Blood Pressure Control and Risk of Stroke: A Population-Based Prospective Cohort Study

Background and Purpose— Adequate control of blood pressure (BP) is a cornerstone in stroke prevention. This study explored the risk of stroke in relation to the quality of BP control in a population-based cohort and whether control of hypertension was related to background characteristics of patients. Methods— A total of 27 936 subjects (10 953 men and 16 983 women), 45 to 73 years old, living in Malmö, Sweden participated in the study. Incidence of stroke was followed-up for a mean period of 6 years. Controlled BP was defined as BP <140/90 mm Hg in subjects with pharmacological treatment for hypertension. Results— In the whole cohort, 16 648 subjects (60%) had hypertension (BP ≥140/90 mm Hg) and 23% of them received treatment. Among treated hypertensives, 88.2% had BP levels ≥140/90 mm Hg and 49.5% had BP levels ≥160/100 mm Hg. During the follow-up, 137 strokes occurred among treated hypertensive subjects. The crude incidence of stroke was 289/100 000 person-year in controlled hypertensive subjects and 705/100 000 person-year in treated hypertensive subjects with BP ≥140/90 mm Hg. It was estimated that ≈45% of all strokes among subjects with treatment for hypertension might be attributed to uncontrolled BP. In treated hypertensives, the risk of stroke increased significantly with advancing age, current smoking, high level of diastolic BP, and diabetes. In hypertensive subjects without treatment (n=12 819), incidence of stroke was 363/100 000 person-year. Conclusion— Uncontrolled BP is highly prevalent in patients with pharmacological treatment for hypertension. More than 90% of stroke in this group occurred in those with uncontrolled BP. Adequate hypertension control may prevent a substantial proportion of first-ever stroke among treated hypertensives.

[1]  A. Nordlund,et al.  Increasing Stroke Incidence in Sweden Between 1989 and 2000 Among Persons Aged 30 to 65 Years: Evidence From the Swedish Hospital Discharge Register , 2004, Stroke.

[2]  W. Aronow,et al.  Treatment of hypertension and prevention of ischemic stroke , 2004, Current cardiology reports.

[3]  G. Berglund,et al.  Changes in blood pressure and body weight following smoking cessation in women , 2004, Journal of internal medicine.

[4]  R. Cooper,et al.  Hypertension Treatment and Control in Five European Countries, Canada, and the United States , 2004, Hypertension.

[5]  G. Engström,et al.  Increasing Stroke Incidence and Decreasing Case Fatality, 1989–1998: A Study From the Stroke Register in Malmö, Sweden , 2003, Stroke.

[6]  L. Weinehall,et al.  High remaining risk in poorly treated hypertension: the ‘rule of halves’ still exists , 2002, Journal of hypertension.

[7]  L. Lindholm,et al.  The problem of uncontrolled hypertension , 2002, Journal of Human Hypertension.

[8]  G. Berglund,et al.  The Malmö diet and cancer study: representativity, cancer incidence and mortality in participants and non‐participants , 2001, European journal of cancer prevention : the official journal of the European Cancer Prevention Organisation.

[9]  F. Magrini,et al.  High prevalence of cardiac and extracardiac target organ damage in refractory hypertension , 2001, Journal of hypertension.

[10]  G. Berglund,et al.  Occupational status, educational level, and the prevalence of carotid atherosclerosis in a general population sample of middle-aged Swedish men and women: results from the Malmö Diet and Cancer Study. , 2000, American journal of epidemiology.

[11]  V. Pavlik,et al.  Self-reported hypertension treatment practices among primary care physicians: blood pressure thresholds, drug choices, and the role of guidelines and evidence-based medicine. , 2000, Archives of internal medicine.

[12]  B. Psaty,et al.  Control of blood pressure and risk of stroke among pharmacologically treated hypertensive patients. , 2000, Stroke.

[13]  D. Levy,et al.  Antecedent hypertension confers increased risk for adverse outcomes after initial myocardial infarction. , 1997, Hypertension.

[14]  Xianglin L. Du,et al.  Case-control study of stroke and the quality of hypertension control in north west England , 1997, BMJ.

[15]  G. Berglund,et al.  Design and feasibility , 1993 .

[16]  G. Berglund,et al.  Stroke Registry in Malmö, Sweden , 1992, Stroke.

[17]  L. Kuller,et al.  Systolic Hypertension in the Elderly Program (SHEP) , 1986, Journal of the American Geriatrics Society.

[18]  J. Wilber.  Hypertension as a community problem. , 1974, Preventive medicine.

[19]  E. Kaplan,et al.  Nonparametric Estimation from Incomplete Observations , 1958 .

[20]  C. Weinberg,et al.  Use and misuse of population attributable fractions. , 1998, American journal of public health.

[21]  R. Weinshilboum,et al.  The Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (NIH Publication No. 98-4080) , 1997 .