Trial Files Throwback Thursday: DASH Diet for HTN, Ventilation Volume for ARDS, and MRAs for HFrEF
Why do we recommend a “DASH” diet for patients with hypertension?
A Clinical Trial of the Effects of Dietary Patterns on Blood Pressure (DASH)
The DASH Collaborative Research Group. NEJM (April 1997)
Bottom Line: This randomized controlled trial evaluated the effects of different dietary patterns on blood pressure in 459 adults with systolic blood pressures of less than 160 mm Hg and diastolic blood pressures of 80 to 95 mm Hg. For three weeks, participants were fed a control diet that was low in fruits, vegetables, and dairy products, with a fat content typical of the average diet in the United States. In the eight weeks thereafter, they were randomly assigned to the same control diet, a diet rich in fruits and vegetables, or a “combination” diet rich in fruits, vegetables, and low-fat dairy products and with reduced saturated and total fat. Sodium intake and body weight were maintained at constant levels. The primary outcome was the change in diastolic blood pressure (DBP) at rest and secondary outcomes were changes in systolic blood pressure (SBP) at rest and ambulatory SBP and DBP. The combination diet reduced systolic and diastolic blood pressure by 5.5 and 3.0 mm Hg more, respectively, than the control diet (P<0.001 for each); the fruits-and-vegetables diet reduced SBP by 2.8 mm Hg more (P<0.001) and DBP by 1.1 mm Hg more (P = 0.07) than the control diet. Among participants with hypertension, the combination diet showed even greater reductions in blood pressure of 11.4 (SBP) and 5.5 (DBP) mm Hg compared to control (P < 0.001). This study suggests that a diet rich in fruits, vegetables, and low-fat dairy products with reduced saturated and total fat can be an effective approach for preventing and treating hypertension.
What’s the rationale for low tidal volume ventilation in patients with ARDS?
Ventilation with Lower Tidal Volumes as Compared with Traditional Tidal Volumes for Acute Lung Injury and the Acute Respiratory Distress Syndrome (ARDSNet)
The Acute Respiratory Distress Syndrome Network. NEJM (May 2000)
Bottom Line: This multicenter, randomized trial compared traditional ventilation treatment with lower tidal volume ventilation in patients with acute lung injury and acute respiratory distress syndrome (ARDS). The intervention group received an initial tidal volume of 6 ml per kilogram of predicted body weight and a plateau pressure of 30 cm of water or less, while the comparator group (traditional ventilation treatment) received an initial tidal volume of 12 ml per kilogram of predicted body weight and a plateau pressure of 50 cm of water or less. The primary outcomes were decreased mortality and increased number of days without ventilator use from day 1 to day 28. The trial was stopped after enrolment of 861 patients due to lower mortality in the intervention group (31.0% vs. 39.8%, P=0.007) and increased number of days without ventilator use (mean [±SD], 12±11 vs. 10±11; P=0.007) during the first 28 days after randomization. The mean tidal volumes and plateau pressures were significantly lower in the intervention group compared to the comparator group. In conclusion, mechanical ventilation with lower tidal volumes resulted in improved outcomes in patients with acute lung injury and ARDS.
What’s the evidence for spironolactone as part of goal-directed medical therapy for HFrEF?
The Effect of Spironolactone on Morbidity and Mortality in Patients with Severe Heart Failure (RALES)
The Randomized Aldactone Evaluation Study Investigators. NEJM (September 1999)
Bottom Line: This double-blind study enrolled 1663 patients with severe heart failure (NYHA class III or IV at time of enrolment) and a left ventricular ejection fraction of ≤ 35%, who were already being treated with an angiotensin-converting-enzyme inhibitor, a loop diuretic, and in most cases digoxin. 822 patients were randomly assigned to receive 25 mg of spironolactone daily, while 841 received placebo. The primary end point was death from all causes at 24 months, and the trial was discontinued early due to the efficacy of spironolactone. The results showed a 30% reduction in the risk of death among patients in the spironolactone group, with 284 deaths compared to 386 deaths in the placebo group (relative risk of death, 0.70; 95% confidence interval, 0.60 to 0.82; P<0.001). This was attributed to a lower risk of both death from progressive heart failure and sudden death from cardiac causes. Spironolactone also significantly improved symptoms of heart failure and reduced hospitalizations. Gynecomastia or breast pain was reported in 10% of men in the spironolactone group, and serious hyperkalemia was minimal in both groups. In conclusion, spironolactone, in addition to standard therapy, substantially reduces the risk of both morbidity and death in patients with symptomatic heart failure with reduced ejection fraction.
Trial Files Issue #2024-24
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