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Stroke types in rural and urban northern portugal: incidence and 7-year survival in a community-based study.

Correia M, Magalhães R, Silva MR, Matos I, Silva MC - Cerebrovasc Dis Extra (2013)

Bottom Line: The age-specific rural/urban incidence rate ratios for IS in the youngest group (<55 years) was 0.27 (95% CI, 0.11-0.69), increasing to 1.47 (95% CI, 1.07-2.01) for those aged 65-74 years and to 1.87 (95% CI, 1.39-2.52) for those between 75 and 84 years.Rural compared to urban patients with an IS were predominantly men, had a prevalence ratio (PR) of 1.28 (95% CI, 1.05-1.56), were 65 years or older (PR = 1.18; 95% CI, 1.08-1.30) and had in general a lower prevalence of risk factors.Although patients from rural areas were older, the relatively lower prevalence of simultaneously occurring risk and prognostic factors among them as well as the similar management of rural and urban patients may justify why rurality is not associated with long-term survival.

View Article: PubMed Central - PubMed

Affiliation: Serviço de Neurologia, Hospital de Santo António - Centro Hospitalar do Porto, Portugal ; UNIFAI, Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal.

ABSTRACT

Background/aim: Differences in stroke incidence and mortality between regions could stem from differences in the incidence of particular stroke types and long-term prognosis. The aim of this study was to investigate whether different risk profiles and stroke types underlie the difference in stroke incidence and patient long-term survival in rural and urban populations.

Methods: All suspected first-ever-in-a-lifetime strokes occurring between October 1998 and September 2000 in 37,290 residents of rural municipalities and in 86,023 individuals living in the city of Porto were entered into a population-based registry. Standard definitions of stroke types and overlapping comprehensive sources of information were used for patient identification. Patients were examined by neurologists at 3 months, 1 year and 7 years after the index event.

Results: From a total of 688 patients included (226 in rural and 462 in urban areas), 76.2% had an ischaemic stroke (IS; 75.3 vs. 77.9%), 16.1% a primary intracerebral haemorrhage (PICH; 16.3 vs. 14.6%) and 3.3% a subarachnoid haemorrhage (SAH; 2.7 vs. 3.7%); in 4.4% (4.9 vs. 4.1%), the stroke type could not be determined. The annual incidence rate per 1,000 was 2.13 (95% CI, 1.95-2.31), 0.45 (95% CI, 0.37-0.53), 0.09 (95% CI, 0.06-0.14) and 0.12 (95% CI, 0.08-0.17), respectively. The age-specific rural/urban incidence rate ratios for IS in the youngest group (<55 years) was 0.27 (95% CI, 0.11-0.69), increasing to 1.47 (95% CI, 1.07-2.01) for those aged 65-74 years and to 1.87 (95% CI, 1.39-2.52) for those between 75 and 84 years. Rural compared to urban patients with an IS were predominantly men, had a prevalence ratio (PR) of 1.28 (95% CI, 1.05-1.56), were 65 years or older (PR = 1.18; 95% CI, 1.08-1.30) and had in general a lower prevalence of risk factors. There was no evidence of rural/urban differences in 28-day case fatality for the stroke types, although IS tended to be less fatal among urban patients (10.3 vs. 13.1%), whereas PICH (33.3 vs. 24.2%) and SAH (35.3 vs. 16.7%) were less fatal among rural patients. Independently of rural/urban residence, predictors of poor survival after the acute phase (28 days) were age >65 years (HR = 3.57; 95% CI, 2.6-4.9), diabetes (HR = 1.5; 95% CI, 1.2-1.9), ischaemic heart disease (HR = 1.8; 95% CI, 1.3-2.6), atrial fibrillation (HR = 1.5; 95% CI, 1.1-2.0) and smoking habits (HR = 1.6; 95% CI, 1.1-2.3).

Conclusions: The age pattern of IS incidence marks the difference between rural and urban populations; the youngest urban and the oldest rural residents were at a higher risk. Although patients from rural areas were older, the relatively lower prevalence of simultaneously occurring risk and prognostic factors among them as well as the similar management of rural and urban patients may justify why rurality is not associated with long-term survival.

No MeSH data available.


Related in: MedlinePlus

Joint distribution of standardized IS and intracerebral haemorrhage incidence in community-based studies. The lines represent the median values.
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Figure 3: Joint distribution of standardized IS and intracerebral haemorrhage incidence in community-based studies. The lines represent the median values.

Mentions: Figure 3 shows the joint distribution of IS and PICH incidence across community-based studies with standardized rates (European population) or if data were available for calculation [12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34]. The IS incidence ranged from 57/100,000 in Menorca [29] to 255/100,000 in Mashhad [33], and the incidence of PICH ranged from 6/100,000 in Dijon [29] to 39/100,000 in Tbilisi [26]. Both Portuguese urban and rural populations are in the upper-right quadrant, indicating a relatively high incidence of both IS and PICH, with the first being only higher in Mashhad, Kaunas, Orebro and Matão [23,28,29,33] and the latter in Mashhad, Tbilisi and Takashima [14,26,33]. Apart from Japan, studies in Greece [16], Italy [15,19,21] and Georgia [26] also reported a relatively high incidence of PICH, probably linked to the high prevalence of hypertension and excess of salt in the Mediterranean diet, similar to the Japanese diet with a high consumption of salted fish [35]. The standardized incidence of SAH in this group of studies ranged from 1 to 16/100,000 (median = 6/100,000), and the values in Portugal are close to the median. The comparison of the incidence of stroke types may be biased since the incidence of undetermined strokes could be as high as 59/100,000 (Trivandrum [30]), resulting from the low proportions of patients investigated with brain CT/MR scan and/or with a postmortem examination. Though we verified that there was no linear correlation between the year of the study and the standardized incidence of the different stroke types, the same could not be said in relation to the prevalence of VRF as a trend towards a lower incidence of PICH was found in repeated studies in Takashima [14], South London and Dijon [18,29] (fig. 2). Nevertheless, in comparison with other studies, the prevalence of hypertension in patients from an urban area, representing a population-attributable risk for IS of 45.2% and for PICH of 73.6% [36], is among the highest (only exceeded in Oxfordshire [12] and Iquique [24]) for IS, and is the highest among Portuguese patients with PICH [15,27,37]; the same was found for diabetes mellitus, though the proportion of active smokers was relatively low compared to other studies [12,15]. Besides traditional risk factors, environmental factors such as cold weather [38] and dietary habits may explain the relatively high variation shown in incidence rates.


Stroke types in rural and urban northern portugal: incidence and 7-year survival in a community-based study.

Correia M, Magalhães R, Silva MR, Matos I, Silva MC - Cerebrovasc Dis Extra (2013)

Joint distribution of standardized IS and intracerebral haemorrhage incidence in community-based studies. The lines represent the median values.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3843922&req=5

Figure 3: Joint distribution of standardized IS and intracerebral haemorrhage incidence in community-based studies. The lines represent the median values.
Mentions: Figure 3 shows the joint distribution of IS and PICH incidence across community-based studies with standardized rates (European population) or if data were available for calculation [12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34]. The IS incidence ranged from 57/100,000 in Menorca [29] to 255/100,000 in Mashhad [33], and the incidence of PICH ranged from 6/100,000 in Dijon [29] to 39/100,000 in Tbilisi [26]. Both Portuguese urban and rural populations are in the upper-right quadrant, indicating a relatively high incidence of both IS and PICH, with the first being only higher in Mashhad, Kaunas, Orebro and Matão [23,28,29,33] and the latter in Mashhad, Tbilisi and Takashima [14,26,33]. Apart from Japan, studies in Greece [16], Italy [15,19,21] and Georgia [26] also reported a relatively high incidence of PICH, probably linked to the high prevalence of hypertension and excess of salt in the Mediterranean diet, similar to the Japanese diet with a high consumption of salted fish [35]. The standardized incidence of SAH in this group of studies ranged from 1 to 16/100,000 (median = 6/100,000), and the values in Portugal are close to the median. The comparison of the incidence of stroke types may be biased since the incidence of undetermined strokes could be as high as 59/100,000 (Trivandrum [30]), resulting from the low proportions of patients investigated with brain CT/MR scan and/or with a postmortem examination. Though we verified that there was no linear correlation between the year of the study and the standardized incidence of the different stroke types, the same could not be said in relation to the prevalence of VRF as a trend towards a lower incidence of PICH was found in repeated studies in Takashima [14], South London and Dijon [18,29] (fig. 2). Nevertheless, in comparison with other studies, the prevalence of hypertension in patients from an urban area, representing a population-attributable risk for IS of 45.2% and for PICH of 73.6% [36], is among the highest (only exceeded in Oxfordshire [12] and Iquique [24]) for IS, and is the highest among Portuguese patients with PICH [15,27,37]; the same was found for diabetes mellitus, though the proportion of active smokers was relatively low compared to other studies [12,15]. Besides traditional risk factors, environmental factors such as cold weather [38] and dietary habits may explain the relatively high variation shown in incidence rates.

Bottom Line: The age-specific rural/urban incidence rate ratios for IS in the youngest group (<55 years) was 0.27 (95% CI, 0.11-0.69), increasing to 1.47 (95% CI, 1.07-2.01) for those aged 65-74 years and to 1.87 (95% CI, 1.39-2.52) for those between 75 and 84 years.Rural compared to urban patients with an IS were predominantly men, had a prevalence ratio (PR) of 1.28 (95% CI, 1.05-1.56), were 65 years or older (PR = 1.18; 95% CI, 1.08-1.30) and had in general a lower prevalence of risk factors.Although patients from rural areas were older, the relatively lower prevalence of simultaneously occurring risk and prognostic factors among them as well as the similar management of rural and urban patients may justify why rurality is not associated with long-term survival.

View Article: PubMed Central - PubMed

Affiliation: Serviço de Neurologia, Hospital de Santo António - Centro Hospitalar do Porto, Portugal ; UNIFAI, Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal.

ABSTRACT

Background/aim: Differences in stroke incidence and mortality between regions could stem from differences in the incidence of particular stroke types and long-term prognosis. The aim of this study was to investigate whether different risk profiles and stroke types underlie the difference in stroke incidence and patient long-term survival in rural and urban populations.

Methods: All suspected first-ever-in-a-lifetime strokes occurring between October 1998 and September 2000 in 37,290 residents of rural municipalities and in 86,023 individuals living in the city of Porto were entered into a population-based registry. Standard definitions of stroke types and overlapping comprehensive sources of information were used for patient identification. Patients were examined by neurologists at 3 months, 1 year and 7 years after the index event.

Results: From a total of 688 patients included (226 in rural and 462 in urban areas), 76.2% had an ischaemic stroke (IS; 75.3 vs. 77.9%), 16.1% a primary intracerebral haemorrhage (PICH; 16.3 vs. 14.6%) and 3.3% a subarachnoid haemorrhage (SAH; 2.7 vs. 3.7%); in 4.4% (4.9 vs. 4.1%), the stroke type could not be determined. The annual incidence rate per 1,000 was 2.13 (95% CI, 1.95-2.31), 0.45 (95% CI, 0.37-0.53), 0.09 (95% CI, 0.06-0.14) and 0.12 (95% CI, 0.08-0.17), respectively. The age-specific rural/urban incidence rate ratios for IS in the youngest group (<55 years) was 0.27 (95% CI, 0.11-0.69), increasing to 1.47 (95% CI, 1.07-2.01) for those aged 65-74 years and to 1.87 (95% CI, 1.39-2.52) for those between 75 and 84 years. Rural compared to urban patients with an IS were predominantly men, had a prevalence ratio (PR) of 1.28 (95% CI, 1.05-1.56), were 65 years or older (PR = 1.18; 95% CI, 1.08-1.30) and had in general a lower prevalence of risk factors. There was no evidence of rural/urban differences in 28-day case fatality for the stroke types, although IS tended to be less fatal among urban patients (10.3 vs. 13.1%), whereas PICH (33.3 vs. 24.2%) and SAH (35.3 vs. 16.7%) were less fatal among rural patients. Independently of rural/urban residence, predictors of poor survival after the acute phase (28 days) were age >65 years (HR = 3.57; 95% CI, 2.6-4.9), diabetes (HR = 1.5; 95% CI, 1.2-1.9), ischaemic heart disease (HR = 1.8; 95% CI, 1.3-2.6), atrial fibrillation (HR = 1.5; 95% CI, 1.1-2.0) and smoking habits (HR = 1.6; 95% CI, 1.1-2.3).

Conclusions: The age pattern of IS incidence marks the difference between rural and urban populations; the youngest urban and the oldest rural residents were at a higher risk. Although patients from rural areas were older, the relatively lower prevalence of simultaneously occurring risk and prognostic factors among them as well as the similar management of rural and urban patients may justify why rurality is not associated with long-term survival.

No MeSH data available.


Related in: MedlinePlus