Comparison of case ascertainment by medical record linkage and cohort follow-up to determine incidence rates for transient ischemic attacks and stroke

Cumulative rehospitalizations and implications for subsequent mortality after first-ever ischemic stroke

INTRODUCTION

Clinical implications of readmission following initial hospitalization for acute ischemic stroke (AIS) are not known. We examined predictors of readmissions and impact of readmissions on subsequent mortality after first-ever AIS.

MATERIALS AND METHODS

Adults aged ≥18 years who survived to discharge after hospitalization for first-ever AIS from 2003 to 2019 were included in the study. For each patient, the overall burden of hospitalizations was measured as total number of hospitalizations and aggregate days spent hospitalized during follow-up. We used Poisson regression to estimate incident rate ratios (IRR) for predictors of re-hospitalization and time-dependent Cox regression to estimate hazard ratios (HR) for mortality.

RESULTS

Of 908 AIS survivors, 537 died, 669 had 2,645 readmissions over 4,535 person-years follow-up. Adjusted independent predictors of cumulative readmission inlcuded being white (IRR 1.21, 95% CI 1.03-1.42), dependency on discharge (IRR 1.27, 95% CI 1.17-1.38), cardio-embolism (IRR 1.35, 95% CI 1.18-1.45), smoking (IRR 1.21, 95% CI 1.08-1.35), anemia (IRR 1.40, 95% CI 1.24-1.57), arthritis (IRR 1.20, 95% CI 1.10-1.31), coronary artery disease (IRR 1.34, 95% CI 1.23-1.47), cancer (IRR 1.96, 95% CI 1.64-2.30), chronic kidney disease (IRR 1.36, 95% CI 1.21-1.57), COPD (IRR 1.18, 95% CI 1.04-1.34), depression (IRR 1.50, 95% CI 1.37-1.66), diabetes mellitus (IRR 1.48, 95% CI 1.36-1.48), and heart failure (IRR 1.17, 95% CI 1.03-1.34). Conversely, hyperlipidemia was associated with a lower risk of readmission (IRR 0.79, 95% CI 0.71-0.88). Mortality was significantly increased with each hospitalization and cumulative days spent in hospital.

CONCLUSIONS

Among survivors of AIS hospitalization, certain sociodemographic indicators, stroke-specific features, and several key comorbid conditions were associated with increased risk of readmissions, which in turn correlated with increased mortality. Therefore, lifestyle modification and optimal treatment of comorbidities are likely to improve the outcome after AIS.

Hyperlipidaemia and mortality among patients hospitalised with pneumonia: retrospective cohort and propensity score matched study

Objective

To characterise the potential association of hyperlipidaemia (HLP) versus no HLP with all-cause mortality among patients hospitalised for pneumonia.

Design

Propensity score matched retrospective study.

Participants

The study cohort consisted of consecutive 8553 adults hospitalised at a large academic centre with a discharge diagnosis of pneumonia from 1996 through 2015, followed until death or end of the study period, 17 August 2017.

Outcomes

The outcome was HR for mortality at 28 days and in the long term in patients with pneumonia with concurrent HLP compared with those with no HLP. We first constructed multivariable Cox proportional regression models to estimate the association between concurrent HLP versus no HLP and mortality after pneumonia hospitalisation for the entire cohort. We then identified 1879 patients with pneumonia with concurrent HLP and propensity score matched in a 1:1 ratio to 1879 patients with no HLP to minimise the imbalance from measured covariates for further analysis.

Results

Among 8553 unmatched patients with pneumonia, concurrent HLP versus no HLP was independently associated with lower mortality at 28 days (HR 0.52, 95% CI 0.41 to 0.66) and at a median follow-up of 3.9 years (HR 0.75, 95% CI 0.70 to 0.80). The risk difference in mortality was consistent between 1879 propensity score matched pairs both at 28 days (HR 0.65, 95% CI 0.49 to 0.86) and at a median follow-up of 4 years (HR 0.88, 95% CI 0.81 to 0.96). In the subgroup of patients with clinically measured low-density lipoprotein cholesterol (LDL-C), graded inverse associations between LDL-C levels and mortality were found in both unmatched and matched cohorts.

Conclusions

Among hospitalised patients with pneumonia, a diagnosis of HLP is protective against both short-term and long-term risk of death after adjustment for other major contributors to mortality in both unmatched and propensity score matched cohorts. These findings should be further investigated.

Association between hyperlipidemia and mortality after incident acute myocardial infarction or acute decompensated heart failure: a propensity score matched cohort study and a meta-analysis

OBJECTIVE

To examine the effect of HLP, defined as having a pre-existing or a new in-hospital diagnosis based on low density lipoprotein cholesterol (LDL-C) level ≥100 mg/dL during index hospitalisation or within the preceding 6 months, on all-cause mortality after hospitalisation for acute myocardial infarction (AMI) or acute decompensated heart failure (ADHF) and to determine whether HLP modifies mortality associations of other competing comorbidities. A systematic review and meta-analysis to place the current findings in the context of published literature.

DESIGN

Retrospective study, 1:1 propensity-score matching cohorts; a meta-analysis.

SETTING

Large academic centre, 1996-2015.

PARTICIPANTS

Hospitalised patients with AMI or ADHF.

MAIN OUTCOMES AND MEASURES

All-cause mortality and meta-analysis of relative risks (RR).

RESULTS

Unmatched cohorts: 13 680 patients with AMI (age (mean) 68.5 ± (SD) 13.7 years; 7894 (58%) with HLP) and 9717 patients with ADHF (age, 73.1±13.7 years; 3668 (38%) with HLP). In matched cohorts, the mortality was lower in AMI patients (n=4348 pairs) with HLP versus no HLP, 5.9 versus 8.6/100 person-years of follow-up, respectively (HR 0.76, 95% CI 0.72 to 0.80). A similar mortality reduction occurred in matched ADHF patients (n=2879 pairs) with or without HLP (12.4 vs 16.3 deaths/100 person-years; HR 0.80, 95% CI 0.75 to 0.86). HRs showed modest reductions when HLP occurred concurrently with other comorbidities. Meta-analyses of nine observational studies showed that HLP was associated with a lower mortality at ≥2 years after incident AMI or ADHF (AMI: RR 0.72, 95% CI 0.69 to 0.76; heart failure (HF): RR 0.67, 95% CI 0.55 to 0.81).

CONCLUSIONS

Among matched AMI and ADHF cohorts, concurrent HLP, compared with no HLP, was associated with a lower mortality and attenuation of mortality associations with other competing comorbidities. These findings were supported by a systematic review and meta-analysis.

Predictors of Recurrent Hospitalizations and the Importance of These Hospitalizations for Subsequent Mortality After Incident Transient Ischemic Attack

BACKGROUND

We examined predictors of recurrent hospitalizations and the importance of these hospitalizations for subsequent mortality after incident transient ischemic attacks (TIA) that have not yet been investigated.

METHODS

Adults hospitalized for TIA from 2000 through 2017 were examined for recurrent hospitalizations, days, and percentage of time spent hospitalized and long-term mortality.

RESULTS

Of 266 patients hospitalized for TIA, 122 died, 212 had 826 anycondition hospitalization (59 from TIA-related conditions) corresponding to 3384 inpatient days during 1693 person-years of follow-up. Of 42 patient-level characteristics, age greater than or equal to 65 years (Incidence rate ratio [IRR] 1.75, 95% confidence interval [CI] 1.19-2.55), current smoking (IRR 2.15, 95% CI 1.39-3.33), concurrent heart failure (IRR 1.81, 95% CI 1.17-2.80) or anemia (IRR 1.90, 95% CI 1.40-2.48), and no prescription statin (IRR 1.45, 95% CI 1.04-2.03, P = .0289) emerged as significant predictors of anycondition rehospitalization. All these variables except heart failure remained significant predictors of TIA-related rehospitalizations. All-cause mortality was significantly increased after each hospitalization from anycondition (hazard ratio [HR] 1.32, 95% CI 1.26-1.39), TIA-related condition (HR 1.72; 95% CI 1.28-2.30), and per each day (HR 1.05, 95% CI 1.04-1.05) and per 1% of follow-up time spent hospitalized from anycondition (HR 1.45, 95% CI 1.34-1.58).

CONCLUSIONS

Older age, current tobacco smoking, concurrent heart failure or anemia, and no prescription statin, easily measured patient-level characteristics, identifies patients with TIA at high risk for recurrent hospitalizations and the burden of these hospitalizations predicts subsequent mortality.

Incremental risk of long-term mortality with increased burden of comorbidity in hospitalized patients with pneumonia

BACKGROUND

Patients hospitalized for pneumonia often have concurrent comorbid conditions (CCs). The influence of CCs on the risk of subsequent death is not fully understood.

METHODS

We examined adults hospitalized for pneumonia between 1996 through 2015 at Mayo Clinic for the presence of 20 priori selected CCs. We estimated cumulative all-cause mortality by number of CCs using multivariable Cox regression model.

RESULTS

Study comprised of 9580 adults (age 70 ± 17.0 years, men 53%, whites 88%) with median number of CCs 3 (interquartile 1-4), and overall deaths 6032 (62.9%) during 50,934 person-years of follow up (118.5 deaths/1000 person-years). After adjustment, any single comorbid condition was associated with 9% greater risk of death (95% confidence interval 1.08-1.11, P < 0.0001). When study cohort was stratified according to number of comorbidities (none, 1, 2, 3, 4, 5, and ≥6 CCs), the risk of death increased as the number of CCs increased (33 for no CCs vs 252 deaths for ≥6 CCs per 1000 person-years).

CONCLUSIONS

Long-term mortality after hospitalization for pneumonia increases as the burden of comorbidities increases. Therefore, a simple comorbidity count help improve prognostic accuracy in identifying patients at increased risk of death following an episode of pneumonia.

Secular trends in the incidence, risk factors, and prognosis of transient ischemic attack in Japan: The Hisayama Study

BACKGROUND AND AIMS

We aimed to investigate secular trends in the incidence, risk factors, and prognosis of transient ischemic attack (TIA) in a general Japanese population.

METHODS

Two cohorts consisting of stroke-free Japanese individuals aged ≥40 years in 1961 (n = 1621) and 1988 (n = 2646) were followed up for 24 years. The associations of potential risk factors with the development of TIA were estimated by a Cox proportional hazards model. The influence of TIA on the risk of total stroke over the subsequent 10 years was compared between the sub-cohorts of subjects with TIA and age- and sex-matched control subjects from each cohort.

RESULTS

During follow-up, 28 subjects in the 1961 cohort and 34 in the 1988 cohort experienced TIA. The age-standardized incidence of TIA was significantly lower in the 1988 cohort than the 1961 cohort (0.66 vs. 1.01 per 1000 person-years, p = 0.02). While elevated systolic blood pressure was significantly associated with the risk of TIA in both cohorts, glucose intolerance and higher serum cholesterol levels were associated with TIA risk only in the 1988 cohort. The subjects experiencing TIA had approximately 7-8-fold higher risks for the 10-year incidence of total and ischemic strokes compared with the corresponding control subjects without TIA both in the 1961 and 1988 sub-cohorts, and the relative risks were not significantly different between sub-cohorts.

CONCLUSIONS

Our results suggest that the incidence of TIA decreased during the past half century, probably due to the spread of antihypertensive treatments in the general Japanese population.

Effect of early hospital readmission and comorbid conditions on subsequent long-term mortality after transient ischemic attack

BACKGROUND

The implications of early readmission on long-term mortality after transient ischemic attack (TIA) are not known. We aimed at examining the effect of 180-day readmission on subsequent long-term mortality after index hospitalization for TIA.

METHODS

A retrospective study of patients hospitalized for first-ever TIA at Mayo Clinic from 2000 through 2017. Patients readmitted within 180 days postdischarge were compared with those not readmitted in long-term risk of death.

RESULTS

Of 251 TIA patients aged 73 ± 15 years with 1509 person-years of follow-up, 65 (26%) were readmitted within 180 days of discharge and 125 died during a median follow-up of 5.7 years. The mortality was 10 vs. 7 deaths per 100 person-years in patients who were readmitted compared to those who were not readmitted with hazard ratio (HR) 1.73 (95% confidence interval [CI] 1.13-2.66). Other competing predictors of mortality were age ≥65 years (HR 5.70, 95% CI 2.72-11.96), cancer (HR 1.65, 95% CI 1.03-3.38), chronic obstructive pulmonary disease (HR 1.90, 95% CI 1.07-3.38), heart failure (HR 3.03, 95% CI 1.82-5.06), dementia (HR 5.87, 95% CI 3.27-10.52), creatinine ≥1.4 mg/dl (HR 1.89, 95% CI 1.17-3.06), and hemoglobin level <10 g/dl (HR 2.80, 95% CI 1.20-6.66).

CONCLUSIONS

Hospital readmission within 180 days of discharge from index TIA was associated with increased risk of death several years after initial readmission. Older age and several comorbidities identified during index hospitalization also confer increased risk for long-term mortality.

Carotid atherosclerotic plaque instability and cognition determined by ultrasound-measured plaque strain in asymptomatic patients with significant stenosis

OBJECTIVE This article describes the use of ultrasound measurements of physical strain within carotid atherosclerotic plaques as a measure of instability and the potential for vascular cognitive decline, microemboli, and white matter changes. METHODS Asymptomatic patients with significant (> 60%) carotid artery stenosis were studied for dynamic measures of plaque instability, presence of microemboli, white matter changes, and vascular cognitive decline in comparison with normative controls and premorbid state. RESULTS Although classically asymptomatic, these patients showed vascular cognitive decline. The degree of strain instability measured within the atherosclerotic plaque directly predicted vascular cognitive decline in these patients thought previously to be asymptomatic according to classic criteria. Furthermore, 26% of patients showed microemboli, and patients had twice as much white matter hyperintensity as controls. CONCLUSIONS These data show that physical measures of plaque instability are possible through interpretation of ultrasound strain data during pulsation, which may be more clinically relevant than solely measuring degree of stenosis. The data also highlight the importance of understanding that the definition of symptoms should not be limited to motor, speech, and vision function but underscore the role of vascular cognitive decline in the pathophysiology of carotid atherosclerotic disease. Clinical trial registration no.: NCT02476396 (clinicaltrials.gov).

Incidence and predictors of myocardial infarction after transient ischemic attack: a population-based study

BACKGROUND AND PURPOSE

Coronary artery disease is the leading cause of death after TIA. Reliable estimates of the risk of MI after TIA, however, are lacking.

METHODS

Our purpose was to determine the incidence of and risk factors for MI after TIA. We cross-referenced preexisting incidence cohorts from the Rochester Epidemiology Project for TIA (1985-1994) and MI (1979-2006) to identify all community residents with incident MI after incident TIA. Incidence of MI after TIA was determined using Kaplan-Meier life-table methods. This was compared to the age-, sex-, and period-specific MI incidences in the general population. Proportional hazards regression analysis was used to examine associations between clinical variables and the occurrence of MI after TIA.

RESULTS

Average annual incidence of MI after TIA was 0.95%. Relative risk for incident MI in the TIA cohort compared to the general population was 2.09 (95% CI, 1.52-2.81). This was highest in patients younger than 60 years old (relative risk, 15.1; 95% CI, 4.11-38.6). Increasing age (hazard ratio, 1.51 per 10 years; 95% CI, 1.14-2.01), male sex (hazard ratio, 2.19; 95% CI, 1.18-4.06), and the use of lipid-lowering therapy at the time of TIA (hazard ratio, 3.10; 95% CI, 1.20-8.00) were independent risk factors for MI after TIA.

CONCLUSIONS

Average annual incidence of MI after TIA is ≈1%, approximately double that of the general population. The relative risk increase is especially high in patients younger than 60 years old. These data are useful for identifying subgroups of patients with TIA at highest risk for subsequent MI.

Validation and refinement of the ABCD2 score: a population-based analysis

BACKGROUND AND PURPOSE

Transient ischemic attacks are a frequent diagnosis in the emergency department setting, yet expert opinion as to the proper follow-up and need for hospitalization differs widely. Recently, an effort has been made to risk-stratify patients presenting with transient ischemic attacks through scoring systems such as the ABCD and ABCD2 scales. The aim of our study was to independently validate these scores using a population-based cohort.

METHODS

Using the data from the Rochester Stroke and Transient Ischemic Attack Registry and resources of the Rochester Epidemiology Project, medical records of all residents of Rochester, Minn, with a diagnosis of incident transient ischemic attack from 1985 through 1994 were examined (N=284). Patients were scored on the ABCD and ABCD2 scales and new scores were created by adding hyperglycemia and a history of hypertension. The end points of stroke and death were collected previously and were verified through the Rochester Epidemiology Project data.

RESULTS

Although our study did find that scores >4 had a statistically significant predictive value for future stroke, a substantial proportion of strokes within 7 days (9 of 36 cases [25%]) occurred in patients with low or intermediate risk scores (< or =4) on the ABCD2 scale. Including history of hypertension and hyperglycemia on presentation increased the sensitivity of the score to identify patients who had a stroke within 7 days.

CONCLUSIONS

Reliance on the ABCD and ABCD2 scores misses some patients who will have a stroke within 7 days of a transient ischemic attack. Adding hyperglycemia and a history of hypertension to the predictive model could be useful, but the value of these additions need to be evaluated further.

Sex and classic risk factors after myocardial infarction: a community study

BACKGROUND

Sex-specific data on classic risk factors and their impact after myocardial infarction (MI) in the community are lacking. We evaluated the prevalence and association of classic risk factors with recurrent ischemic events in patients with MI and tested the hypothesis that they differed by sex.

METHODS

All patients (1104, 45% women) from Olmsted County, Minnesota, hospitalized with an incident MI between 1990 and 1998 were identified using standardized criteria and followed-up (mean 3.7 years) for recurrent ischemic events, defined as recurrent MI, ischemic stroke, or coronary death. Data on hypertension, diabetes, hypercholesterolemia, smoking, and obesity at index hospitalization were analyzed individually and in clusters.

RESULTS

Women were older than men (73 vs 64 years, P < .001) and had more risk factors. During follow-up, 423 events occurred. For women, the adjusted risk of recurrent events increased with hypertension, diabetes, and hypercholesterolemia. For men, no increase in risk was detected with any risk factor. The population attributable risk of all risk factors combined was 46% (95% CI 29%-62%) in women and 19% (95% CI 6%-35%) in men. As the number of risk factors increased from 1 to > or = 4, compared with no risk factors, the adjusted hazard ratio in women increased progressively (1.12, 1.82, 2.34, and 2.68, respectively), whereas no trend was detected in men (1.40, 1.27, 1.24, and 1.37, respectively) (P = .01 for effect modification by sex).

CONCLUSIONS

Classic risk factors are highly prevalent and often clustered in MI, especially among women. Although their predictive value for recurrent ischemic events is marginal in men, strong associations exist in women, which define secondary prevention opportunities.

Ischemic stroke after heart failure: a community-based study

BACKGROUND

Although studies have examined the incidence of stroke in heart failure (HF), their findings are inconsistent and difficult to interpret because of heterogeneity in study design and population. Although HF remains a highly fatal disease, the excess mortality imparted from stroke is unknown.

METHODS

A random sample of cases of HF from 1979 to 1999 was identified and validated according to Framingham criteria. Strokes were identified by screening medical diagnoses and subsequent physician validation. Stroke risk in HF was compared with the risk in the general population with standardized morbidity ratios. Associations between selected characteristics and stroke were examined using proportional hazards regression.

RESULTS

The study cohort included 630 persons with incident HF. During a median of 4.3 years of follow-up, 102 (16%) experienced an ischemic stroke. Heart failure was associated with a 17.4-fold increased risk for stroke compared with the general population in the first 30 days after HF diagnosis and remained elevated during 5 years of follow-up. Older persons with prior stroke or diabetes were more likely to experience stroke after HF diagnosis. Persons with stroke after HF were 2.31 times more likely to die compared with persons without stroke.

CONCLUSIONS

In the community, persons with HF have a large increase in the risk for ischemic stroke compared with the general population. Stroke results in a >2-fold increase in mortality. Thus, prevention of stroke has the potential to improve survival among patients with HF, particularly among the elderly and those with diabetes or prior stroke.

Population-based study of the relationship between atherosclerotic aortic debris and cerebrovascular ischemic events

OBJECTIVE

To assess the validity of the suggestion that protruding atheromatous material in the thoracic aorta is an important cause of cerebrovascular ischemic events (CIEs) (ie, transient ischemic attack or ischemic stroke).

METHODS

This case-control study of Olmsted County, Minnesota, residents who underwent transesophageal echocardiography (TEE) from 1993 to 1997 included controls without CIE randomly selected from the population, controls without CIE referred for TEE because of cardiac disease, cases with incident CIE of obvious cause (noncryptogenic), and cases with incident CIE of uncertain cause (cryptogenic).

RESULTS

Of the 1135 subjects, 520 were randomly selected controls without CIE, 329 were controls without CIE referred for TEE, 159 were noncryptogenic CIE cases, and 127 were cryptogenic CIE cases. Complex atherosclerotic aortic debris in ascending and transverse segments of the arch was detected in 8 randomly selected controls (1.5%), 13 referred controls (4.0%), and 15 noncryptogenic (9.4%) and 4 cryptogenic (3.1%) CIE cases. After adjusting for age, sex, hypertension, smoking, atrial fibrillation, valvular heart disease, congestive heart failure, and atherosclerosis other than in the thoracic aorta, complex atherosclerotic aortic debris was not significantly associated with group status. With randomly selected controls as the referent group, odds ratios (95% confidence intervals) were 1.72 (0.61-4.87) for referred controls, 3.16 (1.18-8.51) for noncryptogenic CIE cases, and 1.39 (0.39-4.88) for cryptogenic CIE cases.

CONCLUSIONS

Complex atherosclerotic aortic debris is not a risk factor for cryptogenic ischemic stroke or transient ischemic attack but is a marker for generalized atherosclerosis and well-established atherosclerotic and cardioembolic mechanisms of cerebral ischemia. Embolization from the aorta is not a common mechanism of ischemic stroke or transient ischemic attack.

Population-based study of the relationship between patent foramen ovale and cerebrovascular ischemic events

OBJECTIVE

To determine whether patent foramen ovale (PFO) is a risk factor for a cryptogenic cerebrovascular ischemic event (CIE).

METHODS

This case-control study of 1072 residents of Olmsted County, Minnesota, who underwent contrast transesophageal echocardiography between 1993 and 1997 included 519 controls without CIE randomly selected from the population, 262 controls without CIE referred for transesophageal echocardiography because of cardiac disease, 158 cases with incident CIE of obvious cause (noncryptogenic), and 133 cases with incident CIE of uncertain cause (cryptogenic).

RESULTS

Large PFOs were detected in 108 randomly selected controls (20.8%), 22 referred controls (8.4%), 17 noncryptogenic CIE cases (10.8%), and 22 cryptogenic CIE cases (16.5%). After adjustment for age, sex, hypertension, smoking, atrial fibrillation, ischemic heart disease, and number of contrast injections, the presence of a large PFO was not significantly associated with group status (P=.07). Using the odds of the presence of large PFO in the randomly selected controls as the reference, the odds ratio (95% confidence interval) of the presence of large PFO was 0.47 (0.26-0.87) for referred controls, 0.69 (0.37-1.29) for noncryptogenic CIE cases, and 1.10 (0.63-1.90) for cryptogenic CIE cases.

CONCLUSIONS

Patent foramen ovale is not a risk factor for cryptogenic ischemic stroke or transient ischemic attack in the general population. The PFO's importance in the genesis of cryptogenic CIE may have been overestimated in previous studies because of selective referral of cases and underascertainment of PFO among comparison groups of patients referred for echocardiography for clinical indications other than cryptogenic CIE.

The impact of stroke on the cost and level of care in nursing homes: a retrospective population-based study

OBJECTIVE

To estimate the impact of incident stroke on nursing home (NH) costs and level of care.

SUBJECTS AND METHODS

This retrospective population-based cohort study is part of a larger study that identified all Rochester, Minn, residents with a confirmed first stroke occurring between January 1, 1988, and December 31, 1989. One Rochester resident who had not had a stroke was matched to each person with stroke. Persons with and without stroke were followed up in provider-linked medical records and NH files from baseline (i.e., date of stroke) through December 31, 1994, for evidence of NH use. This study characterized the NH activity of those individuals with any NH activity after baseline (58 persons with major stroke, 36 persons with minor stroke, and 63 persons without stroke) as to NH case mix at first assessment, number of NH days, and per diem Medicaid reimbursement.

RESULTS

Characteristics at first NH assessment after baseline revealed that NH residents with major stroke were younger and more disabled and required more services than residents without stroke. Over the full period of follow-up, the mean number of NH days was similar for NH residents with major stroke and those without stroke, yet per diem Medicaid reimbursement was 11% higher for residents with major stroke compared with residents without stroke. Nursing home residents with minor stroke appeared similar to those without stroke with respect to time to admission, characteristics at first assessment, number of NH days, and per diem Medicaid reimbursement.

CONCLUSION

Lower incidence and severity of stroke may contribute to lower care needs and per diem cost, but no fewer NH days.

Predictors of cerebrovascular events and death among patients with valvular heart disease: A population-based study

BACKGROUND AND PURPOSE

There is little population-based information on cerebrovascular events and survival among valvular heart disease patients. We used the Kaplan-Meier product-limit method and the Cox proportional hazards model to determine rates and predictors of cerebrovascular events and death among valve disease patients.

METHODS

This population-based historical cohort study in Olmsted County, Minnesota, reviewed residents with a first echocardiographic diagnosis of mitral stenosis (n=19), mitral regurgitation (n=528), aortic stenosis (n=140), and aortic regurgitation (n=106) between 1985 and 1992.

RESULTS

During 2694 person-years of follow-up, 98 patients developed cerebrovascular events and 356 died. Compared with expected numbers, these observations are significantly elevated, with standardized morbidity ratio of 3.2 (95% CI, 2.6 to 3.8) and 2. 5 (95% CI, 2.2 to 2.7), respectively. Independent predictors of cerebrovascular events were age, atrial fibrillation, and severe aortic stenosis. The risk ratio of severe aortic stenosis was 3.5 (95% CI, 1.4 to 8.6), with atrial fibrillation conferring greater risk at younger age. Predictors of death were age, sex, cerebrovascular events, ischemic heart disease, and congestive heart failure, the greatest risk being among those with both congestive heart failure and cerebrovascular events (risk ratio=8.8; 95% CI, 5. 8 to 13.4). Valve disease type and severity were not independent determinants of death.

CONCLUSIONS

The risk of cerebrovascular events and death among patients with valve disease remains high. Age, atrial fibrillation, and severe aortic stenosis are independent predictors of cerebrovascular events, and age, sex, cerebrovascular events, congestive heart failure, and ischemic heart disease are independent predictors of death in these patients.

Prevalence of potential risk factors for stroke assessed by transesophageal echocardiography and carotid ultrasonography: the SPARC study. Stroke Prevention: Assessment of Risk in a Community

OBJECTIVE

The SPARC (Stroke Prevention: Assessment of Risk in a Community) study was designed to identify risk factors for stroke and cardiovascular disease using transesophageal echocardiography and carotid ultrasonography. This protocol was undertaken to establish a cohort in which putative risk factors for stroke were identified so that subsequent follow-up could discern the roles these risk factors play in stroke incidence.

SUBJECTS AND METHODS

This was a prospective, population-based study. A randomly selected cohort comprised 1475 Olmsted County, Minnesota, residents aged 45 years or older, of whom 588 agreed to participate. Transesophageal echocardiography and carotid ultrasonography were used for evaluation of the subjects. Prevalences of various cardiovascular and cerebrovascular conditions were determined.

RESULTS

Transesophageal echocardiography was successfully completed in 581 subjects. The prevalence (+/-SE) of patent foramen ovale was 25.6% (+/-1.9%), and that of atrial septal aneurysm was 2.2% (+/-0.6%). The prevalence of aortic atherosclerosis increased with age and was most common in the descending aorta, particularly in subjects 75 to 84 years old. The prevalence of strands on native valve was 46.4% (+/-2.2%). Carotid ultrasonography data for 567 participants revealed minimal atherosclerotic disease. Most subjects had minimal or mild carotid occlusive disease. The prevalence of moderate (50%-79%) and severe (80%-99%) stenosis was 7.7% (+/-1.1%) and 0.3% (+/-0.2 %), respectively.

CONCLUSIONS

This prospective study defines the prevalence of multiple potential cardiovascular and cerebrovascular risk factors, providing population-based data for ongoing follow-up of the risk of stroke.

Detection and control of high blood pressure in the community : Do we need a wake-up call?

At the community level, the effect of national programs in increasing hypertension awareness, prevention, treatment, and control is unclear. This study evaluated the degree of detection and control of high blood pressure in a random population-based sample of Olmsted County, Minnesota, residents >/=45 years old, of whom 636 subjects among 1245 eligible residents agreed to participate. Home interview and home and office measurements of blood pressure were used to estimate awareness, treatment, and control rates for hypertension in the community. Mean blood pressures (+/-SD) were 138/80+/-20/12 mm Hg for men and 137/76+/-23/11 mm Hg for women. The overall prevalence of hypertension was 53%. The percentage of subjects with treated and controlled hypertension was 16.6%. Thirty-nine percent of subjects were unaware of their hypertension. Despite clinical trial evidence of reduced morbidity and mortality with antihypertensive therapy, recently reported national data suggest a leveling-off trend for treatment and control of hypertension. This population-based study supports these observations and suggests that at a community level, hypertension awareness and blood pressure control rates are suboptimal, presumably because of decreased attention to the detection and control of hypertension.

Use of nursing home after stroke and dependence on stroke severity: a population-based analysis

BACKGROUND AND PURPOSE

There are few population-based data available regarding nursing home use after stroke. This study clarifies the use of a nursing home after stroke, as well as its dependence on stroke severity, in a defined population.

METHODS

All first stroke events among residents of Rochester, Minn, during 1987-1989 were ascertained, subtyped, and assigned Rankin disability scores (RS) before the event, at maximal deficit, and at specified intervals after stroke. Persons were followed from the date of stroke event to death, emigration from Rochester, or December 31, 1994, in complete community-based medical records and Minnesota Case Mix Review Program data tapes to determine nursing home residency before stroke and at 90 days and 1 year after stroke, proportion of survival days in a nursing home, and cumulative risk of admission to a nursing home.

RESULTS

There were 251 cases of first cerebral infarction, 24 intracerebral hemorrhages, and 15 subarachnoid hemorrhages among residents of Rochester during 1987-1989. The maximal deficit RS was 1 or 2 for 62 (25%), RS 3 for 72 (29%), and RS 4 or 5 for 117 (47%) of the cerebral infarct patients. Among patients surviving to 90 days or 1 year after cerebral infarction, 25% were in nursing home at 90 days and 22% at 1 year, respectively. Within these maximal deficit RS categories, the percentages of follow-up time spent in a nursing home during the first post-cerebral infarction year are as follows: RS 1 to 2, 4%; RS 3, 10%; and RS 4 to 5, 54%. Multivariate logistic regression revealed that increasing age and RS 4 to 5 at maximal deficit were independent predictors (P<0.0001) of nursing home residency at 90 days and 1 year after stroke, whereas stroke type was not an independent predictor. At 1 year after cerebral infarction, the Kaplan-Meier estimates of proportion of people with at least 1 nursing home admission were 11% for RS 1 to 2, 22% for RS 3, and 68% for RS 4 to 5.

CONCLUSIONS

This study provides unique population-based data regarding the short- and long-term use of a nursing home after stroke and its dependence on stroke severity. More than 50% of people with a severe cerebral infarction are in a nursing home 90 days and 1 year after the stroke, and by 1 year, nearly 70% will have required some nursing home stay. Age and stroke severity are independent predictors of nursing home residency after stroke.

Frequency of atrial septal aneurysms in patients with cerebral ischemic events

BACKGROUND

Atrial septal aneurysm (ASA) is a putative risk factor for cardioembolism. However, the frequency of ASA in the general population has not been adequately determined. Therefore, the frequency in patients with cerebral ischemic events, compared with the frequency in the general population, is poorly defined. We sought to determine the frequency of ASA in the general population and to compare the frequency of ASA in patients with cerebral ischemic events with the frequency in the general population.

METHODS AND RESULTS

The frequency of ASA in the population was determined in 363 subjects, a sample of the participants in the Stroke Prevention: Assessment of Risk in a Community study (control subjects), and was compared with the frequency in 355 age- and sex-matched patients undergoing transesophageal echocardiography in search of a cardiac source of embolism after a focal cerebral ischemic event. The proportion with ASA was 7.9% in patients versus 2.2% in control subjects (P=0.002; odds ratio of ASA, 3.65; 95% CI, 1.64 to 8.13, in patients versus control subjects). Patent foramen ovale (PFO) was detected with contrast injections in 56% of subjects with ASA. The presence of ASA predicted the presence of PFO (odds ratio of PFO, 4.57; 95% CI, 2.18 to 9.57, in subjects with versus those without ASA). In 86% of subjects with ASA and cerebral ischemia, transesophageal echocardiography did not detect an alternative source of cardioembolism other than an associated PFO.

CONCLUSIONS

The prevalence of ASA based on this population-based study is 2.2%. The frequency of ASA is relatively higher in patients evaluated with transesophageal echocardiography after a cerebral ischemic event. ASA is frequently associated with PFO, suggesting paradoxical embolism as a mechanism of cardioembolism. In patients with cerebral ischemia and ASA, ASA (with or without PFO) commonly is the only potential cardioembolic source detected with transesophageal echocardiography.

Identification of incident stroke in Norway: hospital discharge data compared with a population-based stroke register

BACKGROUND AND PURPOSE

The validity of hospital discharge diagnoses is essential in improving stroke surveillance and estimating healthcare costs of stroke. The aim of this study was to assess sensitivity, positive predictive value, and accuracy of discharge diagnoses compared with a stroke register.

METHODS

A record linkage was made between a population-based stroke register and the discharge records of the hospital serving the population of the stroke register (n=70 000). The stroke register (including patients aged 15 and older and with no upper age limit), applied here as a "gold standard," was used to estimate sensitivity, positive predictive value, and accuracy of the discharge diagnoses classification. The length of stay in hospital by stroke patients was measured.

RESULTS

Identifying cerebrovascular diseases by hospital discharge diagnoses (International Classification of Diseases, 9th Revision [ICD-9], codes 430 to 438.9, first admission) lead to a substantial overestimation of stroke in the target population. Restricting the retrieval to acute stroke diagnoses (ICD-9 codes 430, 431, 434, and 436) gave an incidence estimate closer to the "true" incidence rate in the stroke register. Selecting ICD-9 codes 430 to 438 of cerebrovascular diseases gave the highest sensitivity (86%). The highest positive predictive value (68%) was achieved by selecting acute stroke diagnoses (ICD-9 codes 430, 431, 434, and 436), at the expense of a lower sensitivity (81%). Accuracy of ICD codes 430 to 438.9 (n=678) revealed the highest proportion of incident strokes identified by the acute stroke diagnoses (ICD-9 codes 430, 431, 434, and 436). Seventy-four percent of hospital discharge diagnoses classified as first-ever stroke kept the original diagnosis. Only 4.6% of the discharge diagnoses were classified as nonstroke diagnoses after validation. The estimation of length of stay in the hospital was improved by selection of acute stroke diagnoses from hospital discharge data (ICD-9 codes 430, 431, 434, and 436), which gave the same estimate of length of stay, a median of 8 days (2.5 percentile=0 and 97.5 percentile=56), compared with a median of 8 days (2.5 percentile=0 and 97.5 percentile=51) based on the stroke register.

CONCLUSIONS

Hospital discharge data may overestimate stroke incidence and underestimate the length of stay in the hospital, unless selection routines of hospital discharge diagnoses are restricted to acute stroke diagnoses (ICD-9 codes 430, 431, 434, and 436). If supplemented by a validation procedure, including estimates of sensitivity, positive predictive value, and accuracy, hospital discharge data may provide valid information on hospital-based stroke incidence and lead to better allocation of health resources. Distinguishing subtypes of stroke from hospital discharge diagnoses should not be performed unless coding practices are improved.

Stroke incidence and survival in three Sicilian municipalities. Sicilian Neuro-Epidemiologic Study (SNES) Group

We investigated the incidence of first-ever stroke in three Sicilian municipalities over the years 1984-1987. Case ascertainment involved two approaches: a door-to-door two-phase prevalence survey and a study of death certificates. Only first-ever strokes occurring within the study time interval were included, and diagnoses were based on specified criteria. We found 138 subjects who had experienced a first stroke over 73 488 person-years; the average incidence rate (new cases per 1000 population per year) was 1.9 overall, 1.7 in men, and 2.1 in women. Incidence increased steeply with age and was similar in men and women. Incidence was similar in the three study municipalities. The overall case-fatality rate was 35% at 30 days and 22% at one week. Survival after stroke was similar in men and women but better in younger compared to older stroke patients. Comparisons with previous studies suggest the absence of major geographic variations in stroke incidence within Italy.

Incidence of transient ischemic attack in Rochester, Minnesota, 1985-1989

BACKGROUND AND PURPOSE

There is scant information available on the incidence of transient ischemic attack (TIA) in a defined population. This study defines incidence rates of first TIA and subtypes of TIA during 1985-1989 and compares the incidence to that obtained from a 1960-1972 cohort study.

METHODS

Medical records of all residents of Rochester with potential diagnosis of TIA during 1985-1989 were screened to determine whether the case met the criteria for TIA. All available data were used to determine the vascular distribution of the TIA. Average annual age- and sex-adjusted incidence rates were calculated for 1985-1989, and results were compared with incidence rates determined in a Rochester-based 1960-1972 cohort study. RESILTS: Two hundred two cases of first TIA or amaurosis fugax occurred among Rochester residents during 1985-1989. The age- and sex-adjusted incidence rate for any TIA was 68/100 000 population. Incidence of amaurosis fugax was 13/100 000; anterior circulation (cerebral) TIA, 38/100 000; and vertebrobasilar distribution TIA, 14/100 000. Rates were similar to those determined from a 1960-1972 cohort study.

CONCLUSIONS

The incidence rate of TIA is 41% that of stroke incidence. TIA incidence in Rochester, Minn, is higher than has been previously reported for other sites throughout the world. Although comparison with prior time periods is difficult because of ascertainment issues, it appears that there has been no significant change in TIA incidence since the decade of the 1960s or earlier. This suggests that the most common mechanism for TIA (atherosclerosis) has not changed in prevalence, nor have risk factors leading to this mechanism.

Accuracy of administrative data for assessing outcomes after knee replacement surgery

OBJECTIVE

To assess the accuracy of information in an administrative database (Canadian Institute for Health Information; CIHI) compared with the hospital record for patients undergoing knee replacement (KR).

METHODS

A stratified random sample of 185 KR recipients from 5 Ontario hospitals were chosen. Their hospital records and corresponding CIHI files were compared to assess percent complete agreement, false negative (FN) and false positive (FP) rates for demographic data, procedures, and diagnoses.

RESULTS

Of 185 records, 175 (95%) were reviewed. Percent complete agreement was greater than 94% for each of patient demographics and procedures (mean FN rates: 0%; mean FP rates: 0-5%). For comorbidities and complications, although mean percent complete agreement was high, and FP rates were low, mean FN rates were 63% for specific comorbid conditions and 70% for organ systems.

CONCLUSIONS

High FN rates have been found in documentation of comorbidities and in-hospital complications for CIHI data compared with the hospital record. Under-coding of comorbidities and in-hospital complications has potential implications for researchers using administrative databases.

Comparable studies of the incidence of stroke and its pathological types: results from an international collaboration. International Stroke Incidence Collaboration

BACKGROUND AND PURPOSE

Comparing stroke rates in different parts of the world may increase our understanding of both etiology and prevention. However, comparisons are meaningful only if studies use standard definitions and methods, with comparably presented data. We compared the incidence of stroke and its pathological types (cerebral infarction, primary intracerebral hemorrhage, and subarachnoid hemorrhage) in recent studies from around the world.

METHODS

Studies with a midyear of 1984 or later, fulfilling standard criteria for a comparable, community-based study, provided original data for comparative analyses.

RESULTS

By mid-1995, data were available from 11 studies in Europe, Russia, Australasia, and the United States, comprising approximately 3.5 million person-years and 5575 incident strokes. Age- and sex-standardized annual incidence rates for subjects aged 45 to 84 years were similar (between approximately 300/100,000) and 500/100,000) in most places but were significantly lower in Dijon, France (238/100,000), and higher in Novosibirsk, Russia (627/100,000). In subjects aged 75 to 84 years, however, Novosibirsk no longer ranked higher than the other studies. The distribution of pathological types, when these were reliably distinguished, did not differ significantly between studies.

CONCLUSIONS

The similarities in stroke incidence and pathological types are perhaps not surprising given that all the populations were westernized and mainly white. The higher rates in Novosibirsk, disappearing in the elderly, and the lower rates in Dijon have several potential explanations. These include methodological artifact and different patterns of population risk factors. Further work is needed to explore these possibilities and to extend our knowledge of stroke incidence to other parts of the world, especially developing countries.

Comparing stroke incidence worldwide: what makes studies comparable?

BACKGROUND

Comparing stroke rates in different parts of the world and at different points in time may increase our understanding of the disease. Comparisons are only meaningful if they are based on studies that use similar definitions, methods, and data presentation.

SUMMARY OF REVIEW

We discuss the criteria that make such studies comparable, drawing on the experiences of recent studies performed around the world. If only those studies that fulfill the proposed criteria for comparison are considered, comparable data do not exist for vast areas of the world, including Africa, Asia, and South America. The importance of complete, community-based case ascertainment, including strokes managed outside the hospital, is emphasized. An approach for measuring and comparing the incidence of the pathological types of stroke (cerebral infarction, primary intracerebral hemorrhage, and subarachnoid hemorrhage) and subtypes of cerebral infarction is suggested.

CONCLUSIONS

The "ideal" stroke incidence study does not exist, but studies closely approaching it will reveal the most reliable and comparable results. There is a need for further studies to fill the gaps in our knowledge of the worldwide incidence of stroke, particularly for developing countries.

Fish consumption and stroke in men. 30-year findings of the Chicago Western Electric Study

BACKGROUND AND PURPOSE

Evidence of a relationship of fish intake to stroke incidence or mortality is weak. This report examines the association of fish consumption with stroke.

METHODS

A cohort of 2107 men aged 40 to 55 years from the Chicago Western Electric Study who were free of coronary heart disease and stroke through their first annual reexamination was investigated in relation to baseline fish intake and 30-year risk of fatal and nonfatal stroke. Data on baseline fish intake, categorized into four levels (> or = 35 g/d, 18 to 34 g/d, 1 to 17 g/d, and 0 g/d), were available for 1847 men. Average values of macronutrients and micronutrients from the first two examinations and major coronary and stroke risk factors were assessed in relation to fish consumption. Stroke mortality was ascertained from death certificates and nonfatal stroke from records of the Health Care Financing Administration.

RESULTS

During 46,426 person-years of follow-up, 76 stroke deaths occurred. Men consuming > or = 35 g/d of fish (highest level) had a higher age-adjusted death rate from stroke (23.5 per 10,000 person-years) than men in the three other categories of fish consumption. Based on a Cox proportional hazards regression model with adjustment for age, systolic blood pressure, cigarette smoking, serum cholesterol level, diabetes, electrocardiographic abnormalities, and table salt use, hazards ratios (and 95% confidence intervals) for fish consumers compared with nonconsumers were 1.34 (0.53 to 3.41) for > or = 35 g/d, 0.96 (0.41 to 2.21) for 18 to 34 g/d, and 1.00 (0.43 to 2.33) for 1 to 17 g/d. Age-adjusted and multivariate analyses for fatal and nonfatal strokes (n = 222) yielded similar results.

CONCLUSIONS

With stroke rates highest in the subgroup reporting highest fish intake, these data do not support the hypothesis of an inverse association of fish consumption with strokes.

Familial aneurysmal subarachnoid hemorrhage: a community-based study

The familial occurrence of intracranial aneurysms has been well described. However, intracranial aneurysms are not rare and the great majority of reported families consist of only two affected members. Therefore, the familial aggregation of intracranial aneurysms could be fortuitous. The authors investigated the familial occurrence of aneurysmal subarachnoid hemorrhage (SAH) in their community to determine whether family members of patients with a ruptured aneurysm are at an increased risk of developing an SAH. All 81 patients from Rochester, Minnesota, who suffered an SAH between 1970 and 1989 from a proven aneurysmal rupture were identified, and they or their families were contacted and a family history was obtained. The number of expected SAHs among first-degree relatives was calculated using previously established age- and sex-specific incidence rates in the community of Rochester. Of the 81 index patients, 76 had complete follow up for family history. Fifteen (20%) of these 76 patients had a first- or second-degree relative with aneurysmal SAH. The number of observed first-degree relatives with aneurysmal SAH was 11, compared to an expected number of 2.66, giving a relative risk of 4.14 (95% confidence interval 2.06-7.40; p < 0.001). In the authors' community, aneurysmal SAH was familial in one of five patients, and this familial aggregation was not fortuitous. The increase in familial risk of aneurysmal SAH is approximately fourfold among first-degree relatives.

The poor prognosis of ruptured intracranial aneurysms of the posterior circulation

The first 48 hours after aneurysmal subarachnoid hemorrhage are critical in determining final outcome. However, most patients who die during this initial period are not included in hospital-based studies. We investigated the occurrence of subarachnoid hemorrhage in a population-based study to evaluate possible predictors of poor outcome. All patients diagnosed with aneurysmal subarachnoid hemorrhage between 1955 and 1984 were selected for analysis of mortality in the first 30 days using the medical record-linkage system employed for epidemiological studies in Rochester, Minnesota. One hundred and thirty-six patients were identified. The mean age of these 99 women and 37 men was 55 years. Rates for survival to 48 hours were 32% for the 19 patients with posterior circulation aneurysms, 77% for the 87 patients with anterior circulation aneurysms, and 70% for the 30 patients with a presumed aneurysm (p < 0.0001). Rates for survival to 30 days were 11%, 57%, and 53%, respectively, in these three patient groups (p < 0.0001). Clinical grade on admission to the hospital, the main variable predictive of death within 48 hours, was significantly worse in patients with posterior circulation aneurysms than in others (p < 0.0001). The prognosis of ruptured posterior circulation aneurysms is poor. The high early mortality explains why posterior circulation aneurysms are uncommon in most clinical series of patients with subarachnoid hemorrhage. The management of incidentally discovered intact posterior circulation aneurysms may be influenced by these findings.

Accuracy of hospital discharge abstracts for identifying stroke

BACKGROUND AND PURPOSE

Much of the available data on stroke occurrence, service use, and cost of care originated with hospital discharge abstracts. This article uses the unique resources of the Rochester Epidemiology Project to estimate the sensitivity and positive predictive value of hospital discharge abstracts for incident stroke.

METHODS

The Rochester Stroke Registry was used to identify all confirmed first strokes (hospitalized and nonhospitalized) among Rochester residents for 1970, 1980, 1984, and 1989 (n = 364). The sensitivity of discharge abstracts was estimated by following these individuals for 12 months after stroke to determine the proportion assigned a discharge diagnosis of cerebrovascular disease (International Classification of Diseases [ICD] codes 430 through 438.9). The positive predictive value of discharge abstracts was assessed by identifying all hospitalizations of Rochester residents with an ICD code of 430-438.9 in 1970, 1980, and 1989 (n = 377). Events were categorized as incident stroke, recurrent stroke, stroke sequelae, or nonstroke after review of the complete community-based medical record by a neurologist.

RESULTS

Only 86% (n = 313) of all first-stroke patients in 1970, 1980, 1984, and 1989 were hospitalized. Of hospitalized patients, only 76% were assigned a principal discharge diagnosis code of 430-438.9. Fatal strokes and those occurring during a hospitalization were less likely to be identified. Among all hospitalizations of Rochester residents in 1970, 1980, and 1989, there were 377 with a principal diagnosis code of 430-438.9. Less than half (n = 177) were determined by the neurologist to be incident stroke; only 60% (n = 225) were either incident or recurrent stroke. Comparison of alternative approaches showed the validity of discharge abstracts was enhanced by increasing the number of diagnoses and excluding codes with poor positive predictive value.

CONCLUSIONS

This study provides previously unavailable estimates of the sensitivity of stroke-coded hospitalizations for a US community. A model for improving the sensitivity and positive predictive value of discharge abstracts is presented.

The sensitivity and specificity of computerized databases for the diagnosis of rheumatoid arthritis

OBJECTIVE

To examine the accuracy of a computerized medical database for the diagnosis of rheumatoid arthritis (RA).

METHODS

The complete medical records of all prevalent cases of RA (according to the 1987 American College of Rheumatology diagnostic criteria) on January 1, 1987 were reviewed to determine the sensitivity, specificity, and predictive value of database diagnoses compared with those obtained by medical record review. Agreement between database and medical record diagnoses was calculated using the kappa statistic.

RESULTS

Computerized database diagnoses of RA had a sensitivity of 89%, a specificity of 74%, a positive predictive value of 57%, and a negative predictive value of 94% compared with diagnoses based on clinical information abstracted from the complete medical record. Agreement between database and medical record diagnoses was poor (kappa = 0.54).

CONCLUSION

The sole reliance on such databases for the diagnoses of RA can result in substantial misdiagnosis.

Factors affecting survival and occurrence of stroke in patients with transient ischemic attacks

OBJECTIVE

To assess the predictive value of a series of demographic and clinical variables for stroke and survival in a population after a first transient ischemic attack (TIA).

DESIGN

Cox proportional hazards regression analysis was used to determine the association of various demographic and clinical factors with survival and stroke in 330 residents of Rochester, Minnesota, who had an initial TIA with first medical attention within 120 days during the period 1955 through 1979.

MATERIAL AND METHODS

We investigated several demographic, diagnostic, and treatment variables, including initial clinical manifestations (pure sensory TIA and unilateral carotid hemispheric TIA), to estimate the significant (P < or = 0.01) predictors of survival and of stroke. Follow-up was limited to 10 years.

RESULTS

Relative survival for patients with a first TIA was 94% at 1 year and 87% at 5 years after first medical attention. Three interactions were significant predictors of survival: (1) age at TIA and gender (young women had the best survival and older women had the worst survival), (2) systolic blood pressure and congestive heart failure (patients with low systolic blood pressure and congestive heart failure had the worst survival), and (3) calendar year of onset and diabetes mellitus (survival was worst for patients with diabetes during the early years of the study). Only age was a significant independent predictor of stroke after TIA (hazards ratio, 1.45 per 10 years).

CONCLUSIONS

Estimating risks of stroke and death after TIA on the basis of demographic and clinical variables without reference to the mechanism of TIA is of limited clinical utility. Age is the most significant such predictor. Interactions that reflect comorbidity, such as diabetes, blood pressure abnormalities, or heart disease, may affect survival but not the risk for occurrence of stroke.

Long-term risk of recurrent stroke after a first-ever stroke. The Oxfordshire Community Stroke Project

BACKGROUND AND PURPOSE

There have been few community-based studies of long-term prognosis after acute stroke. This study aims to provide precise estimates of the absolute and relative risks of stroke recurrence in an unselected cohort of patients with a first-ever stroke.

METHODS

Six hundred seventy-five patients were registered in a community-based stroke register (the Oxfordshire Community Stroke Project) and prospectively followed for up to 6.5 years. Their relative risk of recurrent stroke was calculated using age- and sex-specific incidence rates for first stroke in Oxfordshire.

RESULTS

One hundred eighty recurrent episodes of stroke were identified, of which 135 were first recurrences. Given survival, the actuarial risk of suffering a recurrence was 30% (95% confidence interval, 20% to 39%) by 5 years, about nine times the risk of stroke in the general population. The risk was highest early after the first stroke: 13% (95% confidence interval, 10% to 16%) by 1 year, 15 times the risk in the general population. After the first year the average annual risk was about 4%. The risk of stroke recurrence did not appear to be related to age or pathological type of stroke.

CONCLUSIONS

The absolute and relative risks of recurrent stroke are highest early after the first stroke but remain elevated for several years thereafter. Efforts at secondary prevention should be initiated as soon as possible and continued for several years to gain greatest benefit.

Internal carotid artery dissection in a community. Rochester, Minnesota, 1987-1992

BACKGROUND AND PURPOSE

Cervical internal carotid artery dissections are diagnosed with an increasing frequency, but reliable epidemiologic data are not available. The aim of this study was to determine the incidence rate of spontaneous cervical internal carotid artery dissection in a defined population.

METHODS

Using the medical record linkage system used for epidemiologic studies in Rochester, Minn, all patients diagnosed with spontaneous cervical ICA dissection for 1987 through 1992 were identified.

RESULTS

A total of 10 patients with spontaneous cervical internal carotid artery dissection (6 women and 4 men; mean age, 44 years) were identified. For the period 1987 through 1992, the average annual incidence rate for all ages was 2.6 per 100,000 (95% confidence intervals, 0.9 to 4.2).

CONCLUSIONS

This study, for the first time, provides incidence rates for spontaneous cervical internal carotid artery dissections. No diagnoses were made before 1987, probably reflecting an increased awareness of the disorder among physicians.

Stroke trends in an aging population. The Technology Assessment Methods Project Team

BACKGROUND AND PURPOSE

Trends in stroke incidence and survival determine changes in stroke morbidity and mortality. This study examines the extent of the incidence decline and survival improvement in the Netherlands from 1979 to 1989. In addition, it projects future changes in stroke morbidity during the period 1985 to 2005, when the country's population will be aging.

METHODS

A state-event transition model is used, which combines Dutch population projections and existing data on stroke epidemiology. Based on the clinical course of stroke, the model describes historical national age- and sex-specific hospital admission and mortality rates for stroke. It extrapolates observed trends and projects future changes in stroke morbidity rates.

RESULTS

There is evidence of a continuing incidence decline. The most plausible rate of change is an annual decline of -1.9% (range, -1.7% to -2.1%) for men and -2.4% (range, -2.3% to -2.8%) for women. Projecting a constant mortality decline, the model shows a 35% decrease of the stroke incidence rate for a period of 20 years. Prevalence rates for major stroke will decline among the younger age groups but increase among the oldest because of increased survival in the latter. In absolute numbers this results in an 18% decrease of acute stroke episodes and an 11% increase of major stroke cases.

CONCLUSIONS

The increase in survival cannot fully explain the observed mortality decline and, therefore, a concomitant incidence decline has to be assumed. Aging of the population partially outweighs the effect of an incidence decline on the total burden of stroke. Increase in cardiovascular survival leads to a further increase in major stroke prevalence among the oldest age groups.

Hospitalized stroke in blacks and Hispanics in northern Manhattan

BACKGROUND AND PURPOSE

The growing black and Hispanic populations in the United States call for studies of the rates and prognosis for cerebral infarction to help plan more focused prevention programs.

METHODS

Using the Statewide Planning and Research Cooperative System, we obtained discharge data for 1,034 patients over age 39, who were hospitalized for stroke from 1983 to 1986, using four zip code areas of the ethnically mixed community of Northern Manhattan.

RESULTS

Stroke incidence increased with age in both men and women in all three race/ethnic groups. The age-adjusted stroke incidence per 100,000 per year for men greater than or equal to 40 years of age was 567 for blacks, 306 for Hispanics, and 351 for whites. Incidence in women greater than or equal to 40 years was 716 in blacks, 361 in Hispanics, and 326 in whites. Hypertension and diabetes were more prevalent in blacks and Hispanics with stroke, whereas whites had more ischemic cardiac disease. Crude in-hospital mortality was greater in younger blacks and Hispanics compared with whites, whereas 2-year readmission rates, overall and for stroke, were similar in the three groups.

CONCLUSIONS

These estimates of hospitalized stroke incidence and mortality substantiate the greater incidence of stroke in blacks and provide new data concerning Hispanics for public health planning.