Department of Emergency Medicine, Los Angeles County and University of Southern California Medical Center, Los Angeles, CA.
Institute for Clinical Evaluative Sciences, Toronto, ON, Canada; Department of Health Policy, Management and Evaluation, Toronto, ON, Canada.
Ann Emerg Med. 2013 Nov;62(5):486-494.e3. doi: 10.1016/j.annemergmed.2013.02.018. Epub 2013 May 14.
We compare secular trends in computed tomography (CT) utilization in emergency departments (EDs) in the United States and Ontario, Canada.
Using a systematic survey in the US (The National Hospital Ambulatory Medical Care Survey) and administrative databases in Ontario, we performed a retrospective study of ED visits from 2003 to 2008. We calculated utilization overall, by visit characteristics, and for 5 clinical conditions in which CT is commonly indicated: abdominal pain, complex abdominal pain (abdominal pain, age ≥65 years, urgent to most urgent triage), admitted complex abdominal pain (abdominal pain, age ≥65 years, urgent to most urgent triage, and admitted to hospital), headache, and chest pain/shortness of breath. US data were weighted to produce national estimates.
On-site CT was available for 97% (95% confidence interval [CI] 95% to 99%) of visits in the United States compared with 80% (95% CI 80% to 80%) in Ontario. Visits were more frequently triaged as higher acuity in the United States than in Ontario, with 15.1% (95% CI 13.9% to 16.4%) of US visits categorized as most urgent versus 11.8% (95% CI 11.8% to 11.8%) in Ontario. The proportion of all ED visits in which CT was performed was 11.4% (95% CI 10.8% to 12.0%) in the United States versus 5.9% (95% CI 5.9% to 5.9%) in Ontario. The proportion for children was 4.7% (95% CI 4.3% to 5.1%) in the United States versus 1.4% (95% CI 1.4% to 1.4%) in Ontario. The rate of visits involving CT per year increased faster from 2003 to 2008 in the United States (odds ratio 2.00; 95% CI 1.81 to 2.21) than Ontario (odds ratio 1.69; 95% CI 1.68 to 1.70). Over time, all subgroups experienced increases in CT rate except Ontario children younger than 10 years, who experienced a significant decrease. United States-Ontario differences in CT proportions were significant among patients presenting with headache, abdominal pain, chest pain/shortness of breath, and complex abdominal pain. Proportions for visits involving admitted complex abdominal pain in the two jurisdictions were indistinguishable: 45.8% in the United States (95% CI 39.9% to 51.7%) versus 44.7% (95% CI 44.4% to 45.0%) in Ontario.
CT was more readily available in US EDs, and US clinicians used the technology more frequently than their colleagues in Ontario for nearly every category of patients, including children. CT utilization increased over time in both jurisdictions, but faster in the United States. Different demographic features between the two jurisdictions, including triage severity, frequency of hospitalization, and availability of CT scanners, likely account for at least some of the differences in CT utilization. Investigation of both clinical and nonclinical reasons for the differences in CT utilization between the United States and Canada would be a fruitful area for further research.
我们比较了美国和加拿大安大略省急诊部（ED）中计算机断层扫描（CT）利用的长期趋势。
我们使用美国的系统调查（国家医院门诊医疗调查）和安大略省的行政数据库，对 2003 年至 2008 年的 ED 就诊情况进行了回顾性研究。我们计算了总体利用情况、就诊特征，并对 5 种常见 CT 检查的临床情况进行了计算：腹痛、复杂腹痛（腹痛、年龄≥65 岁、紧急至最紧急分诊）、入院复杂腹痛（腹痛、年龄≥65 岁、紧急至最紧急分诊且入院）、头痛、胸痛/呼吸急促。美国的数据经过加权处理，得出了全国估计数。
与安大略省 80%（95%置信区间 80%至 80%）相比，美国 97%（95%置信区间 95%至 99%）的就诊现场可提供 CT。与安大略省相比，美国的就诊分类更倾向于更高的严重程度，15.1%（95%置信区间 13.9%至 16.4%）的美国就诊被归类为最紧急，而安大略省为 11.8%（95%置信区间 11.8%至 11.8%）。美国所有 ED 就诊中进行 CT 的比例为 11.4%（95%置信区间 10.8%至 12.0%），而安大略省为 5.9%（95%置信区间 5.9%至 5.9%）。儿童的比例为 4.7%（95%置信区间 4.3%至 5.1%），而安大略省为 1.4%（95%置信区间 1.4%至 1.4%）。从 2003 年到 2008 年，美国涉及 CT 的就诊率每年增长更快（比值比 2.00；95%置信区间 1.81 至 2.21），而安大略省为 1.69（95%置信区间 1.68 至 1.70）。随着时间的推移，除了 10 岁以下的安大略省儿童外，所有亚组的 CT 使用率都有所增加，而该亚组的 CT 使用率显著下降。美国和安大略省在头痛、腹痛、胸痛/呼吸急促和复杂腹痛患者中 CT 比例存在显著差异。两个司法管辖区中涉及入院复杂腹痛的就诊比例没有区别：美国为 45.8%（95%置信区间 39.9%至 51.7%），安大略省为 44.7%（95%置信区间 44.4%至 45.0%）。
美国 ED 中 CT 更容易获得，美国临床医生比安大略省的同事更频繁地使用该技术，几乎涵盖了所有类别的患者，包括儿童。在两个司法管辖区，CT 利用率都随着时间的推移而增加，但在美国增加得更快。两个司法管辖区之间的不同人口统计学特征，包括分诊严重程度、住院频率和 CT 扫描仪的可用性，可能至少在一定程度上解释了 CT 利用率的差异。对美国和加拿大 CT 利用差异的临床和非临床原因进行调查，将是进一步研究的一个富有成效的领域。
