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作者：Laurie Barclay, MD  
出處：WebMD醫學新聞

　　May 4, 2010 — 根據一項線上發表於4月29日美國腎臟學會臨床期刊的研究結果，微蛋白尿可以預測高血壓但沒有糖尿病患者的腎臟與心血管疾病。
　　
　　資深作者、來自義大利熱那亞熱那亞大學的Roberto Pontremoli醫師在一篇新聞稿中表示，我們的發現強調了更廣泛採用微蛋白尿評估在指引高血壓處理的可用性。
　　
　　試驗作者寫到，增加尿中白蛋白排除是糖尿病患者心血管事件與臨床腎臟病變的一個已知危險因子。微蛋白尿是否可以預測沒有糖尿病但有原發性高血壓患者的慢性腎臟功能不全（CRI）仍然未知。
　　
　　研究者們進行了一項後續追蹤11.8年、共917位高血壓但沒有糖尿病患者（總共後續追蹤10,286人-年）的研究，這些患者於1993年與1997年被收納在「MAGIC（the Microalbuminuria: A Genoa Investigation on Complications）世代研究中。試驗前，未接受治療的患者接受尿蛋白質與肌酐酸比值（ACR）來確認是否有微蛋白尿，定義為ACR男性至少22 mg/g，女性至少31 mg/g。
　　
　　試驗前微蛋白尿與後續追蹤CRI（相對風險[RR]為7.61；95%信賴區間[CI]為3.19-8.16；P<0.0001）、心臟血管事件（以致命或非致命心臟及腦血管事件綜合終點定義；RR為2.11；95% CI為1.08-4.13；P<0.028）、以及心臟腎臟事件（以其他終點綜合定義；RR為3.21；95% CI為1.83-5.53；P<0.0001）風險增加有關。
　　
　　在校正許多試驗共變項後，包括年齡、身體質量指數、血壓、膽固醇濃度與腎臟功能，微蛋白尿仍是與CRI（RR為12.75；95% CI為3.62-44.92；P<0.0001）及心臟腎臟事件（RR為2.58；95% CI為1.32-5.05；P=0.0056）相關的顯著影響因子。
　　
　　試驗作者們寫到，微蛋白尿是罹患原發性高血壓但沒有糖尿病患者，發生腎臟與心臟血管併發症的一個獨立預測因子。
　　
　　這項研究的限制包括可能低估了新發生CRI的盛行率，以及微蛋白尿及心臟血管與腎臟試驗終點之間的關連性。除此之外，以公式估計腎絲球廓清率（eGFR）有一定程度的不準確性，且沒有根據治療形式或是血壓控制的與微蛋白尿相關心血管及腎臟風險資料。
　　
　　試驗作者們的結論是，需要進一步的研究來確認特定治療是否可以協助改善預後，就如同已經於糖尿病患者進行的研究，而有微蛋白尿的患者們應該積極地減少腎臟與心血管危險因子。
　　
　　試驗作者們表示沒有相關資金上的往來。


Microalbuminuria May Predict Renal, Cardiovascular Disease in Hypertensive Patients

By Laurie Barclay, MD
Medscape Medical News

May 4, 2010 — Microalbuminuria may predict renal and cardiovascular disease in patients with hypertension but without diabetes, according to the results of a study reported online April 29 in the Clinical Journal of the American Society of Nephrology.

"Our findings emphasize the usefulness of a more widespread evaluation of microalbuminuria in an effort to guide the management of hypertension," said senior author Roberto Pontremoli, MD, PhD, from the University of Genoa in Genoa, Italy, in a news release.

"Increased urinary albumin excretion is a known risk factor for cardiovascular events and clinical nephropathy in patients with diabetes," the study authors write. "Whether microalbuminuria predicts long-term development of chronic renal insufficiency (CRI) in patients without diabetes and with primary hypertension remains to be documented."

The investigators performed an 11.8-year follow-up of 917 patients with hypertension but without diabetes (total follow-up, 10,268 person-years) who were enrolled in the Microalbuminuria: A Genoa Investigation on Complications (MAGIC) cohort between 1993 and 1997. At baseline, untreated patients underwent testing of urinary albumin-to-creatinine ratio (ACR) for determination of microalbuminuria, defined as an ACR of at least 22 mg/g in men and an ACR of at least 31 mg/g in women.

Microalbuminuria at baseline was associated with an increased risk during follow-up for the development of CRI (relative risk [RR], 7.61; 95% confidence interval [CI], 3.19 - 8.16; P < .0001), cardiovascular events (defined as a composite of fatal and nonfatal cardiac and cerebrovascular events; RR, 2.11; 95% CI, 1.08 - 4.13; P < .028), and cardiorenal events (defined as a composite of these other endpoints; RR, 3.21; 95% CI, 1.86 - 5.53; P < .0001).

After adjustment for several baseline covariates, including age, body mass index, blood pressure, cholesterol level, and renal function, microalbuminuria continued to be significantly associated with CRI (RR, 12.75; 95% CI, 3.62 - 44.92; P < .0001) and cardiorenal events (RR, 2.58; 95% CI, 1.32 - 5.05; P < .0056).

"Microalbuminuria is an independent predictor of renal and cardiovascular complications in patients without diabetes and with primary hypertension," the study authors write.

Limitations of this study include possible underestimation of the prevalence of new-onset CRI and of the association between microalbuminuria and cardiovascular and renal endpoints. In addition, estimated glomerular filtration rate (eGFR) by use of equations has a certain degree of inaccuracy, and there are no definitive data regarding the relationship between cardiovascular and renal risk associated with microalbuminuria based on the type of treatment or on blood pressure control.

"Patients with microalbuminuria should be aggressively targeted for renal and cardiovascular risk factor reduction, although further research is warranted to determine whether specific treatment would help to improve outcomes, as already reported for patients with diabetes," the study authors conclude.

The study authors have disclosed no relevant financial relationships.

Clin J Am Soc Nephrol. Published online April 29, 2010.