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By Louis Kuritzky, MD
Rapid Magnetic Resonance Imaging vs Radiographs for Patients with Low Back Pain
The role of radiologic evaluation for acute low back pain (LBP) has been plagued with uncertainty, since as many as one-third of asymptomatic persons examined by MRI have signs consistent with herniated disk, and a substantially greater number manifest disk bulges or degeneration, despite an absence of symptoms. On the other hand, the high sensitivity of MRI might provide an opportunity for early diagnosis of problems that could benefit from prompt intervention. Making the possible use of MRI more attractive has been the recent evolution of rapid MRI, which requires only about 2 minutes of scanner activity.
Jarvik and colleagues compared plain x-rays with rapid MRI in subjects older than age 18 (n = 380) suffering acute LBP. Outcomes included functional disability, pain frequency, days of reduced or lost work, and patient satisfaction with care. Patients were interviewed at 1, 3, 6, 9, and 12 months after randomization.
Study results indicated that rapid MRI did not provide any statistically significant long-term advantage over plain films. Indeed, rapid MRI was associated with more frequent use of specialist consultants and more frequent invasive management techniques. Based upon these data, as well as cost considerations, Jarvik et al suggest that rapid MRI does not offer demonstrable long-term advantage over plain films.
Jarvik JG, et al. JAMA. 2003;289:2810-2818.
Effectiveness of Anticholinergic Drugs Compared with Placebo in the Treatment of Overactive Bladder
Overactive bladder (OAB) comprises a syndrome that may include urgency, urge incontinence, frequency and/or nocturia. Incontinence troubles as many as one-third of all overactive bladder patients, but even symptoms of frequency or nocturia may cause substantial negative effect upon quality of life.
The most commonly offered treatment for OAB is anticholinergic pharmacotherapy, which provides reduction of detrusor muscle contraction through blockade of the parasympathetic (cholinergic) pathway. To date, impact upon detrusor contraction has been afforded at the cost of adverse drug effects such as dry mouth, dry eyes, and constipation. Herbison and associates posited that the efficacy of anticholinergic medications is uncertain and sought to provide further insight by performing a systematic review of anticholinergic drug treatment provided in randomized trials.
On the basis of 32 randomized trials (n = 6800), Herbison et al determined that for persons with incontinence, likelihood of an incontinent episode was reduced approximately once in 48 hours; frequency of urination was reduced by approximately 1 micturition per 24 hours.
Herbison et al observe that improvements in treated patients, despite being statistically significant, are clinically modest compared to placebo. Additionally, they comment that bladder training may provide similar magnitude of benefit.
Herbison P, et al. BMJ. 2003;326:841-844.
A Randomized Trial of a Low Carbohydrate Diet for Obesity
At the current time in America, almost half of women and a substantial minority of men (30%) are dieting to lose weight. Unfortunately, diet interventions have had surprisingly little favorable effect upon the weight of the nation, as manifest by a doubling of the prevalence of obesity in the past 20 years.
Much contention surrounds what is the "best" diet for persons trying to lose weight, and a diversity of suggested methodologies abound. If sales of diet books are in any way indicative of public interest, the Atkins diet (low carbohydrate) has been the most popularly addressed, with a readership 4 times greater than any other diet book. Although popular, no randomized controlled trial of the Atkins diet vs, for instance, a high-carbohydrate, low-fat diet has been performed.
Foster and associates report upon subjects who were randomly assigned to either a low-carbohydrate diet (like Atkins) or a "conventional" diet (low calorie, high carbohydrate, low fat) and followed for 12 months.
Although an early difference in favor of the low carbohydrate diet was evident in the first 3 months, there was no statistically significant difference in weight lost at 12 months. Similarly, there were no significant enduring differences in frequency of urinary ketones, blood pressure, glucose tolerance, or LDL. The low-carbohydrate diet did produce more favorable changes in HDL and triglycerides, but Foster et al question whether even these changes would remain beneficial over the long term, in the face of high fat intake associated with chronic adherence to the Atkins diet.
Foster GD, et al. N Engl J Med. 2003;348:2082-2090.
Dr. Kuritzky, Clinical Assistant Professor, University of Florida, Gainesville, is Associate Editor of Internal Medicine Alert.