PDF: PAST-BP
(2016)Objective
Assess whether an intensive systolic blood pressure (SBP) target (<130 mm Hg or ≥10 mm Hg reduction) reduces SBP more than a standard target (<140 mm Hg) in patients with prior stroke or TIA in primary care.
Study Summary
Intervention
Open-label randomized controlled trial in 99 UK general practices. Patients were randomized to intensive SBP target (<130 mm Hg or ≥10 mm Hg drop if baseline <140) vs. standard SBP target (<140 mm Hg). Follow-up: 12 months.
Study Design
Arms: Array
Outcome
• Target BP <130 mm Hg achieved in 51% (intensive) vs. 54% (standard); p=0.36
• More consultations and treatment changes in the intensive group
• Clinical events: 1 vs. 5 major CV events (HR 0.19; p=0.16)
• Emergency admissions similar (HR 1.26; p=0.16)
• No significant difference in reported symptoms or side effects
Bottom Line
Targeting SBP <130 vs <140 mmHg in post-stroke/TIA primary care patients produced only 2.9 mmHg additional reduction at 12 months (P=0.03). Both arms achieved large reductions (~13-16 mmHg). Only 51% achieved the individualised intensive target. Active management matters more than the specific target. 529 patients, 99 UK practices, open-label.
Major Points
- Small but significant BP difference: intensive target reduced SBP by additional 2.9 mmHg (95% CI 0.2-5.7; P=0.03) at 12 months.
- Both arms achieved large reductions: -16.1 mmHg (intensive) vs -12.8 mmHg (standard). >80% in both achieved SBP <140 mmHg.
- Only 51% achieved the individualised intensive target (<130 mmHg or 10 mmHg reduction). Clinician/patient reluctance common near target.
- Intensive target increased workload: more GP visits (median 2 vs 1; P<0.001), more nurse visits, more treatment intensifications (458 vs 278; P<0.001).
- Higher withdrawal in intensive arm: 20% vs 12% (P=0.02) — despite no objective increase in side effects.
- Only 6 cardiovascular events total (1 intensive, 5 standard) — grossly underpowered for clinical endpoints.
- Pragmatic primary care trial: 529 patients, 99 UK practices. Prevalent population including 51-54% TIA-only.
- Authors conclude a full pragmatic trial of intensive targets in primary care is not warranted.
Study Design
- Study Type
- Randomized, open-label, primary care-based controlled trial
- Randomization
- Yes
- Blinding
- Open-label
- Sample Size
- 529
- Follow-up
- 12 months
- Centers
- 99
- Countries
- United Kingdom
Primary Outcome
Definition: Change in systolic blood pressure from baseline to 12 months
| Control | Intervention | HR/OR | P-value |
|---|---|---|---|
| −12.8 mm Hg | −16.1 mm Hg | - (−5.68 to −0.21 mm Hg (between-group difference −2.94)) | 0.03 |
Limitations & Criticisms
- Open-label design introduces potential bias
- Relatively short follow-up (12 months)
- Underpowered for clinical outcomes such as recurrent stroke or cardiovascular events
- 28% missing primary outcome data with differential loss to follow-up in intensive arm
- Trial population younger and less disabled than typical prevalent cerebrovascular disease population; over-represented TIA-only patients
Citation
Mant J, McManus RJ, Roalfe A, et al. Different systolic blood pressure targets for people with history of stroke or transient ischaemic attack: PAST-BP (Prevention After Stroke—Blood Pressure) randomised controlled trial. BMJ. 2016;352:i708.