Clinical Briefs: Creatine Supplements & Anaerobic Performance; Delayed Prescriptions & Antibiotic Use; Immediate Repair vs. Surveillance of Small AAAs
The Effect of Creatine Supplementation on Anaerobic Performance: A Meta-Analysis
Male and female athletes of all ages sometimes use supplementation with various herbal and medicinal substances touted to enhance performance, appearance, or energy levels. Creatine monohydrate, more commonly known simply as creatine (CRT), has enjoyed a good deal of popularity among athletes interested in physical activities that require short bursts of high-intensity energy, such as sprinting or weight lifting. Despite the publication of more than 100 trials to date on CRT, consensus about the effect on speed, strength, or stamina remains elusive.
Misic and colleagues surveyed placebo-controlled studies (n = 29) addressing brief anaerobic activities in which CRT was the only known "performance aid" administered. Interested clinicians may be a bit stymied by the "fine print" which details the resulting data analysis, since they chose a somewhat unfamiliar measurement tool called an ES (reportedly similar to a z-score’) to report their results; an ES of 0.2 is considered a small effect, 0.5 is moderate, and 0.8 is large.
The bottom line was that CRT did not show any significant favorable (or detrimental) effect on anaerobic performance. Though earlier trials have shown that CRT supplementation does enhance muscle levels of CRT, such augmentation does not appear to be reflected by enhanced performance.
Misic M, Kelley GA. Am J Sports Med. 2002;4:116-124.
Do Delayed Prescriptions Reduce the Use of Antibiotics for the Common Cold?
Despite well-established educational principles that decry the use of antibiotics for viral upper respiratory infections (URI), clinicians continue to prescribe them both here and abroad. Studies from the United States and United Kingdom have found that up to 60% of patients in some studies receive antibiotics for the common cold, with little encouraging news from distant neighbors like New Zealand, where as many as 78% of common cold sufferers are prescribed antibiotics.
One technique that holds promise for reducing the use of unnecessary antibiotics is that of delayed prescriptions (DRx), in which the clinician provides a prescription with the suggestion that it not be filled unless the patient remains symptomatic for a specific time period, usually 48-72 hours. Initial studies of DRx in the situation of pharyngitis have reported as much as a 66% reduction in subsequent prescription filling. This trial looked at the same technique in patients (n = 129) suffering the common cold.
Arroll and colleagues found that using the DRx technique resulted in a substantial reduction in use of antibiotics, from 89% in those patients who had been instructed to take antibiotics now, to 48% in those advised with DRx. Though optimally no patient with a common cold will use unnecessary antibiotics, the DRx method may be a valuable step toward achieving this goal.
Arroll B, et al. J Fam Pract. 2002;51: 324-328.
Immediate Repair Compared with Surveillance of Small Abdominal Aortic Aneurysms
Abdominal aortic aneurysms (AAA) are responsible for 9000 deaths annually in the United States. Surgical procedures for elective AAA repair are performed over 30,000 times annually, incurring up to 2800 deaths. Since risk of rupture is closely linked to AAA size, there is little disagreement about the appropriateness of surgical interventions for large (5-6 cm) lesions. Fewer consensus exists, however, about whether elective repair of "small" AAA (mean size, 4.7 cm) results in net gain for patients. This study randomized 1136 patients with small AAA to immediate repair vs. surveillance. Surveillance was performed with ultrasound, and patients were referred for surgical intervention if they became symptomatic, or if AAA enlargement rate suggested the need. Patients were followed for up to 4.9 years.
At the conclusion of follow-up, there was no demonstrable difference for all-cause mortality or death related to AAA between the group assigned to surveillance and the group receiving early surgical intervention. These findings are strengthened by the low operative mortality rate seen in the study group (2-2.4%). In concordance with the United Kingdom Small Aneurysm Trial, this trial demonstrated no benefit for early elective surgical repair of AAA less than 5.4 cm in diameter.
Lederle FA, et al. N Engl J Med. 2002; 346:1437-1444.
Dr. Kuritzky, Clinical Assistant Professor, University of Florida, Gainesville, is Associate Editor of Internal Medicine Alert.
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