What is the Systolic Hypertension in the Elderly Program? Understanding the SHEP Trial

In 1991, the results of the Systolic Hypertension in the Elderly Program (SHEP) were published, conclusively proving that antihypertensive drug therapy benefits older individuals with isolated systolic hypertension, a condition once considered benign. The multicenter, randomized, placebo-controlled trial challenged previous medical beliefs by demonstrating that lowering blood pressure could significantly reduce the risk of major cardiovascular events.

Quick Summary

The SHEP trial was a randomized, double-blind study testing if treating isolated systolic hypertension in older adults prevents fatal and nonfatal stroke and other cardiovascular events using a diuretic-based therapy.

Key Points

• Landmark Clinical Trial: The Systolic Hypertension in the Elderly Program (SHEP) was the first major clinical trial to prove that treating isolated systolic hypertension (ISH) in older adults was effective.

• Significant Outcome Reduction: The study found that drug treatment with a diuretic-based regimen resulted in a 36% reduction in stroke incidence and a 32% reduction in overall cardiovascular events over 4.5 years.

• Diuretic Therapy: SHEP successfully used a thiazide-type diuretic as the primary medication, with other medications added as needed.

• Shift in Medical Practice: The trial's results fundamentally changed the perception of ISH from a benign consequence of aging to a serious, treatable cardiovascular risk factor.

• Long-Term Benefits: Extended follow-up confirmed that the cardiovascular benefits and improved life expectancy from the initial treatment persisted for decades.

• Influence on Guidelines: SHEP provided the crucial evidence that led to the development of modern medical guidelines recommending the treatment of isolated systolic hypertension in older adults.

The Context for the SHEP Trial

Before the Systolic Hypertension in the Elderly Program (SHEP), there was significant clinical controversy regarding isolated systolic hypertension (ISH) in the elderly. ISH is characterized by elevated systolic blood pressure (SBP) with normal diastolic blood pressure (DBP). It was often considered a benign consequence of aging, but large studies like the Framingham Heart Study showed it was a risk factor for cardiovascular disease. The SHEP trial aimed to provide definitive evidence on the benefits of treating ISH.

SHEP Study Design and Methodology

The SHEP trial was a large-scale, multicenter, randomized, double-blind, placebo-controlled study conducted from 1985 to 1990. It included 4,736 participants aged 60 and over with isolated systolic hypertension (SBP 160-219 mm Hg and DBP < 90 mm Hg).

Intervention Groups

Participants were randomly assigned to either an active treatment or a placebo group. The active treatment group received a stepped-care therapy starting with a thiazide-type diuretic, with potential additions of other medications if needed. The placebo group received matching pills.

Primary and Secondary Outcomes

The primary outcome assessed was the 5-year incidence of fatal and nonfatal stroke. Secondary outcomes included other cardiovascular events, coronary heart disease, and total mortality.

Key Findings and Study Results

Over an average of 4.5 years, the SHEP trial found that active treatment significantly reduced total stroke by 36% and all major cardiovascular events by 32%. It also showed a 27% reduction in coronary heart disease incidence and a 51% reduction in heart failure.

The SHEP Study vs. Placebo: A Comparison of Key Outcomes

Outcome	Active Treatment Incidence	Placebo Incidence	Risk Reduction	Significance
Total Stroke	Significantly Lower	Higher	36%	Significant
Major Cardiovascular Events	Significantly Lower	Higher	32%	Significant
Coronary Heart Disease	Significantly Lower	Higher	27%	Significant
Heart Failure	Significantly Lower	Higher	51%	Significant

The SHEP trial demonstrated significant benefits of active treatment over placebo for various cardiovascular outcomes. For detailed results, please refer to {Link: JAMA Network https://jamanetwork.com/journals/jama/fullarticle/386293} and {Link: AHA Journals https://www.ahajournals.org/doi/10.1161/01.hyp.21.3.335}.

Long-Term Impact and Implications

A follow-up study over 22 years showed the benefits of the initial SHEP treatment persisted, including longer life expectancy. The SHEP study significantly impacted medical practice by establishing ISH as a treatable risk factor and leading to its inclusion in standard guidelines, validating the use of thiazide-type diuretics as a first-line therapy.

Treatment Strategies Informed by SHEP

SHEP supports a stepped-care approach that includes lifestyle changes like the DASH diet, sodium restriction, exercise, weight management, and limited alcohol. Pharmacological therapy, influenced by SHEP, often begins with thiazide-like diuretics, and may include Calcium Channel Blockers, ACE inhibitors, or ARBs, with beta-blockers reserved for specific cases.

Conclusion: SHEP's Enduring Legacy

In conclusion, what is the systolic hypertension in the elderly program? It's the SHEP trial, a landmark study that proved treating isolated systolic hypertension in older adults significantly reduces stroke, heart attacks, and other major cardiovascular events. SHEP transformed the understanding of ISH from a harmless aspect of aging to a serious, treatable risk factor. Its findings, particularly the success of diuretic therapy, continue to influence modern hypertension guidelines and are a cornerstone of geriatric medicine.

Frequently Asked Questions

What is isolated systolic hypertension?

Isolated systolic hypertension is a condition where the systolic blood pressure (the top number) is elevated (≥130 mm Hg by current guidelines) while the diastolic blood pressure (the bottom number) is normal (<80 mm Hg). It is the most common form of hypertension in older adults.

What was the main purpose of the SHEP trial?

The main purpose of the SHEP trial was to determine if antihypertensive drug treatment for isolated systolic hypertension in people aged 60 and over could reduce the incidence of fatal and nonfatal stroke over five years.

What types of drugs were used in the SHEP trial?

In the SHEP trial, the active treatment began with a thiazide-type diuretic. If the blood pressure goal was not met, other medications were added to the regimen.

How did the SHEP trial affect older adults with high blood pressure?

The SHEP trial proved that treating high systolic blood pressure in older adults is beneficial. It showed that blood pressure-lowering therapy significantly reduces the risk of serious cardiovascular events like strokes, heart attacks, and heart failure.

What were the main findings of the SHEP study?

The SHEP study found that treating isolated systolic hypertension reduced total stroke incidence by 36%, major cardiovascular events by 32%, and coronary heart disease events by 27% compared to a placebo group.

Did the SHEP trial find any long-term benefits?

Yes, a 22-year follow-up study of SHEP participants revealed that the initial 4.5-year period of active treatment was associated with a longer life expectancy and a lower risk of cardiovascular death over the long term.

Why is the SHEP trial considered historically significant?

The SHEP trial is historically significant because it was the first randomized controlled trial to prove that isolated systolic hypertension in older adults is not benign and that treatment is effective. It laid the foundation for modern guidelines recommending active treatment for this common condition.