Stroke: clinical factors increased the risk of stroke.

Clinical bottom line (level 2b)

  1. A twentieth of patients with isolated systolic hypertension had a stroke at a mean of 4.5 years.
  2. All patients were at an increased risk of stroke if they had a history of stroke or diabetes, were a current smoker, had ECG abnormalities, were older, had a higher systolic blood pressure or resting heart rate.
  3. Patients were at an increased risk of haemorrhagic stroke if they had a history of stroke or a higher body mass index
  4. Patients were at increased risk of lacunar stroke if they were a current smoker, had a history of diabetes or as they got older.
  5. Patients were at an increased risk of atherosclerotic stroke if they had carotid bruits.
Davis et al: Stroke 1998; 29: 1333-1340
Expires December 2002

The study

Retrospective cohort study with objective outcomes, adjusted for confounding factors, not validated in an independent set of patients.

Setting: general hospitals , USA

4736 patients (aged mean 72 years, 57% female) isolated systolic hypertension defined as mean systolic blood pressure of 160 to 219 mmHg and diastolic blood pressure <90 mmHg

Excluded if
  • <60 years old
  • history and/or signs of specified major cardiovascular diseases, other major diseases or medical management problems


    • Patients were originally randomised to chlorthalidone (12.5 to 25 mg/d) with step-up to atenolol (25 to 50 mg/d) or reserpine (0.05 to 0.10 mg/d), or placebo.

    Multivariate analysis was used to adjust for confounding factors.

    99.8% followed for mean 4.5 years
    Outcomes studied:
  • stroke
  • ischaemic stroke
  • haemorrhagic stroke
  • lacunar stroke
  • atherosclerotic stroke
  • embolic stroke
  • stroke or TIA

    • 86% of patients were white or other non black.

    The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)
    stroke mean 4.5 years 262/4736 5.53%
    (4.88% to 6.18%)
    ischaemic stroke mean 4.5 years 217/4736 4.58%
    (3.99% to 5.18%)
    haemorrhagic stroke mean 4.5 years 28/4736 0.59%
    (0.37% to 0.81%)
    lacunar stroke mean 4.5 years 66/4736 1.39%
    (1.06% to 1.73%)
    atherosclerotic stroke mean 4.5 years 26/4736 0.55%
    (0.34% to 0.76%)
    embolic stroke mean 4.5 years 25/4736 0.53%
    (0.32% to 0.73%)
    stroke or TIA mean 4.5 years 384/4736 8.11%
    (7.33% to 8.89%)

    prognostic factor for
    stroke     		time to outcome adjusted RR
    (95% CI)
    history of stroke mean 4.5 years 2.13
    (1.00 to 4.56)
    history of diabetes mean 4.5 years 1.80
    (1.26 to 2.57)
    current smoker mean 4.5 years 1.63
    (1.14 to 2.34)
    ECG abnormalities mean 4.5 years 1.47
    (1.09 to 1.99)
    age per 5 year increase mean 4.5 years 1.24
    (1.12 to 1.38)
    systolic blood pressure per 10 mmHg increase mean 4.5 years 1.15
    (1.01 to 1.32)
    pulse per 10 beats per minute higher mean 4.5 years 1.15
    (1.01 to 1.30)
    high density lipoprotein cholesterol (HDL-C) per 0.39 mmol/L increase mean 4.5 years 0.82
    (0.70 to 0.96)
    randomisation to active drug mean 4.5 years 0.60
    (0.45 to 0.79)

    prognostic factor for
    ischaemic stroke     		time to outcome adjusted RR
    (95% CI)
    history of diabetes mean 4.5 years 2.29
    (1.60 to 3.29)
    current smoker mean 4.5 years 1.81
    (1.25 to 2.62)
    ECG abnormalities mean 4.5 years 1.39
    (1.02 to 1.90)
    age increase of 5 years mean 4.5 years 1.32
    (1.19 to 1.47)
    systolic blood pressure per 10 mmHg increase mean 4.5 years 1.17
    (1.02 to 1.33)
    pulse per 10 beats per minute increase mean 4.5 years 1.14
    (1.01 to 1.30)
    HDL-C per 0.39 mmol/L increase mean 4.5 years 0.81
    (0.69 to 0.95)
    randomisation to active drug mean 4.5 years 0.66
    (0.50 to 0.87)

    prognostic factor for
    haemorrhagic stroke     		time to outcome adjusted RR
    (95% CI)
    history of stroke mean 4.5 years 5.86
    (1.39 to 24.8)
    body mass index ² per [kg/m ² ] ² increase mean 4.5 years 1.01
    (1.00 to 1.01)
    body mass index per kg/m ² increase mean 4.5 years 0.60
    (0.43 to 0.82)

    prognostic factor for
    lacunar stroke     		time to outcome adjusted RR
    (95% CI)
    current smoker mean 4.5 years 3.04
    (1.73 to 5.37)
    history of diabetes mean 4.5 years 3.03
    (1.70 to 5.40)
    age per 5 year increase mean 4.5 years 1.40
    (1.17 to 1.66)
    randomisation to active drug mean 4.5 years 0.53
    (0.32 to 0.88)

    prognostic factor for
    atherosclerotic stroke     		time to outcome adjusted RR
    (95% CI)
    presence of carotid bruits mean 4.5 years 5.75
    (2.50 to 13.2)

    prognostic factor for
    embolic stroke     		time to outcome adjusted RR
    (95% CI)
    age per 5 year increase mean 4.5 years 1.65
    (1.25 to 2.18)

    • Factors are the same, and in the same direction for stroke or TIA, except that age and pulse increase are not significant.
    • Treatment had the greatest effect for lowering the rate of hemorrhagic, lacunar, and embolic stroke

    Comments

    1. Data was taken from a randomised controlled trial.
    2. Not enough data was available to calculate NNF+s.

    Citation

    1. Davis BR, Vogt T, Frost PH, et al: Risk factors for stroke and type of stroke in persons with isolated systolic hypertension. Stroke 1998; 29: 1333-1340
    Contributor: Clare Wotton and Musab Hayatli, December 1999
    Reviewer: Daniel Sontheimer

    Clinical Question.
    Patient isolated systolic hypertension
    Intervention or Exposure presence of prognostic factors
    Comparison absence of prognostic factors
    Outcome stroke and stroke type