirm the current observations. Third, the study is based on the subjective evidence of tobacco use only and data on nicotine levels in the blood are not available. Finally, although 1-year follow-up was part of the study, it was only limited to survival and information about tobacco use status at follow-up as well as other complications apart from survival such as recurrent myocardial infarction was not obtained. Furthermore, follow-up was only possible in 73% of the patients studied and it is possible that if complete follow-up was obtained the long-term survival findings would have been different. Nonetheless, we believe this is the first study that evaluates outcome using the various tobacco types used among ACS patients.

Conclusion

Tobacco use is prevalent among Middle Eastern patients presenting with ACS. Waterpipe smoking and smokeless tobacco use are low. Waterpipe smoking was associated with a worse outcome when compared with cigarette smokers, which may be attributed to baseline variables. The current study underscores the urgent need of further studies on the effects of emerging tobacco use modalities and cardiovascular disease.

Main messages

  • Tobacco use is prevalent among Middle Eastern patients presenting with acute coronary syndrome.

  • The clinical characteristics and outcomes of acute coronary syndrome patients vary according to the tobacco modality used; waterpipe smokers and smokeless tobacco users are older and more likely to be women when compared with cigarette smokers.

  • The differences in inhospital outcome among tobacco users may in part be attributed to variability in clinical characteristics.

Current research questions

  • Do the clinical characteristics and outcomes of acute coronary syndrome (ACS) patients vary according to the tobacco modality used?

  • What are the clinical characteristics and outcomes of waterpipe and smokeless tobacco users presenting with ACS?

  • Does the outcome of ACS tobacco users depend on the quantity and duration of tobacco use?

Key references

  • Global Youth Tobacco Survey Collaborating Group. Differences in worldwide tobacco use by gender: findings from the global youth tobacco survey. J Sch Health 2003;73:207–15.

  • Maziak W, Ward KD, Soweid RAA, et al. Tobacco smoking using a waterpipe: a re-emerging strain in a global epidemic. Tob Control 2004;13:327–33.

  • Piano MR, Benwitz NL, FitzGerald GA, et al; American Heart Association Council on Cardiovascular Nursing. Impact of smokeless tobacco products on cardiovascular disease: implications for policy, prevention, and treatment: a policy statement from the American Heart Association. Circulation 2010;122:1520–44.

Acknowledgments

We thank the staff in all the participating centres for their invaluable cooperation.

References

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Footnotes

  • Funding Gulf RACE is a Gulf Heart Association (GHA) project and was financially supported by the GHA, Sanofi Aventis and the College of Medicine Research Center at King Khalid University Hospital, King Saud University, Riyadh, Saudi Arabia. The sponsors had no role in the study design, data collection, data analysis, writing of the report or submission of the manuscript. The study obtained ethical approvals prior to the study.

  • Competing interests None.

  • Ethics approval Ethics approval was provided by the Institutional Review Board of each participating hospital.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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