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作者：Fran Lowry  
出處：WebMD醫學新聞

　　March 23, 2010 — 根據發表於3/4月家庭醫學誌(Annals of Family Medicine)的新研究，於診間進行C反應蛋白(CRP)檢測以辨識身體的發炎或感染，可幫助醫師確認哪些呼吸道感染病患可以獲益於抗生素治療，因而減少不必要的抗生素使用。
　　
　　荷蘭馬斯垂克大學的Jochen W. L. Cals博士等人寫道，在全科醫療中，抗生素是急性下呼吸道感染(lower respiratory tract infections，LRTI)與鼻竇炎病患的唯一有用方式，但是經常被過度處方，根據徵兆與症狀對於確認這些病患是否需使用抗生素的幫助有限。
　　
　　研究作者寫道，不確定診斷、病患的期待與壓力等因素往往會促使家庭醫師處方不合理使用的抗生素。
　　
　　研究目標為探討於診間進行CRP檢測是否有助於醫師將病患區分為無需處方、之後再處方、立即需要處方，且不會有害於結果。
　　
　　因此，研究者於2007年11月至2008年4月間隨機指派107名LRTI病患以及151名鼻竇感染病患，接受CRP檢測或不予檢測，病患來自荷蘭東南部11 個全科醫療中心的33個家庭醫師。
　　
　　研究者使用QuikRead CRP分析器(芬蘭艾斯博(Espoo)、Orion Diagnostica公司製造)進行CRP分析，在3分鐘之內可以獲得結果。
　　
　　若CRP檢測結果為小於20 mg/L，則建議醫師不要開立抗生素，若結果為大於100 mg/L，則建議立即開立抗生素，若CRP檢測結果介於20-99 mg/L，則建議延後開立抗生素，不過，他們隨時可以決定跳脫此建議處方計劃 。
　　
　　初級結果是指標諮商後的抗生素使用情況，次級結果包括追蹤28天期間的抗生素使用情形、病患滿意度以及臨床恢復程度。
　　
　　研究者發現，在指標諮商之後，CRP組的病患(43.4%)比對照組病患(56.6%)使用較少抗生素(相對風險[RR]為0.77；95%信心區間[CI]為0.56 -0.98)。
　　
　　此一差異在追蹤期間依舊顯著(52.7% vs 65.1%；RR，0.81；95% CI，0.62 - 0.99)。
　　
　　再者，延後開立處方或者開立症狀持續時方可使用之處方方面，相較於對照組(72%)，CRP組較少人(23%)實際領用藥品(P < 0.001)。
　　
　　研究者也發現，當有在診間進行CRP檢測時，病患對於照護的滿意度也較高 (P = .03)。
　　
　　兩組的恢復率相當。
　　
　　研究限制是，強度不足以偵測出呼吸道感染與鼻竇炎病患之間的差異，另外，醫師無法對研究過程不知情，因為他們必須知道病患的CRP結果，以決定合適的臨床處置。
　　
　　研究作者結論表示，定點照護檢測CRP可以幫助醫師決定處方或延遲處方抗生素，他們寫道，重要的是，這類檢查可以幫助減少不適當的抗生素使用，也可在不影響恢復下增加病患滿意度。
　　
　　賓州匹茲堡大學醫學中心肺部、過敏與重症照護醫療小組主任Mark T. Gladwin醫師受邀對此研究發表評論時向Medscape Family Medicine表示，在其他許多研究中，使用另一種稱為「前降鈣素(procalcitonin) 」的標記，以類似的方法來辨識那些細菌感染風險較高或嚴重細菌感染的病患。
　　
　　他表示，使用這些標記與決策模式，研究者可以減少使用抗生素的病患比率，雖然未使用抗生素的病患比率只有適度降低，這些策略有助於減少目前美國病毒性上呼吸道感染的抗生素使用情況。仍需更大型的研究來確認這些方法的一般性，探討這些方法是否可以降低抗生素抗藥性的發生。
　　
　　製造QuikRead定點照護CRP檢測裝置的Orion Diagnostica公司(芬蘭)資助該研究。
　　
　　Cals醫師接受荷蘭健康研究與發展組織之資助，研究作者之一(Rogier M. Hopstaken, MD, PhD) 宣告與Axis-Shield (挪威)和Orion Diagnostica (芬蘭)有財務關係。  


CRP Test Guides Antibiotic Prescribing for Respiratory Tract Infections

By Fran Lowry
Medscape Medical News

March 23, 2010 — C-reactive protein (CRP) testing done in the office to identify inflammation or infection in the body may help physicians determine which patients with respiratory tract infection will benefit from antibiotic treatment, and so reduce unnecessary antibiotic use, according to a new study published in the March/April issue of the Annals of Family Medicine.

"Antibiotics are only beneficial for subgroups of patients with acute lower respiratory tract infections (LRTI) and rhinosinusitis in family practice, yet overprescribing for these conditions is common," write Jochen W. L. Cals, MD, PhD, from Maastricht University, Maastricht, the Netherlands, and colleagues. "Signs and symptoms are of limited value in identifying those patients in need of antibiotic treatment for these conditions."

Uncertainty about the diagnosis and patient expectations and pressure can often prompt family physicians to prescribe antibiotics that are not justified, the study authors write.

The goal of this study was to see whether CRP testing at the time of the office visit would help the physician triage patients into no prescription, delayed prescription, or immediate prescription categories, without compromising their outcomes.

To do so, the investigators randomly assigned 107 patients with LRTI and 151 patients with sinus infections to testing with CRP vs no testing. The patients were recruited from 33 family physicians working in 11 family practice centers in the southeastern part of the Netherlands from November 2007 until April 2008.

The researchers carried out the CRP analysis using QuikRead CRP analyzers (Orion Diagnostica, Espoo, Finland), and results from the test were available within 3 minutes.

The physicians were advised not to prescribe antibiotics when the CRP test results were less than 20 mg/L, to give immediate antibiotics when the results were greater than 100 mg/L, and to consider writing a prescription for delayed antibiotics when the CRP levels were between 20 and 99 mg/L. However, they were free to deviate from this proposed prescribing plan at any time.

The primary outcome was antibiotic use after the index consultation. Secondary outcomes included antibiotic use during the 28-day follow-up, patient satisfaction, and clinical recovery.

The investigators found that patients in the CRP group used fewer antibiotics (43.4%) than patients in the control group (56.6%) after the index consultation (relative risk [RR], 0.77; 95% confidence interval [CI], 0.56 - 0.98).

This difference remained significant during the follow-up period (52.7% vs 65.1%; RR, 0.81; 95% CI, 0.62 - 0.99).

Moreover, in the CRP group, delayed prescriptions, or prescriptions written under the condition that they were not to be used immediately but only if symptoms persisted, were filled only in a minority of patients (23%) vs 72% in the control group (P < 0.001).

The researchers also found that patient satisfaction with care was higher when CRP testing was used during the office visit (P = .03).

Both groups had similar recovery rates.

A limitation of the study is that it was not powered to detect differences between patients with respiratory tract infections and rhinosinusitis. Another is that physicians were not blinded because they needed to know patients' CRP results to decide on appropriate clinical management.

The study authors conclude that point-of-care CRP testing can assist clinicians in making decisions about prescribing, or delaying prescribing, antibiotics. Importantly, they write, such testing may help decrease inappropriate antibiotic use and also increase patient satisfaction without compromising recovery.

Asked to comment on this study by Medscape Family Medicine, Mark T. Gladwin, MD, chief of the Division of Pulmonary, Allergy and Critical Care Medicine at the University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, said that a similar approach to identifying patients at higher risk of having a bacterial infection or a more severe bacterial infection has been used in many studies using another marker called procalcitonin.

"Using these markers and decision protocols, the investigators were able to reduce the percentage of people who received antibiotics. While the percentage of patients that do not receive antibiotics is only modestly reduced, these strategies may help reduce our current high use of antibiotics for viral upper respiratory illnesses in the US," he said. "Larger studies will be needed to confirm the generalizability of these approaches and to show that these approaches reduce the development of antibiotic resistance."

This study was funded by Orion Diagnostica (Finland), which is the maker of the QuikRead point-of-care CRP testing device.

Dr. Cals is supported by a grant of the Netherlands Organization for Health Research and Development. One of the study authors (Rogier M. Hopstaken, MD, PhD) has disclosed financial relationships with Axis-Shield (Norway) and Orion Diagnostica (Finland).

Ann Fam Med. 2010;8:124-133.