例行性尿液試紙篩檢對於腎病不具成本效益
作者：Norra MacReady
出處：WebMD醫學新聞
March 15, 2010 — 根據一項發表於3月15日小兒科(Pediatrics)期刊，分析將近9000名孩童之資料的結果，例行性尿液試紙篩檢對於慢性腎臟病(chronic kidney disease，CKD)的臨床價值有限，且不具成本效益。
總體而言，研究者發現，每篩檢800名孩童才會檢查出1名CKD案例，相當於每篩檢1個CKD案例需費用為2779.50美元。
第一作者、賓州醫學院Deepa L. Sekhar醫師等人寫道，仍未證明透過診間例行性尿液試紙早期檢查顯微鏡下血尿和/或蛋白尿，可顯著改善預期從CKD惡化成末期腎臟病孩童的病程，也少有證據認為早期偵測無症狀的病患可緩解其他任何的終器官影響(end-organ effect)。
這些發現支持美國小兒科學會2007年的建議，認為尿液試紙分析篩檢不應再被納入小兒科預防保健指引中，但是許多小兒科醫師依舊進行此項檢查，促使作者們著手評估成本效益。
研究者使用Vesa M. Vehaskari醫師等人發表的資料，他們對年紀8-15歲之間的8954名孩童進行試紙篩檢，Sekhar醫師等人發展一套決策樹，讓初次檢查血尿或蛋白尿的孩童接受第2次檢查，第2次檢查結果為異常者進行後續臨床檢查，所有檢查的孩童中，最後有11人證明為CKD，換算成發生率約為0.1%。
合格的執業護士進行一次試紙檢查所需的整體醫院成本估計為3.05美元。增加的成本效益比、或者與效果相關的檢測的額外費用，估計為每名病患3.47美元。每篩檢800名孩童才會檢查出1名CKD案例，依此推算，所需費用為2779.50美元。
作者們解釋道，試紙尿液分析不貴且廣為使用，也可對異常結果及時追蹤，不過，在小兒科CKD案例中，並無證據支持早期篩檢可以改變臨床結果。他們認為，許多醫師依舊進行該項檢查，可能是因為對指引感到困惑，該指引從1977年以來已經改版多次，也可能是為了獲得檢查附加的收入。作者們寫道，如果使用血管張力素轉換酶抑制劑等藥物進行早期治療被證明可以延緩孩童CKD病程，那麼進行這項檢查或許會變得比較有成本效益。
該研究有許多重要的限制：回溯分析非美籍孩童4次尿液樣本的資料，推測這些研究者當時是在診間進行檢查，只有獲得一個試紙樣本。許多孩童失去追蹤，其結果不得而知，另外，種族上的差異可能會影響CKD發生率，這些都未被納入。
但是，作者們寫道，我們的研究傾向支持將尿液試紙篩檢從預防性小兒保健指引中移除，等到發展出有效的早期介入方式之後，再重新檢視相關建議。
作者們皆宣告沒有相關財務關係。
Routine Urine Dipstick Screening for Kidney Disease Not Cost-Effective
By Norra MacReady
Medscape Medical News
March 15, 2010 — Routine dipstick urinalysis screening for chronic kidney disease (CKD) has little clinical value and is not cost-effective, according to the results of a study analyzing data on nearly 9000 children, reported online March 15 in Pediatrics.
All in all, the investigators found 1 case of CKD for every 800 children screened, at a cost of $2779.50 per detected case of CKD.
"It remains unproven that early detection of microscopic hematuria and/or proteinuria through screening by office urine dipstick significantly alters the course of a child who is destined to progress from CKD to end-stage renal disease," write the authors, led by Deepa L. Sekhar, MD, from the Penn State College of Medicine, Hershey, Pennsylvania. There is also little evidence suggesting that early detection in asymptomatic patients mitigates any other end-organ effects.
These findings support the 2007 recommendation by the American Academy of Pediatrics that dipstick urinalysis screening no longer be included in the pediatric preventive health guidelines. Yet many pediatricians still perform the test, which led the authors to evaluate its cost-effectiveness.
The researchers used data published by Vesa M. Vehaskari, MD, and colleagues, who performed dipstick screening on 8954 children ranging in age from 8 to 15 years. Dr. Sekhar and coauthors developed a decision tree such that children with hematuria or proteinuria on the initial test underwent a second test. Abnormal results on the second test were an indication for further clinical workup. Of the children tested, 11 turned out to have CKD, for an incidence of about 0.1%.
The total hospital costs for a licensed practical nurse to perform a single dipstick test were calculated at $3.05. The incremental cost-effectiveness ratio, or extra cost incurred by performing the test relative to its effectiveness, was calculated at $3.47 per patient. At a rate of 800 tests per case of CKD found, this brought the ratio to $2779.50.
Dipstick urinalysis is inexpensive and widely available, and abnormal results elicit timely follow-up. However, there is no evidence that, in the case of pediatric CKD, early intervention can change clinical outcomes, the authors explained. They suggested that many clinicians may still perform the test because of confusion over the guidelines, which have been revised several times since 1977, or because of the extra income it generates. If early treatment with drugs such as angiotensin-converting enzyme inhibitors can be shown to slow the progression of CKD in children, the test may become more cost-effective, the authors write.
The study had several important limitations: it relied on a retrospective analysis of data on non-American children who had actually given 4 urine specimens, which these investigators then extrapolated to the office setting, in which a single dipstick specimen is obtained. Several children were lost to follow-up, so their outcomes are unknown, and any racial or ethnic differences that might have influenced the incidence of CKD were not taken into account.
Still, the authors write, "our study lends support to the removal of the screening dipstick urinalysis from the preventive pediatric healthcare guidelines." They suggested the recommendations be reexamined as effective early interventions are developed.
The authors have disclosed no relevant financial relationships.
Pediatrics. 2010;125:660-663.
