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Stroke in Qatar: A one-year, hospital-based study
Stroke in Qatar: A One-Year, Hospital-Based Study Ahmed Hamad, FRCP, cFAAN,* Ayman Hamad, CABM,* Tag Eldin O. Sokrab, MD, PhD,* Samir Momeni, JMB,* Bonauar Mesraoua, and Arne Lingren, MD, PhD†
MD,*
Background and Purpose: Stroke is a major health problem in Qatar, yet no stroke studies have been reported from this region. This hospital-based study was conducted to determine the types and the 30-day fatality rate of stroke. The data were collected from the only hospital in Qatar and, therefore, are considered to be community-based estimations. Methods: Clinical information was collected from discharge records of all patients with International Classification of Diseases, 9th Revision, (ICD 9) codes 430 to 438 from January 1 to December 31, 1997. Identification of cases included review of death certificates and brain computed tomography (CT) records for the same period. Results: First-ever stroke was found in 217 patients (157 men and 60 women). The overall incidence rate was 41 per 100,000 inhabitants per year (95% CI, 30.2-52.4/100,000/year) and 238/100,000/year for the population over 45 years old. The age standardized incidence was 57.5 per 100,000 inhabitants per year (95% CI, 43.1-73.8). The crude incidence for native Qataris was 75 per 100,000 inhabitants per year. The mean age of patients experiencing their first stroke was 57 years. Thirty-nine (18%) patients were younger than 45 years. Clinical subtypes of stroke were ischemic (80%), intracerebral hemorrhage (19%), and subarachnoid hemorrhage (1%). Risk factors included hypertension (63%), diabetes mellitus (42%), ischemic heart disease (17%), and atrial fibrillation (4.5%). The overall patient fatality rate at 30 days was 16%. Conclusion: Stroke incidence in Qatar is lower than in other countries; a low incidence of subarachnoid hemorrhage was noted. The low mean age of stroke patients reflects the demographic characteristics of the population in Qatar. The high percentage of stroke patients suffering from hypertension and diabetes reflects the high prevalence of these risk factors in the population. Key Words: Stroke—Qatar—Cerebrovascular disease. Copyright © 2001 by National Stroke Association
Stroke is a major cause of long-term disability and the third leading cause of death in most developed countries.1 Epidemiologic data on stroke are important for diagnostic, therapeutic, rehabilitation, and preventive purposes. Increased global interest in stroke has resulted
From the *Neurology Section, Hamad General Hospital, Doha, Qatar; and the †Neurology Department, University Hospital, Lund, Sweden. Received June 15, 2001; accepted October 10, 2001. Address reprint requests to Ahmed Hamad, FRCP, cFAAN, Neurology Section, Hamad General Hospital, PO Box 3050, Doha, Qatar. Copyright © 2001 by National Stroke Association 1052-3057/01/1005-0007$35.00/0 doi:10.1053/jscd.2001.30382
236
in an increasing number of publications.2 However, relatively few reports on stroke incidence in the countries of the Arabian Peninsula have been published,3,4 and there have been no previously published reports on stroke in Qatar. Stroke is a major health problem in Qatar because of its associated mortality and morbidity. Stroke patients are often hospitalized for long periods of time, and their quality of life is severely affected socially and economically. Many of these patients are eventually admitted to the long-term wards in geriatric hospitals. Currently, 10% of the hospital beds in Qatar are occupied by stroke patients. The purpose of this hospital-based study was to determine the types of stroke, incidence of first-ever stroke, and 30-day fatality rate of stroke in Qatar.
Journal of Stroke and Cerebrovascular Diseases, Vol. 10, No. 5 (September-October), 2001: pp 236-241
STROKE IN QATAR
237
police force, and the big oil companies have their own clinics. Medical services are free for all residents of Qatar who have a personal health number, and any visiting patient will be seen in the emergency department (ED) free of charge. There are no neurology or neuroradiology services outside of the hospital, and there are no private hospitals with inpatient medical care. Because medical services are free and easily accessible, any person with acute illness, such as stroke, will be seen in the ED without referral from a health center. The standard practice is that most patients suspected to have a stroke are referred to the hospital for assessment. Those who die at home in Doha and in nearby areas are brought to the ED to obtain death certificates. Subjects
Figure 1.
Map of the state of Qatar.
Materials and Methods Study Area and Population The state of Qatar lies midway along the East Coast of the Arabian Peninsula, east of Saudi Arabia. It is a small peninsula that extends northward in the Gulf with an area of 11,437 km2, and it shares a border only with Saudi Arabia (see Fig 1). The nearest Saudi town is 160 km away from the border. Qatar’s geography precludes the movement of its people freely across borders. All parts of the country are within 100 km from the hospital in Doha, the capital town where 80% of the Qatar population reside. Oil and natural gas form the backbone of Qatar’s economy. The population in 1997 comprised 522,033 inhabitants (342,459 men and 179,564 women).5 Fourteen percent of the population were older than 45 years, but only 1% were over 65 years old. Foreign nationals constitute the majority of Qatar’s population and are mainly men between 20 and 50 years old. The exact number of each nationality including Qataris is not released officially by the government. The entire country of Qatar is served by 1 medical corporation in Doha, which consists of Hamad General Hospital, a geriatric hospital, a women’s hospital, and a psychiatric hospital. The same Medical Records Department and Radiology Department serve all of these hospitals. Hamad General Hospital has 600 beds, 213 of which are used by the Medical Department. Of the 680 physicians working in the corporation, 75 work in the Medical Department, which includes the Neurology Section. There are 8 health centers in Doha and 12 other health centers, which employ 300 general practitioners, that serve the rest of the country. In addition, the army,
We reviewed the records of all patients with a discharge diagnosis including International Statistical Classification of Diseases, 9th Revision, codes 430 to 438 from January 1, 1997 to December 31, 1997. Only cases of first-ever stroke (FES) were included. History, physical examination, and computed tomography (CT) scans were used to exclude previous stroke. Case fatality at 30 days was determined. For the purpose of this study, the old definition of systemic hypertension (HTN), a blood pressure reading of greater than 160/90 mm Hg in the nonacute phase or the use antihypertensive medications, was used.6-8 Diabetes mellitus (DM) was diagnosed in patients with a fasting blood glucose concentration of greater than 6.6 mmol/L or if the patient had been treated with antidiabetic medication.9-11 Coronary artery disease (CAD) and arterial fibrillation (AF) were considered if diagnosed by a cardiologist. To ensure complete case ascertainment, we reviewed hospital admission and discharge lists (including the women’s hospital), inpatient records in the geriatric ward, CT scans for outpatients with symptoms of stroke in 1997, and death certificates to ensure inclusion of patients dying from stroke inside and outside of the hospital. Stroke was defined according to the World Health Organization (WHO) criteria as “rapidly developing clinical symptoms and/or signs of focal and at times global, loss of cerebral function with symptoms lasting more than 24 hours or leading to death, with no apparent cause other than that of vascular origin.”12 All acute events occurring within 21 days from the onset of the first event were considered as part of the same event. Clinical subtypes of stroke were determined by reviewing medical records and death certificates and by telephone calls. No expatriates returned to his or her home country before 1 month from the onset of stroke. Cerebral ischemia (CI), intracerebral hemorrhage (ICH), and subarachnoid hemorrhage (SAH) were determined by noncontrast brain CT scan within 3 days of admission to the hospital. No
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Table 1. Numbers and sex-specific incidence rates of first-ever stroke in Qatar, 1997 Men Age group (y)
No. of cases/ No. at risk
Women
Total
Rate (per 100,000)
95% CI
No. of cases/ No. at risk
Rate (per 100,000)
95% CI
No. of cases/ No. at risk
Rate (per 100,000)
95% CI
0 2 5 32 122 263 684 1,421 46
0 0.05-13.0 1.2-11.6 21.5-46.7 87.6-159.6 179.0-373.9 428.7-1,035.6 910.4-2,114.2 87.6-159.6
0/67,009 0/27,919 1/33,618 7/32,035 13/11,731 14/4,820 16/1,773 9/659 60/179,564
0 0 3 22 111 290 902 1,365 33
0 0 0.07-16.5 0.07-17.3 65.2-200.2 158.7-487.3 515.7-1,465.4 624.4-2,592.5 22.5-48.7
0/137,705 1/70,490 5/121,208 35/118,541 60/50,156 45/16,236 38/4,989 33/2,345 217/522,023
0 1 4 30 120 277 762 1,407 41
0 0.03-7.9 1.3-9.6 16.3-35.1 91.2-153.9 197.8-363.0 539.0-1,045.4 967.4-1,973.7 30.2-52.4
0-14 0/70,696 15-24 1/42,571 25-34 4/87,590 35-44 28/86,506 45-54 47/38,425 55-64 31/11,766 65-74 22/3,216 75⫹ 24/1,689 TOTAL 157/342,459
patient required lumbar puncture. Repeat CT scan or magnetic resonance imaging (MRI) was performed within 2 weeks of admission if the initial CT scan was normal. Vascular investigations were performed occasionally, but these data were not analyzed. Statistical Methods Age and sex specific incidence rates were calculated, and to make the results comparable with other studies, rates were presented in 10-year age groups. The calculations of age standardized incidence were adjusted directly to world standard population with the direct age standardization method.13 The 95% confidence intervals (CI) for the incidence were calculated with standard techniques.14
Results During 1997, 217 subjects were identified. Of these, 99% were inpatients. All patients were admitted to the medical wards except 2 patients who resided in the
geriatric ward and another 2 patients who were identified by reviewing outpatient CT scan reports. No patients were included from the review of death certificates, and 14 patients with recurrent stroke were found and excluded. FES occurred in 157 men (72.4%) and in 60 women (27.6%). The mean age of patients with FES was 57 years for men and 60 years for women. Men outnumbered women in all age groups by a ratio 2.6:1. Stroke incidence rose steeply with age in both men and women. Thirty-nine patients (18%) were younger than 45 years. Native Qataris comprised 132 patients, 88 men with a mean age of 59 years and 44 women with a mean age of 61 years. The remaining 85 were expatriates of different nationalities, 69 men with a mean age of 55 and 16 women with a mean age of 58. All patients included in the study had CT scans within 3 days after admission; 173 patients (80%) were diagnosed with CI, 42 patients (19%) were diagnosed with ICH, and 2 patients (1%) were diagnosed with SAH. The age and sex incidence rates for FES are shown in Tables 1 and 2. The overall crude annual incidence rate
Table 2. Numbers and sex-specific incidence rates of first-ever stroke by subtypes in Qatar, 1997 Cerebral infarction Men Age Rate (per group, No. of cases/ 100,000) Y (y) No. at risk 0-14 15-24 25-34 35-44 45-54 55-64 65-74 75⫹ Total
0/70,696 1/42,571 3/87,590 23/86,506 34/38,425 26/11,766 17/3,216 19/1,689 123/342,459
0 2 3 27 88 221 529 1,125 36
Intracerebral hemorrhage Women
Men
Women
No. of cases/ No. at risk
Rate (per 100,000)
No. of cases/ No. at risk
Rate (per 100,000)
No. of cases/ No. at risk
Rate (per 100,000)
0/67,009 0/27,919 1/33,618 5/32,035 10/11,731 12/4,820 14/1,773 8/659 50/179,564
0 0 3 16 85 249 790 1,214 28
0/70,696 0/42,571 1/87,590 5/86,506 11/38,425 5/11,766 5/3,216 5/1,689 32/342,459
0 0 1 6 30 42 155 296 9
0/67,009 0/27,919 0/33,618 1/32,035 4/11,731 2/4,820 2/1,773 1/659 10/179,564
0 0 0 4 34 41 113 152 6
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Table 3. Distribution of risk factors according to nationality and type of stroke Men
Women
Risk factor
CI
ICH
CI
ICH
Total
Qataris (n) Hypertension Diabetes mellitus Ischemic heart disease Atrial fibrillation Expatriates (n) Hypertension Diabetes mellitus Ischemic heart disease Atrial fibrillation
74 33 32 12 3 49 38 36 8 5
14 10 2 6 0 18 19 0 0 0
36 18 21 8 2 14 7 3 2 0
8 7 2 2 0 2 2 0 0 0
132 68 (55%) 57 (46%) 28 (22%) 5 (4%) 83 66 (77%) 39 (45%) 10 (11%) 5 (5%)
was 41 per 100,000 inhabitants per year (95% CI, 30.252.4). The crude incidence for people older than 45 years was 238 per 100,000 inhabitants per year. When standardized to world standard population, the FES incidence rate becomes 58 per 100,000 inhabitants per year (95% CI, 43.1-73.8), and if standardized to the European population, the incidence rate rises to 100 per 100,000 per year. Because Qataris account for approximately 35% of the general population (no official figure has been released), the crude incidence among them is 73 per 100,000 per year. The overall 30-day fatality rate for patients with FES was 16%. Patients with ICH had a higher mortality rate than patients with CI (31% v 12%). The frequencies of risk factors are shown in Table 3. HTN in native Qatari men was significantly less frequent than in expatriate men (48% v 77%, P ⫽ .02), but DM was more common in native Qatari women than in expatriate women (52% v 18%, P ⫽ .02).
Discussion In many circumstances, population-based studies provide the best estimation of stroke incidence.15 However, the particular circumstances of Hamad General Hospital are favorable to such a study in Qatar. We made every effort to ensure complete case ascertainment. The dramatic presentation of stroke, the small area of the country, and the free access to the only available ED means that almost all patients with acute stroke will come to the hospital. Therefore, the results of this study very likely reflect the incidence of stroke in Qatar. It is possible that some patients with mild symptoms and those, especially the very elderly, who died from stroke at home outside Doha and in whom the diagnosis was missed in their death certificates were excluded. Therefore, the results of this study do not truly reflect the incidence of stroke in Qatar. Nonetheless, they represent the true incidence as
closely as possible, and will serve to guide Qatar health authorities in stroke management. The crude annual incidence rate that we observed is in line with that of 43 to 63 per 100,000 found in Saudi Arabia4 and Libya16 and is much less than the rate of 150 to 500 per 100,000 reported from Western countries12,17 and Japan.18 This is explained by the pattern of population structure in Qatar, which is similar to that in Saudi Arabia but different from that in Europe and Japan. The crude incidence of 238 per 100,000 per year in Qatar is older than 45 years is within the same range as the incidence in this age group in Western countries.19 The age-adjusted annual incidence rate of 58 per 100,000 per year is less than the range of 105 to 280 per 100,000 per year observed in most worldwide studies.19,20 The incidence of 26 per 100,000 inhabitants in Nigeria is far below the Qatari rates.21 The high male to female ratio of stroke in Qataris was inexplicable, because Qatari women visit the hospital as, if not more, frequently as men. The fact that elderly Qatari women (who constitute the minority of our patient population) were reluctant to be admitted to the hospital, despite easy access and equal care, could contribute to this finding. The male to female ratio in Saudi Arabia was also high, ranging from 1.4 to 3.4, and no explanation was given for this observation.3,4,22 A higher ratio was expected in expatriates, because men grossly outnumber women. The 80% CI is similar to that reported in North America and Europe.19 The incidence of ICH (19%) is higher than in Western countries19 but lower than in Eastern countries like Japan.18 It is similar to the figures reported in Saudi Arabia,3 Libya,16 and Greece.23 The low incidence of SAH (1%) is less than that (3.5%-17%) found in other countries,16,19 but similar to that of the eastern province of Saudi Arabia (1.4%).3 A similar trend was noted in the Arab populations of other countries in the Middle East.24
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The 30-day patient fatality rate in Qatar is much lower than in Nigeria24 and the United States25 but similar to that in Saudi Arabia,3 Libya,16 and Germany.26 As we expected, the fatality rate in patients with ICH (31%) was higher than that of patients with CI (13%). The relatively young age of stroke patients and the frequency of their admission to the hospital may explain Qatar’s low 30-day fatality rate. Thirtynine (18%) of our patients were younger than 45 years; 80% of them had CI and 20% had ICH. Common risk factors were HTN (69%), DM (33%), and cardiac disease (8%). In Libya, a comparable percentage of stroke victims were younger than 45 years (19%),16 but a lower percentage was reported in Saudi Arabia (10%).3 Risk factors were not mentioned in these studies. In Sweden, 25% of young patients with CI were hypertensive, and 5% were diabetic.27 In our Qatari patient population, HTN was the most common risk factor for stroke (63%). Likewise, 54% of stroke patients in Libya16 and 34% in Saudi Arabia were hypertensive.3,4 In other developed countries, HTN ranged from 12% to 17% depending on the patients’ ethnic groups.8,28 DM was the second most common risk factor (42%), especially among native Qatari women, and, similarly, accounted for 44% of stroke patients in Tripoli Libya.16 In Saudi Arabia, 37% of stroke patients were diabetic,3 and 0.5% to 23% were diabetic in the developed countries.12,29 In a recent survey of Qataris older than 30 years, 20% were found to be hypertensive, and 15% were diabetic (personal communication). These high figures are attributed to a sedentary lifestyle, stress (especially among expatriates), diet, and consanguineous marriage. However, the rate of HTN and DM in Qatari stroke patients clearly exceeded the rates in the overall native population. In addition, the proportion of Qatari stroke patients with coronary artery disease (17%) is less than that reported in other countries (26%),3,30 which may be a result of the inclusion of rheumatic heart disease in the other studies, the young age of the Qatari patients, and the low incidence of atrial fibrillation (4.5%) noted in our study (incidence of atrial fibrillation in Sweden, for example, is 19%31). In conclusion, the results of our hospital-based (not community-based) study do not reflect the true incidence of stroke and 30-day fatality rate in Qatar, but they represent the true incidence as nearly as possible and take some risk factors into account. A national stroke registry has been initiated to overcome the few limitations of this study. We believe that the low crude stroke incidence that we found in Qatar may increase in the future because of the population’s expected age increase. A national program dealing with the common risk factors for stroke is necessary to combat this potential rise in stroke incidence.
References 1. Bonita R, Stewart AW, Beaglehole R. International trends in stroke mortality: 1970-1985. Stroke 1990;21:989-992. 2. Bonita R. Epidemiology of stroke. Lancet 1992;339:342344. 3. Al-Rajeh S, Larbi EB, Bademosi O, et al. Stroke register: Experience from the eastern province of Saudi Arabia. Cerebrovasc Dis 1998;8:86-89. 4. Al-Rajeh S, Awada A, Niazi G, et al. Stroke in a Saudi Arabian National Guard Community. Analysis of 500 consecutive cases from a population-based hospital. Stroke 1993;24:1635-1639. 5. Central Statistical Organization, State of Qatar. March 1997 Census. Doha, Qatar: Government of Qatar, 1998. 6. Kannel WB, Philip AW, Verter J, et al. Epidemiological assessment of the role of blood pressure in stroke. The Framingham Study. JAMA 1970;214:301-310. 7. Shekelle RB, Ostfeld AM, Kalavans HL. Hypertension and risk of stroke in elderly population. Stroke 1974;5: 71-75. 8. Stegmayr B, Asplund K, Kuulasmaa K, et al. Stroke incidence and mortality correlated to stroke risk factors in the WHO MONICA project. Stroke 1997;28:1367-1374. 9. Riddle MC, Hart J. Hyperglycemia, recognized and unrecognized, as a risk factor for stroke and transient ischemic attacks. Stroke 1982;13:356-359. 10. Barrett-Connor E, Khaw KT. Diabetes mellitus: An independent risk factor for stroke? Am J Epidemiol 1988;128: 116-123. 11. El Hazmi MAF, Warsy AS. A comparative study of hyperglycemia in different regions of Saudi Arabia. Ann Saudi Med 1989;10:471-476. 12. Aho K, Harmsen P, Hatano S, et al. Cerebrovascular disease in the community: Results of a WHO collaborative study. Bull World Health Organ 1980;58:113-130. 13. Waterhouse J, Muir C, Correo P, et al. Cancer incidence in five continents, vol. 11. IARC Scientific Publication No. 15. Lyon, France: International Agency for Research on Cancer, 1976:453-459. 14. Gardner MJ, Altman DG (eds). Statistics with confidence. London: British Medical Journal, 1989:116-118. 15. Sudlow CLM, Warlow CP. Comparing stroke incidence worldwide: What makes studies comparable? Stroke 1996;27:550-558. 16. Ashok PP, Radhakrishnan K, Sridharan R, et al. Incidence and pattern of cerebrovascular disease in Benghazi, Libya. J Neurol Neurosurg Psychiatry 1986;49:512523. 17. Bamford J, Sandercock P, Dennis M, et al. A prospective study of acute cerebrovascular disease in the community: The Oxfordshire Community Stroke Project 198186. Methodology, demographic and incidence of cases of first-ever stroke. J Neurol Neurosurg Psychiatry 1988;51: 1373-1380. 18. Tanaka H. Age-specific incidence of stroke subtypes in Shibata Japan 1976-1978. Stroke 1982;13:110. 19. Sudlow CLM, Warlow CP. Comparable studies of incidence of stroke and its pathological subtypes. Stroke 1997;28:491-499. 20. Alter M, Zhang ZX, Sobel E, et al. Standardized incidence of ratios of stroke: A worldwide review. Neuroepidemiology 1986;5:148-158. 21. Osuntokun BO, Bademosi O, Akinkughe OO, et al. Incidence of stroke in an African city: Results from stroke registry at Ibadan, Nigeria. Stroke 1979;10:205-207.
STROKE IN QATAR 22. Qari FA. Profile of stroke in a teaching university hospital in the Western region. Saudi Med J 2000;21:1030-1033. 23. Vemmos KN, Bots ML, Tsibouris PK, et al. Stroke incidence and case fatality in southern Greece, the Arcadia Stroke Registry. Stroke 1999;30:363-370. 24. Al-Mefty O, Al-Rodhan N, Fox J. The low incidence of cerebral aneurysms in the Middle East: Is it a myth? Neurosurgery 1988;22:951-954. 25. Baum HM, Robins M. National survey of stroke. Stroke 1981;12:59-68 (suppl 1). 26. Kolominsky-Rabas PL, Sarti C, Heuschmann PU, et al. A prospective community-based study of stroke in Germany—The Erlangen Stroke Project (ESPro), incidence and case fatality at 1, 3 and 12 months. Stroke 1998;29: 2501-2506.
241 27. Kristensen B, Malm J, Carlberg B, et al. Epidemiology and etiology of ischemic stroke in young adults aged 18 to 44 years in northern Sweden. Stroke 1997;28:17021709. 28. Sacco RL, Hauser WA, Mohr JP, et al. One-year outcome after cerebral infarction in whites, blacks and hispanics. Stroke 1991;22:305-311. 29. Wolf PA, D’Agnostino RB, Belanger AJ, et al. Probability of stroke: A risk profile from the Framingham Study. Stroke 1991;22:312-318. 30. Awada A, Al Rajeh S, D’Arhela PG, et al. Cardiac disorders in stroke patients. A study from Saudi Arabia. Trop Cardiol 1995;21:69-75. 31. Jentorp P, Bergland G. Stroke registry in Malmo, Sweden. Stroke 1992;23:357-361.
MD,*
Background and Purpose: Stroke is a major health problem in Qatar, yet no stroke studies have been reported from this region. This hospital-based study was conducted to determine the types and the 30-day fatality rate of stroke. The data were collected from the only hospital in Qatar and, therefore, are considered to be community-based estimations. Methods: Clinical information was collected from discharge records of all patients with International Classification of Diseases, 9th Revision, (ICD 9) codes 430 to 438 from January 1 to December 31, 1997. Identification of cases included review of death certificates and brain computed tomography (CT) records for the same period. Results: First-ever stroke was found in 217 patients (157 men and 60 women). The overall incidence rate was 41 per 100,000 inhabitants per year (95% CI, 30.2-52.4/100,000/year) and 238/100,000/year for the population over 45 years old. The age standardized incidence was 57.5 per 100,000 inhabitants per year (95% CI, 43.1-73.8). The crude incidence for native Qataris was 75 per 100,000 inhabitants per year. The mean age of patients experiencing their first stroke was 57 years. Thirty-nine (18%) patients were younger than 45 years. Clinical subtypes of stroke were ischemic (80%), intracerebral hemorrhage (19%), and subarachnoid hemorrhage (1%). Risk factors included hypertension (63%), diabetes mellitus (42%), ischemic heart disease (17%), and atrial fibrillation (4.5%). The overall patient fatality rate at 30 days was 16%. Conclusion: Stroke incidence in Qatar is lower than in other countries; a low incidence of subarachnoid hemorrhage was noted. The low mean age of stroke patients reflects the demographic characteristics of the population in Qatar. The high percentage of stroke patients suffering from hypertension and diabetes reflects the high prevalence of these risk factors in the population. Key Words: Stroke—Qatar—Cerebrovascular disease. Copyright © 2001 by National Stroke Association
Stroke is a major cause of long-term disability and the third leading cause of death in most developed countries.1 Epidemiologic data on stroke are important for diagnostic, therapeutic, rehabilitation, and preventive purposes. Increased global interest in stroke has resulted
From the *Neurology Section, Hamad General Hospital, Doha, Qatar; and the †Neurology Department, University Hospital, Lund, Sweden. Received June 15, 2001; accepted October 10, 2001. Address reprint requests to Ahmed Hamad, FRCP, cFAAN, Neurology Section, Hamad General Hospital, PO Box 3050, Doha, Qatar. Copyright © 2001 by National Stroke Association 1052-3057/01/1005-0007$35.00/0 doi:10.1053/jscd.2001.30382
236
in an increasing number of publications.2 However, relatively few reports on stroke incidence in the countries of the Arabian Peninsula have been published,3,4 and there have been no previously published reports on stroke in Qatar. Stroke is a major health problem in Qatar because of its associated mortality and morbidity. Stroke patients are often hospitalized for long periods of time, and their quality of life is severely affected socially and economically. Many of these patients are eventually admitted to the long-term wards in geriatric hospitals. Currently, 10% of the hospital beds in Qatar are occupied by stroke patients. The purpose of this hospital-based study was to determine the types of stroke, incidence of first-ever stroke, and 30-day fatality rate of stroke in Qatar.
Journal of Stroke and Cerebrovascular Diseases, Vol. 10, No. 5 (September-October), 2001: pp 236-241
STROKE IN QATAR
237
police force, and the big oil companies have their own clinics. Medical services are free for all residents of Qatar who have a personal health number, and any visiting patient will be seen in the emergency department (ED) free of charge. There are no neurology or neuroradiology services outside of the hospital, and there are no private hospitals with inpatient medical care. Because medical services are free and easily accessible, any person with acute illness, such as stroke, will be seen in the ED without referral from a health center. The standard practice is that most patients suspected to have a stroke are referred to the hospital for assessment. Those who die at home in Doha and in nearby areas are brought to the ED to obtain death certificates. Subjects
Figure 1.
Map of the state of Qatar.
Materials and Methods Study Area and Population The state of Qatar lies midway along the East Coast of the Arabian Peninsula, east of Saudi Arabia. It is a small peninsula that extends northward in the Gulf with an area of 11,437 km2, and it shares a border only with Saudi Arabia (see Fig 1). The nearest Saudi town is 160 km away from the border. Qatar’s geography precludes the movement of its people freely across borders. All parts of the country are within 100 km from the hospital in Doha, the capital town where 80% of the Qatar population reside. Oil and natural gas form the backbone of Qatar’s economy. The population in 1997 comprised 522,033 inhabitants (342,459 men and 179,564 women).5 Fourteen percent of the population were older than 45 years, but only 1% were over 65 years old. Foreign nationals constitute the majority of Qatar’s population and are mainly men between 20 and 50 years old. The exact number of each nationality including Qataris is not released officially by the government. The entire country of Qatar is served by 1 medical corporation in Doha, which consists of Hamad General Hospital, a geriatric hospital, a women’s hospital, and a psychiatric hospital. The same Medical Records Department and Radiology Department serve all of these hospitals. Hamad General Hospital has 600 beds, 213 of which are used by the Medical Department. Of the 680 physicians working in the corporation, 75 work in the Medical Department, which includes the Neurology Section. There are 8 health centers in Doha and 12 other health centers, which employ 300 general practitioners, that serve the rest of the country. In addition, the army,
We reviewed the records of all patients with a discharge diagnosis including International Statistical Classification of Diseases, 9th Revision, codes 430 to 438 from January 1, 1997 to December 31, 1997. Only cases of first-ever stroke (FES) were included. History, physical examination, and computed tomography (CT) scans were used to exclude previous stroke. Case fatality at 30 days was determined. For the purpose of this study, the old definition of systemic hypertension (HTN), a blood pressure reading of greater than 160/90 mm Hg in the nonacute phase or the use antihypertensive medications, was used.6-8 Diabetes mellitus (DM) was diagnosed in patients with a fasting blood glucose concentration of greater than 6.6 mmol/L or if the patient had been treated with antidiabetic medication.9-11 Coronary artery disease (CAD) and arterial fibrillation (AF) were considered if diagnosed by a cardiologist. To ensure complete case ascertainment, we reviewed hospital admission and discharge lists (including the women’s hospital), inpatient records in the geriatric ward, CT scans for outpatients with symptoms of stroke in 1997, and death certificates to ensure inclusion of patients dying from stroke inside and outside of the hospital. Stroke was defined according to the World Health Organization (WHO) criteria as “rapidly developing clinical symptoms and/or signs of focal and at times global, loss of cerebral function with symptoms lasting more than 24 hours or leading to death, with no apparent cause other than that of vascular origin.”12 All acute events occurring within 21 days from the onset of the first event were considered as part of the same event. Clinical subtypes of stroke were determined by reviewing medical records and death certificates and by telephone calls. No expatriates returned to his or her home country before 1 month from the onset of stroke. Cerebral ischemia (CI), intracerebral hemorrhage (ICH), and subarachnoid hemorrhage (SAH) were determined by noncontrast brain CT scan within 3 days of admission to the hospital. No
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Table 1. Numbers and sex-specific incidence rates of first-ever stroke in Qatar, 1997 Men Age group (y)
No. of cases/ No. at risk
Women
Total
Rate (per 100,000)
95% CI
No. of cases/ No. at risk
Rate (per 100,000)
95% CI
No. of cases/ No. at risk
Rate (per 100,000)
95% CI
0 2 5 32 122 263 684 1,421 46
0 0.05-13.0 1.2-11.6 21.5-46.7 87.6-159.6 179.0-373.9 428.7-1,035.6 910.4-2,114.2 87.6-159.6
0/67,009 0/27,919 1/33,618 7/32,035 13/11,731 14/4,820 16/1,773 9/659 60/179,564
0 0 3 22 111 290 902 1,365 33
0 0 0.07-16.5 0.07-17.3 65.2-200.2 158.7-487.3 515.7-1,465.4 624.4-2,592.5 22.5-48.7
0/137,705 1/70,490 5/121,208 35/118,541 60/50,156 45/16,236 38/4,989 33/2,345 217/522,023
0 1 4 30 120 277 762 1,407 41
0 0.03-7.9 1.3-9.6 16.3-35.1 91.2-153.9 197.8-363.0 539.0-1,045.4 967.4-1,973.7 30.2-52.4
0-14 0/70,696 15-24 1/42,571 25-34 4/87,590 35-44 28/86,506 45-54 47/38,425 55-64 31/11,766 65-74 22/3,216 75⫹ 24/1,689 TOTAL 157/342,459
patient required lumbar puncture. Repeat CT scan or magnetic resonance imaging (MRI) was performed within 2 weeks of admission if the initial CT scan was normal. Vascular investigations were performed occasionally, but these data were not analyzed. Statistical Methods Age and sex specific incidence rates were calculated, and to make the results comparable with other studies, rates were presented in 10-year age groups. The calculations of age standardized incidence were adjusted directly to world standard population with the direct age standardization method.13 The 95% confidence intervals (CI) for the incidence were calculated with standard techniques.14
Results During 1997, 217 subjects were identified. Of these, 99% were inpatients. All patients were admitted to the medical wards except 2 patients who resided in the
geriatric ward and another 2 patients who were identified by reviewing outpatient CT scan reports. No patients were included from the review of death certificates, and 14 patients with recurrent stroke were found and excluded. FES occurred in 157 men (72.4%) and in 60 women (27.6%). The mean age of patients with FES was 57 years for men and 60 years for women. Men outnumbered women in all age groups by a ratio 2.6:1. Stroke incidence rose steeply with age in both men and women. Thirty-nine patients (18%) were younger than 45 years. Native Qataris comprised 132 patients, 88 men with a mean age of 59 years and 44 women with a mean age of 61 years. The remaining 85 were expatriates of different nationalities, 69 men with a mean age of 55 and 16 women with a mean age of 58. All patients included in the study had CT scans within 3 days after admission; 173 patients (80%) were diagnosed with CI, 42 patients (19%) were diagnosed with ICH, and 2 patients (1%) were diagnosed with SAH. The age and sex incidence rates for FES are shown in Tables 1 and 2. The overall crude annual incidence rate
Table 2. Numbers and sex-specific incidence rates of first-ever stroke by subtypes in Qatar, 1997 Cerebral infarction Men Age Rate (per group, No. of cases/ 100,000) Y (y) No. at risk 0-14 15-24 25-34 35-44 45-54 55-64 65-74 75⫹ Total
0/70,696 1/42,571 3/87,590 23/86,506 34/38,425 26/11,766 17/3,216 19/1,689 123/342,459
0 2 3 27 88 221 529 1,125 36
Intracerebral hemorrhage Women
Men
Women
No. of cases/ No. at risk
Rate (per 100,000)
No. of cases/ No. at risk
Rate (per 100,000)
No. of cases/ No. at risk
Rate (per 100,000)
0/67,009 0/27,919 1/33,618 5/32,035 10/11,731 12/4,820 14/1,773 8/659 50/179,564
0 0 3 16 85 249 790 1,214 28
0/70,696 0/42,571 1/87,590 5/86,506 11/38,425 5/11,766 5/3,216 5/1,689 32/342,459
0 0 1 6 30 42 155 296 9
0/67,009 0/27,919 0/33,618 1/32,035 4/11,731 2/4,820 2/1,773 1/659 10/179,564
0 0 0 4 34 41 113 152 6
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239
Table 3. Distribution of risk factors according to nationality and type of stroke Men
Women
Risk factor
CI
ICH
CI
ICH
Total
Qataris (n) Hypertension Diabetes mellitus Ischemic heart disease Atrial fibrillation Expatriates (n) Hypertension Diabetes mellitus Ischemic heart disease Atrial fibrillation
74 33 32 12 3 49 38 36 8 5
14 10 2 6 0 18 19 0 0 0
36 18 21 8 2 14 7 3 2 0
8 7 2 2 0 2 2 0 0 0
132 68 (55%) 57 (46%) 28 (22%) 5 (4%) 83 66 (77%) 39 (45%) 10 (11%) 5 (5%)
was 41 per 100,000 inhabitants per year (95% CI, 30.252.4). The crude incidence for people older than 45 years was 238 per 100,000 inhabitants per year. When standardized to world standard population, the FES incidence rate becomes 58 per 100,000 inhabitants per year (95% CI, 43.1-73.8), and if standardized to the European population, the incidence rate rises to 100 per 100,000 per year. Because Qataris account for approximately 35% of the general population (no official figure has been released), the crude incidence among them is 73 per 100,000 per year. The overall 30-day fatality rate for patients with FES was 16%. Patients with ICH had a higher mortality rate than patients with CI (31% v 12%). The frequencies of risk factors are shown in Table 3. HTN in native Qatari men was significantly less frequent than in expatriate men (48% v 77%, P ⫽ .02), but DM was more common in native Qatari women than in expatriate women (52% v 18%, P ⫽ .02).
Discussion In many circumstances, population-based studies provide the best estimation of stroke incidence.15 However, the particular circumstances of Hamad General Hospital are favorable to such a study in Qatar. We made every effort to ensure complete case ascertainment. The dramatic presentation of stroke, the small area of the country, and the free access to the only available ED means that almost all patients with acute stroke will come to the hospital. Therefore, the results of this study very likely reflect the incidence of stroke in Qatar. It is possible that some patients with mild symptoms and those, especially the very elderly, who died from stroke at home outside Doha and in whom the diagnosis was missed in their death certificates were excluded. Therefore, the results of this study do not truly reflect the incidence of stroke in Qatar. Nonetheless, they represent the true incidence as
closely as possible, and will serve to guide Qatar health authorities in stroke management. The crude annual incidence rate that we observed is in line with that of 43 to 63 per 100,000 found in Saudi Arabia4 and Libya16 and is much less than the rate of 150 to 500 per 100,000 reported from Western countries12,17 and Japan.18 This is explained by the pattern of population structure in Qatar, which is similar to that in Saudi Arabia but different from that in Europe and Japan. The crude incidence of 238 per 100,000 per year in Qatar is older than 45 years is within the same range as the incidence in this age group in Western countries.19 The age-adjusted annual incidence rate of 58 per 100,000 per year is less than the range of 105 to 280 per 100,000 per year observed in most worldwide studies.19,20 The incidence of 26 per 100,000 inhabitants in Nigeria is far below the Qatari rates.21 The high male to female ratio of stroke in Qataris was inexplicable, because Qatari women visit the hospital as, if not more, frequently as men. The fact that elderly Qatari women (who constitute the minority of our patient population) were reluctant to be admitted to the hospital, despite easy access and equal care, could contribute to this finding. The male to female ratio in Saudi Arabia was also high, ranging from 1.4 to 3.4, and no explanation was given for this observation.3,4,22 A higher ratio was expected in expatriates, because men grossly outnumber women. The 80% CI is similar to that reported in North America and Europe.19 The incidence of ICH (19%) is higher than in Western countries19 but lower than in Eastern countries like Japan.18 It is similar to the figures reported in Saudi Arabia,3 Libya,16 and Greece.23 The low incidence of SAH (1%) is less than that (3.5%-17%) found in other countries,16,19 but similar to that of the eastern province of Saudi Arabia (1.4%).3 A similar trend was noted in the Arab populations of other countries in the Middle East.24
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The 30-day patient fatality rate in Qatar is much lower than in Nigeria24 and the United States25 but similar to that in Saudi Arabia,3 Libya,16 and Germany.26 As we expected, the fatality rate in patients with ICH (31%) was higher than that of patients with CI (13%). The relatively young age of stroke patients and the frequency of their admission to the hospital may explain Qatar’s low 30-day fatality rate. Thirtynine (18%) of our patients were younger than 45 years; 80% of them had CI and 20% had ICH. Common risk factors were HTN (69%), DM (33%), and cardiac disease (8%). In Libya, a comparable percentage of stroke victims were younger than 45 years (19%),16 but a lower percentage was reported in Saudi Arabia (10%).3 Risk factors were not mentioned in these studies. In Sweden, 25% of young patients with CI were hypertensive, and 5% were diabetic.27 In our Qatari patient population, HTN was the most common risk factor for stroke (63%). Likewise, 54% of stroke patients in Libya16 and 34% in Saudi Arabia were hypertensive.3,4 In other developed countries, HTN ranged from 12% to 17% depending on the patients’ ethnic groups.8,28 DM was the second most common risk factor (42%), especially among native Qatari women, and, similarly, accounted for 44% of stroke patients in Tripoli Libya.16 In Saudi Arabia, 37% of stroke patients were diabetic,3 and 0.5% to 23% were diabetic in the developed countries.12,29 In a recent survey of Qataris older than 30 years, 20% were found to be hypertensive, and 15% were diabetic (personal communication). These high figures are attributed to a sedentary lifestyle, stress (especially among expatriates), diet, and consanguineous marriage. However, the rate of HTN and DM in Qatari stroke patients clearly exceeded the rates in the overall native population. In addition, the proportion of Qatari stroke patients with coronary artery disease (17%) is less than that reported in other countries (26%),3,30 which may be a result of the inclusion of rheumatic heart disease in the other studies, the young age of the Qatari patients, and the low incidence of atrial fibrillation (4.5%) noted in our study (incidence of atrial fibrillation in Sweden, for example, is 19%31). In conclusion, the results of our hospital-based (not community-based) study do not reflect the true incidence of stroke and 30-day fatality rate in Qatar, but they represent the true incidence as nearly as possible and take some risk factors into account. A national stroke registry has been initiated to overcome the few limitations of this study. We believe that the low crude stroke incidence that we found in Qatar may increase in the future because of the population’s expected age increase. A national program dealing with the common risk factors for stroke is necessary to combat this potential rise in stroke incidence.
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