週末時入院與較高的急性腎臟損傷死亡率有關
作者：Norra MacReady
出處：WebMD醫學新聞
April 15, 2010 — 一篇新研究顯示，因為急性腎臟損傷(acute kidney injury，AKI)住院的人，如果是在週末入院，住院後3天內死亡的風險比在週間入院者高出22%。
這個差異在一些小型醫院特別明顯，週末入院相關的校正3天死亡率風險增加了35%，比在大型醫院之週間入院者的24%還高。
加拿大Alberta Calgary大學Matthew T. James醫師等作者指出，在整個住院期間，週末入院的校正高死亡率風險範圍從大型醫院的7%到小型機構的17%。
作者們在線上發表於4月15日美國腎臟學會期刊(Journal of the American Society of Nephrology)的報告中寫道，這些差異看起來或許相對中等，但是，根據這些估計，我們推算，在週末入院的AKI病患中，每年多出將近4000例死亡，也就是說，每65個週入住院的AKI病患就多1個人死亡。
利用美國私人急性照護醫院的大型住院資料庫，作者們檢視了在2003至2006年間住院的963,730名病患的診斷，當然也包括了AKI。AKI是其中214,962名病患的主要診斷：169,759人在週間入院，45,203人在週末入院，主要診斷是AKI的病患共有14,686 (6.8%) 人死亡，包括7.3%在週末入院、6.7%在週間入院。
在校正了年紀、性別、種族、共病症、需要機械輔助呼吸等因素之後，作者們發現，週末因AKI入院者依舊和3天時的死亡風險增加22%有關，和住院期間延長7%有關。週末入院也和接受機械輔助呼吸增加20%、接受透析減少6%有關。
另外7種主要診斷若次要診斷為AKI，有類似的死亡率模式：週末入院與死亡率風險高於週間入院者有關。
有關這個差異的原因還不清楚，其他研究曾經指出，當病患在週末入院時，其他急性醫療狀況的處置和診斷都有所延遲，對AKI病患而言可能也是如此，目前這篇研究的作者們寫道，週末入院可能會延遲一些照護元素的準備，包括診斷與治療介入方式，例如透析或照會腎臟科，不過需要更多資料來加以確認此一狀況。
喬治亞州亞特蘭大Emory大學的William McClellan醫師在編輯評論中寫道，然而，兩組之間的透析比率並沒有太多改變，所以它並非主要原因，如果是，僅佔這些發現之中的小部分。藉由更多證據顯示這些和其他因素如時機和適當診斷、感染控制、非透析容積處置、營養支持等的影響，可能可以提出週間和週末、醫院和醫院之間的AKI病患死亡率差異，而這些資訊可以用來表達照護之間的差異。
研究限制包括，可能無法辨識所有的AKI病患，週末定義為星期六和星期日，而未包括週五夜間和週一清晨這兩個可能和週末一樣的照護時段；排除了出院之後可能死於AKI相關原因的病患；可能有導致無法測量之特徵的干擾因素。
作者們結論表示，總體來說，這些發現強調需要進一步探討AKI住院病患的診斷與治療策略之準備時機以及提供的程度。
作者們皆宣告沒有相關財務關係。
J Am Soc Nephrol. 線上發表於2010年4月15日。
Weekend Admission Associated With Higher Mortality From Acute Kidney Injury
By Norra MacReady
Medscape Medical News
April 15, 2010 — People admitted to the hospital with acute kidney injury (AKI) are 22% more likely to die by day 3 of their stay if they come in over the weekend than on a weekday, a new study shows.
The difference was most pronounced at smaller hospitals, where weekend admission was associated with a 35% increase in adjusted 3-day mortality risk versus weekday admission compared with a 24% increase at large hospitals.
Over the total length of hospital stay, the adjusted excess mortality risk associated with weekend admission ranged from 7% at larger hospitals to 17% at smaller institutions, report the authors, led by Matthew T. James, MD, from the University of Calgary, Alberta, Canada.
These differences may appear relatively modest, but "on the basis of these estimates, we project that approximately 4000 additional deaths per year occur in patients with AKI admitted on the weekend, representing 1 additional death for every 65 weekend admissions with AKI," the authors write in their report, published online April 15 in the Journal of the American Society of Nephrology.
Using data from a large database of admissions to private, acute-care hospitals in the United States, the authors identified 963,730 patients admitted with diagnoses including AKI between 2003 and 2006. AKI was the primary diagnosis for 214,962 of those patients: 169,759 admitted on a weekday, and 45,203 on a weekend. A total of 14,686 (6.8%) of patients with a primary diagnosis of AKI died, including 7.3% admitted on a weekend and 6.7% admitted on a weekday.
After adjustment for age, sex, race, comorbidities, and the need for mechanical ventilation, the authors found that "weekend admission with AKI remained associated with a 22% increased odds of death by day 3 of admission and a 7% increase for the duration of the hospital stay." Weekend admission also was associated with a 20% increase in the odds of receiving mechanical ventilation and a 6% decrease in the odds of undergoing dialysis.
The pattern was similar for mortality associated with 7 other primary diagnoses to which AKI was secondary: weekend admission was associated with a consistently higher risk compared with admission on a weekday.
The reasons for the disparity are unclear. Other researchers have described delays in the diagnosis and management of other acute medical conditions when patients are admitted over the weekend, and this may be true for patients with AKI as well. Weekend admission "may delay the provision of some elements of care, including diagnostic and therapeutic interventions," the current study authors write, such as dialysis or nephrology consultations, although more data are needed to confirm that suggestion.
However, dialysis rates did not vary that much between the groups, so it is not certain what role, if any, small difference played in these findings, William McClellan, MD, from Emory University, Atlanta, Georgia, writes in an accompanying editorial. With more evidence showing the contribution of these and other factors such as timely and appropriate diagnosis, infection control, nondialytic management of volume, and nutritional support, "it would be possible to draw inferences about the weekday-to-weekend and hospital-to-hospital variability in mortality of patients with AKI. In turn, this information could be used to address variations in care."
Study limitations include the possible failure to identify all patients with AKI; defining "weekend" as Saturday and Sunday rather than including Friday evening and early Monday morning, when care is similar to that provided over the weekend; the exclusion of patients who may have died from AKI-related causes after they left the hospital; and possible confounding resulting from unmeasured characteristics.
All in all, the authors concluded, "these findings highlight the need to further investigate the availability and timing of provision of diagnostic and therapeutic strategies to patients hospitalized with AKI."
The authors have disclosed no relevant financial relationships.
J Am Soc Nephrol. Published online April 15, 2010.
