透析與護理之家末期腎臟疾病病患功能下降有關
作者：Laurie Barclay, MD
出處：WebMD醫學新聞
October 14, 2009 — 根據10月15日發表於新英格蘭醫學期刊的一項未經控制研究結果，居住在護理之家的末期腎臟疾病（ESRD）患者，開始透析與功能下降有關。
來自加州Palo Alto史丹佛大學的Manjula Kurella Tamura醫師與同事們表示，罹患ESRD的老年病患，透析前的功能狀態，在開始治療後是否可以繼續維持仍然未知。我們研究居住於護理之家的ESRD老年病患，在透析前後的功能狀態。我們想要在開始透析後，評估短期與長期維持的功能性狀態，並且估計開始透析對於功能狀態軌跡的效應。
研究者透過透析病患的全國註冊試驗，與全國護理之家居民的註冊試驗相連結，確認出在1998年6月到2000年10月之間，3,702位居住在護理之家的居民，這些居民在透析開始前至少有一次的功能狀態評估。以日常生活活動最低資料分數（0-28分，分數越高代表功能依賴性越大）來將日常生活功能計分成七類。
在開始透析前三個月，日常生活活動最低資料分數中位數為12分，在透析開始後三個月增加到16分。透析開始後三個月的功能狀態，在護理之家維持39%，但是到了12個月後，有58%的患者死亡，只有13%維持透析前的功能狀態。
開始透析與功能狀態急速下降的關聯性反應在日常生活活動最低資料分數增加2.8分（95%信賴區間為2.5-3.0分），在隨機效應模式下，功能下降與年齡、性別、種族及最初功能狀態無關。經校正後發現在透析3個月後功能下降1.7分（95%信賴區間為1.4-2.1分）。
研究作者寫到，居住在護理之家的末期腎臟疾病（ESRD）患者，在透析後功能狀態顯著且持續下降。加強照護、控制不適的症狀與提供支持性療法對於這群病患是很重要的，不論是否開始接受透析。
本研究的限制在於缺乏此類病患未接受透析的控制組，因此無法確定透析是否真的會造成功能下降。假如是，那影響的程度有多少，或者透析是否能改善病患的存活時間。除此之外，透析後的臨床事件發生率與開始接受透析的理由尚未確認，也沒有腎絲球過濾率決定透析的數據。
在一篇評論中，來自賓州匹茲堡大學醫學院的Robert M. Arnold博士與來自貝斯以色列女執事醫療中心及麻州波士頓哈佛醫學院的Mark L. Zeidel博士表示，本研究缺乏評估老年病患接受透析效益的分析。
Arnold與Zeidel博士提到，目前迫切需要前瞻性研究來確定此類病患接受透析後所帶來的臨床效益，如果透析是有好處的，我們必須決定何時該接受透析，這可能與實質上為年輕、健康的末期腎臟疾病病患是不同的。最後，我們必須了解更多關於如何確保我們取得病患的知情同意，如何支持他們得到最佳的治療決定，以及如何最有效的減輕他們的症狀。
國家老年疾病研究院，國家研究資源中心與美國國家糖尿病及消化、腎臟疾病協會支持這項研究。某些研究的作者與Amgen公司，AMAG製藥，Biogen Idec公司，Triaxis醫療器械，以及/或是Ardelyx有財務方面的關係。研究數據由美國腎臟病數據系統所提供，但解釋和報告這些數據的責任為本研究的作者，並不能代表官方政策或代表美國政府。
研究作者表示已無相關資金上的往來。
Dialysis Linked to Functional Decline in Nursing Home Residents With End-Stage Renal Disease
By Laurie Barclay, MD
Medscape Medical News
October 14, 2009 — In nursing home residents with end-stage renal disease (ESRD), starting dialysis is linked to functional decline, according to the results of an uncontrolled study reported in the October 15 issue of the New England Journal of Medicine.
"It is unclear whether functional status before dialysis is maintained after the initiation of this therapy in elderly patients with...ESRD," write Manjula Kurella Tamura, MD, MPH, from Stanford University School of Medicine in Palo Alto, California, and colleagues. "We studied the trajectory of functional status before and after the initiation of dialysis among elderly nursing home residents with ESRD. We aimed to evaluate the frequency of short-term and long-term maintenance of functional status after the initiation of dialysis and to estimate the effect of the initiation of dialysis on the trajectory of functional status."
The investigators identified all 3702 US nursing home residents who started dialysis between June 1998 and October 2000 and who had at least 1 measurement of functional status before dialysis started, using a national registry of dialysis patients linked to a national registry of nursing home residents. Functional status for 7 activities of daily living was scored with the Minimum Data Set-Activities of Daily Living scale (0 - 28 points, with higher scores indicating greater functional dependence).
During the 3 months before dialysis began, median Minimum Data Set-Activities of Daily Living score was 12 points, and this increased to 16 points during the 3 months after dialysis was started. Functional status was maintained in 39% of nursing home residents at 3 months after dialysis began, but by 12 months, 58% had died and only 13% maintained predialysis functional status.
Starting dialysis was associated with a sharp decline in functional status, reflected in an increase of 2.8 points in the Minimum Data Set-Activities of Daily Living score (95% confidence interval [CI], 2.5 - 3.0 points), In a random-effects model, the functional decline was independent of age, sex, race, and functional-status trajectory before dialysis was started. After adjustment for the presence or absence of an accelerated functional decline during the 3-month period before dialysis was started, the decline in functional status associated with dialysis was 1.7 points (95% CI, 1.4 - 2.1 points).
"Among nursing home residents with ESRD, the initiation of dialysis is associated with a substantial and sustained decline in functional status," the study authors write. "Efforts to address the goals of care, control symptomatic distress, and provide supportive care for disability are critical in this population, regardless of whether dialysis is started."
Limitations of this study include lack of a control group of nursing home residents with ESRD who did not start treatment with dialysis, preventing determination of whether dialysis was the cause of functional decline and, if so, to what extent, or whether dialysis might actually improve life expectancy. In addition, clinical events occurring when dialysis started and the reasons for starting dialysis could not be determined, and there were no serial estimated glomerular filtration rates before dialysis was started.
In an accompanying editorial, Robert M. Arnold, MD, from the University of Pittsburgh School of Medicine in Pittsburgh, Pennsylvania, and Mark L. Zeidel, MD, from Beth Israel Deaconess Medical Center and Harvard Medical School in Boston, Massachusetts, note that randomized trials are lacking to evaluate the benefits of dialysis in the elderly population.
"Prospective studies to define predictors of good outcomes in the population of patients undergoing dialysis are urgently needed," Drs. Arnold and Zeidel write. "In persons who will benefit, we must determine when we should initiate dialysis; this may differ substantially from the initiation of dialysis in younger, healthier patients with ESRD. Finally, we must learn much more about how to ensure that we obtain truly informed consent from our patients, how to support them optimally in their therapeutic decisions, and how to relieve their symptoms most effectively."
The National Institute of Aging, the National Center for Research Resources, and the National Institute of Diabetes and Digestive and Kidney Diseases supported this study. Some of the study authors have disclosed various financial relationships with Amgen, AMAG Pharma, Biogen Idec, Triaxis Medical Devices, and/or Ardelyx. The reported data were provided by the US Renal Data System, but the interpretation and reporting of these data are the responsibility of the study authors and do not reflect an official policy or interpretation of the US government.
The editorialists have disclosed no relevant financial relationships.
N Engl J Med. 2009;361:1539-1547, 1597-1598.
