What are the implications of the SPRINT (Systolic Blood Pressure Intervention Trial) trial for the management of hypertension?

SPRINT Trial Implications for Hypertension Management

The SPRINT trial fundamentally changed hypertension management by demonstrating that intensive blood pressure lowering to a systolic target <120 mmHg reduces cardiovascular events by 25% and all-cause mortality by 27% compared to standard treatment targeting <140 mmHg in high-risk patients. 1

Key Trial Findings and Mortality Benefits

The SPRINT trial enrolled 9,361 hypertensive patients aged ≥50 years with elevated cardiovascular risk but excluded patients with diabetes, stroke, dementia, heart failure, and those institutionalized. 1 After median follow-up of 3.3 years (stopped early for benefit):

• Primary cardiovascular outcome reduced by 25% (HR 0.75; 95% CI 0.64-0.89) 1
• All-cause mortality reduced by 27% (HR 0.73; 95% CI 0.60-0.90) 1
• Benefits consistent across subgroups, including patients with and without CKD (interaction P=0.36) 1

Current Guideline Recommendations Based on SPRINT

Blood Pressure Targets by Population

For high-risk patients without diabetes or CKD:

• Initiate treatment at BP ≥130/80 mmHg if 10-year ASCVD risk ≥10% 1
• Target BP <130/80 mmHg 1

For patients with CKD:

• Initiate treatment at BP ≥130/80 mmHg 1
• Target BP <130/80 mmHg based on SPRINT evidence showing mortality benefit (HR 0.72; 95% CI 0.53-0.99) in the CKD subset 1

For patients with diabetes:

• Initiate treatment at BP ≥130/80 mmHg 1
• Target BP <130/80 mmHg (extrapolated from SPRINT and meta-analysis with ACCORD) 1
• Note: SPRINT excluded diabetics, but meta-analysis with ACCORD showed consistent findings 1

For older adults (≥65 years):

• Intensive treatment safely reduced CVD events in those aged 65,75, and 80+ years 1
• Target BP <130/80 mmHg for noninstitutionalized, ambulatory, community-dwelling adults 1
• SPRINT included frail older adults living independently and showed substantial benefit 1

Critical Implementation Requirements: Blood Pressure Measurement

The single most important caveat is that SPRINT used standardized automated BP measurement following AHA guidelines, which differs substantially from typical clinical practice. 1

Required Measurement Protocol:

• Use validated automated oscillometric device (SPRINT used Omron 907XL) 1
• 5 minutes of quiet rest before measurement 1
• Take 3 readings and average them 1
• Patient seated alone or with staff present (no significant difference found between attended vs. unattended readings) 1

Common pitfall: Casual office BP measurements typically read 5-15 mmHg higher than standardized automated measurements, meaning a SPRINT target of <120 mmHg may correspond to casual office readings of 125-135 mmHg. 1

Treatment Intensity and Medication Strategy

For intensive BP control (targeting <120 mmHg):

• Start with ≥2 antihypertensive medications from different classes if BP is >20/10 mmHg above target 1
• Monthly medication adjustments until goal achieved 1
• In SPRINT, intensive group averaged 2.7 medications vs. 1.8 in standard group 2
• 52.4% achieved goal by 6 months; 61.6% achieved SBP <120 mmHg at final visit 2

Preferred first-line agents:

• Thiazide diuretics (especially chlorthalidone) and calcium-channel blockers for most patients 1
• ACE inhibitors or ARBs as alternatives 1

Adverse Events and Safety Monitoring

Intensive treatment increased specific adverse events: 3

• Hypotension 3
• Syncope 3
• Electrolyte abnormalities 3
• Acute kidney injury 3
• Bradycardia 3
• Hyperkalemia 3
• Elevated serum creatinine 3

Critical monitoring requirement: Monthly evaluation until BP control achieved, with careful attention to orthostatic hypotension especially in older adults. 1

Populations Where SPRINT Evidence Does NOT Apply

Exercise extreme caution or use different targets in:

• Patients with diabetes (excluded from SPRINT; use ACCORD data instead) 1
• History of stroke (excluded from SPRINT) 1
• Dementia or cognitive impairment (excluded from SPRINT) 1
• Heart failure (excluded from SPRINT) 1
• Institutionalized patients (excluded from SPRINT) 1
• Age <50 years (excluded from SPRINT) 1
• High comorbidity burden with limited life expectancy (requires individualized approach) 1

Heterogeneity of Treatment Effect

Greatest benefit observed in:

• Younger patients (<75 years) without pre-existing CKD or CVD 4
• Older patients (≥75 years) WITH pre-existing CKD or CVD 4

This suggests that intensive treatment should be prioritized in these specific subgroups where absolute risk reduction is greatest. 4

Controversies and Limitations

Methodological concerns raised about SPRINT: 1

• Limited external generalizability due to restrictive enrollment (excluded 91% of those not on prior BP medications) 1
• Open-label design with 30% more study visits in intensive arm 1
• Early trial termination may overestimate benefit and underestimate harm 1
• No benefit demonstrated for stroke (the outcome most sensitive to BP lowering) 1
• No benefit for probable dementia (SPRINT MIND primary endpoint) 1

However, the 2017 ACC/AHA guidelines prioritized SPRINT as the highest-quality recent evidence for intensive BP targets. 1

Practical Translation to Clinical Practice

To replicate SPRINT benefits:

• Implement standardized automated BP measurement protocols 1
• Target SBP <130 mmHg (not <120 mmHg) as the guideline-recommended threshold 1
• Use ≥2 medications for most patients requiring intensive control 1
• Monitor monthly until control achieved 1
• Screen carefully for adverse events, especially in older adults 1

The American College of Cardiology recommends NOT targeting mean achieved BP <120/80 mmHg as this is associated with increased adverse events. 3