在之前已有診斷的成人中 許多並未確認氣喘


  【24drs.com】根據發表於1月17日JAMA期刊的一篇加拿大研究,在已有醫生診斷氣喘的成年人中,很多人在重新評估時並未確認氣喘。
  
  加拿大安大略渥太華大學、渥太華醫院研究中心Shawn Aaron醫師等人寫道,曾有醫師診斷氣喘的成年人中,33.1%在目前並未確認氣喘診斷,這些人並未每天使用氣喘藥物或者是已經停藥,對於這類患者,可能需要重新評估氣喘診斷。
  
  作者們推測,這些患者可能是已經經歷自發性緩解或者是可能被誤診。
  
  目前的指引建議,透過測試可逆氣流限制來診斷氣喘,以及透過測試呼氣氣流確認陽性結果。不過,疾病的可變表現及其復發和緩解之過程可能會使診斷複雜化,從而可能導致社區的許多醫生根據經驗診斷和治療氣喘。
  
  這篇研究包括了隨機取樣的701名自我報告表示在5年內曾有醫師診斷氣喘之成人,是透過電話在加拿大的10大都會區域篩選,研究者也運用來自主治醫師的資訊確認如何做出第一次診斷。
  
  然後,研究人員藉由連續監測症狀、居家尖峰流量、肺量計(測量肺功能)以及驗證支氣管激發試驗確認或排除氣喘。
  
  使用預先定義之協議,讓陰性檢測結果的參加者逐漸減少藥物,一年後再度進行支氣管激發試驗以追蹤。
  
  必要時,由一名研究肺部專家評估患者並確認氣喘或指定替代之診斷。
  
  共納入完成研究的613名患者(平均年齡51歲; 67%是女性)進行分析。
  
  研究排除了203名參與者的氣喘(33.1%; 95%信賴區間[CI], 29.4% - 36.8%),大多數參與者有良性的替代診斷;不過,12人(2.0%)有嚴重的心肺疾病,卻被誤診為氣喘。
  
  與確診的氣喘患者相比,被排除氣喘者比較不可能是使用氣流限制測試而被初次診斷(分別是43.8% vs 55.6%;絕對差異為11.8%; 95% CI, 2.1% - 21.5%)。
  
  另有獲得530名患者的醫師初次診斷資訊,其中269人(50.8%)已經進行了驗證氣流限制測試,其餘的人則是根據症狀和/或身體檢查結果而被診斷。
  
  被排除氣喘者,超過90%安全地停用氣喘藥物達一年,其中181人(29.5%; 95% CI, 25.9% - 33.1%)仍然沒有氣喘的臨床或檢驗證據。
  
  作者認為這些結果有兩個可能的解釋:參與者可能經歷了氣喘的自發緩解,或者,他們被誤診了。
  
  作者們也指出,被排除氣喘的患者有35.0%每天使用氣喘藥物,這對他們並無好處,作者們表示,還使他們不必要地暴露於不利的藥物作用之下,且增加醫療成本。
  
  來自麻州波士頓大學醫學院的Helen Hollingsworth醫師和George O'Connor醫師在編輯評論寫道,這些結果提供了兩個重要的見解,有助於臨床管理;O'Connor醫師也是JAMA的副編輯。
  
  首先,成人氣喘可能會變成慢性,而某些患者可能並不需要無限期的治療;其次,呼氣氣流測試是必不可少的氣喘診斷,以避免誤診和不必要的治療。
  
  他們寫道,雖然這些結果認為,某些患者可以安全地減少他們的氣喘藥物,他們也支持更頻繁地使用生理測試來指導氣喘管理。
  
  他們也指出,研究結果不能一般化到各種嚴重度之氣喘,該研究排除了長期使用口服皮質類固醇的患者,只有45%的參與者有每天使用氣喘藥物;因此,該研究並未納入許多中度到重度氣喘的患者。
  
  然而,編輯們總結指出,Aaron等人的研究是重要的提醒,除了檢查氣喘的症狀和治療,試圖瞭解該氣喘診斷是否依舊適當,是臨床照護的重要部分。
  
  資料來源:http://www.24drs.com/
  
  Native link:Asthma Not Confirmed in Many Previously Diagnosed Adults
  

Asthma Not Confirmed in Many Previously Diagnosed Adults

By Veronica Hackethal, MD
Medscape Medical News

In a substantial number of adults with physician-diagnosed asthma, asthma was not confirmed on revaluation, according to a Canadian study published in the January 17 issue of JAMA.

"Among adults with physician-diagnosed asthma, a current diagnosis of asthma could not be established in 33.1% who were not using daily asthma medications or had medications weaned. In patients such as these, reassessing the asthma diagnosis may be warranted," Shawn Aaron, MD, from the Ottawa Hospital Research Institute, University of Ottawa, Ontario, Canada, and colleagues write.

These patients may have experienced spontaneous remission or may have been misdiagnosed, the authors speculate.

Current guidelines recommend diagnosing asthma by testing for reversible airflow limitation and confirming positive results by testing expiratory airflow. However, the variable presentation of the disorder and its relapsing and remitting course can complicate diagnosis and may lead many physicians in the community to diagnose and treat asthma empirically.

The study included 701 adults randomly sampled and screened via telephone in Canada's 10 largest metropolitan areas who had self-reported having physician-diagnosed asthma within the last 5 years. Researchers used information from treating physicians to confirm how diagnoses were first made.

Researchers then confirmed or ruled out asthma with serial monitoring of symptoms, home peak flow, spirometry (a measure of lung function), and confirmatory bronchial challenge tests.

Participants with negative tests had their medications tapered off, using a predefined protocol, and were followed with repeat bronchial challenge tests for 1 year.

A study pulmonologist evaluated patients and confirmed asthma or assigned alternative diagnoses when necessary.

The analysis included 613 patients (mean age, 51 years; 67% women) who completed the study.

The study ruled out asthma in 203 participants (33.1%; 95% confidence interval [CI], 29.4% - 36.8%). Most participants had benign alternative diagnoses; however, 12 (2.0%) had serious cardiorespiratory conditions that had been misdiagnosed as asthma.

Compared with those with confirmed asthma, those in whom asthma was ruled out were less likely to have received initial diagnoses using airflow limitation testing (43.8% vs 55.6%, respectively; absolute difference, 11.8%; 95% CI, 2.1% - 21.5%).

Information from physicians on initial diagnoses was available for 530 of the patients, of whom 269 (50.8%) had had confirmatory airflow limitation testing. The remainder received their diagnoses on the basis of symptoms and/or physical exam findings.

More than 90% of participants whose asthma was ruled out safely stopped asthma medication for 1 year. Of these, 181 participants (29.5%; 95% CI, 25.9% - 33.1%) still had no clinical or laboratory evidence of asthma.

The authors suggest two possible explanations for these results: participants may have experienced spontaneous remission of asthma, or they may have been misdiagnosed.

The authors also point out that 35.0% of patients in whom asthma was ruled out were using daily asthma medications, which would have done them no good. It would also have exposed them unnecessarily to adverse medication effects and increased cost, the authors say.

"These results provide 2 important insights that inform clinical management," write Helen Hollingsworth, MD, and George O'Connor, MD, both from Boston University School of Medicine in Massachusetts, in an accompanying editorial. Dr O'Connor is also associate editor of JAMA.

First, adult asthma may not become chronic and may not require indefinite treatment in some patients. Second, expiratory airflow testing is "essential" for asthma diagnosis to avoid misdiagnosis and unnecessary treatment.

"[A]lthough these results suggest that some patients can safely reduce their asthma medications, they also support more frequent use of physiological testing to guide asthma management," they write.

They also note that the findings may not generalize across the range of asthma severity. The study excluded people receiving long-term oral corticosteroids, and just 45% of participants used daily asthma medications; therefore, the study may have excluded many people with moderate to severe asthma.

Nevertheless, the editorialists conclude, "The study by Aaron and colleagues is an important reminder that in addition to reviewing asthma symptoms and treatment, trying to understand if the diagnosis of asthma is still appropriate is an important part of clinical care."

One or more authors reports honoraria and other fees, advisory board or other membership, grants, and/or consulting for one or more of the following: Boehringer Ingelheim Canada, GlaxoSmithKline, Teva, AstraZeneca, Methapharm, Canadian Thoracic Society, Novartis, Synertec, Grifols, Roche, Actelion, Bayer, CSL Behring, Prometic.Altair, Amgen, Asmacure, Boston Scientific, Genentech, Ono Pharma, Schering, Wyeth, Merck, Global Initiative for Asthma, and/or Laval University. Dr O'Connor reports consulting for AstraZeneca and grants from Janssen Pharmaceuticals and the National Institutes of Health. Dr Hollingsworth has disclosed no relevant financial relationships.

JAMA. 2017;317(3):262-263, 269-279.

    
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