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Study Title and Description

Impact of acute caffeine ingestion on endothelial function in subjects with and without coronary artery disease.



Key Questions Addressed
1 For [population], is caffeine intake above [exposure dose], compared to intakes [exposure dose] or less, associated with adverse effects on cardiovascular outcomes?
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Primary Publication Information
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TitleData
Title Impact of acute caffeine ingestion on endothelial function in subjects with and without coronary artery disease.
Author M Shechter,G Shalmon,M Scheinowitz,N Koren-Morag,MS Feinberg,D Harats,BA Sela,Y Sharabi,P Chouraqui,
Country
Year 2011
Numbers

Secondary Publication Information
There are currently no secondary publications defined for this study.


Extraction Form: Cardiovascular Design
Design Details
Question... Follow Up Answer Follow-up Answer
What outcome is being evaluated in this paper? Cardiovascular
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What is the objective of the study (as reported by the authors)? To explore the effect of acute caffeine ingestion on brachial artery flow-mediated dilation (FMD) in subjects without coronary artery disease (CAD; controls) and patients with CAD, we prospectively assessed brachial artery FMD in 40 controls and 40 age- and gender-matched patients with documented stable CAD on 2 separate mornings 1 week to 2 weeks apart.
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Provide a general description of the methods as reported by the authors. Information should be extracted based on relevance to the SR (i.e., caffeine related methods) Volunteers without CAD were defined as subjects without a history of chest pain or myocardial infarction, coronary artery bypass grafting surgery, coronary angiography with angioplasty and/or stenting, cerebrovascular accident, or peripheral vascular disease with normal electrocardiogram and echocardiogram on admission. After an overnight fast, discontinuation of all medications for >/- 12 hours, absence of caffeine ingestion for >48 hours (including coffee, tea, cola, alcohol and flavonoid- containing beverages, and energy supplements), >48-hour cessation of cigarette smoking, and response to a specifically designed dietary questionnaire (for caffeine estimation), participants received capsules containing caffeine 200 mg (80-mg caffeine ingestion = 1 cup of coffee) or placebo administered at 7.00 am with tap water 250 ml. Distribution was in a rotating randomized fashion, such that each subject received caffeine or placebo capsules once throughout the study period. Before (baseline) and 1 hour after study drug ingestion, participants underwent brachial artery FMD and nitroglycerin-mediated dilation (NTG) using high-resolution ultrasound. Electrocardiographic ad echocardiographic assessments and blood tests for serum caffeine levels, lipids, complete blood cell count, electrolytes, fasting glucose, homocysteine, adiponectin, and high-sensitivity C-reactive protein (hs-CRP) were performed. Caffeine 200 mg and placebo capsules were manufactured by the Sheba Medical Center pharmacy and the therapy sequence for each patient (caffeine at first visit, placebo at second visit, or vice versa) was prepared before study initiation by computer-generated randomization software. Investigators, coordinators, and patients were blinded to the drugs throughout the study. All capsule codes were kept locked at the Sheba Medical Center pharmacy throughout the study period and delivered to the study statistician only at closeout. Endothelial function in the form of endothelium-dependent brachial artery FMD was measured as previously described16 –22 using a 15- to 6-MHz linear array (15-6L HP) ultrasound system (HP SONOS 7500 cv System, Agilent Technologies, Inc., Andover, Massachusetts).
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How many outcome-specific endpoints are evaluated? 6
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What is the (or one of the) endpoint(s) evaluated? (Each endpoint listed separately) FMD
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List additional health endpoints (separately). 2 NTG
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List additional health endpoints (separately).3 C-reactive protein
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List additional health endpoints (separately).4 Blood lipids
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List additional health endpoints (separately).5 Heart rate
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List additional health endpoints (separately).6 Blood pressure
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Clinical, physiological, other Physiological
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What is the study design? Controlled Trial
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Randomized or Non-Randomized? RCT
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What were the diagnostics or methods used to measure the outcome? Objective
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Optional: Name of Method or short description Endothelial function in the form of endothelium-dependent brachial artery FMD was measured as previously described16 –22 using a 15- to 6-MHz linear array (15-6L HP) ultrasound system (HP SONOS 7500 cv System, Agilent Technologies, Inc., Andover, Massachusetts).
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Caffeine (general) Caffeine (general)
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Coffee, Chocolate, energy drink, gum, medicine/supplement, soda, tea, other?
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Measured or self reported? Measured
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Children, adolescents, adults, or pregnant included? Adults
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What was the reference, comparison, or control group(s)? (e.g. high vs low consumption, number of cups, etc.) Placebo exposure.
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What were the listed confounders or modifying factors as stated by the authors? (e.g. multi-variable components of models.  Copy from methods) A power calculation assessment based on the effect of caffeine on endothelial function in healthy subjects was performed before the study. Assuming a standardized difference of 0.72, a p value of 0.05, and a power of 85%, the number per group (healthy subjects and those with CAD) was estimated to be 30. Accounting for a 2-week 5% drop-out rate, we estimated that the total number of enrolled subjects should be 72. Values are expressed as mean +/- SD for continuous variables and frequency and percentage for categorical variables. Distributions of continuous variables were assessed using Kolmogorov–Smirnov test. Comparisons between controls and patients with CAD were assessed using independent t test for continuous variables and chi-square test for categorical variables. Changes within caffeine and placebo treatments and differences between healthy subjects and those with CAD were calculated by repeated analysis measurements, which produced 3 tests of significance: difference in treatment changes between groups (interaction between treatment and group), total changes between treatments, and differences between groups in general. Correlations between serum caffeine levels and other continuous variables were assessed using Pearson or Spearman correlation test. Multivariate regression analysis was performed to predict percent FMD by independent variables.
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What conflicts of interest were reported? Not mentioned.
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Refid 21349479
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What were the sources of funding? Not mentioned.
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Results & Comparisons

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