Wednesday, January 25, 2012

How often should you screen for osteoporosis?

Last year, AFP published the U.S. Preventive Services Task Force's updated recommendations on screening for osteoporosis, which advised dual-energy x-ray absorptiometry (DEXA) in "women 65 years or older and in younger women whose fracture risk is equal to or greater than that of a 65-year-old white woman with no additional risk factors." However, the USPSTF statement left one important question unanswered: when should a woman be re-screened if her first test shows normal or slightly decreased bone mineral density (BMD)? Put another way, what are the chances that a woman without osteoporosis today will develop it in the future?

A research team led by former AFP medical editor Margaret Gourlay, MD, MPH recently shed light on this question by following nearly 5000 U.S. women age 67 years or older with normal BMD or osteopenia for up to 15 years. They defined the BMD re-testing interval as the estimated time it took for 10% of women to develop osteoporosis before having a hip or clinical vertebral fracture. According to their report in the January 19th issue of the New England Journal of Medicine, more than 90% of women with initially normal BMD or mild osteopenia did not develop osteoporosis after 15 years. As might be expected, women with moderate and advanced osteopenia progressed faster, with 10% of each group developing osteoporosis after 5 years and 1 year, respectively.

This study's results have substantial implications for family physicians and their patients. In the absence of new risk factors for osteoporosis (e.g., significant weight loss, corticosteroid use), a woman with normal BMD at age 65 may not need to be re-tested until age 80, an interval that is substantially longer than current clinical practice. That's good news, since as Dr. Gourlay pointed out in a previous AFP editorial, many U.S. women who are at risk for osteoporosis have yet to receive any screening at all. Armed with this new information, family physicians and other primary care clinicians can now work to redirect testing resources to where they are needed most.

Wednesday, January 18, 2012

AFP Journal Club casts doubt on NEJM study

Do children younger than 2 years of age with acute otitis media (AOM) require antibiotics, or is a watchful waiting approach just as effective? A study designed to answer this question was published last year in the New England Journal of Medicine and concluded that a 10-day course of amoxicillin-clavulanate "tended to reduce the time to resolution of symptoms and reduced the overall symptom burden and the rate of persistent signs of acute infection on otoscopic examination." However, an analysis of this study by Drs. Andrea Darby-Stewart, Mark Graber, and Robert Dachs in the November 15, 2011 AFP Journal Club concluded that the results actually supported a watchful waiting strategy because the primary outcome (likelihood of treatment failure) was disease-oriented rather than patient-oriented:

The only clinically significant outcome was likelihood of treatment failure; yet, this was defined as the presence of any symptom of AOM and persistent otoscopic signs of AOM on day 10 to 12. Treatment did not fail in any children based on symptoms alone—all treatment failures were defined by persistent inflammation on examination. The treatment failed even if the patient was symptomatically better. Most of these asymptomatic children likely would never have presented for follow-up in routine practice. And, only four to six children had to be treated to cause diarrhea, rash, or diaper dermatitis.

The January 15th AFP Journal Club continues this story by reporting an apparent discrepancy between the predesignated primary outcomes in study's original protocol (published on and posted to the NEJM's website) and those that were ultimately reported in the study abstract's conclusions:

There were only three primary outcomes planned and the fourth outcome, otoscopic resolution, was one of many planned secondary outcomes. ... What is even more concerning is that the otoscopic findings are only one of 22 secondary outcomes evaluated in this study. It amazes me that a significant number of these findings, the ones that just happen to support placebo, were never reported. The secondary outcomes that demonstrated no difference between placebo and amoxicillin/clavulanate were analgesia requirements in these children; number of needed follow-up visits to a primary care physician; number of visits to the emergency department; missed hours of work by the parents; and parental satisfaction. 

The bottom line: family physicians should not conclude that this NEJM study showed that antibiotics are superior to watchful waiting for acute otitis media in young children. In fact, by showing that only 6 children needed to be treated with antibiotics to cause one additional episode of diarrhea, it suggests that the opposite conclusion may be true.

Wednesday, January 11, 2012

Curbing overuse of CT scans

The urban public hospital where I completed most of my training as a medical student had a single CT scanner. To ensure that this precious resource was put to effective use, any physician ordering a non-emergent CT scan was required to personally present the patient's case to the on-call Radiology fellow and explain how the result of the scan would potentially change management. Since my attending surgeons were usually too busy to trudge down to the Radiology suite, they deputized their residents to do so, and most of the time my residents passed this thankless task down to the students. Thus, my classmates and I learned early on the difference between appropriate and inappropriate reasons for ordering CT scans.

Today, the widespread availability of CT scanners has made this sort of explicit rationing uncommon in the U.S. In fact, an editorial published last year in AFP reviewed the accumulating evidence that CT scans are highly overused in current medical practice, which puts patients at unnecessary risk of radiation-induced cancers and detection of incidental findings that can lead to overdiagnosis and overtreatment. Identifying overuse of CT scans often isn't easy, though. And some might argue that increasing use of CT scans may have the positive effect of improving diagnosis of common symptoms, allowing physicians to institute appropriate management of serious conditions more quickly.

Family physicians Andrew Coco and David O'Gurek investigated this possibility in a research study published recently in the Journal of the American Board of Family Medicine. They analyzed data on common chest symptom-related emergency department visits from the National Hospital Ambulatory Medical Care Survey from 1997 to 1999 and 2005 to 2007. Unsurprisingly, the proportion of these visits in which a CT scan was performed rose from 2.1% to 11.5% during this time period. However, the proportion of visits that resulted in a clinically significant diagnosis (pulmonary embolism, acute coronary syndrome or MI, heart failure, pneumonia, pleural effusion) actually fell slightly, challenging that notion that increased CT utilization leads to improved detection and treatment of serious health conditions.

In their AFP editorial, Drs. Diana Miglioretti and Rebecca Smith-Bindman recommend that physicians and referring clinicians take several steps to reduce harms from CT scan overuse:

1. Use CT only when it is likely to enhance patient health or change clinical care.
2. When CT is necessary, apply the ALARA (as low as reasonably achievable) principle to radiation doses.
3. Inform patients of CT risks before imaging.
4. Monitor individual exposure over time and provide the information to patients.

Since 2007, AFP has published a series of articles in collaboration with the American College of Radiology on appropriate criteria for diagnostic imaging (including CT) in specific clinical situations. The ACR Appropriateness Criteria are periodically updated, and current versions are available on the ACR website.