Risk Of Hospitalization For Stroke Research Articles

Abstract TP200: Independent Contribution of HbA1c, Systolic Blood Pressure, and LDL Cholesterol Control to Risk of Ischemic Stroke Hospitalizations in Type 2 Diabetes

Risk of ischemic stroke is approximately doubled in patients with diabetes. To reduce risk, managing diabetes includes optimizing glycemic, blood pressure (BP), and low-density lipoprotein cholesterol (LDL-C) control. We studied which risk factors alone or in combination were most strongly associated with stroke hospitalizations. We identified 26,924 Kaiser Permanente Northwest members with type 2 diabetes and no known prior cardiovascular disease hospitalization. Beginning in 2002, we identified the earliest point patients had glycosolated hemoglobin (HbA1c), systolic BP (SBP), and LDL-C measurements within 6 months of each other and followed them until they died, disenrolled, or 31 December 2011. Outcome was hospitalization with primary diagnosis of ischemic stroke. Using mean HbA1c, SBP, and LDL-C between baseline and end of follow-up, we identified dichotomous categories of control of HbA1c (<7%), SBP (<130 mm Hg) and LDL-C (<100 mg/dL) and estimated the relative risk of stroke hospitalization independently associated with all combinations of risk factors controlling for age, sex, diabetes duration, comorbidities, body mass index, smoking, and pharmacotherapy. Mean (SD) age of patients was 59 (12) years; 50% were men. Over mean (SD) follow-up of 6.2 (2.8) years, 606 (2.3%) patients were hospitalized for ischemic stroke. Compared with patients with all 3 risk factors in control, patients who had no risk factors controlled or only HbA1c controlled had >2-fold increased risk of ischemic stroke. Patients who controlled both SBP and LDL-C had significantly lower risk relative to control of all 3 risk factors. In this observational study, maintaining control of SBP over 6.2 years was essential to reduction of ischemic stroke risk. Simultaneous control of LDL-C further reduced risk, but HbA1c control <7% did not mitigate stroke risk beyond SBP and LDL-C control. Further research is needed to evaluate the relationship between HbA1c control and stroke risk.

Airborne pollutants and lacunar stroke: a case cross-over analysis on stroke unit admissions

Particulate air pollution is known to be associated with cardiovascular disease. The relation of particulate air pollution with cerebrovascular disease (CVD) has not been extensively studied, particularly in relation to different subtypes of stroke. A time-series study was conducted to evaluate the association between daily air pollution and acute stroke unit hospitalizations in Mantua, Italy. We analyzed 781 CVD consecutive patients living in Mantua county admitted between 2006–08. Data on stroke types, demographic variables, risk factors were available from the Lombardia Stroke Registry. Daily mean value of particulate matter with a diameter <10 µm (PM10), carbon monoxide, nitric oxide, nitrogen dioxide, sulphur dioxide, benzene and ozone were used in the analysis. The association between CVD, ischemic strokes subtypes and pollutants was investigated with a case-crossover design, using conditional logistic regression analysis, adjusting for temperature, humidity, barometric pressure and holidays. Among the 781 subjects admitted 75.7% had ischemic stroke, 11.7% haemorrhagic stroke 12.6% transient ischemic attack. In men admission for stroke was associated with PM10 [odds ratio (OR) 1.01, 95%; confidence interval (CI) 1.00–1.02; P<0.05]. According to the clinical classification, lacunar anterior circulation syndrome stroke type was related to PM10 level registered on the day of admission for both genders (OR: 1.01, 95%; CI: 1.00–1.02; P<0.05) while for total anterior circulation syndrome stroke only in men (OR: 1.04, 95%; CI 1.01–1.07; P<0.05).In conclusion, our study confirms that air pollution peaks may contribute to increase the risk of hospitalization for stroke and particulate matter seems to be a significant risk factor, especially for lacunar stroke.

A retrospective cohort study of stroke onset: implications for characterizing short term effects from ambient air pollution

BackgroundCase-crossover studies used to investigate associations between an environmental exposure and an acute health response, such as stroke, will often use the day an individual presents to an emergency department (ED) or is admitted to hospital to infer when the stroke occurred. Similarly, they will use patient's place of residence to assign exposure. The validity of using these two data elements, typically extracted from administrative databases or patient charts, to define the time of stroke onset and to assign exposure are critical in this field of research as air pollutant concentrations are temporally and spatially variable. Our a priori hypotheses were that date of presentation differs from the date of stroke onset for a substantial number of patients, and that assigning exposure to ambient pollution using place of residence introduces an important source of exposure measurement error. The objective of this study was to improve our understanding on how these sources of errors influence risk estimates derived using a case-crossover study design.MethodsWe sought to collect survey data from stroke patients presenting to hospital EDs in Edmonton, Canada on the date, time, location and nature of activities at onset of stroke symptoms. The daily mean ambient concentrations of NO2 and PM2.5 on the self-reported day of stroke onset was estimated from continuous fixed-site monitoring stations.ResultsOf the 336 participating patients, 241 were able to recall when their stroke started and 72.6% (95% confidence interval [CI]: 66.9 - 78.3%) experienced stroke onset the same day they presented to the ED. For subjects whose day of stroke onset differed from the day of presentation to the ED, this difference ranged from 1 to 12 days (mean = 1.8; median = 1). In these subjects, there were no systematic differences in assigned pollution levels for either NO2 or PM2.5 when day of presentation rather than day of stroke onset was used. At the time of stroke onset, 89.9% (95% CI: 86.6 - 93.1%) reported that they were inside, while 84.5% (95% CI: 80.6 - 88.4%) reported that for most of the day they were within a 15 minute drive from home. We estimated that due to the mis-specification of the day of stroke onset, the risk of hospitalization for stroke would be understated by 15% and 20%, for NO2 and PM2.5, respectively.ConclusionsOur data suggest that day of presentation and residential location data obtained from administrative records reasonably captures the time and location of stroke onset for most patients. Under these conditions, any associated errors are unlikely to be an important source of bias when estimating air pollution risks in this population.

Risk of Hospitalization for Stroke Associated with Antipsychotic Use in the Elderly

Antipsychotics are commonly used in the elderly despite a lack of safety data from randomized trials, particularly for the typical antipsychotics. Observational studies have investigated the association between antipsychotics and stroke but results vary, which may be due to lack of control for unmeasured confounding. To estimate the risk of hospitalization for stroke in elderly users of antipsychotics. Using the Australian Government Department of Veterans' Affairs administrative claims dataset we utilized a self-controlled case series design to risk-adjust for potential unmeasured confounding. Risk periods prior to antipsychotic initiation were also included to search for evidence of confounding by indication. Unexposed patients were included to adjust for the increasing incidence of hospitalization for stroke with age. There were 10 638 patients aged ≥65 years with at least one hospitalization for stroke identified during the 4-year period from 1 January 2003 to 31 December 2006. Of these, 514 patients were initiated on typical antipsychotics and 564 patients were initiated on atypical antipsychotics. Hospitalization for stroke was increased in the first week after initiation of a typical antipsychotic (incidence rate ratio [IRR] 2.3; 95% CI 1.3, 3.8). There was no evidence of an increased risk of hospitalization for stroke after initiation of atypical antipsychotics. The risk of hospitalization for stroke progressively increased in the weeks leading up to first-time antipsychotic treatment. However, while the risk of hospitalization for stroke in the week prior to initiating antipsychotic therapy was significantly increased for patients initiated on typical antipsychotics (IRR 7.2; 95% CI 5.3, 9.8), patients initiated on atypical antipsychotics had no excess risk in the same period (IRR 1.2; 95% CI 0.7, 2.3). The results of this study are consistent with randomized controlled trial evidence indicating that there is no increased risk of serious cerebrovascular events requiring hospitalization in patients taking atypical antipsychotics. No randomized controlled trial evidence is available on the risk of hospitalization for stroke with use of typical antipsychotics in the elderly. This study found a small but significantly increased risk of hospitalization for stroke immediately following the initiation of typical antipsychotics. Antipsychotics are likely to be initiated after hospitalization for stroke. This practice is likely to reflect the prescribing of antipsychotics during hospital admission for post-stroke complications such as delirium; however, the long-term effects of this practice are unknown.

A Propensity-Matched Study of Hypertension and Increased Stroke-Related Hospitalization in Chronic Heart Failure

Hypertension is a risk factor for heart failure and stroke. However, the effect of hypertension on stroke in patients with heart failure has not been well studied. In the Digitalis Investigation Group trial, 3,674 (47%) of the 7,788 patients had a history of hypertension. Probability or propensity scores for a history of hypertension were calculated for each patient through use of a multivariable logistic regression model and were then used to match 2,386 pairs of patients with and without a history of hypertension. Kaplan-Meier and matched Cox regression analyses were used to estimate associations of a history of hypertension hospitalization for stroke during 37 months of median follow-up. After matching, patients without and with a history of hypertension had a mean systolic blood pressure of 127 mm Hg. Hospitalization for stroke occurred in 90 patients (rate, 129/10,000 person-years of follow-up) without a history of hypertension and 121 patients (rate, 178/10,000 person-years of follow-up) with a history of hypertension (hazard ratio when hypertension was compared with no hypertension=1.52; 95% confidence interval=1.11 to 2.08; p=0.010). This association was also observed among patients with baseline systolic blood pressure <140 mm Hg (hazard ratio=1.35; 95% confidence interval=1.01 to 1.81; p=0.044). In conclusion, a history of hypertension was associated with increased risk of hospitalization for stroke among patients with heart failure who were balanced in all measured baseline covariates, including blood pressure.

Supraclavicular radiation for breast cancer does not increase the 10‐year risk of stroke

Modern radiation techniques, which limit the radiation dose to the heart during treatment for breast cancer, have greatly reduced the risk of radiation-induced cardiac injury. However, the risk of radiation damage to the carotid artery, which is often incidentally included in the supraclavicular radiation field for breast cancer treatment, is not routinely examined, and the technique used to treat this field has not changed significantly from early radiation trials. The purpose of the current study was to compare the incidence of hospitalization for stroke among women with breast cancer treated with supraclavicular radiation with those who received radiation therapy to the breast but not the supraclavicular fossa. Data from the Surveillance, Epidemiology, and End Results (SEER)-Medicare database for 5752 women who were diagnosed with American Joint Committee on Cancer (AJCC) Stage I-III nonmetastatic breast cancer between 1988 and 1997 were analyzed. Women included were age > or = 66 years, had known lymph node (LN) status, had tumors measuring < or = 5 cm, underwent breast surgery, and received adjuvant radiation therapy (with or without supraclavicular irradiation). Patients with < 5 years of follow-up were excluded because events in the first 5 years after radiation were unlikely to be radiation induced. A Cox proportional hazards model was used to compare patients with 0 positive LNs (surrogate group for no supraclavicular radiation, n = 5281) with patients with > 4 positive LNs (surrogate for supraclavicular radiation group, n = 471) for the endpoint of hospitalization for stroke. Time-to-event curves were calculated using the conditional Kaplan-Meier method. The median follow-up for the 0 and 4+ LN cohorts were 92 months and 90 months, respectively (minimum of 60 months). The 10-year and 15-year actuarial freedom from hospitalization for stroke was 91% (0 LN) versus 89.5% (4+ LN) and 79% (0 LN) versus 81.6% (4+ LN), respectively (P = .28). Estrogen receptor status was balanced between the 2 cohorts. As expected, the 4+ cohort had more advanced tumors, higher stage, larger tumor size, and higher grade (P < .0001). In multivariate analysis including LN group, year of diagnosis, age, race, type of surgery, stage, tumor size, grade, estrogen receptor status, and Charlson comorbidity score, only increased age (hazard ratio [HR] for ages 70-74 years, 1.6; HR for ages 75-79 years, 2.1; and HR for age 80 + years, 2.7) and increasing comorbidity score were predictive of an increased risk of hospitalization for stroke. Although patients with nonbreast malignancies treated with higher doses to the carotid arteries have been shown to have an increased risk of carotid injury, no evidence was found that radiation to the carotid delivered during supraclavicular irradiation for breast cancer increases the risk of hospitalization for stroke.

Lower ambient temperature was associated with an increased risk of hospitalization for stroke and acute myocardial infarction in young women

Objective Results of investigations into the impact of seasonal variation on the incidence of cardiovascular diseases (CVD) have been inconsistent. Using the WHO Collaborative Study of CVD and Steroid Hormone Contraception database, we attempted to examine the relationship between variation in three climatic variables and risk of hospitalization for venous thromboembolism (VTE), arterial stroke, and acute myocardial infarction (AMI). Study design and setting We compared the monthly mean temperature, rainfall, and humidity with rates of hospitalized VTE, stroke, and AMI among young women aged 15–49 from 17 different countries in Africa, Asia, Europe, Latin America, and the Caribbean by using a negative binomial regression model. Results The study included 1146, 2,269, and 369 cases of VTE, stroke, and AMI, respectively. Significant associations between temperature and hospital admission rates of stroke and AMI, but not VTE, were apparent. Lagging the effects of temperature suggested that these effects were relatively acute, within a period of a month. Conclusion These data may help in understanding the mechanisms whereby stroke and AMI events are triggered.