Stroke in the Very Old: Incidence, Risk Factors, Clinical Features, Outcomes and Access to Resources – A 22-Year Population-Based StudyBéjot Y.a · Rouaud O.a · Jacquin A.a · Osseby G.-V.a · Durier J.a · Manckoundia P.b · Pfitzenmeyer P.b · Moreau T.a · Giroud M.a
aStroke Registry of Dijon (Inserm et Institut de Veille Sanitaire), EA4184, University Hospital and Faculty of Medicine and Department of Neurology, and bDepartment of Geriatrics, University Hospital and Faculty of Medicine of Dijon, Dijon, France Corresponding Author
Background: For several years, the burden of stroke in very old patients has been increasing in western countries. Nevertheless, we have little information about this new challenge in individuals ≧80. Methods: We ascertained all first-ever strokes in the population of Dijon, France (150,000 inhabitants), from 1985 to 2006. The incidence of stroke, risk factors, clinical presentation, resource mobilization and 1-month outcome were evaluated in individuals ≧80 and compared to the data obtained in younger patients. Results: We collected 1,410 first-ever strokes in people ≧80 years (39%) versus 2,130 in those <80 years. The incidence was 997/100,000, and 68/100,000, respectively. Over the 22 years, the incidence of stroke in individuals ≧80 years rose significantly. A lower prevalence of diabetes, hypercholesterolemia and alcohol intake, as well as a higher prevalence of hypertension, atrial fibrillation, previous myocardial infarction and use of prestroke antiplatelet agents were noted in patients ≧80 years. The clinical presentation was severer and the 1-month outcome in terms of case fatality and handicap was worse, despite improvements observed over time. Finally, in patients ≧80 years, the use of CT scan, MRI, cervical Doppler, angiography and carotid surgery were significantly lower than for younger patients. Length of stay >30 days was more frequent, and discharge to prestroke residence was less common. However, all these improved between the first and the last study periods. Conclusions: Our findings have important implications not only for clinical management but also for initiating preventive strategies and health policy.
Copyright © 2009 S. Karger AG, Basel
Population aging is a rapidly increasing phenomenon worldwide with important consequences for the organization of health care systems. Considering that stroke incidence is largely related to age, a rise in the absolute number of strokes is expected in elderly people. Moreover, thanks to medical progress in both prevention and acute care for stroke, there has been a decrease in case fatality and mortality in the elderly and thus both an increase in the number of survivors with handicap and longer periods of handicap before death [1,2,3,4,5]. Since the very elderly are the fastest-growing segment of the elderly population in developed countries, the burden of stroke-related disability is expected to rise further [1,2,4]. Consequently, it is necessary to have accurate data on the specific characteristics of stroke in old patients in order to plan health care systems and to allocate resources.
Unfortunately, there is little information on stroke care in patients >80, and very elderly patients are rarely included in clinical trials . Some data are available but are of limited interest because they come from hospital-based studies or only assess ischemic stroke over a short period [1,2,7,8].
The objective of the present study was to evaluate the differences in demographics, risk factors, clinical presentation, resource mobilization and 1-month outcome of first-ever stroke in patients aged ≧80 years and to compare these data with those of younger age groups. Data were obtained from the population-based registry of Dijon, France, from 1985 to 2006.
Material and Methods
The study population comprised all residents of the town of Dijon, in eastern France. According to the national census, the population of Dijon was 146,723 in 1990 and 150,138 in 1999. The number of individuals aged ≧80 years increased by 7.3% between 1985 and 2006.
The detailed methodology of case ascertainment has already been described elsewhere . Briefly, multiple overlapping sources of information were used to ensure the completeness of case ascertainment by identifying both hospitalized and nonhospitalized cases of fatal and nonfatal strokes, as recommended for the running of ‘ideal’ stroke incidence studies . Hence, information was obtained from 6 sources: (1) from the emergency rooms, as well as all of the clinical and radiological departments of Dijon University Hospital, with diagnosis of stroke made by one of the neurologists of the Department of Neurology; (2) from the emergency rooms and all of the clinical departments of the 3 private hospitals of the city and its suburbs, with diagnosis made by private neurologists working in these establishments; (3) from the patient’s home or from the nursing homes of the city, with diagnosis assessed by the 250 general practitioners with the help of an outpatient clinic with either a public or private neurologist who notified and registered the cases; (4) from the 3 private radiological centers, where the medical records were reviewed to identify missed cases that had not been transferred to the registry by the general practitioners; (5) from the ultrasound Doppler centers of the University Hospital and private centers, where medical records were reviewed, and (6) from the death certificates with stroke as the underlying cause of death obtained from the local Social Security Bureau that is responsible for registering all deaths in the community. All of the collected death certificates were checked by a member of our team in order to include only patients who died from stroke.
To assess the quality and the validity of the registry, an external audit check has been performed every 4 years by the National Medical Research Institute.
Stroke was defined according to World Health Organization recommendations  and the International Classification of Disease . The stroke subtype was always diagnosed on a clinical basis completed by cerebral imaging, complementary investigations including 2-dimensional echocardiography (transthoracic or transeosophageal cardiography), carotid and vertebral ultrasonography, as well as standard blood and urine tests.
The classification used since 1985 in the Dijon Stroke Registry is as follows: (1) ischemic strokes from lipohyalinosis of small arteries, so-called lacunar infarct (LACI) defined as a stroke presenting one of the classical lacunar syndromes and confirmed by a small (<15 mm in diameter) subcortical infarct on brain CT scan or MRI in the absence of any other morphological cause of ischemic stroke found in the neuroimaging examination; (2) ischemic stroke from cardiac embolism (CE) due to either atrial fibrillation (AF) diagnosed on EKG or Holter EKG, or to valve disease, patent foramen ovale associated with atrial septal aneurysm or spontaneous intracavitar thrombus on echocardiography; (3) all other ischemic strokes characterized by focal cortical symptoms and cortical infarct on a large vascular territory on CT or MRI. This subtype included ischemic stroke from both atheroma of large arteries, and from other or undetermined cause, but the distinction between these was not made before 2005, which explains why they were gathered together in 1 category; (4) spontaneous intracerebral hemorrhage, and (5) subarachnoid hemorrhage. For cerebral infarction, when it was difficult to differentiate between LACI, CE and other ischemic stroke, medical staff meetings were held to classify the type.
In addition, ischemic strokes were categorized according to the clinical presentation according to the classification of the Oxfordshire Community Stroke Project (OCSP) . Hence we distinguished LACI, total anterior circulation infarct (TACI), partial anterior circulation infarct (PACI) and posterior circulation infarct (POCI).
We collected prestroke vascular risk factors using the same methodology throughout the study period . Hypertension was defined by a history of known hypertension or antihypertensive treatment. Diabetes mellitus was recorded if a glucose level of ≧7.8 mmol/l had been reported in the medical record or if the patient was on insulin or oral hypoglycemic agents. Hypercholesterolemia was defined by total cholesterol level ≧5.7 mmol/l or if the patient was under lipid-lowering therapy. We also recorded alcohol intake (≧1 glass per day), AF, history of transient ischemic attack (TIA), previous myocardial infarction and peripheral vascular disease. Smoking was not included in the analysis because >10% of the data was missing.
Prestroke antithrombotic therapy was also recorded. We distinguished between anticoagulants (warfarin, acenocoumarol or fluindione) and antiplatelet agents (aspirin, clopidogrel, ticlopidine or dipyridamole).
At stroke onset, the following neurological data were recorded: coma, confusion, aphasia, hemiplegia, hemianopsia, hemianesthesia, cerebellar dysfunction, cranial nerve palsy and seizure.
Outcome data were collected 1 month after stroke onset. They comprised information on vital status, and for all patients, a self-constructed handicap scale was used to measure functional impairment. The handicap scale included 6 grades (1 = walking alone; 2 = walking with support; 3 = walking stick; 4 = wheelchair; 5 = bedridden; 6 = dead). This scale has been in use since establishment of the registry in 1985. We initially chose it because information for the modified Rankin (m-Rankin) scale  was only introduced into the registry database in 1997. Nevertheless, since this date, functional impairment has been measured both by handicap scale and m-Rankin score in 1,315 patients. The level of agreement between the 2 scales (weighted ĸ coefficient) was 0.92. Hence, in this study the outcome is expressed according to the m-Rankin scale for all patients.
We collected the type of procedure used for the patients (cerebral CT scan and MRI, cervical ultrasound, echocardiography, conventional angiography, carotid surgery), the length of stay (LOS), the type of care system and discharge to prestroke residence.
We assumed Poisson distribution for the annual number of events to calculate 95% confidence intervals (CI) for the incidence rates. To evaluate the impact of the time period on stroke incidence, incidence rate ratios (IRR) were calculated using a Poisson regression in which time was considered a continuous variable. Case fatality rates (CFR) based on survival at 1 month were estimated by the Kaplan-Meier method. Their temporal trends were evaluated by linear regression. The χ2 test was used to assess differences in the proportion of stroke subtypes by age, vascular risk factors, prestroke treatments, baseline clinical features, distribution of ischemic strokes according to OCSP classification, outcome at 1 month and resource use.
The associations between stroke subtype, risk factors and prestroke treatments and both 1-month case-fatality and high handicap, defined as m-Rankin score 4–5, were analyzed using logistic regression to estimate odds ratios (ORs) and 95% CI. In multivariate analyses, we introduced gender, stroke subtype and all potential confounders into the models, with a p value <0.20 in univariate analysis.
p values <0.05 were considered statistically significant. Statistical analysis was performed with STATA® 9.0 software.
The study protocol of the Stroke Registry of Dijon was approved by the national and local ethics review board.
Over the 22 years, we collected 1,410 consecutive first-ever strokes in patients ≧80 years (39.8%, including 33% of males) versus 2,130 in those <80 years (60.1%, including 56% of males).
Over the whole study period, the incidence of first-ever stroke in people ≧80 years was 997/100,000/year (95% CI: 945–1,050) versus 68/100,000/year (95% CI: 65–71) in those <80 years (table 1). From 1985 to 2006, the IRR was 1.013 (95% CI: 1.004–1.021, p = 0.003), which indicates a significant and continuous increase of 1.3% per year in the incidence of stroke in individuals ≧80. A similar increase was noted in people <65 years, which is in contrast with a decrease observed in those aged 65–80 years.
|Table 1. Incidence rates of first-ever stroke in patients <65, 65–80 and 80 years, by study periods|
For every stroke subtype except spontaneous intracerebral hemorrhage, the incidence among people ≧80 years was higher than that among younger patients. Concerning the distribution, a greater proportion of CE ischemic stroke was noted in patients ≧80 years compared to younger patients (table 2). In contrast, the distribution of the other stroke subtypes was similar in the 2 groups.
|Table 2. Incidence rates of first-ever stroke subtypes from 1985 to 2006|
Whatever the sex, there was a lower prevalence of diabetes, hypercholesterolemia and alcohol intake among stroke patients ≧80 years compared with younger patients (table 3). In contrast, in this older group, a significantly higher prevalence of hypertension, AF, previous myocardial infarction and use of antiplatelet agents was found. Of note, the use of anticoagulants in patients with a history of AF was lower in men ≧80 years.
|Table 3. Distribution of vascular risk factors, prestroke treatments, baseline clinical features, outcome at 1 month and resource use in stroke patients ≤65, 65–80 and 80 years, over the whole study period|
Among men ≧80 years, a significantly higher proportion of coma, hemiplegia and aphasia at stroke onset was noted compared with younger patients (table 3). In women ≧80 years, hemiplegia and aphasia were more frequent. Conversely, whatever the sex, cerebellar dysfunction was more frequent in younger patients. For ischemic stroke, TACI was more common in older subjects. Nevertheless, the frequency of this clinical presentation decreased over time (table 4).
|Table 4. Distribution of vascular risk factors, prestroke treatments, baseline clinical features, outcome at 1 month and resource use in stroke patients 80 years, by time periods|
In stroke patients ≧80 years, a higher proportion of moderate (m-Rankin score 2–3) and severe handicap (m-Rankin score 4–5) at 1 month was observed (table 3). After multivariate analysis, TACI presentation, hemorrhagic stroke and male sex were associated with an increased risk of severe handicap (table 5).
|Table 5. Predictors of 1-month case fatality and high handicap defined as m-Rankin score 4–5 in patients 80 years|
The CFR in stroke patients ≧80 years were higher than those in patients ≤65 and 65–85 years (23.2 vs. 7.2 and 14.2%, respectively; p < 0.001), but they significantly decreased over the 22-year study period (linear trend: –0.56%, p = 0.041; table 6). This decrease was due to a fall in the CFR of hemorrhagic stroke, whereas those of ischemic stroke did not change over time. After multivariate analysis, both TACI and POCI presentation, hemorrhagic and undetermined stroke, as well as history of AF were predictors of 1-month case fatality (table 5). In contrast, history of hypercholesterolemia was associated with lower risk.
|Table 6. Case fatality rates at 1 month according to age, stroke subtype and study period|
Compared with younger patients, stroke patients ≧80 years were more frequently managed at the public hospital and less frequently at private hospitals (table 3). In addition, elderly women were less often treated at home. Over time, a slight shift from management at public hospital to management at private hospital was observed in stroke patients ≧80 years (table 4). In these older people, the use of CT scan, MRI, cervical Doppler, angiography and carotid surgery were significantly lower than for younger patients (table 3). LOS >30 days was more frequent, whereas a higher proportion of younger patients had a LOS <10 days. Both men and women ≧80 years were less likely to be discharged to their prestroke residence after stroke. However, all these patients improved between the first and the last study periods (table 4).
In this comprehensive population-based study, we found that 39% of the strokes occurred in individuals aged ≧80. This proportion is similar to the few data reported in the literature [1,2,4]. The growth in the number of old people is faster than that in the population at large, and it is well known that the prevalence of vascular risk factors, lower compliance with medication and low socioeconomic status all increase with age [14,15,16], leading to a rise in the risk of stroke in the elderly [3,4,17].Despite these observations, people aged ≧80 are rarely included in clinical trials. However, primary prevention seems to be efficient in this age group, as demonstrated by trials on antihypertensive therapy [18,19]. In addition, there is little information about either the management or the epidemiology of stroke in this population [14,15,16,17].
Several factors could explain the increase in the incidence of stroke observed in this study. As the incidence rises with age, it could be the consequence of an increase in the mean age of those in the >80-year stratum over time. Another reason could be a change in the prevalence of risk factors in this age group. Indeed, although we cannot extrapolate our results to all residents in our community, since patients who suffer from stroke represent a failure of preventive therapies, an increase in the prevalence of prestroke diabetes and hypercholesterolemia was noted. Finally, changes in the incidence could be partly related to the better detection of minor stroke thanks to improvements in diagnosis techniques.
In the comparison with younger patients, the predominance of women in patients ≧80 years can be explained by the natural higher mortality in men [1,2,3,4,5,16]. With regard to the stroke subtype, the proportion of cardioembolic stroke in patients ≧80 years is characteristic of this age, as previously reported [2,20,21], because the prevalence of AF, which accounts for approximately half of the overall CE strokes, rises with age [20,21], and may explain, for a large part, the greater incidence of stroke in patients ≧80 years. In addition, this high proportion of CE strokes could explain in part the relatively lower occurrence of diabetes, hypercholesterolemia, as well as alcohol and tobacco abuse in this age group, as these risk factors are rather associated with other ischemic stroke subtypes .
The similarly large proportion of untreated hypertension in patients <80 and ≧80 years may suggest that the early diagnosis and treatment of hypertension is not efficient enough in our city, whatever the age, indicating a need for new preventive strategies. In addition, only 8.6% of the men and 9.9% of the women ≧80 years with a history of AF were on anticoagulants, even though this treatment is efficient in preventing stroke in this age group . However, the increase in the use of anticoagulants as well as that of antiplatelet agents over the 22 years suggests a real improvement in medical practices.
Some differences in clinical features at onset were noted according to the age group. For ischemic stroke, TACI presentation was more frequent in elderly patients. One possible reason is the large proportion of cardioembolic ischemic strokes that are known to be associated with severer stroke symptoms. These data might explain the poor functional prognosis ≧80 years observed in our work and by others [1,2]. Hence, in our multivariate analysis, TACI presentation was associated with a greater risk of both 1-month case fatality and severe handicap. In addition, CFR were significantly higher in patients ≧80 years. The effect of age on acute and short-term mortality is consistent with previous reports [1,2,23]. Nevertheless, CFR in the elderly decreased over the 22 years, concurrently with the increase in the proportion of patients with either no or slight handicap (m-Rankin score 0–1), or moderate handicap (m-Rankin score 2–3), suggesting an improvement in the quality of acute management, better control of prestroke risk factors but also, at least in part, in the ability to diagnose minor stroke. The decrease in the proportion of patients ≧80 years with TACI presentation and the increase in that of those with LACI is consistent with this last remark. However, considering the stroke subtype, the decrease in CFR was only significant in hemorrhagic stroke. This result underlines the need to enroll elderly patients in clinical trials to give them the opportunity to benefit from specific treatments including thrombolysis.
Age seemed to be the major discriminating factor for the use of diagnostic resources as demonstrated by Di Carlo et al. . Other authors observed a lower quality of care in elderly stroke patients compared to that in younger ones [24,25]. Despite severer stroke and handicap in older patients, brain imaging, Doppler sonography, echocardiography and angiography were performed significantly less often. The more frequent use of palliative care in the elderly could contribute to this lower application of diagnostic resources. However, the limited use of complementary investigations in older patients may also contribute to the worse prognosis [2,26]. Indeed, a higher level of access to care is generally associated with lower stroke mortality rates . Further analyses will be needed to evaluate the relationship between limited investigations and outcome in older patients.
Older patients were more likely to have a longer LOS and to be discharged to an institution other than home, as previously reported in other studies [25,26]. The higher LOS in patients ≧80 years could be the consequence of the greater stroke severity in this age group. In addition, these patients were more frequently admitted to and cared for in public hospitals. Hence, these results could be explained, at least in part, by the lack of family and social support [25,28]. Moreover, medical, cognitive and social factors are all known to affect the risk of being institutionalized [1,2,25,28]. Finally, despite the universal funded health care system in France, unequal access to specialized stroke care may exist among different subgroups (very elderly, rural areas, and social exclusion). These factors, which were not evaluated in our study, are also known to affect the success of rehabilitation and influence recovery after stroke [25,29,30].
Our work presents a number of strengths. The exhaustiveness of case ascertainment was ensured by using multiple overlapping sources of information. In contrast to other multicenter studies [1,2,7,29], our data set was particularly homogenous in demographic features with a stable population, little migratory flow and a stable ethnic composition, and we included a wider range of elderly patients (n = 1,410) than that in previously published works [1,2,23].
However, some limitations must be mentioned. We were not able to differentiate between ischemic stroke from atheroma of large arteries, and undetermined and other causes because the TOAST classification [31,32] had only been introduced in our registry in 2005. Actually before this date, we had not distinguished between these 3 ischemic stroke subtypes in our database. In addition, the NIHSS was not used to measure the severity of stroke at onset. Finally, the outcome was measured at 1 month, which is a short-term evaluation.
To conclude, considering the increasing number of strokes in the most elderly segment of the population, the longer stays in hospital and the use of resources, our results provide information to help understand the stroke outcomes in patients >80 and the approaching burden and challenges faced by health care systems.
Our findings suggest that stroke in the elderly is a specific medical issue with important implications not only for clinical management but also for initiating preventive strategies, therapeutic research and health policy. The recognition of this public health problem may encourage organizations to design clinical trials for the elderly, to facilitate access to stroke prevention and to stroke emergency care, which may lead to improvements in survival and quality of life in the elderly.
We thank Mr. Philip Bastable for reviewing the English.
Dr. Yannick Béjot
Stroke Registry of Dijon, Department of Neurology, University Hospital
3, rue du Faubourg Raines
FR–21000 Dijon (France)
Tel. +33 3 80 29 37 53, Fax +33 3 80 29 36 72, E-Mail email@example.com
Received : May 17, 2009
Accepted : August 8, 2009
Published online: December 1, 2009
Number of Print Pages : 11
Number of Figures : 0, Number of Tables : 6, Number of References : 32
Vol. 29, No. 2, Year 2010 (Cover Date: January 2010)
Journal Editor: Hennerici M.G. (Mannheim)
ISSN: 1015-9770 (Print), eISSN: 1421-9786 (Online)
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