Blood Pressure as a Risk Factor for Stroke and the Impact of Antihypertensive Treatment

Moderate and Severe Blood Pressure Elevation Associated with Stroke in the Mexican Hispanic Population

BACKGROUND

Stroke is the fourth leading cause of death in US. Amongst other factors such as age, sex, race, genetics, obesity, diabetes etc., hypertension continues to be the leading contributing factor towards stroke. Studies regarding stroke in Hispanics are sparse and inconclusive.

OBJECTIVES

The objective of the present study is to investigate the potential association between blood pressure elevation and risk of ischemic stroke among the Mexican Hispanic population.

METHODS

A retrospective data analysis was carried out for a planned case-control study with case-control ratios of 1:2. Mexican Hispanic cases were from the ElPasoStroke database with diagnosed hypertension that had sustained an ischemic stroke (n = 505) and Mexican Hispanics diagnosed with hypertension who were stroke-free as controls from the 2005-2010 NHANES databases (n = 1010). In this analysis, we included subjects who had data on systolic, diastolic or mean arterial blood pressures for cases (327) and controls (772). In cases, blood pressure was determined by the initial admission measurement, and in controls, the first measured blood pressure was used. The unadjusted and adjusted effects of continuous measurements of systolic, diastolic and mean arterial blood pressure on stroke were determined using logistic regression analyses. Subjects were further classified into groups based on prehypertension and hypertension ranges, as established by the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC7). Unadjusted and adjusted logistic regression models were also used to determine the effect of categorized blood pressures.

RESULTS

Our data indicate that per unit increase in systolic, diastolic or mean arterial blood pressure elevates the odds of stroke among the Mexican Hispanic population. Adjusted analysis of categorized blood pressures showed that mild or moderate/severe high blood pressure significantly associated with odds of stroke. Maintaining and controlling blood pressure at more stringent and lower levels, specifically lowering mean arterial pressure may effectively reduce the odds of ischemic stroke among the Mexican Hispanic population.

CONCLUSION

Elevation of blood pressure increases the odds of stroke among the Mexican Hispanic population. Our results provide new strategies to manage the stroke prevention and health disparity issues among the Mexican Hispanic population.

Cardiovascular consequences of famine in the young

Aims The developmental origins hypothesis proposes that undernutrition during foetal life, infancy, or childhood is associated with an increased risk of cardiovascular disease in adulthood. As data on postnatal developmental programming are scarce, we investigated whether exposure to undernutrition during childhood, adolescence, or young adulthood is related to coronary heart disease (CHD) and stroke in adult life. Methods and results We studied 7845 women from the Prospect-EPIC cohort who had been exposed at various degrees to the 1944-45 Dutch famine when they were aged between 0 and 21 years. We used Cox proportional hazard regression models to explore the effect of famine on the risk of CHD and stroke, overall and within exposure age categories (0-9, 10-17, ≥18 years). We adjusted for potential confounders, including age at famine exposure, smoking, and level of education as a proxy for socio-economic status. Overall, stronger famine exposure was associated with higher CHD risk. Among those who experienced the famine between ages 10 and 17 years, CHD risk was significantly higher among severely exposed women compared with unexposed women (HR 1.38; 95% CI 1.03-1.84), which only slightly attenuated after adjustment for confounding (HR 1.27; 95% CI 0.94-1.71). We observed a lower stroke risk among famine exposed women (HR 0.79; 95% CI 0.61-1.02). Adjustment for potential confounders produced similar results (HR 0.77; 95% CI 0.59-0.99). Conclusion Exposure to undernutrition during postnatal periods of development, including adolescence, may affect cardiovascular health in adult life.

Prevalence of inadequate blood pressure control among veterans after acute ischemic stroke hospitalization: a retrospective cohort

BACKGROUND

Reducing blood pressure (BP) after stroke reduces risk for recurrent events. Our aim was to describe hypertension care among veterans with ischemic stroke including BP control by discharge and over the 6 months after the stroke event.

METHODS AND RESULTS

The Office of Quality and Performance Stroke Special Study included a systematic sample of veterans hospitalized for ischemic stroke in 2007. We examined BP control (<140/90 mm Hg) at discharge excluding those who died, enrolled in hospice, or had unknown discharge disposition (n=3640, n=3382 adjusted analysis). The second outcome was BP control (<140/90 mm Hg) within 6-months after stroke, excluding patients who died/readmitted within 30 days, were lost to follow-up, or did not have a BP recorded (n=2054, n=1915 adjusted analysis). The population was 62.7% white and 97.7% men; 46.9% were <65 years of age; and 29% and 37% had a history of cerebrovascular or cardiovascular disease, respectively. Among the 3640 stroke patients, 1573 (43%) had their last documented BP before discharge as >140/90 mm Hg. Black race (adjusted odds ratio, 0.77; 95% confidence interval, 0.65 to 0.91), diabetes (odds ratio, 0.73; 95% confidence interval, 0.62 to 0.86), and hypertension history (odds ratio, 0.51; 95% confidence interval, 0.42 to 0.63) were associated with lower odds for controlled BP at discharge. Of the 2054 stroke patients seen within 6 months from their index event, 673 (32.8%) remained uncontrolled. By 6 months after the event, neither race nor diabetes was associated with BP control, whereas history of hypertension continued to have lower odds of BP control. For each 10-point increase in systolic BP >140 mm Hg at discharge, odds of BP control within 6 months after discharge decreased by 12% (95% confidence interval [8%, 18%]).

CONCLUSIONS

BP values in excess of national guidelines are common after stroke. Forty-three percent of patients were discharged with an elevated BP, and 33% remained uncontrolled by 6 months.

Antihypertensive medication adherence, ambulatory visits, and risk of stroke and death

BACKGROUND

This study seeks to determine whether antihypertensive medication refill adherence, ambulatory visits, and type of antihypertensive medication exposures are associated with decreased stroke and death for community-dwelling hypertensive patients.

METHODS

This retrospective cohort study included all chronic medication-treated hypertensives enrolled in Tennessee's Medicaid program (TennCare) for 3-7 years during the period 1994-2000 (n = 49,479). Health care utilization patterns were evaluated using administrative data linked to vital records during a 2-year run-in period and 1- to 5-year follow-up period. Antihypertensive medication refill adherence was calculated using pharmacy records.

RESULTS

Associations with stroke and death were assessed using Cox proportional hazards modeling. Stroke occurred in 619 patients (1.25%) and death in 2,051 (4.15%). Baseline antihypertensive medication refill adherence was associated with decreased multivariate hazards of stroke [hazard ratio (HR) 0.91; 95% confidence interval (CI), 0.86-0.97 for 15% increase in adherence]. Adherence in the follow-up period was associated with decreased hazards of stroke (HR 0.92; CI 0.87-0.96) and death (HR 0.93; CI 0.90-0.96). Baseline ambulatory visits were associated with decreased death (HR 0.99; CI 0.98-1.00). Four major classes of antihypertensive agents were associated with mortality reduction. Only thiazide-type diuretic use was associated with decreased stroke (HR 0.89; CI 0.85-0.93).

CONCLUSIONS

Ambulatory visits and antihypertensive medication exposures are associated with reduced mortality. Increasing adherence by one pill per week for a once-a-day regimen reduces the hazard of stroke by 8-9% and death by 7%.

Lack of association between dietary protein intake and risk of stroke among middle-aged men

BACKGROUND

Prospective cohort studies in Japanese populations have shown an inverse association between dietary protein and stroke risk. However, this association has not been examined among any study populations of US men.

OBJECTIVE

Our objective was to examine the relation between dietary protein and risk of stroke in men who participated in the Health Professionals Follow-Up Study.

DESIGN

A total of 43,960 men who were free of cardiovascular disease and cancer at baseline were included in the analysis. Dietary protein (total, animal, and vegetable) was assessed with the use of a food-frequency questionnaire at 5 time points during the follow-up period of 1986-2004. Cox proportional hazards models were used to calculate multivariate relative risks and 95% CIs, which represented the effect of the substitution of protein for an equal percentage of energy from carbohydrate.

RESULTS

During 18 y of follow-up there were 1057 incident stroke events (638 ischemic, 171 hemorrhagic, and 248 of unknown type). For total stroke, the relative risk for the top quintile of percentage energy from protein compared with the bottom was 1.14 (95% CI: 0.90, 1.43; P for linear trend: 0.43) for total protein, 1.11 (95% CI: 0.87, 1.41; P for linear trend: 0.52) for animal protein, and 0.82 (95% CI: 0.60, 1.12; P for linear trend: 0.17) for vegetable protein. The results were similar when ischemic and hemorrhagic stroke subtypes were considered separately.

CONCLUSION

In contrast to studies in Japanese populations, this study did not show a statistically significant association between total, animal, or vegetable protein and risk of stroke in this population of US men.

Performance of Comorbidity Measures to Predict Stroke and Death in a Community-Dwelling, Hypertensive Medicaid Population

Background and Purpose— The Charlson and Elixhauser comorbidities are widely used to control for differences in comorbidity in epidemiological studies but have not been validated for outpatient studies of hypertension. This study sought that validation using death and stroke outcomes.

Methods— Using Cox models in a retrospective cohort study of 49 479 hypertensive patients, Modified Charlson Index was compared with 6 alternative approaches to assessing comorbidity: individual Charlson comorbidities, Elixhauser comorbidities, prior major cardiovascular disease event, traditional risk factors for cerebrovascular accident, healthcare utilization, and antihypertensive medication utilization. Comorbidity measures were calculated at baseline and for a period before occurrence of the study outcome of interest or study conclusion.

Results— The Charlson comorbidities had the smallest Akaike information criterion value for both the stroke and death outcomes when baseline data were used. The Elixhauser comorbidities had the smallest Akaike information criterion value for both the stroke and death outcomes when follow-up data were used. Modified Charlson Index also predicted stroke and death, but alternative models were more robust.

Conclusion— This study indicates that both the Charlson and Elixhauser comorbidities are valid prediction tools that could enable clinicians and health systems to better assess risk for stroke and death in patients with hypertension. However, the Charlson comorbidities perform better when comorbidities are assessed using baseline data, whereas the Elixhauser comorbidities perform better for short follow-up periods when comorbidities are assessed proximal to events of interest.

Arterial Events after Ischemic Stroke at a Young Age: A Cross-Sectional Long-Term Follow-Up of Patients and Controls in Western Norway

BACKGROUND

There is little information in the literature on the risk of vascular events among patients after ischemic stroke at a young age.

METHODS

We examined 144 (77%) of 187 long-term survivors of ischemic stroke and compared them with 167 controls. Mean age of the 187 survivors at inclusion was 41.0 years and mean age of the participating patients was 40.8 years.

RESULTS

After a mean duration of observation of 11.8 years, we registered arterial events among 54 patients and 14 controls. Ninety patients with index stroke only had no significant risk factors compared with controls without arterial events. Compared with 54 patients with several arterial events, age, incidence of diabetes mellitus, smoking and family history of coronary disease were significantly lower.

CONCLUSIONS

The results from index-stroke-only patients suggest that a subgroup of patients has a benign course, probably without chronic vascular disease.