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Thứ Tư, 15 tháng 1, 2014


AJR: Using ultrasound 1st for appendicitis saves money

January 14, 2014 -- Using ultrasound as a first-line evaluation tool for patients suspected of having appendicitis -- and sending equivocal cases on to CT -- reduces radiation dose and saves healthcare dollars compared with a CT-only protocol, according to a new study in the January American Journal of Roentgenology.

Researchers from Thomas Jefferson University conducted a comparative effectiveness research study to compare the costs of an ultrasound-CT protocol versus a CT-only protocol for assessing appendicitis. They found that ultrasound is effective enough to be used as a first-line evaluation tool, even though it's slightly less accurate than CT.

What really tips the scales in favor of ultrasound is its lack of radiation dose. When the downstream costs of CT radiation dose are included, using ultrasound first results in savings of more than $330 million, according to study authors Laurence Parker, PhD, Dr. Levon Nazarian, and colleagues (AJR, January 2014, Vol. 202:1, pp. 124-135).

Advantages of ultrasound

Ultrasound's advantages include its relatively low cost, wide availability, and lack of radiation; its perceived disadvantage is that it is more dependent on the operator's skill than other imaging tests, the authors wrote. CT is highly accurate for detecting acute appendicitis, but it is expensive and exposes patients to radiation.

"The reason we did this study is that there are quite a few articles in the literature that compare how good ultrasound and CT are for the diagnosis of appendicitis, but we felt that none of them had an algorithmic approach that addressed the ramifications of the two technologies in terms of cost," Nazarian told AuntMinnie.com. "Just to compare CT to ultrasound for this purpose and to say that CT is more accurate than ultrasound, while true, only gives part of the story."

For their study, the researchers used information from the U.S. Centers for Medicare and Medicaid Services (CMS), national hospital discharge surveys, and U.S. Census Bureau life tables.

The group proposed the following imaging protocol: Patients presenting in the emergency department with right lower quadrant abdominal pain would receive an ultrasound first. If the ultrasound was positive, the patient would be sent for an appendectomy because ultrasound has a high positive predictive value for appendicitis.

However, if the ultrasound findings were negative or uncertain, patients would undergo a CT exam. If the CT findings were positive, they would have an appendectomy; if negative, no further treatment would be performed.

The group performed a meta-analysis of ultrasound's performance versus CT for detecting acute appendicitis.

Ultrasound vs. CT for appendicitis
Mean sensitivity
Mean specificity
Positive predictive value
Negative predictive value

Meanwhile, the analysis of CMS files showed that CT was used for almost exactly two examinations per patient (one abdominal and one pelvic) and ultrasound was rarely used. The cost of the CT-only imaging protocol was $547 per patient, whereas the cost of a limited ultrasound study was $88 per patient. For the total U.S. population, the cost savings of an ultrasound-first protocol minus the cost of extra surgeries and extra surgical deaths would be $24.9 million per year, according to the authors.

High costs of radiation

Not only does the study underscore the cost savings an ultrasound-first protocol could provide, it emphasizes the surprisingly high downstream costs of radiation exposure in diagnostic imaging.

"The ultrasound-CT protocol we have proposed saves $24.9 million over the CT-only protocol when the costs of the tests and excess surgeries and mortalities from using a less sensitive test are considered," they wrote. "Radiation exposure savings are more than an order of magnitude greater -- $339.5 million."

Appendicitis evaluation represents another diagnostic imaging problem for which ultrasound could provide substantial cost savings but is underutilized, and when current radiation exposure models are applied to appendicitis evaluation, the number of excess cancer deaths resulting from current practice is striking -- approximately 50 full lives per year, the group wrote.

But clinicians should not necessarily stop using CT to evaluate appendicitis, Parker said.

"It's not that we're taking CT out of it," he said. "But if we can do an ultrasound first, we can avoid enough CTs to gain significant cost savings and avoid radiation exposure. It's interesting that a slightly less accurate technique is actually superior when you look at the big picture."

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Study shows preabortion ultrasound doesn't often change decisions

January 14, 2014 -- Although many abortion opponents believe that women who view ultrasound scans of their fetuses will cancel their decision to pursue abortions, a new study in Obstetrics and Gynecology suggests the impact of the scans may be limited.

In an analysis of medical records of more than 15,000 women seeking abortion care at Planned Parenthood Los Angeles (PPLA), the researchers found that 98.4% of women who voluntarily elected to view preabortion ultrasound images went on to terminate the pregnancy, compared with 99% of women who did not view the images.

However, viewing ultrasound images was significantly associated with a decision not to terminate the pregnancy in the 7.4% of women who had medium or low certainty in their decision to have an abortion.

"Voluntarily viewing the ultrasound image may contribute to a small proportion of women with medium or low decision certainty deciding to continue the pregnancy; such viewing does not alter decisions of the large majority of women who are certain that abortion is the right decision," wrote a team led by Dr. Mary Gatter, medical director of PPLA.

Small but statistically significant difference

Preabortion ultrasound has become a political lightning rod in the U.S. as a number of states have implemented laws requiring pregnant women to view an ultrasound image before going ahead with the decision to terminate a fetus. However, whether such laws actually affect the decision to go ahead with an abortion hasn't been heavily studied.

Seeking to add to the small body of research, a group from PPLA and the University of California, San Francisco (UCSF) analyzed deidentified records for 15,575 women who sought abortion care at PPLA in 2011 (Obstetrics and Gynecology, January 2014, Vol. 123:1, pp. 81-87).

A previous analysis of this dataset had found that ultrasound images were viewed 42.5% of the time. Of these women, 98.4% went on to terminate their pregnancy, a difference of 0.6% (p < 0.001) from the 99% termination rate among those who did not view the images.

Among the group of patients who viewed the images, 95.2% of women with a medium or low decision certainty proceeded to an abortion, compared with 97.5% of women who had a high degree of certainty.

In contrast to two existing studies in the literature that did not show a link between ultrasound viewing and termination rates, the current study found that voluntary viewing was associated with the decision of some women to continue their pregnancy.

"However, the effect was very small -- and should be considered with caution -- and limited to the 7% of patients with medium or low decision certainty," they wrote. "This population may not have been substantially present in prior studies drawing on much smaller samples of patients."

The authors emphasized that the role of ultrasound viewing in abortion care needs to be viewed in context. Other factors, such as gestational age, had stronger effects on the likelihood of whether a woman continued a pregnancy, according to the researchers. The study showed an increase in the odds of continuing a pregnancy that was associated with each gestational age category after nine weeks.

"The importance of gestational age for women deciding to continue the pregnancy suggests that it is the information the ultrasound scan renders -- i.e., gestational dating -- rather than the image that influences women's decision-making," the authors wrote.

The results cannot be generalized to women's experience of ultrasound viewing in settings where it is mandatory, "although given the very high percentage of women proceeding with abortion after viewing the ultrasound image, it is unlikely that mandatory viewing would substantially affect the number of abortions performed," the authors noted.

"It may, however, affect patient satisfaction and health outcomes, which research shows are enhanced when patients feel control over decisions related to their care," they wrote."Mandating that women view their ultrasound images may have negative psychological and physical effects even on women who wish to view."

Voluntary viewing

As for the clinical implications of their findings, the researchers said that women should be offered the opportunity to voluntarily view their ultrasound images before abortion. Mandatory viewing should be avoided, however, as less than half of women want to view the images, according to the group.

"Second, healthcare providers engaged in ultrasound viewing should be sensitive to how patients react to their images but avoid making assumptions about the effect of viewing on patient decision-making," they wrote. "Patients with low decisional certainty about the abortion decision may need more time and support in reaching a decision about whether abortion is the correct decision for them."

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